Effects of D-penicillamine on circulating protein complexes in rheumatoid arthritis and primary biliary cirrhosis.

Not immunosuppressive in conventional test systems, D-penicillamine causes minor reductions in Ig levels and occasionally induces IgA deficiency. Rather limited evidence indicates actual decline in immune complexes; more data show reductions in levels of 9S IgG and alpha1-antitrypsin-IgA complexes. On the other hand, a number of instances of toxic reactions are most readily explained on the basis of autoimmunization. Changes in redox equilibrium, haptenization, and influence on T cell function are possible mechanisms.