Pediatric secondary hemophagocytic lymphohistiocytosis: Single-center experience

Objective: Hemophagocytic lymphohistiocytosis (HLH) is a rare disorder in children that are characterized by a persistent fever, splenomegaly with cytopenia, hypertriglyceridemia, and hypofibrinogenemia.HLH can be classified into two major forms: Primary HLH includes familial HLH and several primary immunodeficiencies, which exhibit genetic inheritance and usually occur in infancy.Secondary HLH (sHLH) is associated with infections, autoimmune disorders, or malignancies.It is essential to identify the disorders underlying HLH and provide the disorder appropriate treatment.The main objectives of this study were to identify the etiology of sHLH and prognostic factors. Material and Methods:We retrospective analyzed clinical and laboratory findings as well as prognostic factors for our pediatric patients diagnosed with sHLH.All statistical tests were performed using the Statistical Package for the Social Sciences (SPSS, Chicago, USA) version 21.0.Ethics committee approval (January 26, 2021) was obtained for the study.Our study was conducted by the principles of the Declaration of Helsinki.Results: Our patients had Epstein-Barr virus, tuberculosis infection, Hodgkin lymphoma, and desmoplastic small round cell tumor.Six pediatric patients with sHLH were identified.Age ranged from 7 months to 16 years.There were five males and one female patient.Three patients were triggered by infection, two cases were triggered by malignant disease and one patient was suspected of rheumatic disease.All patients fulfilled the criteria fever, cytopenia, and ferritin >500 µg/L.The patients started immunosuppressive therapy according to the HLH-2004 protocol.Only one patient (malignancy-associated HLH) died.Conclusion: Although HLH is a rare disease, clinicians should be aware of its existence and actively pursue appropriate diagnostic tests in all children suffering from unexplained fever, cytopenias, and/or hepatosplenomegaly, regardless of whether hemophagocytosis is observed or not.It should be remembered that patients diagnosed with hemophagocytosis may have another underlying disease.