The role of infections in primary hemophagocytic lymphohistiocytosis: a case series and review of the literature.

There is a paucity of literature addressing infection-related morbidity and mortality in children with primary hemophagocytic lymphohistiocytosis (HLH), a rare condition characterized by abnormal proliferation of macrophages, hypercytokinemia, and T cell immunosuppression. Therefore, a retrospective chart review was done of patients diagnosed with primary HLH over a 15-year period. Significant infections present at diagnosis, during the course of illness, and just prior to death or at autopsy were noted. Of the 18 children identified with primary HLH, an infectious agent was documented at the initial presentation of HLH in 5. Significant infections occurred during therapy in 10 (56%) of 18. Of the 12 fatal cases, invasive infection was the cause of death in 8 children, and 6 of these deaths were directly attributable to invasive fungal infection. Significant infections were common during therapy in children with primary HLH, and fungal infections were an important cause of mortality in this group.