Increased calmodulin levels in fibroblasts from progressive systemic sclerosis.

Calmodulin levels in cultured skin fibroblasts from patients with progressive systemic sclerosis (PSS) and healthy controls were measured by their ability to activate cyclic AMP-phosphodiesterase. Calmodulin levels were significantly increased in PSS fibroblasts compared with normal control fibroblasts. The changes in calmodulin content of PSS fibroblasts were also assessed by a radioimmunoassay. These findings suggest that an elevated level of calmodulin may play a role in the pathogenesis of PSS.