DEFECTIVE INVITRO SUPPRESSOR CELL-FUNCTION IN IDIOPATHIC CONGESTIVE CARDIOMYOPATHY

Because abnormalities of the immune system may be involved in the pathogenesis of idiopathic congestive cardiomyopathy (ICCM), suppressor cell function in patients with ICCM was studied. Previously described in vitro techniques were modified for optimal demonstration of concanavalin (Con) A-inducible suppressor activity by peripheral blood mononuclear cells (PBM). Baseline responses in the mixed luekocyte reaction (MLR) were similar for PBM from 16 normal subjects, 8 patients with end-stage coronary artery disease (CAD) and 18 patients with ICCM. In the presence of autologous, Con A-treated PBM, MLR responses were significantly suppressed for normals (geometric mean disintegrations/min decreasing from 36,308 to 4677; P < 0.001) and for CAD patients (25,703 decreasing to 5011; P < 0.001). Autologous, Con A-treated PBM from patients with ICCM failed to suppress MLR responses (30,902 increasing to 44,688; P < 0.005). Similar results were observed in mitogen stimulation experiments. Con A-treated PBM from a normal subject suppressed the MLR response of PBM from an ICCM patient. The failure of Con A-treated PBM to inhibit in vitro immune responses may reflect an in vivo defect in suppressor cell function in patients with ICCM.