Antibodies of Epstein-Barr virus (EBV), EBV-specific cytotoxic T lymphocyte (EBVCTL) activity and the lymphocyte subset of CTL were examined in 13 Japanese children with chronic active EBV infection (CAEBV) and their parents (eight fathers and 10 mothers).
Anti-virus-capsid antigen (VCA)-IgG antibody titers ranged from 1: 640 to 1: 5120 in the patients with CAEBV and from 1: 40 to 1: 640 in the parents. While anti-VCA-IgM antibody was detected in three patients, anti-VCA-IgA antibody in five and anti-early-antigen (EA)-IgG antibody in 11, no antibody was detected in the parents except anti-EA antibody, which was positive in the mothers of cases 5 and 13 (1: 10 and 1: 40). Anti-EBV-associated nuclear antigen (EBNA) antibody was ≥ 1: 10 in six out of 13 patients with CAEBV and in 10 out of 18 parents tested. Epstein-Barr virus activity was significantly lower (P < 0.005) both in the children with CAEBV and in their parents than in seropositive age-matched controls. Proportions of a CTL subset (CD8+ CD11− lymphocytes) in the patients with CAEBV were significantly higher (P< 0.005) than in controls, while those in the parents were at the same level as in controls.
Defective EBVCTL activity and anti-EBNA-antibody responses were frequently observed both in children with CAEBV and in their parents, which may suggest that the abnormal immune response to EBV may be based on a familial disorder, though no familial involvement has been reported in Japanese children with CAEBV.