Lam P, et al. - Researchers here reported five cases of reactive hemophagocytic syndrome in patients with underlying HIV infection. All patients presented with fever and had CD3/CD4 cell counts of < 200 cells/µL, had marked cytopenias, with platelet counts falling to 10–15,000/µL and had ferritin levels > 5000 ng/mL. Epstein–Barr virus infection, Pneumocystis jiroveci, multiple myeloma, and Hodgkin’s lymphoma were the concomitant inciting conditions; no inciting condition was identified in one case. Within 1 month of presentation, all five patients died despite receiving broad-spectrum antimicrobial and immunosuppressive therapy. They recommend clinicians to promptly determine a ferritin level among patients with underlying HIV infection who present with fever and cytopenia. If markedly elevated, they emphasize undertaking an aggressive workup for the hemophagocytic syndrome. However, even with prompt recognition, there may be high mortality rates in patients with underlying HIV infection.