Serum procollagen III peptide levels in subjects with sarcoidosis. A 5-year follow-up study.

In a prospective study, Type III procollagen N-terminal peptide was measured in the sera of 38 subjects with biopsy-proven pulmonary sarcoidosis at 6-month intervals over a period of 5 yr. The subjects were divided into four groups according to their radiologic presentation and clinical course: Group A (n = 10) subjects with sarcoidosis Type I without radiologic progression over 5 yr; Group B (n = 5) subjects with sarcoidosis Type I with radiologic progression to Stage II or III; Group C (n = 9) subjects with sarcoidosis Types II and III without progression over 5 yr; and Group D (n = 14) subjects with sarcoidosis Types II and III with radiologic progression. Lung function tests (FVC, FEV1, and DLCO), chest roentgenograms, and measurements of serum angiotensin converting enzyme (S-ACE) were performed concurrently with the S-PCP-III levels. Significantly higher levels of S-PCP-III were found in group B (Type I, progressive) (18.2 +/- 1.09 ng/ml) and in group D (Type II/III, progressive) (13.9 +/- 1.2 ng/ml) compared with those of Group A (Type I, stable) (9.1 +/- 1.09 ng/ml) and Group C (Type II/III, stable) (7.6 +/- 1.1 ng/ml) or normal volunteers (9.4 +/- 4 ng/ml) (p less than 0.001 for all comparisons). Changes in S-PCP-III levels tended to parallel the clinical course, and steroid treatment resulted in a significant decrease in S-PCP-III concentrations (p less than 0.001). In contrast, serum angiotensin converting enzyme (S-ACE) levels did not correlate with either the clinical course or radiologic changes.(ABSTRACT TRUNCATED AT 250 WORDS)