Abstract

Peripheral lymphocytes from 13 Type 1 diabetic patients (age 28 +/- 11 (+/- SD) years) were studied at diagnosis, and 1 month and 7 months later. The lymphocytes were labelled with phycoerythrin-conjugated anti-HLA-DR antibody and/or fluorescein-conjugated OKT4 or OKT8 antibody, and then studied using a double channel flow-cytometer. The overall percentage of activated T-lymphocytes (CD4+ + CD8+ cells) was (mean +/- SE) 3.1 +/- 0.5% at diagnosis, 2.1 +/- 0.3% at 1 month and 2.2 +/- 0.5% at 7 months test. The percentages at diagnosis and 1 month were higher than in 12 healthy control subjects (1.0 +/- 0.2%, p less than 0.001 and p less than 0.01, respectively). Among the CD4+ cells the percentage of activated cells fell from diagnosis (2.8 +/- 0.7%), to 1 month (1.5 +/- 0.3%, p less than 0.05), and 7 months (1.5 +/- 0.4%, p less than 0.05), whereas among the CD8+ cells they remained unchanged (3.3 +/- 0.6, 2.5 +/- 0.5 and 3.1 +/- 0.6%). The percentage of activated CD4+ cells at diagnosis, and of CD8+ cells at all times, were higher (p less than 0.02) than in control subjects (CD4+, 0.8 +/- 0.2%; CD8+, 1.2 +/- 0.2%). In conclusion, the activated T-lymphocytes present in Type 1 diabetic patients at diagnosis are equally increased among CD4+ and CD8+ cells, but after 7 months the increase is predominantly in CD8+ cells.