Acute antibody-mediated rejection after pancreas transplantation

Abstract

Objective: Acute antibody-mediated rejection requires specific treatment and has a negative impact on graft survival. The objectives were to report the incidence of antibody-mediated rejection after pancreas transplantation, the demographic data, the outcome and the pattern of C4d distribution, as well as the correlation with laboratory data. Methods: Optical microscopy, immunofluorescence for C4d staining and donor-specific antibody search by Luminex® in 31 kidney biopsies in 17 patients (median 87 days) and 34 pancreas biopsies in 22 patients (median 192 days), from August 2006 to August 2008. The following tests were performed: χ2, t-Student, Pearson´s correlation coefficient and logistic regression (p < 0.05). Rresults: Forty-seven percent of acute pancreas rejections were of humoral type: five acute; two subclinical and one silent. Before and after treatment of acute rejection (n = 17, 65% of biopsies): amylasuria 1271.3 ± 1214.1 versus 1966.5 ± 1423 U/h (p = 0.004); amylase 188.4 ± 87.9 versus 102.3 ± 47.2 U/l (p < 0.0001) and lipase 1219.1 ± 594.4 versus 419.3 ± 207.3 U/L (p < 0.0001), respectively. There was correlation between acute rejection diagnosis and amylase (p = 0.02) and lipase (p = 0.018), as well as correlation with each other (p = 0.0013, r2 =0.49). 27.3% of kidney acute rejections were of humoral type: one acute, one subclinical and one silent. There was no correlation between C4d staining and graft survivals. C4d pattern was diffuse in more than 60% of biopsies. Cconclusions: antibody-mediated rejection after pancreas transplantation showed elevated rates, which suggests that C4d staining should be routinely investigated. Laboratory data may be a useful tool to diagnosis of acute rejection and to evaluate the response to treatment.

Full text

Page 1

Original article
einstein. 2008; 6(3):311-22
Acute antibody-mediated rejection after pancreas
transplantation
Rejeição aguda mediada por anticorpo após o transplante de pâncreas
Érika Bevilaqua Rangel1, Denise Maria Avancini Costa Malheiros2, Irina Antunes3, Margareth Torres4,
Maria Cristina Ribeiro Castro5, Fábio Crescentini6, Tércio Genzini7, Marcelo Perosa de Miranda8
aBStract
Objective: Acute antibody-mediated rejection requires specific
treatment and has a negative impact on graft survival. The objectives
were to report the incidence of antibody-mediated rejection after
pancreas transplantation, the demographic data, the outcome and the
pattern of C4d distribution, as well as the correlation with laboratory
data. Methods: Optical microscopy, immunofluorescence for C4d
staining and donor-specific antibody search by Luminex® in 31 kidney
biopsies in 17 patients (median 87 days) and 34 pancreas biopsies in
22 patients (median 192 days), from August 2006 to August 2008. The
following tests were performed: χ2, t-Student, Pearson´s correlation
coefficient and logistic regression (p < 0.05). results: Forty-seven
percent of acute pancreas rejections were of humoral type: five acute;
two subclinical and one silent. Before and after treatment of acute
rejection (n = 17, 65% of biopsies): amylasuria 1271.3 ± 1214.1
versus 1966.5 ± 1423 U/h (p = 0.004); amylase 188.4 ± 87.9 versus
102.3 ± 47.2 U/l (p < 0.0001) and lipase 1219.1 ± 594.4 versus
419.3 ± 207.3 U/L (p < 0.0001), respectively. There was correlation
between acute rejection diagnosis and amylase (p = 0.02) and lipase
(p = 0.018), as well as correlation with each other (p = 0.0013,
r2 =0.49). 27.3% of kidney acute rejections were of humoral type:
one acute, one subclinical and one silent. There was no correlation
between C4d staining and graft survivals. C4d pattern was diffuse
in more than 60% of biopsies. conclusions: antibody-mediated
rejection after pancreas transplantation showed elevated rates,
which suggests that C4d staining should be routinely investigated.
Laboratory data may be a useful tool to diagnosis of acute rejection
and to evaluate the response to treatment.
Keywords: Graft rejection; Isoantibodies; Pancreas transplantation
reSUMO
Objetivo: A rejeição aguda mediada por anticorpos requer tratamento
específico e tem impacto na sobrevida do enxerto. Os objetivos
foram: relatar a incidência de rejeição aguda mediada por anticorpos
após o transplante de pâncreas, e descrever os dados demográficos,
os desfechos e o padrão de distribuição do C4d, além da correlação
com exames laboratoriais. Métodos: Microscopia óptica,
imunofluorescência para C4d e pesquisa de anticorpos antidoadores
por Luminex®, em 31 biópsias renais em 17 pacientes (mediana 87
dias) e 34 biópsias pancreáticas em 22 pacientes (mediana 192
dias), de agosto de 2006 a agosto de 2008. Foram realizados os
testes de χ2, t de Student, coeficiente de correlação de Pearson e
regressão logística (p < 0.05). resultados: Um total de 47% das
rejeições pancreáticas foi humoral: cinco agudas; duas subclínicas e
uma silenciosa. O tratamento anterior e posterior da rejeição aguda
(n = 17, 65% das biópsias): amilasúria 1271.3 ± 1214.1 versus
1966.5 ± 1423 U/h (p = 0.004); amilase 188.4 ± 87.9 versus
102.3 ± 47.2 U/l (p < 0.0001) e lipase 1219.1 ± 594.4 versus
419.3 ± 207.3 U/l (p < 0.0001), respectivamente. Houve correlação
do diagnóstico da rejeição aguda pancreática com a amilase
(p = 0.02) e a lipase (p = 0.018) e correlação entre si destes exames
(p = 0.0013, r2 = 0.49). Ao todo, 27.3% das rejeições agudas renais
foram humorais: uma aguda, uma subclínica e uma silenciosa. Não
houve correlação da sobrevida dos enxertos com o C4d (padrão
difuso: > 60% das biópsias). conclusões: A incidência de rejeição
Study carried out at Hospital Israelita Albert Einstein – HIAE, São Paulo (SP), Brazil
Study supported by the Instituto Israelita de Ensino e Pesquisa Albert Einstein at Hospital Israelita Albert Einstein –HIAE, São Paulo (SP), Brazil
1 PhD; Nephrologist at the Pancreas-kidney Transplantation Unit of Hospital Israelita Albert Einstein – HIAE, São Paulo (SP), Brazil.
2 PhD; Pathologist at Hospital Israelita Albert Einstein – HIAE, São Paulo (SP), Brazil.
3 PhD; Nephrologist at the Pancreas-kidney Transplantation Unit of Hospital Israelita Albert Einstein – HIAE, São Paulo (SP), Brazil.
4 PhD; Nephrologist at the Human Laboratory of Histocompatibility of Hospital Israelita Albert Einstein – HIAE, São Paulo (SP), Brazil.
5 PhD; Nephrologist at Hospital Israelita Albert Einstein – HIAE, São Paulo (SP), Brazil.
6 Surgeon at the Pancreas-kidney Transplantation Unit of Hospital Israelita Albert Einstein – HIAE, São Paulo (SP), Brazil.
7 Master’s Degree; Surgeon at the Pancreas-kidney Transplantation Unit of Hospital Israelita Albert Einstein – HIAE, São Paulo (SP), Brazil.
8 Master’s Degree; Surgeon at the Pancreas-kidney Transplantation Unit of Hospital Israelita Albert Einstein – HIAE, São Paulo (SP), Brazil.
There is no conflict of interest.
Corresponding author: Érika Bevilaqua Rangel – Avenida Albert Einstein, 627 – CEP 05651-901 – São Paulo (SP), Brasil – e-mail: erikabr@einstein.br
Received on: Aug 31, 2007 – Accepted on: Jun 17, 2008

