The effect of plasma exchange on synovitis in rheumatoid arthritis.

Eight patients with a severe exacerbation of rheumatoid arthritis were treated by twice weekly plasma-exchange for 3 weeks in order to evaluate the effect of plasma-exchange on synovitis. During the plasma-exchange period, patients remained on the drug regimen they were on at admission to the hospital. Plasma was replaced isovolemically with human, purified plasma protein fraction. Improvement in clinical parameters of synovitis and serological parameters of inflammation occurred in almost all patients. After 6 months the clinical remissions were sustained. Three patients experienced a rebound synovitis and one patient a rebound vasculitis at the end of or just after the plasma-exchange period. The rebound phenomena were moderate and of short duration. Plasma-exchange may exert its beneficial effects by depleting important mediators of injury such a complement fibrinogen and circulating immune complexes, by improving reticuloendothelial function, and by increasing the drug response of the inflammatory target tissue. The role of depletion of circulating immune complexes was not so clear in this study. It is concluded that limited plasma-exchange is an effective means to induce a symptomatic improvement in an acute exacerbation of polyarthritis, without changing the basic therapy and thus avoiding corticosteroid dependency.