Acute Cytomegalovirus Illness in an Immunocompetent Adult Causing Intravascular Hemolysis and Suspected Hemophagocytic Lymphohistiocytosis.

Background: Primary cytomegalovirus (CMV) infection of the immunocompetent host usually produces little-to-no illness. Occasionally, the infection results in mononucleosis syndrome, protracted fever, hepatitis, tissue-invasive disease, or Guillain-Barré syndrome. Hemolytic anemia and hemophagocytic lymphohistiocytosis (HLH) are rare complications that have not been reported to co-occur. Having hemolytic anemia in conjunction with more common findings of fever and hepatitis complicates the diagnosis of HLH. . A 34-year-old male with previously good health presented with a prolonged febrile illness, jaundice, and anemia. An extensive work-up during hospitalization revealed intravascular hemolytic anemia, leukopenia, hepatosplenomegaly, and biopsy evidence of extensive lymphohistiocytic infiltration of the liver with microgranulomata and sinusoidal hemophagocytosis. Soluble CD25 level was mildly elevated at 1200.3 pg/mL and the HScore calculation (fever, bicytopenia, hepatosplenomegaly, aspartate aminotransaminase 99 IU/L, ferritin 1570 ng/mL, fibrinogen 488 mg/dL, and triglycerides 173 mg/dL) suggested a moderate probability of reactive HLH. Primary CMV infection was diagnosed based on CMV IgM positivity, low CMV IgG avidity index, and low-grade CMV DNAemia. The CMV antigen was not detected in the liver biopsy, and the bone marrow biopsy was unremarkable. The illness began to improve before he received oral valganciclovir for 5 days, and he was in good health 10 months later.

Conclusion: Acute CMV illness in an immunocompetent adult can present with hemolytic anemia and clinicopathologic abnormalities consistent with a form fruste of HLH. The illness is likely due to an excessive or unbalanced immune response that may self-correct.