Humoral immune response in infectious mononucleosis. Late emergence of anti-EA(R) and the effects of corticosteroid therapy.

The antibody response to Epstein-Barr virus (EBV) antigens in patients with infectious mononucleosis (IM) was studied to assess antibody appearance to the restricted (R) component of the early antigen (EA) complex and to determine the effect of corticosteroids on all aspects of the humoral immune response. Sixty college students with heterophil-positive clinical IM, confirmed by EBV-specific serology, were followed for a period of 4-26 weeks, Half received prednisone for six days, and the remainder received no corticosteroid therapy. Regardless of therapy, 48% of the patients developed anti-EA(R) antibodies. The response to other antigens was similar in both groups with the exception that antibodies to the EB-associated nuclear antigen (EBNA) developed later during convalescence and at lower titers in the corticosteroid-treated group. We conclude that 1) anti-EA(R) antibodies develop with considerable frequency following IM and are not a marker, as previously proposed, of unusually severe disease, and 2) corticosteroid therapy may retard the formation of anti-EBNA antibodies but it does not otherwise influence the humoral immune response to EBV.