Effects of potassium para-aminobenzoate on growth and macromolecule synthesis in fibroblasts cultured from normal and sclerodermatous human skin, and rheumatoid synovial cells.

Potassium para-aminobenzoate was tested for its ability to affect growth and macromolecule synthesis in vitro using fibroblasts from normal human skin, from affected skin of patients with scleroderma, and rheumatoid synovial cells. The proliferation of all 3 cell types showed dose-dependent inhibition beginning at about 3000 microgram/ml. Acid mucopolysaccharide secretion by rheumatoid synovial cells and scleroderma fibroblasts was inhibited even at 100 microgram/ml, which is within the therapeutic range, and there was over 50% inhibition at 5000 microgram/ml. Collagen synthesis by several different strains, was not affected, despite the use of a range of concentrations and treatment times.