HIGH-LEVELS OF SOLUBLE IFN-GAMMA RECEPTOR-ALPHA CHAIN IN THE PLASMA OF RHEUMATOID-ARTHRITIS PATIENTS

Soluble receptors for hormones and cytokines have been described. They can serve as natural blockers of their respective ligands. The natura l soluble interferon gamma receptor (sIFN gamma R) has been isolated a nd characterized only in urine. Chromatography of human (hu) plasma fr om rheumatoid arthritis (RA) patients and controls on immobilized hu I FN gamma or antibodies against IFN gamma R alpha chain permitted us to isolate the sIFN gamma R. The receptor isolated from one control is a protein with a molecular weight between 60-67 kDa depending on the pr esence of reducing agents. We detected a significantly higher level of plasma sIFN gamma R in patients with rheumatoid arthritis than in app arently healthy subjects.