Page 2

einstein. 2008; 6(3):311-22
312Rangel EB, Malheiros DMAC, Antunes I, Torres M, Castro MCR, Crescentini F, Genzini T, Miranda MP
mediada por anticorpos é elevada em enxertos pancreáticos, de
modo que o C4d deve ser rotineiramente pesquisado. Os exames
laboratoriais são ferramentas úteis para o diagnóstico e seguimento
do tratamento da rejeição aguda.
Descritores: Rejeição de enxerto; Isoanticorpos; Transplante de
pâncreas
intrODUctiOn
Pancreas transplantation is one of the treatments for
patients with insulin-dependent diabetes and chronic
kidney failure. If creatinine clearance is equal to or
lower than 20 ml/min/1.73 m2 or if the patient is under
kidney replacement therapy, simultaneous pancreas-
kidney transplantation (SPKT) or pancreas after kidney
transplantation (PAKT) are recommended(1).
In American centers, the one, five and ten-year
survival rates of patients submitted to SPKT were greater
than 95, 80 and 69%, respectively(2). Pancreas allograft
survival rates in one, five and ten years were 85, 69 and
46%, respectively, whereas kidney allograft survival
in one and five years was 92 and 77%, respectively(2).
European data showed patient survival in five and ten
years of 81 and 67%, respectively; pancreas allograft
survival was 73 and 50%; and kidney allograft survival
was 67 and 44%(3).
According to the United Network for Organ
Sharing (UNOS), the increase of pancreas allograft
survival during the first year after SPKT from 75
to 85% in the period of 1988/1989 to 2002/2003 is
attributed to the decrease of technical failure from 12
to 6%, as well as a decrease of immunological loss from
seven to two percent(2). Likewise, in the PAKT those
clinical complications dropped from 13 to 8% and
from 28 to 7%, respectively, whereas in the pancreas
transplantation alone (PTA), the reduction was from 24
to 7% and from 38 to 8%, respectively(2). The SPKT data
from other non-USA centers showed one-year patient,
kidney allograft and pancreas allograft survivals of 94,
92 and 87%, respectively(2).
In Brazil, the data on SPKT of the State Transplant
System – Secretaria de Estado de Saúde de São Paulo,
from July 1997 to December 2004 were compatible with
one and five-year patient survivals of 83 and 77.3%,
respectively(4).
Pancreas allograft survival is affected by several
factors related to time after transplantation, and
loss within the first 24 hours through the first week
is attributed to thrombosis due to technical failure
and acute rejection(5). After the first week, pancreas
allograft loss could be secondary to those two causes
and to infection complications(5). In addition, after the
first month, acute and chronic rejections were the main
causes of pancreas loss; and after six months, chronic
rejection was the leading cause(5).
Forty-five percent of 4,251 patients undergoing SPKT
did not present acute rejection, 36% had only acute
kidney allograft rejection, 16% had both acute kidney
and pancreas allograft rejection and three percent had
only acute pancreas allograft rejection, according to
UNOS data from 1988 to 1997(6). However, the type of
pancreas transplantation determines the rate of acute
pancreas rejection, even when induction is performed
with SPKT of 25%, PAKT of 33% and PTA of 40%(7).
In addition, pancreas allograft loss attributed to acute
rejection was also related to the transplantation modality
during a follow-up of 39 months with SPKT of 0.3%,
PAKT of 1.8% and PTA of 2.9%(7). In the same follow-
up, pancreas allograft loss secondary to chronic rejection
was 3.7% in SPKT, 11.6% in PAKT and 11.3% in PTA(7).
Furthermore, the grade of acute pancreas allograft
rejection had a positive correlation with pancreas loss:
zero percent in 0-I grades (normal and inflammation
of undetermined significance), 11.5% in grade II
(minimal), 17.3% in grade III (mild), 37.5% in grade IV
(moderate) and 100% in grade V (severe)(8).
Most acute rejections are cell-mediated, although
acute antibody-mediated rejections (AMR) have been
reported as an important cause of graft loss, because
it has a worse prognosis and requires a different form
of therapy than the usual cell-mediated acute rejection.
The diagnostic criteria include morphological evidence
of acute tissue injury, immunopathologic evidence
for antibody action that includes C4d deposition and
serologic evidence of circulating antibodies to donor of
human leukocyte antigen (HLA) or other anti-donor
endothelial antigen(9).
In literature, data of acute AMR after pancreas
transplantation is poor. Recently, it was reported an
incidence of 15% after SPKT(10). However, the impact
of acute AMR on pancreas allograft survival is not well-
established as it is reported in other solid organs(11).
The initial objectives of the present study were
to report the incidence of acute AMR after pancreas
transplantation and to describe the pattern of
deposition of C4d in kidney and pancreas allografts
and the outcome. The secondary objectives were, to
correlate either acute AMR or cell-mediated rejection
diagnosis with laboratory data associated to exocrine
pancreas function, such as serum amylase and lypase
and amylasuria.
MethODS
From August 2006 through August 2008, sixty-five
biopsies of either pancreas or kidney allografts from 32

