Anti-Epstein-Barr virus (EBV) antibodies were tested in 11 children with chronic active EBV infection. Anti-virus capsid antigen (VCA)-IgG antibody titers ranged from 1:640 to 1:10,240. Anti-VCA-IgM antibody was consistently positive in 5 of the 11 patients; anti-VCA-IgA antibody was consistently positive in 6 of the 10 patients; anti-early antigen (EA)-IgG antibody was consistently positive in 10 of the 11 patients and anti-EA-IgA antibody was consistently positive in 4 out of the 7 patients. Anti-EBV nuclear antigen (EBNA) antibody was not detected in two patients. Consistently positive anti-VCA-IgA- and anti-EA-IgA- antibody may be a characteristic feature of abnormal antibody responses in severe chronic active EBV-infection in childhood.</p