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

SUMMARY 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 cell 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+CD45R+ and 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.