Abnormalities within CD4 and CD8 T lymphocyte subsets in type 1 (insulin-dependent) diabetes

Abstract

SUMMARY Abnormalities in the proportions of various T lymphocyte subpopulations have been found in a number of autoimmune diseases. Monoclonal antibodies labelled with various fluorochromes were used here to define the percentages of subsets, and especially to divide CD4+ (helper/inducer) and CD8+ (suppressor/cytotoxic) cells into phenotypic subgroups. Blood samples were analysed from 25 patients (age 10.1±3.7 years) with recently diagnosed insulin-dependent diabetes mellitus (IDDM) and 25 age- and sex-matched control subjects. The percentages of CD4+ cells and CD4+CD45RA+ cells described as naive T helper cells or suppressor/inducers were increased in the IDDM patients (P<0.05 and P<0.05, Student’s t-test, respectively), whereas the percentage of CD4+CD45RA-cells (memory T-helper cells, helper/inducers) was similar in the patients and controls. The percentage of CD8+CD11b+ cells containing suppressor/effector lymphocytes was decreased in the IDDM patients as compared with the controls (P<0.01) but no significant difference was seen in total CD8+ cells. The percentages of CD3+ cells and the proportions of these simultaneously positive for HLA-DR antigen (activated T cells) were also increased in the recent IDDM patients (P<0.001 and P<0.05, respectively), while the proportion of CD20+ B cells was decreased (P<0.05). The findings support the view that disturbed immune regulation occurs in IDDM and indicate that further division of T cell subpopulations may clarify our understanding of the disease process.