[Myasthenia induced by D-penicillamine during the treatment of rheumatoid polyarthritis].

Seven cases of myasthenia induced by D-penicillamine treatment of rheumatoid arthritis are presented. The 86 cases published so far are reviewed. The clinical symptoms do not differ from those of the idiopathic form. Progress is rapid and, generally, good. The duration and dosage of the treatment are not involved. The presence of acetylcholine-antireceptor antibodies confirms the autoimmune origin of the condition. Possible mechanisms by which this disorder could be induced are discussed. Investigation of HLA phenotypes suggests that the genetic basis of induced myasthenia differs from that of the idiopathic form (increased prevalence of DR1).