Study on lymphocyte subsets and NK cell function in patients with dilated cardiomyopathy.

An acquired defect or damage of a subpopulation of suppressor T lymphocytes is reported in connection with autoimmune diseases. In the present study, the role of immunity was examined in 7 patients with dilated cardiomyopathy (DCM). The frequency of lymphocyte subsets using monoclonal antibodies and natural killer (NK) cell activity was evaluated to determine whether DCM patients had lymphocyte abnormalities that would support the hypothesis that the pathological mechanism of DCM is an immune disturbance. The peripheral lymphocyte counts were significantly lower in patients with DCM and higher in patients with ischemic heart disease (IHD) than in normal controls (NC) (p less than 0.01). The percentage of T cells, B cells, OKT4 and OKT8 positive cells was not statistically different among the three groups studied here, whereas the percentage of T gamma cells was significantly reduced in DCM patients (p less than 0.05). NK cell functional activity as tested in DCM and IHD patients was frequently deficient (22.1 +/- 19.3% in DCM, 13.8 +/- 3.0% in IHD, 37.4 +/- 12.7% in NC). Our results suggest that an imbalance in cellular immune reactions partly explain the pathogenesis of DCM.