Increased level of HLA-DR-expressing T lymphocytes in peripheral blood from patients with idiopathic dilated cardiomyopathy.

Peripheral blood leukocytes from 14 patients with idiopathic dilated cardiomyopathy (IDC), 13 patients with ischemic congestive heart failure, and 12 controls were characterized using different antibodies. The proportions of B lymphocytes, T lymphocytes, and the different T lymphocyte subsets were estimated. No difference between the three groups could be found in the various T and B cells subpopulations. Using a two-color direct immunofluorescence technique, the occurrence of circulating T helper/inducer (Leu-3a) and T cytotoxic/suppressor cells (Leu-2a) expressing HLA-DR antigens was examined. Only IDC patients demonstrated increased levels of HLA-DR-positive T helper/inducer cells (2.8 +/- 2.4%) and T cytotoxic/suppressor cells (2.8 +/- 2.3%) as compared with patients with ischemic congestive heart failure (0.8 +/- 0.7 and 1.0 +/- 1.0%, respectively) and controls (0.6 +/- 0.5 and 0.9 +/- 0.6%, respectively). When individual IDC patients were studied, 4 out of 12 patients had an increased level of HLA-DR-expressing T helper/inducer cells, and 7 out of 12 patients had elevated HLA-DR-positive T cytotoxic/suppressor cells. The findings suggest that activation of the T lymphocytes may be of importance in the pathogenesis of IDC.