Hemophagocytic Lymphohistiocytosis Associated With Cytomegalovirus Infection: 5 Cases and a Systematic Review of the Literature

Hemophagocytic lymphohistiocytosis (HLH) is a rare, life-threatening disorder characterized by an uncontrolled, persistent, hyperimmune response. It can be triggered by an infectious, neoplastic, or autoimmune event. The involvement of cytomegalovirus (CMV) in the onset of HLH is subject to debate, and the epidemiology of CMV-associated HLH (HLH-CMV) remains poorly characterized. We identified 5 cases of HLH-CMV in our hospital, systematically searched the PubMed database for publications on HLH-CMV, and reviewed 57 publications with a total of 67 cases of HLH-CMV. Only 48 patients (71.6%) were immunodeficient, suggesting that HLH-CMV can occur in immunocompetent patients. The major cause of underlying immunodepression (51%) was inflammatory bowel disease (mainly treated with azathioprine). CMV infection was nearly always symptomatic, and lung involvement was frequent (31 cases). Fifty-five patients recovered. Nineteen patients were treated for CMV infection only and had a good outcome, suggesting that antiviral drugs might be the cornerstone of HLH-CMV treatment.