Serum Ferritin is a Cost-effective Laboratory Marker
for Hemophagocytic Lymphohistiocytosis
in the Developing World
Juli Renate Switala, MBChB (WITS), MD, DCH(SA),*
Marc Hendricks, MD, MBChB (UCT), FC Paeds (SA), CMO(SA),w and
Alan Davidson, MD, MBChB (UCT), FC Paeds (SA), CMO (PAEDS)(SA), MPhilw
Summary: Hemophagocytic lymphohistiocytosis (HLH) is a rare
disease in children and presents many diagnostic difficulties.
Without prompt intervention, the disease typically runs a rapidly
fatal course. Diagnostic criteria were proposed by the Histiocyte
Society in 1991 and have since been modified. Included in these
criteria is a ferritin level >500mcg/L2. Although not diagnostic, a
high ferritin level is highly suggestive of HLH. Serum ferritin assays
are more accessible and cost-effective compared with other bio-
chemical markers, particularly in resource-limited settings. Fifteen
patients with HLH were treated at Red Cross War Memorial
Children’s Hospital between 1991 and 2010. Hyperferritinemia was
a consistently reliable finding (93%) compared with either serum
fibrinogen or triglycerides, which were elevated in only half of the
patients. It is our contention that analysis of a complete blood
count and serum ferritin (in addition to clinical criteria and tissue
examination of marrow and/or cerebrospinal fluid) is probably the
single most cost-effective and clinically helpful means to make the
diagnosis of HLH when laboratory access is limited.
Key Words: hemophagocytic lymphohistiocytosis, ferritin, devel-
(J Pediatr Hematol Oncol 2012;34:e89–e92)
cases per 100,000 children.1As no published series are
available, the incidence in Africa is unknown. Without treat-
ment the disease runs an often fatal course, making prompt
diagnosis a priority. The diagnosis may be difficult as HLH
is a diagnosis for exclusion with no pathognomonic features
and a clinical picture that may be vague and varied. For this
reason it is usually not considered early as a differen-
tial diagnosis for exclusion, and hence treatment delays are
To aid diagnosis, a set of diagnostic criteria including
clinical and biochemical markers were proposed by the
Histiocyte Society in 1991.2These were modified in 2004
(Table 1), and new recommendations have been made since
but have not yet been codified (Table 2). Included in these
emophagocytic lymphohistiocytosis (HLH) is a rare
disease in children with an estimated incidence of 0.12
criteria is a ferritin level >500mcg/L2. In a study by Allen
et al,3a ferritin level >10000mcg/L was found to be 90%
sensitive and 96% specific for HLH (98% if fever was
added as a criterion). In a series of patients including
both viral-associated and malignancy-associated HLH,
Esumi et al4found ferritin levels to be elevated at diagnosis,
with further increases at the onset of disseminated intra-
vascular clotting. Patients with sustained high ferritin levels
after 3 months died, whereas those with decreased levels
survived, suggesting that ferritin level may be a useful
marker to monitor disease activity and not just as an in-
dicator of the presence of disease.4Serum ferritin levels are
more readily available in most laboratories compared with
functional natural killer cells assays or IL-2-a receptor se-
rum assays, which is of particular importance in Africa,
where laboratory services are often limited or unavailable.
Ferritin production is upregulated by proinflammatory
cytokines from the NKC pathway,3the activated yet in-
effective pathway in HLH. The differential diagnosis for
conditions associated with hyperferritinemia includes other
infections, autoimmune disease such as juvenile systemic
arthritits,5and several very rare syndromes that include
lysinuric protein intolerance, congenital hemochromatosis,
and hereditary hyperferritinemia cataract syndrome.6A
high ferritin level alone is therefore very suggestive but not
diagnostic of HLH.
