Elevated serum procollagen III aminopeptide levels in sarcoidosis.
Procollagen III aminopeptide (P-III-P), a peptide released during the conversion of type III procollagen to type III collagen, is considered a potential marker of fibroblast activity in a variety of pulmonary and extrapulmonary diseases. The aim of the present article was to investigate the levels of P-III-P in serum samples (sP-III-P) from a large number of sarcoid patients, in particular looking at its relationship with other markers of disease activity and its presumed role as a marker of pulmonary fibrosis. sP-III-P has been radioimmunoassayed in an overall series of 57 patients and the levels were higher (19.18 +/- 9.17 ng/ml) than in 25 age- and sex-matched controls (11.32 +/- 2.15 ng/ml; p less than 0.001). The elevation was neither sex-related nor related to obvious liver sarcoid localization. Although sP-III-P levels were slightly higher in patients with stage II, there was no significant difference in patients with stage I or III. We found a positive relationship with serum angiotensin-converting enzyme (S-ACE) levels (p less than 0.04), but not with other markers of disease activity (67Ga uptake, bronchoalveolar lavage [BAL] lymphocyte percent, vital capacity, and lung diffusing capacity). The relationship with S-ACE was confirmed in a longitudinal follow-up study, where sP-III-P strictly paralleled the S-ACE behavior. Finally, the initial sP-III-P levels did not predict cases either with disease relapse or resistance to corticosteroid treatment. We conclude that, in our study, sP-III-P levels failed to characterize sarcoid patients with radiologic fibrotic pattern (stage III), and, in addition, were unable to predict which patients would have a poor prognosis. Rather, they reflect a metabolic activity of sarcoid granuloma cells. Thus, the usefulness of sP-III-P in the treatment of patients with sarcoid may be considered similar to that of S-ACE.
Luisetti
M
M
Istituto di Tisiologia e Malattie Respiratorie, IRCCS Policlinico San Matteo, Università di Pavia, Italy.
Bulgheroni
A
A
Bacchella
L
L
Pasturenzi
L
L
Aprile
C
C
D000328:Adult; D001992:Bronchoalveolar Lavage Fluid; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008168:Lung / Q000000981:diagnostic imaging; D008297:Male; D008875:Middle Aged; D010446:Peptide Fragments / Q000097:blood*; D007703:Peptidyl-Dipeptidase A / Q000097:blood; D011241:Prednisone / Q000627:therapeutic use; D011347:Procollagen / Q000097:blood*; D011859:Radiography; D012507:Sarcoidosis / Q000097:blood* / Q000175:diagnosis / Q000000981:diagnostic imaging / Q000188:drug therapy
D010446:Peptide Fragments; D011347:Procollagen; C041876:procollagen Type III-N-terminal peptide; D007703:Peptidyl-Dipeptidase A; D011241:Prednisone