γδ T-cells alterations in the peripheral blood of high risk diabetes type 1 subjects with subclinical pancreatic B-cells impairment

There is increasing evidence that CD3+ cells bearing gamma delta T-cell receptor (represent the minor subpopulation of the T-cells in the peripheral blood in humans) are involved in autoimmunity development, gamma delta T-cell receptor (TCR)+/CD8+ T-cells have been recently found to play a critical role in the pathogenesis and prevention of autoimmune diabetes in the animal model. The aim of the present study was the estimation the gamma delta T-cell subpopulation levels in the peripheral blood of subjects with preclinical and overt type 1 diabetes and their possible associations with the humoral immunity, metabolic parameters and pancreatic B-cells function. The study was carried out in three groups of subjects: 26 first degree relatives of type 1 diabetes patients (prediabetics) with the combinations of autoantibodies against pancreatic B-cells (ICA, GADA, IA-2A, IAA), 22 patients with a recent onset of type 1 diabetes and age and sex-matched 24 healthy volunteers (control group). A decrease was observed in the absolute numbers and percentages of gamma delta+/CD8+ and gamma delta+/CD8- T-cell subpopulations in peripheral blood in the prediabetics with the impaired first phase of insulin secretion in comparison to relatives with autoantibodies but still with normal B-cells function, patients with clinical diabetes and healthy controls. In conclusion, the study suggests that the gamma delta T-cells play an important role in the development of insulin-dependent diabetes mellitus (IDDM). It is possible that their levels in the peripheral blood could be an additional marker of preclinical detection of the disease, but further prospective studies in high risk of IDDM subjects are needed. (C) 1999 Elsevier Science B.V. All rights reserved.