Serum amino terminal type III procollagen peptide and serum hyaluronan in rheumatoid arthritis: relation to clinical and serological parameters of inflammation during 8 and 24 months' treatment with levamisole, penicillamine, or azathioprine.

Increased serum levels of the amino terminal type III procollagen peptide and serum hyaluronan were demonstrated in patients with rheumatoid arthritis. In patients with active disease a significant correlation was shown between serum levels of the propeptide and hyaluronan and the clinical signs of synovitis reflecting the extent of synovial inflammation. During recovery the serum propeptide and serum hyaluronan showed a delayed decline as compared with the clinical signs of synovitis and the acute phase protein response. This probably reflects the presence of persistent subclinical chronic inflammation. Normal serum propeptide levels in rheumatoid arthritis were associated with a good prognosis without progression of erosive joint lesions. Azathioprine reduced the number of patients with progression of erosive joint lesions and caused a more marked suppression of the serum propeptide than levamisole and penicillamine.