The significance of antinuclear and DNA antibodies in cryptogenic fibrosing alveolitis.

The roles of antinuclear and DNA antibodies in the pathogenesis of cryptogenic fibrosing alveolitis were investigated in 53 patients. Twenty-two patients who had antinuclear antibodies detected in their serum had a significantly higher proportion of women, a higher prevalence of Raynaud phenomenon and digital vasculitis, and higher erythrocyte sedimentation rates, paralleled by raised serum globulin and IgG levels, than patients with no antinuclear antibodies detected. Serum antibodies to double-strand DNA (DS-DNA), assayed by a Farr binding technique, were significantly raised in 25% of patients with cryptogenic fibrosing alveolitis. Serum binding of single-strand DNA (SS-DNA) was greatly increased in all the patients with cryptogenic fibrosing alveolitis, achieving levels similar to those found in systemic lupus erythematosus. Serum DS-DNA binding correlated with IgA levels but not with disease activity. Thus, unlike in systemic lupus erythematosus, antibodies to DS-DNA and SS-DNA with their capacity to form immune complexes are unlikely to be of major importance in the pathogenesis of cryptogenic fibrosing alveolitis.