Acute Cytomegalovirus (CMV) Infection Associated with Hemophagocytic Lymphohistiocytosis (HLH) in an Immunocompetent Host Meeting All Eight HLH 2004 Diagnostic Criteria.

Hemophagocytic lymphohistiocytosis (HLH) is a rare and often deadly syndrome characterized by severe inflammation and cytokine dysregulation. The disease is defined by the HLH-2004 criteria, requiring five of eight findings, and is further differentiated into either primary or secondary causes. Primary HLH tends to be of genetic etiology, while secondary HLH results from other insults such as infection. Secondary HLH is most commonly associated with viral infections in immunocompromised patients. Acute cytomegalovirus (CMV) associated HLH in the immunocompetent host is exceedingly rare and only documented in four case reports to date. We describe the fifth documented case of CMV-associated HLH in an immunocompetent patient, and furthermore, we demonstrate that this patient is the first published case of its type to satisfy all eight of HLH-2004 criteria.