MATERIALS AND METHODS
Between March 1991 and September 2010, 15 patients
were diagnosed with HLH at Red Cross War Memorial
Children’s Hospital. This diagnosis was made on the basis
of the HLH diagnostic criteria (Table 1). These criteria
were modified for our local use to include an abnormal CSF
with other tissues such as the bone marrow and lymph
nodes. This was done because CSF changes may be present
even without any clinical features,5or, in contrast, CSF
may appear normal, even in patients with symptomatic
central nervous system (CNS) involvement.7For this rea-
son, Janka et al recommend a lumbar puncture in all pa-
tients5as CNS involvement is associated with a worse
outcome.7Further, NKC activity testing and IL-2 levels are
not available at our institution. Cases were identified using
the institutional oncology registry, and a retrospective
review of data was performed using hospital records.
Before 1991, 4 patients had histopathologic features
compatible with a hemophagocytic syndrome. These
patients presented before
mendations were made; therefore, many of the inves-
tigations required to meet the criteria were not conducted,
Received for publication June 20, 2011; accepted November 14, 2011.
From the *Department of Paediatrics, Red Cross War Memorial
Children’s Hospital, University of Cape Town; and wPaediatric
Haematology Oncology Service, Red Cross War Memorial Child-
ren’s Hospital, University of Cape Town, South Africa.
The authors declare no conflict of interest.
Reprints: Juli Renate Switala, MBChB (WITS), MD, DCH (SA),
Red Cross War Memorial Children’s Hospital, Klipfontein Road
Rondebosch, Cape Town, 7700, South Africa (e-mail: johnny
Copyrightr2012 by Lippincott Williams & Wilkins
J Pediatr Hematol Oncol?Volume 34, Number 3, April 2012www.jpho-online.com|e89
resulting in insufficient evidence for the diagnosis. These
patients, as well as those with Langerhans cell histiocytosis,
malignant histiocytosis, or those who did not meet the di-
agnostic criteria for HLH, were excluded from this series.
Eight of the 15 patients were girls and 7 were boys.
The median age at diagnosis was 27 months (10 to 79mo)
for boys and 75 months (9 to 225mo) for girls. Three pa-
tients were below 1 year of age at diagnosis, the age when
primary HLH is more likely to present.6
Ten patients were African, 4 were of mixed ancestry, and
1 patient was Bangladeshi. There were no Caucasian in our
cohort. None of the patients included in the study had a
documented family history of HLH, although none of the
folders contained any specific history of consanguity or un-
explained family illnesses or deaths related to hematologic
problems. All of the patients included in the group were clas-
sified as having secondaryHLH.Three patients had precipitants
of Epstein Barr virus infection (viral load log values of >4).
Precipitants were varied and included cytomegalovirus
and respiratory syncytial virus (1) and pneumococcal endocar-
ditis (1), Kawasaki disease (1), and Systemic lupus erythematous
(1). Four patients had malignancy-associated HLH: acute
lymphoblastic leukaemia (1), acute myeloblastic leukaemia (1),
T-cell lymphoma (1), and anaplastic large cell lymphoma (1).
The median time to achieve a diagnosis once the
children had arrived at our own institution was 13.7 days
(1 to 38d). Discussion before referral undoubtedly short-
ened the interval to diagnosis in certain cases.
Fever was documented in 13 (87%) patients. Splenome-
galy was documented in 10 (67%) patients, and hepatomegaly,
despite not being a diagnostic criterion, was present in 11
(73%) patients. Other common features were rash [7, (47%)],
edema [8, (54%)], and lymphadenopathy [7, (47%)]. By
comparison, Henter et al1found the following clinical features
of patients in a literature review, a population-based study,
and the FHL Registry, respectively: fever (91%, 100%, and
93%), splenomegaly (98%, 100%, and 97%), hepatomegaly
(94%, 97%, and no data available), rash (6%, 65%, and
24%), and lymphadenopathy (17%, 52%, and 31%). Five
patients were found to have clinical CNS involvement, which
was lower than the 75% found in a series by Hallahan et al,7
although in most of these patients CNS features were not
present initially but developed later in the clinical course.
Of the 14 patients who had documented serum ferritin
levels, 13 met the diagnostic criterion of levels above
Multiple complete blood counts were analyzed for all
patients. The first values demonstrating an abnormality
were recorded, and in many cases results continued to de-
teriorate before normalizing. Twelve of 15 patients had
serum hemoglobin levels of 9.0g/dL or less. Five patients
had total white blood count values under 4?109/L, and 10
had platelet counts of <100?109/L (13 to 145?109/L).
