Clinical Characteristics and Management of Four Cases of Visceral Leishmaniasis-Associated Hemophagocytic Lymphohistiocytosis.

The aim for the present study was to analyze clinical features, diagnostic approaches, and therapeutic strategies for visceral leishmaniasis (VL)-associated hemophagocytic lymphohistiocytosis (HLH) in pediatric patients. The clinical characteristics and test results of the children were summarized. Among the four patients, three resided in VL-endemic regions, and one had traveled to a VL-endemic region. All patients presented with recurrent fever (>38.5°C), hepatosplenomegaly, and decreased hemoglobin (HGB) levels ([78.75 ± 8.50] g/L) and platelet (PLT) counts ([59.50 ± 17.48] × 109/L). Before a definitive diagnosis could be made, patients exhibited progressive declines in white blood cell counts, HGB levels, and PLT counts, along with elevated triglyceride, serum cytokine (interleukin [IL]-6, IL-10, IL-2R, and tumor necrosis factor α) levels. Bone marrow aspirate smears revealed hemophagocytosis and Leishmania donovani (LD) bodies in all cases: two were diagnosed via direct identification of LD bodies, one was diagnosed through re-examination of bone marrow smears after confirming a travel history, and one was diagnosed via re-examination prompted by metagenomic next-generation sequencing, which revealed leishmaniasis. All the patients were initially diagnosed with HLH and received HLH-directed immunochemotherapy before VL diagnosis, with suboptimal response. After confirmation of VL, sodium stibogluconate therapy was initiated, resulting in a partial response in all cases. Etiological investigation is critical for HLH diagnosis. For VL-associated HLH, sodium stibogluconate as targeted therapy rapidly controls HLH, facilitates immunosuppression withdrawal, and significantly improves patient outcomes. White blood cell count, HGB level, PLT count, and lactate dehydrogenase level may serve as critical prognostic biomarkers for VL-associated HLH.