Abstract
We report a case of severe thrombocytopenia after cytomegalovirus mononucleosis and the changes of the platelet count in 13 cases (including documented case) with CMV mononucleosis (4 cases) or Epstein-Barr virus mononucleosis (9 cases), who were admitted to our hospital from 1991 to 1995. A decrease of the platelet count was observed in some patients at diagnosis compared to the following days, suggesting that thrombocytopenia may be induced by CMV as well as EBV, and mild thrombocytopenia may be more frequent than expected after CMV infection in immunocompetent adults, although severe thrombocytopenia is rare.