PRF1 and autoimmune disease: Several studies have shown a contribution of CD8+ T cells in autoimmune disease through three different mechanisms.8 First, CD8+ effector T cells can contribute to autoimmune disease by increased production of pro-inflammatory cytokines9, 10, 11, 12 or a decrease in regulatory cytokines.13 CD8+ T cells can produce IL-17 (Tc17 cells) and lack production of cytolytic granules like granzyme B and perforin.14 Therefore, the contribution of Tc17 cells to disease progression is mainly through pro-inflammatory cytokine production.