Decreased bradykinin binding sites in fibroblasts from progressive systemic scleroderma.

The numbers of bradykinin receptors (BK-R) in cultured dermal fibroblasts from patients with progressive systemic sclerosis (PSS) and from healthy controls were measured using a receptor binding assay. The numbers of BK-R were significantly fewer in PSS fibroblasts than in control fibroblasts (P < 0.02). However, no differences in affinity were observed in BK-R between PSS and control fibroblasts. The BK-R mRNA levels were determined in PSS and control fibroblasts by Northern blot hybridization using BK-R cDNA, but no significant differences were found. These findings suggest that the decrease in BK-R in PSS fibroblasts might occur during a posttranslational step.