Page 3

einstein. 2008; 6(3):311-22
Acute antibody-mediated rejection after pancreas transplantation313
patients were analyzed. These patients were previously
submitted to SPKT, PAKT or PTA.
Initial immunosuppressive regimen had been
started on the second day and included: tacrolimus
0.15 mg/kg/dose, adjusted according to the period
after transplantation (serum levels of 10 to 15 ng/ml
in the first 30 days and subsequently 5 to 10 ng/ml);
methylprednisolone (500 mg during surgery, 250 mg in
the first day and 125 mg in the second day) followed by
prednisone 1 mg/day with tapering and mycophenolate
mofetil 2 g/day or mycophenolate sodium 1.44 g/ day.
In SPKT, induction with polyclonal antibodies was
not routinely employed, but only in cases of re-
transplantation, in which the panel reactive antibody
(PRA) was greater than 20% or when delayed kidney
allograft function was present (defined as necessity
of dialysis in the first week post transplantation).
On the other hand, in PAKT and in PTA induction
with Thymoglobulin 1.5 mg/kg/day for ten days was
employed in all patients according to peripheral
lymphocytes.
In SPKT, exocrine pancreatic drainage was enteric
or in the bladder. In most of the patients with PAKT,
bladder drainage was more frequent whereas in PTA
bladder drainage was exclusive. Iliac vein or vena cava
anastomosis was performed in all cases. In few cases of
SPKT, the transplanted kidney was from a live donor.
Only heart-beating donors were selected for organ
donation, those older than 45 years and with positive
family history of diabetes in first-degree relatives were
excluded.
Biopsy criteria included delayed graft function or
serum creatinine increase or serum amylase and lipase
increase associated or not with amylasuria decrease
in patients with bladder drainage. Amylasuria was
determined by eight-hour samples collected through
the night. All biopsies were representative and allowed
a correct diagnosis.
The analysis of light microscopy was performed to
diagnose acute cellular rejection, according to Banff
2005 (Banff 07 update)(9,11) for kidney allografts and to
Drachenberg et al. for pancreas allografts(8).
Acute AMR from kidney allograft was defined
by three criteria(9): morphologic evidence of acute
tissue injury, acute tubular injury neutrophils and/
or mononuclear cells in peritubular capillary and/
or glomeruli, and/or capillary thrombosis, fibrinoid
necrosis, intramural or transmural inflammation in
arteries; immunopathologic evidence for antibody
action C4d and/or (rarely) immunoglobulin in
peritubular capillary, immunoglobulin and complement
in arterial fibrinoid necrosis; and serologic evidence
of circulating antibodies to donor HLA or other anti-
donor endothelial antigen.
C4d detection was analyzed in peritubular capillaries
and periacinar capillaries by immunofluorescence.
The stages of acute AMR rejection were defined by
the following criteria(12):
a) latent humoral response: circulating antibody alone
(but with no biopsy finding or graft dysfunction);
b) silent humoral reaction (accommodation versus
pre-rejection state): circulating antibody + C4d
deposition (but with no histological changes or graft
dysfunction);
c) subclinical humoral rejection: circulating antibody
+ C4d deposition + tissue pathology (but with no
graft dysfunction) and;
d) humoral rejection: circulating antibody + C4d
deposition + tissue pathology + graft dysfunction.
The circulating antibodies included either to HLA
or MICA (major histocompatibility complex class
I-related chain A).
The treatment of pancreas acute rejection was
determined by its grade: grades 2 and 3 were treated
with methylprednisolone pulse (500 mg/day for three
days) and non-responsive acute rejections or grades IV
and V were treated with thymoglobulin 1.5 mg/kg/ day
for ten days according to the number of peripheral
lymphocytes. In PAKT and PTA, acute rejection grade
3 was initially treated with thymoglobulin. Kidney acute
rejection was treated with methylprednisolone pulse
(500 mg/day for three days) for grades IA to IIA, and
with thymoglobulin for grades IIB and III.
Briefly, the formalin fixed biopsies were embedded
in paraffin, serially sectioned at 3 to 4 µm thick and
stained with hematoxylin and eosin (HE), Masson
trichrome and periodic acid-Schiff. C4d staining
was routinely performed on all pancreas and kidney
allograft biopsies at our center during the study period.
This was done by indirect immunofluorescence on
cryostat sections using a murine monoclonal anti-
human C4d antibody (Quidel, San Diego, CA, USA)
at 1:40 dilution, followed by fluorescein isothiocyanate
(FITC), which is conjugated goat anti-mouse IgG
(Jackson Immunoresearch Laboratories, West Grove,
PA, USA)(13). C4d staining in the kidney and pancreas
was interpreted as positive when a linear staining along
peritubular capillaries of basement membranes or
interacinar capillaries was evident in 10% more of them.
When this pattern was observed in > 50% of capillaries,
this staining was considered diffuse positive; < 50% was
considered focally positive.
The Luminex® bead-based assay using a panel of
color-coded microspheres coated with HLA antigens
to determine percent PRA and to identify antibody
specificities was employed to detect levels of circulating
antibody(14).

Page 4

einstein. 2008; 6(3):311-22
314Rangel EB, Malheiros DMAC, Antunes I, Torres M, Castro MCR, Crescentini F, Genzini T, Miranda MP
Briefly, for each patient sample, a total of 10 µl of
serum was mixed between two wells, each containing
either HLA class I or class II coated microspheres.
Sera and microspheres were incubated for 30 minutes
on a 96-well membrane filter plate. The specimens
were then washed three times. A phycoerythrin (PE)
– conjugated anti-human IgG was then added to each
well and incubated for 30 minutes. All incubations
were performed at room temperature, in the dark, on a
rotating platform. The LABScan™ 100 flow analyzer was
used for bead and data acquisition. This instrument is a
minidigital processing flow analyser which incorporates
two lasers. When the fluid stream passes through the
lasers, the first beam classifies the beads by HLA type.
The second beam scans each bead for PE-labelled anti-
human IgG bound to the HLA molecules.
All subjects were informed about the study
protocol, and written consents were obtained from all
participants. The Brazilian Committee of Ethics and
Research approved the study.
All results are reported mean ± SD, unless otherwise
indicated. Statistical analysis was performed by SPSS
12.0 (Chicago, IL, USA). Fisher’s exact t-test and
ANOVA were performed for numerical variables and
Pearson’s x2 test for categorical variables. Correlation
was performed using Pearson coefficient. The receiver
operating characteristic curve demonstrated the area
under the curve between acute rejection diagnosis and
laboratory data (serum amylase and lipase, as well as
amylasuria). To determine which factors were associated
with C4d detection and acute rejection, all putative
factors that were univariately associated at p ≤ 0.3 were
entered simultaneously in a backward binary logistic
regression model with those factors analyzed as the
dependent variable. Results were reported as 95%
confidence interval. The statistical analysis was assumed
significant if p < 0.05.
reSUltS
Sixty-five allograft biopsies were performed in 32
patients with 31 biopsies from kidney allografts and 34
from pancreas allografts.
Mean age, time of diabetes history and time on dialysis
were 34.3 ± 9.6 years, 20.9 ± 6.5 years and 35.8 ± 24.8
months, respectively. Twenty out of 32 (62.5%) were
male and 12 (37.5%) were female. Mean follow-up after
kidney and pancreas biopsies were 8.5 ± 6.9 months
(median 8.8 months) and 8.3 ± 7.2 months (median 5.2
months), respectively. As shown in tables 1 and 2, the
transplant modality included 22 patients with SPKT; 11
had enteric drainage (ED) and 11 had bladder drainage
(BD), eight patients with PAKT and BD and two cases
with PTA and BD. One female patient and one male
patient underwent preemptive SPKT with a live donor
kidney (mother and brother, respectively). In PAKT,
seven out of eight patients previously underwent live
kidney transplantation.
Kidney and pancreas biopsies
The kidney biopsies were performed after 335.9 ± 566
days (median 87 days) (Table 1). Of 31 kidney biopsies
performed in 17 patients, three were related to the
same episode of acute rejection and in two biopsies the
period of time between the biopsies was short, e.g. one
week and the diagnosis was the same. In this way, 28
biopsies were separately analyzed.
There were 11 episodes of acute kidney rejection in
eight patients, which represents 47.1% (8/17) patients
submitted to biopsy and 39.3% (11/28) of the biopsies
performed in the period. Three out of those eleven
cases with acute rejection were AMR (27.3%): acute
(n = 1, patient 1), subclinical (n = 1, patient 6) and
silent reaction (n = 1, patient 6).
The pancreatic biopsies were performed after
538.3 ± 678.9 days (median: 192 days), see Table 2,
and 34 biopsies from 22 patients were analyzed. Eight
biopsies represented the same episode of acute rejection,
since 26 pancreatic biopsies were then analyzed (19
with bladder drainage and seven with enteric drainage).
Acute rejection was presented in 17 cases which were
compatible to 65.4% (17/26) of the biopsies analyzed
and 59.1% (13/22) of the patients submitted to pancreas
biopsy.
Eight out of the seventeen cases of acute rejection
(47%) presented humoral activation: acute (n = 5;
patients 1, 19, 22 and 30, with two episodes in patient 19),
subclinical (n = 2, patients 9 and 11) and silent reaction
(n = 1, patient 18). There was one case of chronic
pancreas humoral rejection after PAKT (patient 29).
In seven patients, both kidney and pancreas biopsies
were available: two cases of synchronous rejection
(patients 1 and 7), three cases of isolated acute kidney
rejection (patients 5, 6 and 9), two cases of isolated
acute pancreas rejection (patients 9 and 11) and one
case without rejection (patient 17). Patient 9 had either
kidney or pancreas allograft rejection, but the latter
occurred at different times (Tables 1 and 2).
In the case of patient 1, in the 15th day creatinine
levels increased and kidney biopsy displayed acute
tubular necrosis (ATN), neutrophils in peritubular
capillaries and minimal inflammation. He was treated
with methylprednisolone pulse (0.5 g/day for three
days) followed by eight days of Thymoglobulin (five
doses: three doses of 75 mg and two doses of 50 mg,
according to peripheral lymphocytes). The second
kidney biopsy in day 38 was similar to the previous one;

