T-lymphocyte subsets as noninvasive markers of cardiomyopathy.

Fifty-eight patients with symptomatic congestive heart failure were examined for T-lymphocyte subsets in the peripheral blood using two-color laser flow cytometry as a noninvasive diagnostic procedure. The final diagnosis established by catheterization and endomyocardial biopsy were dilated cardiomyopathy (DCM, n = 24), myocarditis (MC) by the Dallas criteria (n = 12), and coronary heart disease (CHD, n = 16). The CD8+CD11- (cytotoxic T) subset was significantly low in patients with DCM (13.9 +/- 4.4 vs. controls, p less than 0.05) in comparison with MC (20.7 +/- 10.9) and CHD (22.3 +/- 5.9). Moreover, the CD4+2H4+ (suppressor/inducer T) subsets were higher in patients with DCM (27.3 +/- 6.9 vs. controls, p less than 0.01) than in those with MC (17.3 +/- 7.8) and CHD (15.6 +/- 7.9). The CD4/CD8 and CD4+2H4+/CD8+CD11- ratio were examined and compared with those of normal controls (NC n = 16). The CD4+2H4+/CD8+CD11- ratio was clearly higher in patients with DCM (2.2 +/- 0.9 vs. controls, p less than 0001) than in those with MC (1.1 +/- 0.6) CHD (0.9 +/- 0.7). A CD4+2H4+/CD8+CD11- ratio of greater than 1.6 was considered to facilitate diagnosis of dilated cardiomyopathy with 79% sensitivity and 70% specificity. There was no significant increase in the ratios between MC and CHD. However, the proportion of the CD8+Leu7+ (natural suppressor) subset of circulating T lymphocytes in patients with MC was statistically higher (19.1 +/- 6.3% vs. controls, p less than 0.05) than in DCM or CHD. An elevated ratio of CD4+2H4+/CD8+CD11- among peripheral blood lymphocytes may thus be a useful marker for differential diagnosis of dilated chronic cardiomyopathy from myocarditis and coronary heart disease.