Non-EBV infection-associated hemophagocytic lymphohistiocytosis: a distinct subgroup where pathogen-directed therapy is essential and favorable outcomes are expected

EBV is the most prevalent cause of infection-associated hemophagocytic lymphohistiocytosis (IAHLH), non-EBV IAHLH is observed clinically but less documented. We conducted a retrospective research enrolled 36 cases from 1/1/2015 to 31/12/2019. Intriguingly, 92% cases were immunocompetent individuals prior to the onset of HLH. Clinically, the cardinal features were prolonged high fever, splenomegaly and hemophagocytosis. Bicytopenia occurred in most patients, besides, liver dysfunction was characterized by increased transaminase, bilirubin, alkaline phosphatase (ALP), gamma-glutamyl transpeptidase (γ-GGT) and lactate dehydrogenase (LDH). Immunomodulatory agents should be added to control the overwhelming inflammatory storm without delay. Once a certain pathogen was identified as the causative factor of HLH, cytotoxic agents were withdrawn, specific pathogen-directed treatment was initiated. Further, glucocorticoids were tapered off when a stable state of HLH was achieved. After treatment, about 70% patients were fully recovered without relapse. All in all, non-EBV IAHLH is a special group of HLH with admirable outcome.