[Visceral leishmaniasis associated hemophagocytic lymphohistiocytosis: report of four childhood cases].

OBJECTIVE: The clinical features of four cases of visceral leishmaniasis (VL)-associated hemophagocytic lymphohistiocytosis (VL-HLH) were retrospectively analyzed for the purpose of helping the diagnosis of secondary HLH.

METHOD: Clinical data of three childhood cases of VL-HLH documented in our hospital and one case diagnosed in the Capital Institute of Pediatrics was reviewed retrospectively, with particular emphasis on peculiar clinical manifestations and on clues to the diagnosis of this relatively rare disease entity.

RESULT: Three children were from endemic areas of VL, and the other one had lived in endemic area for one year, which was revealed by detailed history-taking. Clinically, VL-HLH is characterized by persistent fever, hepatosplenomegaly and pancytopenia, which is similar to those of HLH, and is one of the important reasons of delayed diagnosis or misdiagnosis. Based on the HLH-2004 protocol, all the four cases met the diagnostic criteria of HLH. In addition, bone marrow aspirate and immunologic detection of VL-specific antibody via rk39 dipstick test during the early disease course of VL-HLH yielded negative results. Two cases who received HLH-targeted therapy responded reasonably well, with rapid temperature normalization and spleen retraction. Nevertheless, Hb remained lower than normal, which we believed to be related to persistent red cell destruction by the invading parasite Leishmania donovani.

CONCLUSION: VL, a parasitic disease caused by Leishmania donovani, which is currently endemic just in 6 provinces in China, shares similar clinical picture of HLH and is an easily ignored underlying cause of secondary HLH. We suggest that VL should be in the list of differential diagnosis for any patients with HLH who lives in or has a definite travel history to endemic areas. Repeated bone marrow studies are highly warranted to make a definite diagnosis of VL, because bone marrow aspirate or rk39 dipstick test during early disease course might yield negative results. Although VL-HLH responds quite well to HLH-tailored chemotherapy, specific therapy against VL must be given to prevent disease recurrence, and HLH-targeted chemotherapy might be discontinued to prevent chemotherapy-related toxicities.