[Show abstract][Hide abstract] ABSTRACT: Background. Current U.S. policy requires screening of all deceased organ donors for syphilis infection. To date, information on syphilis test performance in this population is limited.
Methods. All donors with a positive rapid plasma reagin (RPR) and matched donors with negative RPR who were evaluated by one organ procurement organization from January 1, 2000, to September 30, 2012, were retrospectively tested, using retained, residual serum, with two alternate RPR tests and four treponemal-specific tests: A fluorescent treponemal antibody absorption test, a microhemagglutination test, a chemiluminescence immunoassay (CLIA), and a Treponema pallidum particle agglutination (TP-PA) test.
Results. Thirty-two of 3,555 (0.9%) potential deceased organ donors screened during the study period showed a positive RPR; 61 RPR-negative matched donor samples were studied as well. Thirteen (40.6%) of the RPR-positive donors were found to be false-positive based on confirmatory TP-PA. As compared to TP-PA, the sensitivity of the fluorescent treponemal antibody absorption, microhemagglutination, and CLIA was 87.5%, 91.7% and 100%, respectively. The CLIA and TP-PA results were 100% concordant. Only 17 (53.1%) of the RPR-positive donors had a total of 46 organs recovered for transplantation.
Conclusion. Current screening of deceased organ donors by RPR yields a significant number of false-positive results. Use of alternative tests or the routine use of confirmatory tests may reduce the frequency of false-positive results in deceased organ donors.
[Show abstract][Hide abstract] ABSTRACT: Transplant surgeons have historically traveled to donor hospitals, performing complex, time-sensitive procedures with unfamiliar personnel. This often involves air travel, significant delays, and frequently occurs overnight. In 2001, we established the nation's first organ recovery center. The goal was to increase efficiency, reduce costs and reduce surgeon travel. Liver donors and recipients, donor costs, surgeon hours and travel time, from April 1, 2001 through December 31, 2011 were analyzed. Nine hundred and fifteen liver transplants performed at our center were analyzed based on procurement location (living donors and donation after cardiac death donors were excluded). In year 1, 36% (9/25) of donor procurements occurred at the organ procurement organization (OPO) facility, rising to 93% (56/60) in the last year of analysis. Travel time was reduced from 8 to 2.7 h (p < 0.0001), with a reduction of surgeon fly outs by 93% (14/15) in 2011. Liver organ donor charges generated by the donor were reduced by 37% overall for donors recovered at the OPO facility versus acute care hospital. Organs recovered in this novel facility resulted in significantly reduced surgeon hours, air travel and cost. This practice has major implications for cost containment and OPO national policy and could become the standard of care.
American Journal of Transplantation 02/2014; · 6.19 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Aim
Binding of IgG to FcR on B-cells decreases the sensitivity & specificity of the B-cell FCXM. To prevent this, pronase treatment (PT) of un-separated T- & B-cells is widely used. However, the effect of PT on the T-cell FCXM is not well-documented. We have observed a high rate of positive FCXM with PT T-cells in the absence of DSA in HIV+ patients.
26 HIV+ and 30 HIV- 0% PRA patients were tested. 348 sera from HIV+ patients were crossmatched with PT cells, and 81 sera were crossmatched with non-PT (NT) cells from 196 deceased donors. 60 sera from HIV- patients were crossmatched with PT & NT cells from 48 deceased donors. Selected HIV+ sera were pre-treated with reducing agents. Selected HIV+ sera were pre-absorbed with PT & NT T-cells or PT & NT B-cells and then crossmatched with PT cells.
97% of HIV+ patients exhibited strongly positive FCXM with PT T-cells while 17% exhibited weakly positive FCXM with NT T-cells. Only 9% & 16% of HIV+ patients exhibited weakly positive FCXM with PT & NT B-cells, respectively. Positive FCXM were observed with PT but not with NT CD4+ & CD8+ T-cells. Pre-treatment of HIV+ sera with reducing agents did not have any effect on the FCXM strength. Pre-absorption of HIV+ sera with PT T-cells significantly lowered the T-cell FCXM strength and had no effect on the B-cell FCXM strength. In contrast, pre-absorption of HIV+ sera with PT B-cells or with NT T- & B-cells did not have any effect on the FCXM strength. 12 HIV+ patients have been transplanted with kidney allografts with positive PT T-cell/negative NT T-cell FCXM. 100% of these allografts are functioning today (MST = 991 ± 571 days, range: 253–1966 days).
