AB0113 ANTI-CARBAMYLATED PROTEIN ANTIBODIES POSITIVITY AND DISEASE ACTIVITY IN HISPANIC PATIENTS WITH ESTABLISHED RHEUMATOID ARTHRITIS: AN OBSERVATIONAL STUDY

Abstract

Background:Clinically relevant anti-carbamylated (anti-CarP) antibodies are detected in up to 45% of rheumatoid arthritis (RA) patients and are associated with severe radiological progression, higher disease activity, and significantly more disability when studied in early phases of arthritis.Objectives:We aimed to determine the prevalence of anti-CarP antibodies in Mexican Hispanics with established RA and to assess their relationship with disease activity.Methods:A cohort study was conducted in 278 patients with established RA during an 18-month follow-up. We measured IgG/IgM/IgA rheumatoid factor (RF), IgG anticitrullinated protein antibodies (ACPA) and IgG/IgM/IgA anti-CarP antibodies using enzyme-linked immunosorbent assay (ELISA). For disease activity, we performed the 28-joint disease activity score with erythrocyte sedimentation rate (DAS28-ESR). Repeated measures one-way ANOVA was used to test the association between anti-CarP IgG antibody status and longitudinal DAS28-ESR scores. Patients were evaluated at baseline and at 6, 12, and 18 months during follow-up.Results:Anti-CarP IgG antibodies were positive in 47.8% of patients and, accounting for all isotypes, in 9.5% of patients with negative RF and ACPA. Triple antibody positivity was present in 42.6% of patients in our sample. Anti-CarP IgG antibody positivity did not show statistically significant differences in mean DAS28-ESR when compared to anti-CarP IgG antibody negative patients at baseline, 6, 12 or 18 months.Conclusion:Anti-CarP IgG antibodies are present in almost 50% of RA patients and, accounting for all isotypes, in 9% of RF and ACPA negative patients. Anti-CarP IgG antibody positivity was not associated to a higher disease activity measured by DAS28-ESR in Hispanic patients with established RA.