Dear Editor,
External cytokines produced by cells of the innate immune system induce the differentiation of CD4+ T cells into helper T cell subsets with distinct functions and cytokine profiles.Apart from TH1 and TH2 cells a third subset of helper T cells has been described,which is characterized by increased expression of IL-17A,IL-17F,IL-21 and IL-22 (TH17 cells).TH17 cells are involved in the clearance of infectious agents and contribute to the expression of tissue damage in patients with autoimmune diseases including multiple sclerosis and systemic lupus erythematosus (SLE) (Kom et al.,2009).