Evaluation of suppressor immune regulatory function in idiopathic congestive cardiomyopathy and rheumatic heart disease.

Several diseases with autoimmune features have recently been shown to be characterised by defects in suppressor cell immune regulation. Aberrant immune mechanisms of primary importance have been sought but not yet demonstrated for idiopathic congestive cardiomyopathy and rheumatic heart disease. We tested whether defective immunoregulatory function might explain certain features of these diseases. Peripheral blood mononuclear cells from patients with both diseases showed normal proliferative responses in the mixed leucocyte reaction. Concanavalin A induced similar suppressor activity, quantified in mixed leucocyte reaction as a suppression index, among control subjects, patients with rheumatic heart disease, and patients with idiopathic congestive cardiomyopathy. Similarly, patient serum supported induction of suppressor activity in normal leucocytes equal to that of control serum. A chronic immunoregulatory defect thus does not appear necessary for the development of idiopathic congestive cardiomyopathy or rheumatic heart disease.