Page 5

einstein. 2008; 6(3):311-22
Acute antibody-mediated rejection after pancreas transplantation 315
table 1. Data related to kidney allograft biopsies
SPKT = simultaneous pancreas-kidney transplantation; PAKT = pancreas after kidney transplantation; ED = enteric drainage; BD = bladder drainage; V = live kidney donor; ATN = acute tubular necrosis; AR = acute rejection; IF/TA =
Interstitial fibrosis and tubular atrophy; DSA = donor specific antibody MICA = major-histocompatibility-complex class I- related - chain A
* Enteric conversion after 10 months of transplantation due to persistent hematuria
Patientstransplant
modality
time after
transplant
(days)
26
light microscopyc4dacute rejection
classification
treatment Outcome
Follow-up (months)
Recovery Patient 1 (EBM) SPKT-ED
39
46
68
ATN + neutrophils in
peritubular capillaries in all
biopsies
Diffuse
Diffuse
Diffuse
Negative
Acute humoral
rejection
(positive MICA)
Thymoglobulin +
Plasmapheresis+
Immunoglobulin +
Methylprednisolone
pulse
Antibiotic therapy
(23 m)
Patient 2 (MMS) SPKT-BD 1,414 Acute pyelonephritis with
abscess
IF/AT grade I
AR IA + focal ATN
Negative No rejectionKidney loss
Patient 3 (HAA)
Patient 4 (VLS)
SPKT-ED
SPKT-ED
1,294
57
Negative
Negative
No rejection
AR
Stable function (18.5 m)
Death with functioning
grafts (pulmonary sepsis)
after 19 m)
90 ATN + minimal tubulitis Focal (10%) No rejection
Methylprednisolone
pulse
None
Antibiotic therapyPatient 5 (FF) SPKT-ED 167
358
582
588
ATN + interstitial neutrophils
AR IA
Thrombotic microangiopathy
Thrombotic microangiopathy
+ Borderline AR
Diffuse
Focal (20%)
Focal (40%)
Negative
Pielonephritis
AR
No rejection
(DSA negative)
AR
Methylprednisolone
pulse
Plasma transfusion
Methylprednilone pulse
+ Cyclosporine instead
of Tacrolimus
None
Recovery
Recovery
Antibiotic (diarrhea)
Hemodialysis (4 sessions)
and partial recovery
(1.4 m)
Patient 6 (RCF) SPKT-BD33
40
54
143
152
249
Focal ATN
Normal
Moderate ATN
Mild ATN
Normal
Focal and minimal ATN
Diffuse
Diffuse
Negative
Negative
Negative
Negative
Subclinical humoral
Silent reaction
ATN
ATN
Normal
ATN
(Positive DSA - anti-
DR1: 2333 U and
anti-A1: 559 U).
AR
Recovery
(8.8 m)
Patient 7 (CFS) SPKT-BD87AR IANegativeMethylprednisolone
pulse
None
None
Recovery (12.2 m)
Patient 8 (ALS)
Patient 9 (RSA)
SPKT-BD,V
SPKT-BD
104
13
IF/TA grade II
Interstitial nephritis and mild
capillaritis
Negative
Negative
No rejection
No rejection
Recovery (12.5m)
Recovery
286
AR IB
AR IA and IF/AT grade I
NegattiveARMethylprednisolone
pulse
Methylprednisolone
pulse
None
(3.2 m)
Patient 10 (WFZ)SPKT-ED 383 Negative ARRecovery (11. 6m)
Patient 11 (MMB) SPKT-BD7
24
Mild capillaritis
AR IA
Negative
Negative
No rejection
AR Methylprednisolone
pulse
None
Recovery
(5.8 m)
Patient 12 (ERSM) SPKT-BD60 ATN NegativeATN Death with functioning
grafts (disseminated
toxoplasmosis after 2
months)
Recovery (2.7 m)
Recovery (1.7 m)
Worsening of kidney
function
Patient 13 (LPR)
Patient 14 (MLF)
Patient 15 (ROV)
SPKT-ED
SPKT-ED
PAKT-BD,V
11
15
1,607
ATN
ATN
Calcineurin nephrotoxicity
Negative
Negative
Negative
ATN
ATN
No rejection
None
None
Immunosuppressive
regimen changed
from Tacrolimus-
Prednisone-Sirolimus to
Tacrolimus-Prednisone-
Mycophenolate
None
None
(1.6 m)
Patient 16 (SRM)
Patient 17 (ALBC)
SPKT-ED
PAKT-BD
44
2,372
Normal
Incipient IF/TA
Negative
Negative
No rejection
No rejection
Recovery (0.9 m)
Stable function (1.1 m)

