Long-term study on T lymphocyte subsets in newly diagnosed type 1 diabetes mellitus.

T lymphocyte subsets in peripheral blood from 16 newly diagnosed type 1 diabetic children were studied prospectively at four time intervals: as soon as possible after diagnosis and 1, 4 and 12 months later. T lymphocyte subsets were analysed using monoclonal antibodies and counted by cytofluorimetry. The percentage of T lymphocytes (OKT3+ cells) did not change at the four study times. The percentage of helper/inducer T cells (OKT4+ cells) was high at the diagnosis (43.1 +/- 2.1%), but decreased after 1 and 4 months with no difference in the control values. The percentage of suppressor/cytotoxic T lymphocytes (OKT8+ cells) was low at the diagnosis, but increased after 1 and 4 months. The OKT4/OKT8 ratio was 2.31 +/- 0.22 at the diagnosis study, decreasing to 1.83 after 1 month, compared with 16 sex- and age-matched control children. The high percentage of helper/inducer T lymphocytes and low number of suppressor/cytotoxic T cells at onset of diabetes favour immune reactions that lead to beta-cell damage.