Hemophagocytic lymphohistiocytosis secondary to Epstein Barr virus and Leishmania co-infection in a toddler.

This is the report of an EBV+Leishmanial co-infection. The patient developed hemophagocytic syndrome (HLH) and was treated with the standard HLH-2004 protocol. However, PCR in bone marrow discovered this secondary cause for HLH. In endemic countries, visceral leishmaniasis should be considered in the differential diagnosis even in EBV-related HLH, as chemotherapy toxicity may be avoided.

Introduction

Hemophagocytic lymphohistiocytosis (HLH) is a rare but lethal disease, which may be due to genetic defects, as in familial HLH caused by mutations in FHL1 — HPLH1, FHL2 — PRF1 (Perforin), FHL3 — UNC13D (Munc13-4), FHL4 — STX11 (Syntaxin 11), FHL5 — STXBP2 (Syntaxin binding protein 2)/UNC18-2, or immunodeficiency syndromes as Chediak-Higashi, Hermansky Pudlak, Griscelli or X-linked Lymphoproliferative syndrome. On the other hand, acquired HLH is associated with malignancies, autoimmune diseases, and infections with the Epstein Barr Virus (EBV) being the main trigger.[1]

Case Report

A 22-month-old girl presented to us with 8-day fever (40°C), and mild cough. On examination, she had hepatosplenomegaly. Past medical history included failure to thrive, but normal neurological development. She was the first child of a non-consanguineous marriage. She had normal brown hair and normal skin. There was no family history of albinism. On physical examination, she was stunted, pale, and had non-tender hepatomegaly of 5-6 cm; the spleen was palpable 4 cm below the left costal margin as confirmed by abdominal ultrasound. The WBC count was 5100/mm3 (ANC 1200/mm3), Hb 9.1 g/dl, and platelets 47.000/mm3. She had mild hypertransaminasemia and hypoalbuminemia. Ferritin was 1134 ng/ml. Soluble IL-2 receptor (sCD25) was 3183 UI/ml. Blood cultures were negative. Serum immunoglobulins and lymphocyte subsets were normal. Epstein-Barr virus (EBV) serology yielded seroreactivity (positive IgM and IgG anti-VCA) with negative IgG anti-EBNA. EBV viral load was 637 copies/ml. Leishmania serology showed both negative immunochromatography and indirect immunofluorescence. Conversely, serum ELISA was slightly positive. Leishmanial antigen in the urine was negative. Bone marrow aspiration revealed hemophagocytosis. The patient worsened clinically, with persistent malaise, progressive splenomegaly, and petechial rash on her chest and legs. Subsequent investigations were WBC 4800/mm3 (ANC 800/mm3), Hb 6.8 g/dl and platelets 27000/mm3, triglycerides 686 mg/dl, ferritin 3849 ng/ml, and sCD25 3596 UI/ml with normal clotting tests as well as perforin expression by flow-cytometry. Hair microscopy was not performed because clinical features of albinism were not present neither in our patient nor in her family. HLH-2004 protocol was started. The following day, Leishmania Polymerase Chain Reaction was done where Leishmanial DNA was detected by nested PCR.[2]) This was confirmed on a bone marrow aspirate as well. Standard therapy with liposomal amphotericin B (3 mg/kg/day IV on days 1, 2, 3, 4, 5, 14, and 21) was given. The patient completed HLH-2004 protocol, except for 2 doses of etoposide due to clinical and laboratory improvement without evidence of underlying primary HLH. At 30 month follow up, there is no evidence of relapse. As CD107a degranulation assay was not performed (just normal intracytoplasmic pattern of perforin staining), primary HLH is not absolutely discarded as a differential diagnosis.

Discussion

HLH comprises a rare group of disorders caused by activation of CD8 + T cells and macrophages and high-level secretion of pro-inflammatory cytokines,[3] characterized by persistent fever, cytopenia, hepatosplenomegaly, and hemophagocytosis in bone marrow, lymph nodes, liver or spleen.[4] Primary HLH as well as secondary HLH not controlled by treatment of underlying condition must be treated with HLH-2004 protocol, which includes dexamethasone, cyclosporine A, and etoposide. In EBV-HLH, it has been proposed a multi-step treatment,[5] in an attempt to reduce long-term toxicity of etoposide.

A case of EBV-Leishmania co-infection in a 9-month old girl as a trigger for HLH has been reported.[6] However, EBV viral load was not reported. Transient low-level viremia has been reported without significance in immunocompromised and non-immunocompromised host.

In our patient, we found EBV and Leishmania co-infection, an extremely rare association. Both are well-known causes of secondary HLH. In addition, EBV is the main trigger of primary HLH, what makes it difficult to distinguish between primary and secondary HLH. This is the main reason why investigation of Leishmania by PCR should be done on bone marrow of patients with HLH and EBV infection (specially in endemic areas), to rule out Leishmania infection because its sensitivity and specificity are greater than microscopy or other microbiological test,[5] in order to avoid toxicity derived from drugs contained in HLH-2004 protocol.