Page 6

einstein. 2008; 6(3):311-22
316 Rangel EB, Malheiros DMAC, Antunes I, Torres M, Castro MCR, Crescentini F, Genzini T, Miranda MP
table 2. Data related to pancreas allograft biopsies
Patientstransplant
modality
time after
transplant
(days)
39
light microscopyc4dacute rejection
classification
treatment Outcome
Follow-up (months)
Patient 1 (EBM) SPKT-ED
48
AR grade IV
AR grade III
Diffuse
Diffuse
Acute humoral in all
(positive MICA)
Thymoglobulin +
Plasmapheresis+
Immunoglobulin +
Methylprednisolone pulse
Pancreatic enzyme
normalization and
partial pancreas
function (Insulin NPH
10U) (23.7 m)
Patient 5 (FF) SPKT-ED192 CR grade INegativeNo rejection None Pancreatic enzymes
normalization and
normal pancreas
function
(10 m)
Patient 6 (RCF)SPKT-BD 38
152
Ductular ectasia
AR grade I + CR grade I
Negative
Negative
No rejection
No rejection
None
None
Pancreatic enzymes
normalization and
normal pancreas
function (8.8 m)
Patient 7(CFS) SPKT-BD 87AR grade II + CR grade I Negative ARMethylprednisolone pulse Pancreatic enzymes
normalization and
normal pancreas
function (12.7 m)
Patient 9 (RSA) SPKT-BD20
28
41
AR grade I
AR grade II
AR grade II
Negative
Negative
Focal (20%)
No ejection
AR
Subclinical humoral
None
Methylprednisolone pulse
Thymoglobulin 5 doses
Pancreatic enzymes
normalization and
normal pancreas
function (11.3 m)
Patient 11 (MMB)SPKT-BD7
24
AR grade II
AR grade I
Focal (30%)
Negative
Subclinical humoral
No rejection
Methylprednisolone pulse
None
Pancreatic enzymes
normalization and
partial pancreas
function
(Metformin 1.5g /day )
(5.8m)
Patient 17 (ALBC)PAKT-BD* 2,372Acinar degenerative
alterations
NegativeNo rejectionNone Hyperglycemia
Patient 18 (FO) SPKT-ED 641 Normal Diffuse Silent reaction NonePancreatic enzymes
normalization and
normal pancreas
function (21.6 m)
Patient 19 (RTC) SPKT-BD, V116
164
167
183
AR grade II
AR grade II + CR grade III
AR grade II + CR grade III
AR grade II + CR grade III
Diffuse
Negative
Negative
Focal
Acute humoral
AR
AR
Acute humoral
(DSA not available)
Thymoglobulin 5 doses
Methylprednisolone pulse
OKT3 5 doses
None
Pancreas loss
(8 months after
transplant)
Patient 20 (CP) PAKT-BD 950CR grade I NegativeNo rejection NonePancreatic enzymes
normalization and
normal pancreas
function (14.2 m)
Patient 21 (TC) PTA-BD1,433 AR grade IINegativeARMethylprednisolone pulsePancreatic enzymes
normalization and
normal pancreas
function (19.8 m)
Patient 22 (BJC) PTA-BD394
407
411
457
AR grade II
AR grade II
AR grade IV + CR grade I
AR grade II + CR grade II
Focal
Diffuse
Diffuse
Diffuse
Acute humoral in all
(DSA not available)
Methylprednisolone pulse
Thymoglobulin 8 doses
OKT3 1 dose
Sirolimus conversion
Pancreatic enzymes
normalization and
normal pancreas
function; Amylasuria
less than 100 U /h
(16.4 m)
Continued on next page

Page 7

einstein. 2008; 6(3):311-22
Acute antibody-mediated rejection after pancreas transplantation317
Patient 23 (NRS)PAKT-BD2,243AR grade I + CR grade I NegativeNo rejection NonePancreatic enzymes
normalization and
normal pancreas
function (5.2 m)
Pancreatic enzymes
normalization and
normal pancreas
function (4.6 m)
Pancreatic enzymes
normalization and
normal pancreas
function (4.6 m)
Pancreatic enzymes
normalization and
normal pancreas
function (3.9 m)
Delayed pancreas
function; pancreatic
enzymes normalization
and normal pancreas
function (2.9 m)
Pancreatic enzymes
normalization and
normal pancreas
function (3.4 m)
Persistently elevated
amylase and lipase;
Euglycemic
Patient 24 (ALW) SPKT-BD50 NormalNegative No rejection None
Patient 25 (WP) SPKT-ED620AR grade IINegativeAR
(DSA negative)
Methylprednisolone pulse
Thymoglobulin 5 doses
Patient 26 (TFDL)SPKT-ED, V 1,607AR grade II NegativeARMethylprednisolone pulse
Patient 27 (ES) SPKT-BD34Septal fibrosis Negative No rejection None
Patient 28 (SFS)SPKT-BD 56AR grade II NegativeAR Methylprednisolone pulse
Patient 29 (PAV)PAKT-BD*227 RC grade 1 DiffuseChronic humoral
rejection
None
(1.7 m)
Persistently elevated
amylase and lipase;
Decreased amylasuria
Euglycemic
Patient 30 (ARS)SPKT-BD, V713
734
AR grade III
AR grade II
Diffuse
Negative
Acute Humoral
Acute Humoral
(positive MICA)
Thymoglobulin
Plasmapheresis (11
sessions) + Immunoglobulin
1g/kg 4 doses +
Methylprednisolone pulse
Methylprednisolone pulse
None
(0.9 m)
Recovery (1.2 m)
Recovery + chronic
kidney allograft
dysfunction ** (0.8 m)
Patient 31 (MUS)
Patient 32 (VAF)
PAKT-BD
PAKT-BD
848
929
AR grade II
Acinar degenerative
alterations
Negative
Focal (30%)
AR
No rejection
SPKT = simultaneous pancreas-kidney transplantation; PAKT = pancreas after kidney transplantation; PTA = pancreas transplantation alone; ED = enteric drainage; BD = bladder drainage; V = live kidney donor; AR = acute rejection;
CR = chronic rejection; DSA = donor-specific antibody
* Enteric conversion in the end of the first year due to persistent hematuria; ** C4d not investigated in kidney allograft
Continuation
it showed positive C4d with diffuse pattern whereas
pancreas biopsy disclosed grade IV acute rejection
(Figures 1 A-C) with diffuse C4d staining in interacinar
capillaries (Figure 2). Hemodialysis was indicated
in day 29. Insulin requirement was around 0.5 UI/kg.
Donor HLA specific antigens were negative, although
the panel reactive antibodies increased from zero to
14%. Major histocompatibility complex (MHC) class
I related chain A (MICA) antibodies were positive.
Then, he underwent five plasmapheresis sessions and
two doses of immunoglobulin 1 g/kg. The progression
of pancreatic enzymes according to treatment is shown
in Graphic 1. The third kidney biopsy (day 45) disclosed
acute tubular necrosis and the second pancreas biopsy
was compatible to grade II (minimal) acute rejection.
However, C4d deposition was absent in both allografts.
A second pulse with methylprednisolone with 0.5 g/ day
during three days was performed. Hemodialysis
was interrupted in day 74 and the patient presented
gradual improvement of kidney function. The MICA
investigation was only available after six month, being
negative. After two years of follow-up his creatinine
clearance was 83 ml/ min/1.73 m2 and he was not
under insulin treatment. His last basal C-peptide was
9.6 ng/ ml (normal range, 0.9 to 7.1 ng/ml) and glycated
hemoglobin was 5.3% (normal range, 4.2 to 6%).
Patient 6, a 41-year-old woman was sensitized
before transplantation (Class I 76% and Class II
97%). She was under dialysis for 44 months, had three
previous pregnancies and received more than 20 blood
transfusions. After transplantation, she presented
immediate function of the pancreas allograft and
delayed kidney allograft function (hemodialysis until
the tenth day). Immunosuppressive regimen was based

