PREDICTIVE VALUE OF LYMPHOCYTE ANTIBODIES FOR THE APPEARANCE OF DIABETES IN BB RATS

Lymphocyte antibodies have been described in autoimmune disorders, inc luding insulin-dependent diabetes mellitus (IDDM). We have developed a quantitative method to measure autoantibodies directed against T-lymp hocytes, based on two-color fluorescence labeling of Wistar mononuclea r cells and analysis of fluorescence by flow cytometry. The lymphocyte antibody levels were determined retrospectively in the serum of 73 BB and 18 Wistar rats. We demonstrated the binding of the lymphocyte aut oantibodies of both CD4(+) and CD8(+) T-cells. Lymphocyte antibodies w ere present in 90% of the BB rats at diabetes onset, compared with 11% of the Wistar rats. At 75 days of age, 83% of the BB rats, which late r became diabetic, were positive for the lymphocyte antibodies, compar ed with 15% of their littermates who maintained a normal glucose toler ance. In all cases, the antibodies were of the immunoglobulin M isotyp e. We conclude that lymphocyte antibodies are present before diabetes onset and, using this method, that their presence can predict the deve lopment of diabetes with a sensitivity of 83% and a specificity of 85% in BB rats.