Immunopathology, rheumatic features, and therapy of sarcoidosis.

A spectrum of immune alterations underlies the clinical syndrome of sarcoidosis. There is an increase in the number of helper T lymphocytes at sites of disease activity. Both macrophages and T cells are in a state of activation. Inflammation in sarcoidosis probably attracts specific T lymphocytes, as has been shown by the preferential usage of the C beta 1 elements of the T-cell antigen receptor. Acute sarcoid arthritis is distinctly different in its HLA association and clinical outcome than chronic sarcoid arthritis. Muscle and osseous lesions are well described but are usually asymptomatic. Childhood sarcoidosis may be confused with juvenile rheumatoid arthritis because of the similarity of eye and articular involvement. Nonsteroidal anti-inflammatory drugs and corticosteroids are effective for most patients. Hydroxychloroquine, methotrexate, and cyclosporine have been tried with success in patients with refractory sarcoidosis.