The aim of this study was to assess changes in selected peripheral blood lymphocyte subsets in children and adolescents with newly diagnosed type 1 diabetes mellitus (DM) and determine the correlation between these changes and other immunological markers. The study involved a group of 39 patients aged 2-14 years and a control group. The number of T- and B-lymphocytes and the number of CD4, CD8, CD4/HLA-DR, CD8/HLA-DR, CD5/CD20 subsets were measured by flow-cytometry using monoclonal antibodies. Islet cell antibodies (ICA) and antibodies to glutamic acid decarboxylase (GADA) were assessed. In both the diabetic and control groups the number of T-and B-lymphocytes were within normal limits. In patients with DM, the percentage of CD5+/CD20+ cells was significantly increased compared with the control group (p < 0.0001). ICA were positive in 80% of patients and GADA in nearly 65%. A positive correlation between the CD5/CD20 subset and ICA and GADA was found. In patients with a high percentage of CD5+/CD20+ lymphocytes, a higher percentage of activated subsets (CD4/HLA DR and CD8/ HLA DR) was detected.
In conclusion: CD5/ CD20 lymphocyte subsets are a good additional marker of autoimmunological processes in DM.