Page 8

einstein. 2008; 6(3):311-22
318Rangel EB, Malheiros DMAC, Antunes I, Torres M, Castro MCR, Crescentini F, Genzini T, Miranda MP
on thymoglobulin induction. She was discharged from
hospital on day 16 with a serum creatinine measurement
of 2.5 mg/dl. During the first year of transplantation she
was admitted to the hospital five times, with infection
as the main cause. In two hospitalizations, dialysis was
prescribed. Four of the six kidney allografts biopsies
showed acute tubular necrosis and two were compatible
to normal parenchyma. The two initial biopsies were also
associated with diffuse C4d staining; one showed acute
tubular necrosis and the other had normal parenchyma.
However, clinical improvement was spontaneous. In
subsequent biopsies associated with kidney dysfunction,
C4d deposition was absent and clinical improvement
spontaneous and secondary to tacrolimus doses
adjustment and to the infection process resolution. In the
fourth biopsy of kidney allograft (acute tubular necrosis,
peritubular inflammation and mild tubulitis) and in
the first biopsy of pancreas allograft (ductular ectasia,
mild degenerative alterations of acinar epithelium
and fibrosis), C4d staining was negative, but anti-HLA
antibodies were detected, including anti-DR1 (2,333 U)
and anti-A1 (559 U). However, kidney dysfunction was
Figure 1. Acute pancreas rejection classified as grade IV: A. acinar inflammatory
infiltrate of lymphocytes and eosinophils; B. arteritis; C. normal islet beta cells
(hematoxylin and eosin, magnification X100-400)
graphic 1. Clinical evolution of pancreatic enzymes according to treatment
(Methylprednisolone pulse, Thymoglobulin, Plasmapheresis and Immunoglobulin)
0


500
1,000
1,500
2,000
2,500
3,000
Day 1
Day 6

Day 18
Day 23
Day 28

Day 34
Day 39
Day 50
Day 55
Day 72
Day 366
Amylase (U/l)
Lipase (U/l)
Pulse
Thymoglobuline Pp
PpPp
Pp
Pp
IgIg
Pulse
Figure 2. Diffuse C4d detection in interacinar capillaries in pancreas allograft
biopsy of patient 1 (immunofluorescence, magnification X200)

Page 9

einstein. 2008; 6(3):311-22
Acute antibody-mediated rejection after pancreas transplantation319
spontaneously reverted and after one year of follow-up
her creatinine clearance was 80 ml/ min/1.73 m2; she was
euglycemic with amylasuria 2,584 U/h, serum amylase
120 U/l and lipase 376 U/l.
Patient 22, a case of PTA with bladder drainage,
was treated for acute rejection (Figure 3A-B) and
showed decrease of serum pancreatic enzymes
associated to amylasuria values of less than 100 U/h.
After one year of follow-up he remained euglycemic,
although his basal C-peptide values were decreasing:
4.5 ng/ml after one month, 2 ng/ ml after four months
and 1.25 ng/ ml after one year and three months. His
last glycated hemoglobin was 6%.
Patient 30 is a case of SPKT with live kidney
transplantation (brother, haplo-identical) simultaneously
to deceased pancreas transplantation. In the first biopsy,
he presented acute rejection grade III associated
to diffusely scattered C4d staining in interacinar
capillaries and positive MICA (Figure 4A-B). He
was treated with thymoglobulin, plasmapheresis (11
sessions), immunoglubulin 1 g/ kg (four doses) and
methylprednisolone pulse 0.5 g/ day (three days). Despite
this intensive treatment, he presented a mild decrease of
serum pancreatic enzymes and persistent low levels of
amylasuria, that is, less than 1,000 U/h (usual values of
1,100 to 2,300 U/h). His last exams showed serum amylase
155 U/l and lipase 1244 U/l. However, he is euglycemic
with C-peptide 3.3 ng/ ml. Immunosuppressive regimen
was also changed; prednisone discontinued and sirolimus
added to tacrolimus and mycophenolate sodium.
The C4d detection was positive in 14 pancreas
allograft biopsies of the 34 performed (41.2%) and it
showed a diffuse pattern in nine cases (64.5%). There
was no correlation among C4d detection, serum amylase
and lipase or amylasuria values (either before or after
biopsy), to the modality of pancreas transplantation and
to pancreas allograft loss. When grade 1 acute pancreas
rejection (inflammation of undetermined significance)
was compared to grades II-IV, C4d detection was absent
in all cases of grade 1 (p = 0.031), which suggested that
Figure 3. A. Arteritis with fibrinoid necrosis in a case of acute pancreas rejection
grade IV in patient 22 (Hematoxylin & Eosin, magnification X400); B. C4d
detection in interacinar capillaries (immunofluorescence, magnification X200)
Figure 4. A. Venous endothelitis in a case of acute rejection grade III in patient
30 (Hematoxylin & Eosin, magnification X400); B. C4d deposition in interacinar
capillaries (scattered diffuse pattern), immunofluorescence, magnification X200

