Diabetes, Vol 44, Issue 12 1414-1419, Copyright © 1995 by American Diabetes Association
Aberrant activation of CD8+ T-cell and CD8+ T-cell subsets in patients with newly diagnosed IDDM
B Hehmke, D Michaelis, E Gens, F Laube and KD Kohnert
Department of Experimental and Clinical Endocrinology, University of Greifswald, Karlsburg, Germany.
Two- and three-color cytofluorimetric techniques were used to study the
expression patterns of the activation antigen HLA-DR on peripheral blood
immunoregulatory T-cells from 25 patients with newly diagnosed
insulin-dependent diabetes mellitus (IDDM) and 14 age- and sex-matched
control subjects. The mean percentage of total activated (CD3+HLA-DR+)
T-cells was significantly elevated in the IDDM group compared with the
control group (P < 0.001). In control subjects, basal activation of CD4+
and CD8+ lymphocytes accounted for the low percentage levels of activated
T-cells. In contrast, the majority of IDDM patients showed an unbalanced
activation of CD4+ and CD8+ lymphocytes with predominant activation of the
CD8+ lymphocyte subset. The composition of the activated T-cell fraction
was dependent on the composition of the total (activated + nonactivated)
T-cell population, as indicated by the positive correlation between the
CD4+/CD8+ T-cell ratios in these two cell populations (r = 0.714; P <
0.001). Excessive activation of CD8+ T-cells was attributable to similar
increases in the proportions of CD8+ CD45RA+HLA-DR+ (naive) and
CD8+CD45RA-HLA-DR+ (memory) cells. Analysis of the CD11b-defined subsets
revealed predominant activation of CD8+ CD11b- (cytotoxic) T-cells; CD8+
CD16+ HLA-DR+ natural killer cells were unchanged. The distribution of
HLA-DR+ cells among subsets of CD4+ T-cells differed from the pattern in
the CD8+ population in that selective activation of CD4+ CD45RA- (memory,
helper-inducer) cells accounted for the small increase in activated CD4+
cells.(ABSTRACT TRUNCATED AT 250 WORDS)