Immune activation and T cell subset abnormalities in circulation of patients with recently diagnosed type I diabetes mellitus.

The peripheral blood lymphocytes from patients with insulin-dependent diabetes mellitus (IDDM) and healthy controls were analysed for the HLA-DR+, interleukin-2 receptor-positive (IL-2R+) activating antigens, and for CD45R+ and CDw29+ subsets from the purified CD4+ and CD8+ T cells populations. Patients with IDDM had an increased percentage of HLA-DR+ and IL-2R+ cells in both CD4+ and CD8+ T cells. However, the percentage of CD4+ CD45R+ suppressor/inducer T cells were decreased and CD4+ CDw29+ helper/inducer T cells increased in all patients with IDDM, compared with healthy controls. Thus, IDDM patients exhibit a deficiency in the CD4+ CD45R+ suppressor/inducer T cell subsets, which is probably related to the autoimmune phenomenon in this disease. In contrast, the percentage of CD8+ CDw29+ T cell subsets showed no major differences between patients with IDDM and controls. An alteration in the CD4+ CD45R+ and CD4+ CDw29+ T cell subsets appears to be a characteristic feature, and may relate to the impaired cell-mediated immunity in IDDM. These data provide new evidence for T cell dysregulation in IDDM.