Non-specific IgG binding is not the cause of positive T-cell FCXM in HIV+ patients. Reduction of the T-cell FCXM strength observed on HIV+ sera pre-absorbed with PT T-cells indicates that these positive results are due to autoantibodies recognizing cryptic epitopes exposed by PT on T-cells.
[Show abstract][Hide abstract] ABSTRACT: Presence of donor-specific antibodies (Abs) is detrimental to posttransplant allograft function. Some sensitized recipients have successfully undergone transplantation after pretransplant conditioning regimen using plasmapheresis and/or intravenous immunoglobulin therapy, but underlying mechanisms that confer such allograft protection are undefined.
We developed a single human leukocyte antigen (HLA)-mismatched heterotopic murine heart transplant model (HLA-A2 into HLA-A2-sensitized-C57BL/6) to determine whether pretreatment of donors with low concentration of HLA class I (W6/32) or control Ab (C1.18.4) will confer protection. Expression levels of survival genes, Bcl-2 and heme oxygenase-1, were analyzed by gene array analysis and quantitative real-time polymerase chain reaction. Expression levels of cytokine panel were analyzed by Luminex. Role of Bcl-2 in the induction of allograft protection was analyzed by silencing the Bcl-2 expression in the donor hearts using a small hairpin (shRNA) specific for Bcl-2.
Control Ab-pretreated hearts were rejected in less than 5 days demonstrating hemorrhage, Ab, and C4 deposition. In contrast, W6/32-pretreated hearts were rejected at 15 days (P<0.05) that was prolonged to 25 days with antilymphocyte serum treatment. W6/32-pretreated hearts on day 5 exhibited increased expression of Bcl-2 (5.5-folds), Bcl-xl (5.5-folds), and heme oxygenase-1 (4.4-folds); decreased expression of ICAM-1, VCAM-1 (3.2-fold), along with reduced levels of cytokines interleukin (IL)-1β (4.4-folds), tumor necrosis factor α (3.7-folds), IL-6 (7.5-folds), IL-12 (2.3-folds) and chemokines monocyte chemotactic protein 1 (4.5-folds), MIG (4.4-folds), MIP-1α (3.4-folds), and IL-8 (3.1-folds). Silencing of Bcl-2 in accommodated hearts before transplant resulted in loss of protection with rejection (9±3 vs. 15±2days, P<0.05).
Pretreatment of hearts with low levels of anti-HLA Abs increases expression of antiapoptotic genes that inhibits caspases, leading to decreased inflammatory cytokines and chemokines, which promote allograft survival.
[Show abstract][Hide abstract] ABSTRACT: Selection of donors for kidney transplantation depends on accurate prediction of risk factors for immunologic rejection. Historically, cytotoxicity crossmatch (CXM) examining lysis of donor cells by preformed anti-human leukocyte antigen (HLA) antibodies (Abs) has been considered the best predictor of immunologic rejection. However, there is much interest in defining anti-HLA Ab specificity in recipient sera by immunoassay to predict crossmatch results and aid in donor selection. Current immunoassays for anti-HLA Abs are highly sensitive, though correlation between Abs detected by immunoassay and their functional relevance in CXM and subsequent transplantation is not well defined. In this study, we retrospectively examined the predictive value of detection of donor-specific anti-HLA Abs (DSA) by Luminex Single Antigen assay from 149 consecutive living donor kidney transplant recipients. We demonstrate that detection of DSA by immunoassay accurately predicted negative crossmatch and graft survival. However, this approach had limited sensitivity for predicting positive crossmatch, attributable to either limited typing of donor HLA-DQ and -DP alleles or due to non-HLA Abs. False-positive prediction of CXM correlated with detection of "weak" Abs with low mean fluorescence intensity (MFI < 2000). Furthermore, we found that a ratio of the MFI of the DSA bead to the MFI of the positive control bead was a better method for identifying weak DSA that did not result in CXM-positive reactions. Interestingly, patients with weak DSA and negative CXM had equivalent graft survival over an 18 month follow-up period, suggesting that weak DSA may not preclude transplantation.
