Serologic factors in idiopathic diffuse interstitial pulmonary fibrosis

In nineteen patients with idiopathic diffuse interstitial pulmonary fibrosis, the serum of five (27 per cent) revealed latex-fixing macroglobulins. In four there were accompanying transient arthritic manifestations which were not readily classifiable. A comparable incidence of latex-fixing reactivity has been demonstrated in the serum of patients not afflicted with rheumatoid arthritis suggesting that this finding is not specific for any one disease. It is proposed that consideration of the diagnosis of rheumatoid lung be reserved for the rare combination of pulmonary fibrosis and unequivocal rheumatoid arthritis.