CIRCULATING IMMUNE-COMPLEXES IN PATIENTS WITH CRYPTOGENIC FIBROSING ALVEOLITIS

Abstract

Increased Clq [q fragment of complement component 1] binding levels were obtained in serum from 21 (50%) of 42 patients with cryptogenic fibrosing alveolitis (CFA) suggesting the presence of circulating immune complexes. There was a low frequency of positive results using a number of other tests for circulating immune complexes. The increased Clq binding levels were observed in 6 (35%) of 17 patients with lone lung involvement and in 15 (60%) of 25 patients with extrapulmonary connective tissue disorders. There was an especially close correlation between arthritis and elevated Clq binding. A strong correlation between Clq binding levels and levels of circulating rheumatoid factor (RF) and IgG and enhancement in macrophage radiobioassay tests using RF [rheumatoid factor]-containing sera. RF might be involved in the circulating immune complexes in these patients. DNAase pre-treatment of sera did not influence the findings and there was no correlation between Clq binding and levels of immunofluorescent ANA [antinuclear antibody], C-reactive protein levels or platelet counts. A weak correlation between Clq binding and erythrocyte sedimentation rates and slightly lower binding levels in treated than untreated patients with lone CFA suggested that binding levels may give some indication of disease activity and may be influenced by treatment.