Pediatric Hemophagocytic Lymphohistiocytosis - A Single Center Study

To describe the epidemiological features, outcomes and prognostic factors in diagnosis of pediatric hemophagocytic lymphohistiocytosis (HLH).

118 children fulfilling the inclusion criteria for HLH were identified from review of hospital records for period January, 2010 to December, 2019.

Median age at diagnosis was 4 years (range13 days-15 years). Presenting features were fever (100%), hepatosplenomegaly (91%), neurological symptoms (23%), bicytopenia (76%), transaminitis (67.3%), increased soluble interleukin-2 receptor) (sIL-2R) (78%) and hemophagocytosis on bone marrow (75%). Median follow-up duration was 13.5 months (3 days to 102 months). Primary HLH was identified in 27 (23%) patients. Etiology of secondary HLH was infections in 53 (45%), rheumatologic illnesses in 21 (18%) and malignancies in 8 (6%) children. Treatment modalities were steroid only (25%), anti-infectious agent (58%), multi-agent chemotherapy (43%) and HSCT (40%); mortality among above treatment groups were 25%, 58%, 43% and 40%, respectively. 15 patients (13%) had relapsed/refractory HLH who were treated with salvage chemotherapy and hematopoietic stem cell transplantation (HSCT). The overall mortality rate was 39%; mortality within 30 days seen in 23%. Estimated overall survival (OS) and event free survival (EFS) at 3 years were 62% and 61%, respectively.

Pediatric HLH is an aggressive disease with high mortality. Hyponatremia, hyperbilirubinemia, coagulopathy and increased sIL2 receptor level at diagnosis predicts poor outcome.