Parkinsonism in Caplan's syndrome.

Parkinsonism is a rare feature of immunological diseases. We describe a 67-year-old man with Caplan's syndrome (CS) and parkinsonism. CS is an immunologic disease characterised by the presence of rheumatoid arthritis associated with a specific form of pneumoconiosis. Parkinsonism as a manifestation of involvement of the central nervous system in this condition has never been reported. Following immunosuppressive treatment both the CS and the parkinsonian signs and symptoms showed a marked improvement. The role of immune mechanisms in these parkinsonian syndromes is discussed.