Systemic Lupus Erythematosus Induced by Procaine Amide

Summary A disease resembling spontaneous systemic lupus erythematosus (SLE) and lupus nephritis occurred in a 65‐year‐old man with cardiac arrhythmia given procaine amide. The features included arthralgia, fever, a rheumatoid nodule, glomerulonephritis with deposits of immune complexes in the kidney and high titres of antinuclear antibody. Prednisolone induced a remission but a subsequent pulmonary embolus was fatal. It is not known how auto‐immune disease is induced by drugs, particularly procaine amide, nor why man is susceptible whereas laboratory animals are not. A better understanding of SLE induced by procaine amide and certain other drugs could clarify causal mechanisms of auto‐immune disease in general.