Humoral immunity and lymphocyte subpopulations in patients with dilated cardiomyopathy

The incidence of serum organ and non-organ specific autoantibodies, the peripheral blood lymphocyte blastogenic response to phytohaemagglutinin, concanavalin A and pokeweek mitogen, and the surface markers of peripheral T and B lymphocytes were studied in 15 patients affected by coronary artery disease and in 21 patients with dilated cardiomyopathy. In the latter group there was a significantly impaired blastogenic response to concanavalin A with respect to both the normal control group and patients with coronary artery disease (P less than 0.01). The percentage of peripheral blood lymphocytes with cytotoxic/suppressor activity was also reduced in patients with dilated cardiomyopathy in comparison to normal subjects and patients with coronary artery disease (P less than 0.01 and P less than 0.05, respectively). These data may reflect an in vivo defect in suppressor cell function in patients with dilated cardiomyopathy.