Seven of the 14 patients who had serum triglyceride
levels tested had elevations in excess of 3mmol/L. Six of 13
patients had fibrinogen levels below 1.5g/L.
All patients had bone marrow biopsies at diagnosis.
All but 1 demonstrated hemophagocytosis with histiocytic
infiltration on initial or follow-up biopsy. One patient had
hemophagocytosis present on a lymph node biopsy. Three
of the 4 patients who underwent liver biopsies demon-
strated hemophagocytosis (Table 3).
Thirteen patients were started on steroids. Ten were
started on dexamethasone and 2 on prednisone. One of the
patients who was started on prednisone initially was
switched to dexamethasone 9 days later.
Six patients were started on etoposide and 2 on
cyclosporine (as per the HLH 2004 protocol).
TABLE 2. Proposed Modifications to Diagnostic Criteria, 2009
1. Molecular diagnosis of HLH
Or XLP syndromes
2. Or at least 3 of 4:
Cytopenias (minimum 2 cell lines reduced)
3. And at least 1 of 4:
Increased soluble IL-2 receptor
Absent or very decreased NKC function
4. Other results supportive of HLH diagnosis
HLH indicates hemophagocyte lymphohistiocytosis; XLP, X-linked
TABLE 1. Revised Diagnostic Guidelines for HLH
The diagnosis of HLH can be established if 1 of either 1 or 2 below
1. A molecular diagnosis consistent with HLH
2. Five of the 8 criteria below are met:
A) Initial diagnostic criteria (to be evaluated in all patients with
Cytopaenia affecting 2 or more lineages
Hb<9g/dL (in neonates <10g/dL)
Hypertriglyceridemia—fasting triglycerides Z3mmol/L and/or
Hemophagocytosis in bone marrow, spleen, or lymph nodes. No
evidence of malignancy
B) New diagnostic criteria
Low or absent NK-cell activity (according to local laboratory
Soluble IL-2 receptor Z2400U/mL
1. If hemophagocytic activity is not proven at the time of
presentation, further search for hemophagocytic activity is
encouraged. If the bone marrow specimen is not conclusive,
material may be obtained from other organs. Serial marrow
aspirates over time may also be helpful.
2. The following findings may provide strong supportive evidence
for the diagnosis: (a) spinal fluid pleocytosis (mononuclear cells)
and/or elevated spinal fluid protein, (b) histiologic picture in the
liver resembling chronic persistent hepatitis (biopsy).
3. Other abnormal clinical and laboratory findings consistent with
the diagnosis are: cerebromeningeal symptoms, lymph node
enlargement, jaundice, edema, skin rash. Hepatic enzyme
abnormalities, hypoproteinemia, hyponatremia, VLDL
increased, HDL decreased.
Henter et al.2
Switala et al J Pediatr Hematol Oncol?Volume 34, Number 3, April 2012
r2012 Lippincott Williams & Wilkins
Administration of etoposide did not seem to have any
bearing on outcome, keeping in mind the fact that it was a
small cohort of patients and that our criteria for etoposide were
fairly strict (primary steroid nonresponders, proven Epstein
Barr virus-associated HLH, refractory or reactivated HLH).
No patients required bone marrow transplant.
Four patients have died: 1 from refractory HLH, 1
from reactivated HLH, 1 from end-stage human im-
munodeficiency virus infection, and 1 from an unknown
cause. Ten patients are still alive: 6 are disease free and 4 are
alive with disease. Of the 4 patients alive with disease, 1 had
refractory disease on treatment, 1 had reactivated disease
on second-line treatment, and 2 are still in the induction
phase of treatment. One patient has been lost to follow-up.
The diagnosis of HLH in resource-constrained envi-
ronments is made more difficult by reliance on laboratory
criteria, which are often unavailable or limited. New pro-
posed modifications to the diagnostic criteria (Table 2) will
help to reduce this reliance, as they are somewhat less
laboratory focused compared with the current criteria
(Table 1). However, the onus is still on the clinician to
actively make the diagnosis and pursue treatment early on.
