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.