Absence of virus-induced lymphocyte suppression and interferon production in multiple sclerosis

Lymphocytes from normal adult donors exposed in vitro to inactivated measles virus were found to exert significant suppression (33.9%) of the concanavalin A responses of cryopreserved, autochthonous responder cells. In marked contrast, lymphocytes from multiple sclerosis patients exhibited significantly reduced suppression (1.5%), and in 80% of cases failed to suppress at all. The degree of suppression increased slightly with age of the patient but did not vary with the clinical stage of disease. There was no apparent genetic restriction of suppressor activity. Although specificity of this phenomenon for measles virus has not been established, no differences in the responses of lymphocytes from normal or multiple sclerosis patient donors were found with subacute sclerosing panencephalitis, Sendai, canine distemper, mumps, or influenza viruses. Supernates of measles-treated lymphocytes from normal donors possessed both suppressive and antiviral activities. Both activities were resistant to pH 2 treatment and were neutralized by an anti-human leukocyte interferon antiserum, strongly suggesting that interferon (probably type I) was the mediator of suppression. Consistent with their inability to suppress concanavalin A responses, lymphocytes from multiple sclerosis patients failed to produce significant amounts of interferon in response to measles challenge in vitro. These results extend previous observations that multiple sclerosis patients are unable to respond appropriately to measles virus antigen in vitro.