Pathogenetic mechanisms of interstitial pulmonary fibrosis in patients with serum antinuclear factor: A histologic and clinical correlation

The clinical features and histologie findings in the lung biopsy specimens of six patients with idiopathic interstitial pulmonary fibrosis and serum antinuclear factor are presented. Patients with diseases commonly associated with interstitial pulmonary fibrosis and/or antinuclear factor, such as systemic lupus erythematosus, rheumatoid arthritis or scleroderma, as well as patients with arthritis or positive lupus erythematosus cell tests, were excluded. The histologic changes were characterized by the coexistence of well-established fibrosis in the alveolar walls and/or the peribronchiolovascular tissues and multiple foci of predominantly lymphocytic infiltrates with some plasma cells and eosinophils. The transition from the lymphocytic infiltrates into fibrosis was evident in most of the biopsy specimens, and the presence of lymphoid follicles with germinal center formation was one of the prominent features. These histologic findings, the presence of antinuclear antibodies, the history of preceding virus-like respiratory tract infections in three of the six patients, facial hyperpigmentation in one, discoid lupus lesions of the scalp in another and renal involvement in a third patient, suggest that the pulmonary lesions in these patients resulted from immune reactions to some agents not unlike those seen in systemic lupus erythematosus.