Respiratory involvement in systemic lupus erythematosus. A clinical and immunological study.

Thirty patients fulfilling conventional criteria for systemic lupus erythematosus and who presented with extensive pleural and pulmonary involvement were studied retrospectively. Four overlapping patterns of respiratory disease were identified and observations were made on their clinical presentation, radiographic abnormalities and response to treatment. A low incidence of severe renal disease was found in this series of patients and this was in keeping with the general finding of low serum binding using native DNA in a globulin Farr-binding technique (greater than 20% binding in only 4/21 (19%) of the series) and normal or elevated serum complement (C3) levels. Precipitating antibody detected by double diffusion and counter-current immunoelectrophoresis and probably reacting in most cases with single-stranded DNA was, however, detected in 66% of pretreatment serum samples tested. This evidence supports the idea that different types of anti-nuclear antibody may be associated with different clinical manifestations seen within a group of patients who broadly fulfil the criteria for SLE.