Secretion of plasminogen activator by rheumatoid and nonrheumatoid synovial cells in culture.

The secretion of plasminogen activator by human synovial cultures established from explants was studied. Thirteen cultures established from patients with rheumatoid disease were hyposecretors of plasminogen activator. Seven cultures derived from patients with nonrheumatoid joint disorders all secreted high levels of this enzyme. Rheumatoid and nonrheumatoid cells contained comparable levels of intracellular activator. It is suggested that the secretion of plasminogen activator is a function of normal synovium and that a defect in this function in the rheumatoid synovium perpetuates the inflammatory process.