[Biochemical methods in the assessment of activity in rheumatoid arthritis (author's transl)].

An investigation was carried out in 120 patients with classical rheumatoid arthritis (RA). Prolylhydroxylase activity was determined in the synovial membrane and serum and compared with the level of collagen-like protein in plasma and the hydroxyproline-creatinine quotient in urine. The data were related to the activity of RA as measured according to Voit and Gamp and also according to Lansbury. Activity was, furthermore, also assessed on the basis of newly defined criteria considering clinical, biochemical and histological findings. Prolylhydroxylase activity was significantly correlated to the activity of the RA assessed according to each of these systems. The significance of the known parameters, collagen-like protein in plasma and hydroxyproline-creatinine quotient in urine were confirmed in this larger series of patients. The positive correlation between prolylhydroxylase activities in the synovial membrane, as well as in serum, and the level of collagen metabolites in plasma and urine corroborated the value of biochemical methods in the assessment of activity of RA in order to undertake differentiated therapy.