A Study on Association Between Protein Carbonyl and Anti-cyclic Citrullinated Peptide Antibody in Rheumatoid Arthritis: Introducing a New Supplementary Biomarker.

Redox state and immune mechanisms are two major factors implicated in rheumatoid arthritis (RA). Regarding some limitations of anti-cyclic citrullinated peptide (anti-CCP) antibody in RA diagnosis, recruiting another strong marker of oxidative stress could lead to more definitive diagnosis. To evaluate the potential of protein carbonyl content as a supplementary biomarker for RA. Eighty patients with RA attending the Research Center from 2015 to 2016 were recruited in this study. Smoker and alcoholic subjects, or those with any other systemic illness were excluded from the study. Demographic information and clinical data were collected. Numbers of swollen and tender joints were determined and RA disease activity was assessed. Serum samples were used for assessing protein carbonyl level, platelet count, and anti-CCP antibody values. Statistical analyses for significant differences were performed according to parametric (Student t test) and nonparametric (Mann-Whitney test) tests. The correlation was determined by Pearson coefficient. There was a significant correlation between protein carbonyl levels and anti-CCP antibodies in active RA (p value = 0.01), but not in remission phase (p value = 0.28). A significant positive correlation was observed between protein carbonyl levels and platelets count in active RA (p value = 0.001), but not in remission phase (p value = 0.85). Protein carbonyl could be considered as a future cost-effective supplementary biomarker, alongside anti-CCP antibody, in active RA diagnosis as it showed a significant positive correlation with anti-CCP antibody and platelet, two major mediators in the disease pathogenesis. © Association of Clinical Biochemists of India 2019.