Epstein-Barr virus and cytomegalovirus antibodies in infectious mononucleosis.

A method has been evolved for the demonstration of Epstein-Barr virus (EBV) and cytomegalovirus (CMV) infection in 83 cases of infectious mononucleosis. Serum samples were tested for EBV IgM, anti-VCA IgG, anti-EBNA, CMV IgM and CMV IgG antibodies. An acute-phase sample (or samples) and a convalescence sample were examined in each case, and in 44 cases an additional samples was examined 5-12 months after the illness. Since the different antibodies showed characteristic differences in both titre and persistence, a reliable serodiagnosis has become possible. Acute EBV infection is characterized by the presence of EBV-VCA IgG and EBV IgG antibodies and the lack of anti-EBNA. The latter becomes demonstrable as late as the 4th to 5th month after infection. Mean age of the patients was 19 years. EBV infection was demonstrated in 65%, CMV infection in 18% of the cases. In 12% double infection seemed to be probable.