Studies on endothelial cell cytotoxic activity in sera of patients with progressive systemic sclerosis, Raynaud syndrome, rheumatoid arthritis, and systemic lupus erythematosus.

Abstract

Using human umbilical cord endothelial cell cultures and a modified 3HTdR uptake technique, endothelial cell cytotoxic activity (ECA) has been demonstrated in sera of 95/130 patients with progressive systemic sclerosis (PSS), 14/20 patients with Raynaud syndrome (RS), 52/153 rheumatoid arthritis (RA), and 47/113 systemic lupus erythematosus (SLE) sera. ECA could be enriched by gel filtration from PSS sera in a molecular weight range of 5 k daltons. ECA was partially associated with serum proteins, mainly in the albumin containing fraction, albeit at a lower level of activity. In PSS, no relationship of ECA to the type of skin involvement was observed. ECA appears to be a low molecular weight mediator of, as yet, unknown origin.