CD8A and multiple sclerosis: Tissue infiltration of CD8+ T cells has been described in many autoimmune diseases like type I diabetes (pancreas),17 multiple sclerosis (cortical lesions)18 and RA (synovial tissue).19, 20 In RA, the production of cytolytic proteins by CD8+ T cells has been implicated to be critical for ectopic germinal centre formation in synovial tissue.21