Immunological control of Epstein-Barr virus-transformed lymphocytes in multiple sclerosis.

T-cell control of Epstein-Barr virus (EBV)-infected autologous lymphocytes was examined in 25 multiple sclerosis (MS) patients and in 25 healthy individuals, all seropositive for EBV. By assessing regression of cell transformation, 17 patients and all healthy subjects were scored as "regressors." Eight MS patients proved to be "nonregressors," indicating loss of cytotoxic T-cell control. In this group there was apparently a concurrent fall in the mean titer of antibody to Epstein-Barr nuclear antigen.