Page 10

einstein. 2008; 6(3):311-22
320 Rangel EB, Malheiros DMAC, Antunes I, Torres M, Castro MCR, Crescentini F, Genzini T, Miranda MP
this grade of rejection could be really associated with
mild immunological activation.
There was no correlation between C4d detection and
kidney allograft loss. C4d was positive in eight out of 31
kidney biopsies (25.8%) and the pattern was diffuse in
62% of cases.
laboratory data
The laboratory data, according to time before and after
pancreas biopsies of either humoral or cellular rejection
(n = 17 or 61% of pancreas biopsies) were as follows:
amylasuria, 1271.3 ± 1214.1 (median 625 U/l) versus
1966.5 ± 1423 U/h (median 1,680 U/l) (p = 0.004);
serum amylase 188.4 ± 87.9 versus 102.3 ± 47.2 U/l
(p < 0.0001) and serum lipase 1219.1 ± 594.4 versus
419.3 ± 207.3 U/l (p < 0.0001). Thus, on the occasion
of acute pancreas rejection the values of serum amylase
and lipase were one time and four times greater than
the reference, respectively.
In multivariate analysis, serum amylase (p = 0.02,
95% CI 0.92-0.99) and serum lipase (p = 0.018, 95% CI
1.0-1.02) were correlated to acute rejection diagnosis,
either cellular or humoral. Both enzymes also showed a
positive correlation for the diagnosis of acute rejection (p
= 0.0013, r2 = 0.49, Graphic 2). The receiver operating
characteristic curve for serum amylase and lipase (before
biopsy) demonstrated an area under the curve of 0.48 and
0.72 (p = 0.87, 95% CI 0.24- 0.72 and p = 0.039, 95% CI
0.52-0.92, respectively). Amylasuria values were available
for 13 patients and they corresponded to an area under
the curve of 0.24 (p = 0.036, 95% CI 0.04-0.44).
This is the first Brazilian report of acute pancreas
allograft humoral rejection.
Acute AMR has no distinguishing clinical features,
but typically occurs early after transplantation and
causes rapid functional deterioration. However, AMR
can also occur much later, particularly in the setting
of reduced immunosuppression or noncompliance to
treatment. It is a matter of great debate in all solid
organ transplantations. Acute and chronic AMR in
kidney transplantation has been extensively studied,
although the literature of AMR in other organs, such
as heart and lung, is poor(11). However, it seems that
most AMR episodes after pancreas transplantation
can be diagnosed in a similar way as in isolated kidney
transplantation, with the triad of allograft dysfunction,
C4d positivity and detectable donor-specific antibody
(DSA) in recipient serum.
Recently, one case of AMR in SPKT involving
both grafts was successfully treated with intravenous
immunoglobulin, plasmapheresis and rituximab(15). There
was evidence of donor-specific HLA-DR alloantibodies,
C4d staining and microscopy of pancreas with normal
parenchyma and kidney with neutrophils in peritubular
capillaries. Another case of PAKT showed AMR of
pancreas associated with arteritis, C4d and C1q staining
and donor-specific HLA-I and HLA-II alloantibodies
that were unsuccessfully treated with plasmapheresis and
anti-CD3 mAbs (OKT3)(16). The kidney allograft was not
affected because it was from a different donor.
A study including 136 SPKT recipients showed an
incidence of AMR of 15.3% during a follow-up of 3.1
years(10). In 62% (13/21) of those cases, both pancreas and
kidney allografts presented AMR, although only in two
cases C4d was positive in pancreas allograft. Approximately
30% of these kidney and pancreas allografts were lost after
AMR occurrence; late AMR (> three months) was the
main risk factor(10). Interestingly, female gender was the
only risk for AMR and other known factors, such as HLA
A, B or DR mismatches, time on dialysis, delayed graft
function, peak PRA, cytomegalovirus status, previous
transplant, preservation time and induction treatment did
not show correlation with AMR(10).
In our center, 190 pancreas transplants were
performed between August 2002 and August 2008,
but C4d detection has been only routinely investigated
since August 2006. In addition, mean follow-up of our
patients was extremely short (eight months) and protocol
biopsies were not performed, since the impact of AMR
in our center remains to be established. Some of the
cases reported here with C4d staining and allograft
dysfunction were undoubtedly AMR episodes, despite
the lack of DSA at the time of diagnosis. It is reported
elsewhere that antibodies to donor HLA class I or II
graphic 2. Correlation between serum amylase and lipase and acute pancreas
allograft rejection
p=0.0013
r2=0.49
3,000
2,000
1,000
0
0
500
400
300
200
Amylase (U/l)
100
Lipase (U/l)
DiScUSSiOn
The present study reported the incidence of AMR in
three modalities of pancreas allograft transplantation.
The diagnosis of acute AMR occurred in 27.3 and 47%
of kidney and pancreas allograft biopsies, respectively.

Page 11

einstein. 2008; 6(3):311-22
Acute antibody-mediated rejection after pancreas transplantation 321
antigens are present in 88 to 95% of patients who have
C4d deposition and acute graft dysfunction(17).
In our study, it is interesting to note that four out
of the eight (50%) episodes of pancreas AMR, in
seven patients included cases of isolated pancreas
transplantation (one episode in PTA and three episodes
in SPKT with live kidney donor and pancreas deceased
donor). The other four episodes included one case of
SPKT with AMR of both grafts and the other three
cases with isolated involvement of pancreas allograft in
SPKT. This is the first report of AMR in PTA and in
SPKT with different donors.
C4d positivity predicts either worse allograft survival
or early graft dysfunction, which is reported by several
studies that include all solid organ transplantations(10,11,17-
18). We did not find a correlation between C4d staining
and allograft survivals, which could be attributed to
the short follow-up time and to the reduced number of
cases. However, 41.2 and 25.8% of pancreas and kidney
allograft biopsies, respectively, presented C4d positivity
and diffuse staining was present in more than 60% of
cases. It is a matter of debate if the outcome of the
cases of focal C4d staining are worse than diffuse ones,
but it seems that even focal staining is associated with
decreased graft survival and with elevated rates of acute
cellular rejection(19).
Patient 6 was HLA-presensitized and presented two
kidney biopsies with diffuse C4d staining, one with normal
parenchyma and the other with ATN, whereas C4d
staining was negative in pancreas allograft. It is believed
that her silent reaction and subclinical humoral rejections
could have two directions: accommodation or adverse
warning of future rejection. Although the significance of
C4d in the absence of histological evidence of tissue injury
is unknown, C4d deposition also occurs in 2 to 26% of
histological normal grafts; in that, the higher frequency is
found in HLA-presensitized patients(19).
The occurrence of chronic pancreas humoral
rejection is rarely reported. Our PAKT case presents
fibrosis, diffuse C4d staining and DSA is being
investigated. There is no consensus on the treatment for
such case. Euglycemia is maintained, in spite of elevated
pancreatic enzymes, which could be attributed at least
in part to the impairment of kidney allograft function.
In chronic kidney AMR, diagnostic criteria are based
on histological evidence, such as interstitial fibrosis,
tubular atrophy, arterial intimal fibrosis, duplication of
glomerular basement membrane and multilaminated
peritubular capillary(9). In addition, it seems that C4d
in peritubular capillaries is only predictive of kidney
outcome in the acute setting, as opposed to late acute
rejection(20). In pancreas allograft, it remains to be
elucidated if chronic AMR is associated with specific
histological alterations.
The antibodies to major-histocompatibility-complex
(MHC) class I-related chain (MICA) also predict
either early or late graft failure, even in the absence
of measurable HLA antibodies(21-24). MICA antigens
are surface glycoproteins with functions related to
innate immunity and are expressed in several cells,
including endothelial and epithelial, but not peripheral
lymphocytes. In two of our cases, MICA was positive in
either acute or chronic setting, whereas HLA antibodies
were absent: patient 1 (SPKT) had acute humoral
rejection in both allografts and was successfully treated
with plasmapheresis and immunoglobulin; patient 30
(SPKT with different donors) had late acute pancreas
rejection that was also treated with plasmapheresis
and immunoglobulin and persistently maintained
elevated serum pancreatic enzymes, although maintain
euglycemic until now.
It has been reported that antibodies against MICA
alleles are present in 11.4% of patients before kidney
transplantation(20). In patients with functioning kidney
transplants with HLA antibodies, 24% have MICA/B
antibodies and 19% without HLA antibodies have
MICA/B antibodies(21). It seems that when both
antibodies are present, the kidney allograft is associated
with the worst survival(22). Interestingly, MICA antibodies
were not related to blood transfusions and its association
with reduced graft survival was more evident in recipients
with good HLA matching(21). MICA antibodies could also
be induced by pregnancy, for they were detected in 21%
of pregnant women(23). However, both of our patients
that had MICA antibodies were men and the mechanism
by which MICA antibodies were produced remains to be
elucidated. One limitation of our study was the lack of
proof of donor specificity, because the donor’s DNA was
not available to test against MICA antigens.
The increase of serum pancreatic enzymes and their
correlation with each other, as well as the decrease of
amylasuria for the diagnosis of acute pancreas rejection
that we observed, were in accordance to literature(25-27). In
our study, lipase had more specificity and sensitivity than
amylase, for the diagnosis of acute pancreas rejection.
cOnclUSiOnS
In conclusion, our current study showed the occurrence of
AMR after the three modalities of pancreas transplantation.
The high frequency of C4d staining in pancreas allograft
reinforces the need of its investigation in all cases of
acute pancreas rejection, considering it requires specific
treatment which predicts graft survival. In addition, HLA
and MICA antibodies should be also investigated in a
setting of, either early or late acute rejection. Laboratory
data may be a useful tool to diagnosis and to evaluate the
treatment of acute pancreas rejection.

