Circulating CD8+CD56-perforin+ T cells are increased in multiple sclerosis patients.

Relapsing–remitting multiple sclerosis (RRMS), secondary progressive (SP)MS and primary progressive (PP)MS patients showed higher percentages of circulating CD8+CD56−perforin+ T cells than controls whereas only relapsing RRMS and PPMS patients showed higher perforin expression in CD8+CD56− T cells than controls. MS patients with EDSS ≥3 showed higher percentage of CD8+CD56−perforin+ T cells than patients with EDSS <3 and controls whereas patients with EDSS <3 showed higher percentage of this T cell subpopulation than controls. Our data show that MS is characterized by a dysregulation of CD8+CD56−perforin+ T cells that may play a role in the development of disability.