Urinary protein 1/Clara cell 16 concentrations and lung functions in male subjects with pneumoconiosis

Background Protein 1 (P1)/Clara cell 16kDa protein (CC16, previously named CC10), a potentially immunosuppressive protein secreted by non-ciliated cells of the tracheobronchial epithelium, has been found to be a new useful lung-specific biomarker in several pathological lung conditions. Particularly, urinary P1 (uP1) may reflect the altered lung functions in pneumoconiosis. Methods We investigated the relationship between uP1 values and lung functions in 31 non-smoking pneumoconiotic males (mean age 73 years) with a history of dust exposure work in shipbuilding. The protein was measured using an originally prepared enzyme-linked immunosorbent assay system. The forced expiratory volume in 1 s % (FEV 1.0 %) and % vital capacity (%VC) were tested with a spirometer. Results The mean values of uP1 were 4.62±4.82 (mean±standard deviation) ng/mol creatinine. A univariable correlation test showed a significant positive correlation between uP1 and %VC (r= 0.356, P= 0.049). Also, a multiple regression analysis, when adjusted for age, disease duration, FEV 1.0 % and %VC, showed a significant correlation of uP1 with %VC (β= 0.467, P= 0.030). Conclusion The results suggest that a decreased uP1, corroborated by a decreased %VC, may be the result of damage to secretory cells. Measurement of uP1 may become a possible index of fibrotic changes in pneumoconiosis.