A Comprehensive Study of Etiology and Pathogenesis in Hemophagocytic Lymphohistiocytosis

Abstract

Background: Hemophagocytic syndrome, or hemophagocytic lymphohistiocytosis (HLH), is a rare yet life-threatening hyperinflammatory disorder marked by excessive immune cell activation. This study aims to delineate diverse etiological triggers of HPS and enhance comprehension of its pathogenesis through meticulous analysis of an afflicted cohort. Methods: Conducted within the Hematopathology Section of the Department of Pathology, this retrospective cum prospective observational study involved 64 meticulously selected patients meeting inclusion criteria. Referral for Bone Marrow Aspiration and Biopsy examinations was the basis for patient inclusion, with approval from the Institutional Ethics Committee. Results: The average age of the 64 patients ranged from 10 months to 85 years (mean: 41.5±19.74 years). Males exhibited a predominant presence (65.6% vs. 34.4% females). 82.2% of patients displayed haemophagocytosis solely on bone marrow aspirate, while 17.2% manifested haemophagocytosis in both aspirate and biopsy. Secondary HLH predominated (96.9%), with a minor proportion of primary HLH cases (3.1%). Infections were identified in 68.8% of cases, with viral infection as the prominent etiology (20.3%), followed by typhoid (12.5%), hepatitis C (9.4%), sepsis (7.8%), and tuberculosis (7.8%). Conclusion: This study's amalgamated findings of hematopathological insights and etiological understanding enhance comprehension of HLH, fostering clinical awareness and driving the pursuit of advanced therapeutic approaches. Keywords: Bone marrow, hemophagocytic lymphohistiocytosis (HLH), hyperferritinemia, primary HLH, secondary HLH