Carbonic anhydrase II autoantibody and oxidative stress in rheumatoid arthritis

To investigate the relationship between carbonic anhydrase (CA) II autoantibody and lipid peroxidation, certain antioxidant parameters, and cytokines in rheumatoid arthritis (RA) patients. Serum levels of CA II autoantibody, cytokines (TNFα, IL-6, IFN-γ, IL-1β) and bone markers (crosslaps, osteocalcine) and erythrocyte levels of antioxidant enzyme activities (SOD, CAT, GPx), GSH and MDA, and CA activities were measured in RA patients and healthy controls. The CA II autoantibody titers were significantly higher (P < 0.05), and erythrocyte SOD activities were significantly lower (P < 0.05) in RA patients. A significant negative correlation between CA II autoantibody titers and SOD activities in RA group was established (r = − 0.430, p = 0.006). The elevated cytokine levels could not be correlated with CA II autoantibody levels in RA. These results suggest that increased erythrocyte oxidative stress observed in RA may be effective in the mechanism of CA II autoantibody formation. ► The CA II autoantibody titers increase and erythrocyte SOD activities decrease in RA patients. ► A significant negative correlation between CA II autoantibody titers and SOD activities in RA group is established. ► We concluded increased erythrocyte oxidative stress observed in RA may be effective in the mechanism of CA II autoantibody.