Reduced T lymphoid colony growth in patients with progressive systemic sclerosis and rheumatoid arthritis.

T cell colony growth in semisolid medium, a sensitive indicator of disease-associated lymphoycte defects, was found to be depressed in patients with PSS and RA. In both disorders, more pronounced abnormalities were observed after incubation with suboptimal concentrations of the polyclonal mitogen PHA. Depletion of monocytes by adherence to plastic surfaces of addition of the prostaglandin synthetase inhibitor indomethacin did not correct the growth abnormality observed in PSS. Reduced colony-forming activity could not be attributed to serum inhibitory factors. The cellular abnormalities detected in patients with these connective tissue diseases were less pronounced than those found in SLE patients.