Pathophysiology of Type 1 Diabetes Mellitus Genetic predisposition Environmental factors Autoantigens form on insulin-producing beta cells and circulate in the bloodstream and lymphatics Processing and presentation of autoantigen by antigen presenting cells Activation of T helper 1 lymphocytes Activation of T helper 2 lymphocytes IFN-Y IL-2 IL-4 Activation of macrophages Activation of autoantigen Activation of B lymphocytes to with release of IL-1 and TNF-a specific T cytotoxic(CD8cells produce islet cell autoantibodies and anti GAD65 antibodies Destruction of beta cells with decreased insulin secretionPathophysiology of Type 1 Diabetes Mellitus