Two-color flow cytometry analysis of activated T-lymphocyte subsets in type I diabetes mellitus.

We addressed the question of whether newly diagnosed type I (insulin-dependent) diabetes mellitus patients showed an increased number of DR (la+) T-lymphocytes compared with nondiabetic siblings and normal control subjects. Two-color flow cytometry measurements of peripheral-blood lymphocytes showed a slight but statistically significant increase in DR+ T-lymphocytes in diabetic subjects as well as the nondiabetic sibling control compared with the normal control subjects. This difference was not present in long-term-diabetic subjects. Thus, in addition to minor changes in this lymphocyte subset in peripheral blood, the sibling data demonstrate a lack of specificity for the disease; therefore, these measurements are probably of limited diagnostic usefulness.