The costs related to specific investigations are often
not considered by the user. Cost considerations often move
local, national, or institutional groups to relook at diag-
nostic and treatment criteria, to balance what is best for the
patient against what is affordable for a service provider.
South Africa, although arguably more fortunate than most
other African countries, is not exempt to these pressures
and we have had to make institutional alterations to the
treatment guidelines for patients with HLH because of the
costs of tests (cyclosporine levels) and drugs (cyclosporine,
in particular). Furthermore these “hard” costs do not
include hidden expenses pertaining to access, transport, and
accommodation for poor patients, especially those expenses
required to attend outpatient clinics several times a
week. Table 4 has a list of the costs of the laboratory tests
typically involved in the diagnosis and follow-up of HLH.
Because the disease is a dynamic process, inves-
tigations may need to be repeated before criteria are met
and a diagnosis is made. Laboratory facilities may be lim-
ited in some hospitals and some tests may not be available
at all (eg, soluble IL-2 receptor levels and NKC activity).
This then raises the question as to what the most cost-
effective and clinically instructive strategy is. In our series,
hyperferritinemia was a consistently reliable finding (93%)
compared with either serum fibrinogen or triglycerides,
which were elevated in only half of the patients. This
finding is supported by other studies in which a ferritin level
>500mcg/L was found in 100% of patients with HLH.3
TABLE 3. Patient Results
>500>3.0 <1.6<9.0 <100
Bone marrow, CSF,
Bone marrow, CSF
Bone marrow, liver
Bone marrow, lymph
Bone marrow, CSF
—9 D, C, E
15225 AWD5672.7 184.108.40.206454.5D, C, E
WBC seen is the total white blood count and not the total neutrophil count. Epstein Barr virus VL >4 log considered significantly elevated.
ADF indicates alive disease free; AWD, alive with disease; C, Cyclosporin numbers highlighted indicate abnormal values relative to the diagnostic criteria;
CSF, cerebrospinal fluid; D, Dexamethasone; DD, died of disease; DU, death unrelated; E, Etoposide; P, Prednisone; TG, triglycerides; VL, viral load; WBC,
white blood cell.
TABLE 4. Costs of Laboratory Tests, National Health Laboratory
Services, South Africa
Cost in SA
Cost in US
Complete blood count
Bone marrow examination
TOTAL (All tests)
US dollar: SA rand exchange at time of calculation: 1: 6.7204.
J Pediatr Hematol Oncol?Volume 34, Number 3, April 2012Ferritin as a Diagnostic Tool for HLH in the Developing World
r2012 Lippincott Williams & Wilkinswww.jpho-online.com|e91
Taking clinical comparators into account, fever was
found in 87% of patients, hepatomegaly in 73%, and anemia
in 67%. These were common findings but the differential
diagnosis for each of these, or even in combination, remains
much wider than for those with significant hyperferritinemia,
particularly in our region with high rates of endemic tuber-
culosis and human immunodeficiency virus infection.
It is our contention that analysis of a complete blood
count and serum ferritin (in addition to clinical criteria and
tissue examination of marrow with or without a CSF) is
probably the single most cost-effective and clinically helpful
means to make a diagnosis and that serum fibrinogen and/
or triglycerides are useful adjuncts when there is still suffi-
cient doubt about the diagnosis. A full set of investigations
(complete blood count, fibrinogen, alanine transferase,
lactate dehydrogenase, triglycerides, ferritin, bone marrow
aspiration) will cost roughly US $130 per patient. On the
basis of our small group of patients it seems reasonable to
limit investigations to a complete blood count, serum fer-
ritin, and bone marrow biopsy examination (at a cost of
approximately $95 US) and initially forego the others,
considering the fact that ferritin is consistently more
reliable as an indicator of disease, compared with serum
triglycerides and fibrinogen; this could lead to a cost saving
of approximately US $35 per patient.
Rationalizing costs should be a priority in any clinical
care setting, and often measures taken to limit costs that
arise out of necessity subsequently have real implications on
how patients are managed even in environments in which
resources are not limited.
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r2012 Lippincott Williams & Wilkins