Serum oxidation activities and rheumatoid arthritis.

The serum oxidation activity (SOA) of patients with rheumatoid arthritis (RA) and other connective-tissue diseases (OCTD) was measured by a new colorimetric procedure the authors have devised, using o-phenylene diamine (OPD) as the indicator. A comparison was made between SOA and other clinical data, such as patient age, the particular stages of the disease and its total duration, number of joints with active synovitis, arthritic score, erythrocyte sedimentation rate (ESR), c-reactive protein (CRP), RA test results, rheumatoid arthritis haemagglutination titre (RAHA), ceruloplasmine (CP) and transferrin. Fifty-three out of 73 patients with RA (72.6%) and thirteen out of 34 patients with OCTD (38.2%) showed high levels of SOA (mean + 2SD of the control value). A significant correlation was noted between SOA and the number of joints with active synovitis, serum CP, CRP and ESR in RA patients. SOA and lipid peroxide (LP) were inversely correlated to a very significant extent. In OCTD, SOA showed a significant correlation with CP, but not with CRP or ESR. The number of active synovitis in RA patients indicated their high correlation with SOA. Drugs generally used for RA therapy, such as D-penicillamine and tiobutarit (SA96), were found to have anti-oxidant activity in the presence of RA sera. On the basis of these data, it is apparent that SOA is a reliable indicator of RA activity, and that the oxidation of various body constituents and fluids may be essential to the inflammatory processes of RA.