Page 12

einstein. 2008; 6(3):311-22
322 Rangel EB, Malheiros DMAC, Antunes I, Torres M, Castro MCR, Crescentini F, Genzini T, Miranda MP
reFerenceS
Knoll GA, Nichol G. Dialysis, kidney transplantation, or pancreas
transplantation for patients with diabetes mellitus and renal failure: a
decision analysis of treatment options. J Am Soc Nephrol. 2003;14(2):
500-15.
Gruessner AC, Sutherland DE. Pancreas transplant outcomes for United
States (US) and non-US cases as reported to the United Network for Organ
Sharing (UNOS) and the International Pancreas Transplant Registry (IPTR) as
of June 2004. Clin Transplant. 2005;19(4):433-55.
Drognitz O, Benz S, Pfeffer F, Fischer C, Makowiec F, Schareck W, et
al. Long-term follow-up of 78 simultaneous pancreas-kidney transplants
at a single-center institution in Europe. Transplantation. 2004;78(12):
1802-8.
Ferraz AAB, Sette MJA. Transplante de fígado: realidade brasileira. ABCD
Arq Bras Cir Dig. 2005;18(4):133-7.
Drachenberg CB, Papadimitriou JC, Farney A, Wiland A, Blahut S, Fink JC,
et al. Pancreas transplantation: the histologic morphology of graft loss and
clinical correlations. Transplantation. 2001;71(12):1784-91.
Reddy KS, Davies D, Ormond D, Tuteja S, Lucas BA, Johnston TD, et al.
Impact of acute rejection episodes on long-term graft survival following
simultaneous kidney-pancreas transplantation. Am J Transplant.
2003;3(4):439-44.
Humar A, Khwaja K, Ramcharan T, Asolati M, Kandaswamy R, Gruessner
RW, et al. Chronic rejection: the next major challenge for pancreas transplant
recipients. Transplantation. 2003;76(6):918-23.
Drachenberg CB, Papadimitriou JC, Klassen DK, Racusen LC, Hoehn-Saric
EW, Weir MR, et al. Evaluation of pancreas transplant needle biopsy:
reproducibility and revision of histologic grading system. Transplantation.
1997;63(11):1579-86.
Solez K, Colvin RB, Racusen LC, Sis B, Halloran PF, Birk PE, et al. Banff
‘05 Meeting Report: differential diagnosis of chronic allograft injury and
elimination of chronic allograft nephropathy (‘CAN’). Am J Transplant.
2007;7(3):518-26.
Pascual J, Samaniego MD, Torrealba JR, Odorico JS, Djamali A, Becker YT, et
al. Antibody-mediated rejection of the kidney after simultaneous pancreas-
kidney transplantation. J Am Soc Nephrol. 2008;19(4):812-24.
Solez K, Colvin RB, Racusen LC, Haas M, Sis B, Mengel M, et al. Banff 07
classification of renal allograft pathology: updates and future directions. Am
J Transplant. 2008;8(4):753-60.
Takemoto SK, Zeevi A, Feng S, Colvin RB, Jordan S, Kobashigawa J, et al.
National conference to assess antibody-mediated rejection in solid organ
transplantation. Am J Transplant. 2004;4(7):1033-41.
Nadasdy GM, Bott C, Cowden D, Pelletier R, Ferguson R, Nadasdy T.
Comparative study for the detection of peritubular capillary C4d deposition
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
in human renal allografts using different methodologies. Hum Pathol.
2005;36(11):1178-85.
Billen EV, Voorter CE, Christiaans MH, van den Berg-Loonen EM. Luminex
donor-specific crossmatches. Tissue Antigens. 2008;71(6):507-13.
Melcher ML, Olson JL, Baxter-Lowe LA, Stock PG, Posselt AM.
Antibody-mediated rejection of a pancreas allograft. Am J Transplant.
2006;6(2):423-8.
Carbajal R, Karam G, Renaudin K, Maillet F, Cesbron A, Rostaing L, et al.
Specific humoral rejection of a pancreas allograft in a recipient of pancreas
after kidney transplantation. Nephrol Dial Transplant. 2007;22(3): 942-4.
Mauiyyedi S, Crespo M, Collins AB, Schneeberger EE, Pascual MA, Saidman
SL, et al. Acute humoral rejection in kidney transplantation: II. Morphology,
immunopathology, and pathologic classification. J Am Soc Nephrol.
2002;13(3):779-87.
Zhang Q, Liang LW, Gjertson DW, Lassman C, Wilkinson AH, Kendrick E, et
al. Development of posttransplant antidonor HLA antibodies is associated
with acute humoral rejection and early graft dysfunction. Transplantation.
2005;79(5):591-8.
Colvin RB. Antibody-mediated renal allograft rejection: diagnosis and
pathogenesis. J Am Soc Nephrol. 2007;18(4):1046-56.
Satoskar AA, Lehman AM, Nadasdy GM, Sedmak DD, Pesavento TE, Henry
ML, et al. Peritubular capillary C4d staining in late acute renal allograft
rejection – is it relevant? Clin Transplant. 2008;22(1):61-7.
Terasaki PI, Ozawa M, Castro R. Four-year follow-up of a prospective trial
of HLA and MICA antibodies on kidney graft survival. Am J Transplant.
2007;7(2):408-15.
Panigrahi A, Gupta N, Siddiqui JA, Margoob A, Bhowmik D, Guleria S, et al.
Post transplant development of MICA and anti-HLA antibodies is associated
with acute rejection episodes and renal allograft loss. Hum Immunol.
2007;68(5):362-7.
Mizutani K, Terasaki PI, Shih RN, Pei R, Ozawa M, Lee J. Frequency of MIC
antibody in rejected renal transplant patients without HLA antibody. Hum
Immunol. 2006;67(3):223-9.
Zou Y, Stastny P, Süsal C, Döhler B, Opelz G. Antibodies against MICA
antigens and kidney-transplant rejection. N Engl J Med. 2007;357(13):
1293-300.
Klassen DK, Hoen-Saric EW, Weir MR, Papadimitriou JC, Drachenberg CB,
Johnson L, et al. Isolated pancreas rejection in combined kidney pancreas
tranplantation. Transplantation. 1996;61(6):974-7.
Sugitani A, Egidi MF, Gritsch HA, Corry RJ. Serum lipase as a marker for
pancreatic allograft rejection. Clin Transplant. 1998;12(3):224-7.
Papadimitriou JC, Drachenberg CB, Wiland A, Klassen DK, Fink J, Weir
MR, et al. Histologic grading of acute allograft rejection in pancreas
needle biopsy: correlation to serum enzymes, glycemia, and response to
immunosuppressive treatment. Transplantation. 1998;66(12): 1741-5.
14.
15.
16.
17.
18.
19.
20.
21.
22.
23.
24.
25.
26.
27.