Serum aminoterminal type III procollagen peptide in inflammatory and degenerative rheumatic disorders.

Measurement of the aminoterminal type III procollagen peptide in serum has been suggested as a marker of the biosynthesis of collagen type III, a major connective tissue component in repair processes. In the present study the propeptide level correlated with the inflammatory synovial mass in rheumatoid arthritis and osteoarthritis. This implies that the propeptide level reflects the collagen type III synthesis occurring in the synovial repair processes, whether they were caused by inflammatory or degenerative rheumatic disorders. Physical activity did not enhance the transition of the propeptide from the synovial fluid or the inflamed synovial membrane to the blood. Normal serum propeptide values were observed in most patients with ankylosing spondylitis and degenerative diseases of the spine. This may reflect the lower amount of inflammatory tissue in these diseases and hence the sensitivity of the assays.