Carboxyterminal propeptide of type I procollagen in ELF: elevation in asbestosis, but not in pleural plaque disease

Markers of collagen metabolism may possibly be used in the assessment of pu lmonary involvement in asbestosis-related pulmonary diseases. In this study the levels of the carboxyterminal propeptide of type I procollagen (PICP) and the aminoterminal propeptide of type III procollagen (PIIINP) were eval uated in bronchoalveolar lavage fluid (BALF), epithelial lining fluid (ELF) and serum from patients with asbestos related pulmonary and pleural involv ement. Forty-two consecutive patients,vith occupational exposure to asbestos fibre s who underwent bronchoscopy and bronchoalveolar lavage (BAL) at the time o f the diagnosis were investigated. Five patients were diagnosed as having a sbestosis, while 37 showed no parenchymal involvement. Of the latter group, 25 had pleural plaques, while 12 had no detectable changes in chest radiog raphs. The patients were followed-up for an average of 7 yrs. The PICP in BALF and ELF was detectable in all patients with asbestosis and in 8/ 37 subjects without parenchymal involvement, The levels of PICP in B ALF and ELF were significantly higher: in the asbestosis group compared to the patients without asbestosis (9.8+/-1.8 mu g . L-1 versus 0.6+/-1.3 mu g . L-1, p<0.001 and 488.9+/-208.8 mu g . L-1 versus 22.6+/-50.6 mu g . L-1, p<0.001, respectively). Only 1 patient with asbestosis and 3 patients with out parenchymal involvement had detectable levels of PIIINP in BALE The ser um levels of PICP and PIIINP did not differ between the patients with asbes tosis and those with exposure to asbestos fibres,without asbestosis and wer e within the normal range. None of the 37 patients exposed to asbestos fibr es,without parenchymal involvement at the baseline developed asbestosis dur ing the follow-up period of 7 yrs. In conclusion, the data show that the carboxyterminal propeptide of procoll agen type I, but not the aminoterminal propeptide of type III procollagen i s highly elevated in bronchoalveolar lavage fluid and epithelial lining flu id in patients with asbestosis, but not in those,without parenchymal involv ement. This suggests that the determination of carboxyterminal propeptide o f procollagen type I in bronchoalveolar lavage fluid could be used as a mar ker of parenchymal involvement in patients exposed to asbestos fibres.