Fatal adenovirus serotype 21 infection associated with hemophagocytic lymphohistiocytosis and multiorgan failure

Recent reports describe an increase in the incidence of fatal adenovirus infections. Several severe cases have been linked to adenovirus serotype 21. The exact etiology for this unexpectedly high mortality remains unknown. We report the case of a patient with severe adenovirus serotype 21 pneumonia resulting in hemophagocytic lymphohistiocytosis (HLH) with acute respiratory distress syndrome and rapidly progressive multiorgan dysfunction syndrome (MODS). HLH describes a cytokine storm due to uncontrolled accumulation of activated T-lymphocytes and activated histiocytes. This results in organ infiltration with these cells, and subsequent hemophagocytosis of erythrocytes, leukocytes and platelets. In its most severe form, HLH leads to a sepsis-like picture and MODS. The association between adenovirus 21 and HLH may at least in part explain the recently observed increase in incidence of fatal adenoviral infections. We suggest that HLH should be considered in cases of severe adenoviral infection. If HLH is present, aggressive treatment is warranted.