Background: D-penicillamine can induce autoimmune disease, particularly in patients with associated immune disorders.
Case report: A 67-year old woman who had been taking D-penicillamine for 15 months for rheumatoid arthritis was hospitalized due to the development of a bullous eruption and proximal muscle deficiency. Search for intercellular antisubstance antibodies in serum was negative. The skin biopsy histology revealed intra-epidermal cleavage in the mucosal body and direct immunofluorescence revealed epidermal frame-marking with anti-IgG and anti-C3 antibodies. Other tests revealed muscular cytolysis, and anti-acetylcholine receptor antibodies. The electromyogram showed neuromuscular block without muscle deficiency and muscle biopsy showed moderate myositis. D-penicillamine was interrupted and was followed by cure of the pemphigus and aggravation of the myositis, requiring high-dose systemic corticosteroid therapy.
Discussion: This patient developed D-penicillamine induced pemphigus, a rather frequent observation. The desmoglein immunolabelling favored drug-induced pemphigus and the course was rapidly favorable after withdrawal. Pemphigus had developed simultaneously with signs of myasthenia and polymyositis. Polymyositis and myasthenia are also known complications of D-penicillamine therapy. The association of these three complications suggests that D-penicillamine can unmask certain antigens or have an immunomodulator effect.