Human immunology 03/2010; 71(3):268-73. · 2.55 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Little information has been published about the suitability of candidates for living organ donation who have a past or current psychiatric diagnosis. A retrospective review of 445 living donor kidney transplants performed at Barnes-Jewish Hospital's transplant center from 1995 to 2005 disclosed 42 donor candidates with such a history, prompting detailed psychological evaluation. Although 41 candidates (10% of the donor pool) met criteria for 1 or more psychiatric diagnoses, none were considered psychologically unfit for donation. Of these, 22 candidates underwent kidney donation without medical or surgical complications and without development of subsequent active psychological problems. Several donors maintained long-term contact up to 12 years to report good health and a high degree of satisfaction with the decision to donate. This experience suggests that for donor candidates with a psychiatric diagnosis, formal psychiatric evaluation to evaluate current mental health stability is warranted. Stable individuals, on or off therapy, can be considered fit to donate with expected short- and long-term outcome prognoses similar to those for the general population.
[Show abstract][Hide abstract] ABSTRACT: Presensitization of donor human leukocyte antigens (HLA) demonstrated through a positive crossmatch is detrimental to allograft function and best avoided through donor exclusion. The clinical significance of alloantibody detectable by sensitive solid-phase assay is not completely defined and is the focus of this study. Pretransplant sera from 64 consecutive living-donor renal transplant recipients were screened by enzyme-linked immunosorbent assay (ELISA) and Luminex assays. Results were analyzed for correlation with clinical outcome. Luminex proved more sensitive than ELISA for alloantibody detection, with three identifiable patterns. Twenty-eight patients were antibody negative, 24 had non-donor-specific antibody (non-DSA), and 12 had donor-specific antibody (DSA). The highest number of rejections (n = 4) and graft losses (n = 6) occurred in the antibody-negative group. The non-DSA group had two graft losses, as did the DSA group. The two graft losses in the DSA group were caused by recurrent focal segmental glomerulosclerosis (FSGS) at 35 months and death with a functioning graft at 32 months. Overall, there were no cases of antibody-mediated rejection and allograft function to 4 years was comparable among all three groups. Under our standard immunosuppression protocol and crossmatch criteria for histocompatibility, alloantibody detectable by Luminex was not detrimental to successful living-donor transplantation.
Human immunology 06/2009; 70(8):584-8. · 2.55 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Islet transplantation is a treatment option for type I diabetic patients. Preservation of human pancreata prior to islet isolation using two-layer method with perfluorocarbon (PFC) and University of Wisconsin solution (UW) results in twofold increase in islet yields. The objective of this study was to determine the mechanism by which islets undergo apoptosis and determine PFC's effects on this process. Gene array analysis was used to analyze the expression of pro- and anti-apoptotic genes in islets isolated from pancreata preserved under varying conditions. A 12-fold increase in the expression of inhibitor of apoptosis (IAP) and survivin was observed in islets isolated from pancreata preserved in PFC. This was accompanied by decreased expression of BAD (3.7-fold), BAX (2.7-fold) and caspases (5.2-fold). Levels of activated caspase-9 (77.98%), caspase-2 (61.5%), caspase-3 (68.3%) and caspase-8 (37.2%) were also reduced. 'Rescue' of pancreata after storage (12 h) in UW by preservation using PFC also resulted in a down-regulation of pro-apoptotic genes and inhibition of caspase activation. Apoptosis observed in islets from all groups was mainly mitochondria-dependent, mediated by change in redox potential initiated by hypoxia. We demonstrate that reduction in hypoxia of pancreata preserved using PFC leads to significant up-regulation of anti-apoptotic and inhibition of pro-apoptotic genes.
American Journal of Transplantation 08/2006; 6(7):1696-703. · 6.19 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: In recent years, transplantation of islets and pancreas has become a viable option for patients debilitated with type I diabetes. The success of islet transplantation has been attributed to the ability to isolate high quality islets for transplantation and capacity to maintain the recipient's immunosuppressive levels within a specific target range following transplantation. The purpose of this study was to determine the role of pretransplant sensitization to human leukocyte antigen (HLA) in islet transplantation.
We retrospectively analyzed seven patients that were transplanted with islets under the auspices of the Juvenile Diabetes Research Foundation and Islet Cell Resource Center/National Institutes of Health. Humoral sensitization towards donor antigens both prior to and following islet transplantation was detected by FLOW panel reactive antibodies (PRA) and donor-specific cellular sensitization was detected by performing enzyme-linked immunospot assay analysis for cytokines interferon-gamma and interleukin-2.
