The association between multiple sclerosis and Epstein-Barr virus infection could involve Epstein-Barr virus-specific T cells, provided that these T cells get access to the intrathecal compartment. We report that CD4+ T cells from the cerebrospinal fluid of six out of six multiple sclerosis patients, and four out of six patients with other neurological diseases, recognized autologous B cells transformed with Epstein-Barr virus. The cerebrospinal fluid T-cell responses were predominantly HLA-DR restricted. These T cells did not recognize B cells activated through stimulation of CD40 or the inducible autoantigen alphaB crystalline. These findings support that the immunological response to Epstein-Barr virus could contribute to the pathogenesis of multiple sclerosis.