[Serum type III procollagen peptide in diagnosis of lung fibrosis due to silicosis and bleomycin toxicity].

Early diagnosis of lung fibrosis has been hampered by the lack of a simple, convenient and specific test. Measurement of serum type III procollagen peptide (Pro (III)-N-P) by the method originally developed by Rohde et al. has been shown to be useful for the evaluation of hepatic fibrosis. The present study, therefore, was carried out to investigate the usefulness of the measurement of Pro (III)-N-P in 24 patients with lung fibrosis due to silicosis, and in 7 patients with malignant lymphoma treated with bleomycin, antitumor antibiotic which has the adverse effect of producing fibrosis in the lung. The normal value of the peptide in adults was 8.60 +/- 2.35 ng/ml (mean +/- SD; n = 68) and the normal upper level was set at 13.4 ng/ml (mean +/- 2SD). Patients with silicosis had significantly but not extremely high levels of the peptide and 25% of the patients showed abnormally high values. The level of Pro (III)-N-P was associated with neither physical findings, chest X-p findings nor pulmonary function test results. Three of 7 patients showed increased levels during treatment with bleomycin. In one case, a total dose of 120 mg of bleomycin for over a period of 14 months markedly increased the level of the peptide. These observations suggest that the determination of Pro (III)-N-P may be useful for the detection of lung fibrosis.