Our analysis demonstrates that humoral and cellular sensitization to histocompatibility antigens prior to and after islet transplantation are associated with the failure of transplanted islets
Patient selection based on sensitization to donor HLA may be one of the factors crucial for the success of islet transplant. Further, in some patients, rejection of islets can be associated with sensitization to mismatched donor histocompatibility antigens.
[Show abstract][Hide abstract] ABSTRACT: Although paired donation, list donation and non-directed donation allow more recipients to receive living donor transplants, policy makers do not know how willing incompatible potential donors are to participate. We surveyed 174 potential donors ruled out for ABO-incompatibility or positive cross-match about their participation willingness. They were more willing to participate in paired donation as compared to list donation where the recipient receives the next deceased donor kidney (63.8% vs. 37.9%, p < 0.001) or non-directed donation (63.8% vs. 12.1%, p < 0.001). Their list donation willingness was greater when their intended recipients moved to the top versus the top 20% of the waiting list (37.9% vs. 19.0%, p < 0.001). Multivariate logistic regression modeling revealed that potential donors' empathy, education level, relationship with their intended recipient and the length of time their intended recipient was on dialysis also affected willingness. For paired donation, close family members of their intended recipient (odds ratio (OR) = 3.01, confidence intervals (CI) = 1.29, 7.02), with high levels of empathy (OR = 2.68, CI = 1.16, 6.21) and less than a college education (OR = 2.67, CI = 1.08, 6.61) were more willing to participate compared to other donors. Extrapolating these levels of willingness nationally, a 1-11% increase in living donation rates yearly (84-711 more transplants) may be possible if donor-exchange programs were available nationwide.
American Journal of Transplantation 08/2006; 6(7):1631-8. · 6.19 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Allografts transplanted across ABO incompatibility or human leucocyte antigen (HLA)-sensitization undergoes antibody (Ab) mediated hyperacute rejection. Depleting anti-graft Ab from the recipient by plasmapheresis prior to transplantation can prevent this Ab-mediated rejection. Under these conditions, allografts have been shown to function even when the Ab rebound in the recipients. We have developed an in vitro model using human aortic endothelial cells (EC) and elucidated the ability of W6/32 HLA class I monoclonal Ab to provide signals following binding to MHC class I molecules. Using this model, we show that ECs undergo caspase 3-dependent cell death by apoptosis upon exposure to saturating concentrations of W6/32 and complement. In contrast, exposure of ECs to sub-saturating concentrations of W6/32 conferred resistance towards Ab/complement-mediated lysis that has been termed accommodation. Accommodated ECs exhibited a significant increase in the expression of anti-apoptotic genes Bcl-xL, Bcl-2 and Heme Oxygenase-1 and the induction of Phosphatidylinositol 3 kinase (PI3K) and cyclic adenosine monophosphate (cAMP) dependent protein kinase A activities that facilitate the phosphorylation of Bad at positions Ser(136) and Ser(112). In conclusion, exposure of sub-saturating concentrations of HLA class I Ab results in the induction of signals downstream that confers resistance to endothelial cells against Ab-complement mediated cell death. Together, the observations made in this study will provide the basis for delineating the molecular mechanisms involved in mediating accommodation and developing strategies to induce accommodation in grafts prior to transplantation in highly sensitized patients.
[Show abstract][Hide abstract] ABSTRACT: A program was established within our regional procurement organization to permit evaluation of altruistic living donors (LD) interested in nondirected kidney or liver segment donation prior to transplant center referral. During the initial 30 months of program operations, 731 donor inquiries were received of which 131 individuals called back after review of mailed information materials. Forty-seven candidates initiated and 19 completed the evaluation process. Seven underwent donation to include six kidneys and one liver segment, five are actively pending donation, five were excluded from donation following transplant center evaluation and two took no further action after their intended liver recipients received deceased donor (DD) transplants. Psychological evaluation of these 19 candidates found them to be free of psychopathology, highly cooperative and self-directed. They did not exhibit attention-seeking or religious motivations for their actions. All seven donors and recipients continue to do well postoperatively. This evaluation program has made possible large-scale screening and education of prospective altruistic LD within the general population and also provides a unique opportunity to further our understanding of those individuals interested in living-nondirected donation.
American Journal of Transplantation 02/2006; 6(1):115-20. · 6.19 Impact Factor