Flow-cytometric analysis of lymphocyte subsets in relation to virus infections at the onset of type 1 (insulin-dependent) diabetes.

Alterations in T-lymphocyte subsets have been connected to the autoimmune pathogenesis of Type 1 (insulin-dependent) diabetes. In this study peripheral blood lymphocytes were analysed by flow cytometry using OKT3, OKT4, OKT8, anti-HLA-DR, anti-IL-2 receptor and anti-membrane immunoglobulin antibodies in newly diagnosed Type 1 diabetic children, their healthy siblings and healthy control children. The results were compared to the occurrence of serologically verified recent virus infections, some of which can induce lymphocyte subset alterations and have also been connected with the onset of diabetes. In most diabetic patients the amounts of OKT3, OKT4, OKT8 and membrane-Ig-positive cells were within the normal range. Exceptional helper/inducer and suppressor/cytotoxic T cell profiles were observed in a few patients, most of whom had serologically verified recent Epstein-Barr, rubella, mumps or Coxsackie B virus infection. In addition, increased numbers of activated IL-2 receptor-positive cells were observed in the patient group. These results suggest that significant lymphocyte subset alterations are not characteristic of Type 1 diabetes but can occasionally be induced by recent virus infections in newly diagnosed patients. However, the slight increase in activated lymphocytes could reflect the activation of cellular immune systems to the autoantigens in the pancreas.