Background/Purpose: Anti-cyclic citrullinated peptide (anti-CCP) antibodies are a hallmark of RA but are widely distributed in other autoimmune diseases. Although SLE is well characterized as a complex autoimmune disease eliciting a broad spectrum of autoantibodies, the significance of CCP antibodies in SLE patients (pts) remains poorly understood. This study evaluated the prevalence of anti-CCP antibodies in pts with SLE and their associations with demographic characteristics, clinical history, and other autoantibodies.

Methods: SLE patients pts (n=499) consented for research in the Oklahoma Cohort for Rheumatic Diseases were tested for anti-CCP by ELISA. Demographic information, clinical characteristics, and autoantibody profiles were extracted from medical records. Clinical features of pts who had ever tested positive for anti-CCP antibodies were compared to those who consistently tested negative for anti-CCP antibodies. Variables were analyzed using Fisher’s exact test.

Results: In 499 pts meeting ACR classification criteria for SLE 12% (61) were anti-CCP positive. Malar rash was the only classification criterion significantly less frequent in the CCP+ SLE group (CCP+: 44% vs CCP-: 58%, p < 0.05).  Anti-nuclear antibody positivity did not vary between these groups. Anti-CCP antibodies were not more common in any racial subgroup including African American (AA), Native American (NA), and European American (EA) pts. Subsetting by race into AA, EA, and NA subgroups revealed significant enrichment of serositis criteria in the AA CCP+ subgroup compared to the CCP+ EA and CCP+ NA subgroups. In the CCP- subgroups, EA subjects were enriched for malar rash compared to the CCP- AA subgroup and enriched for photosensitivity compared to the CCP- AA and CCP- NA subgroups. The CCP- AA subgroup was significantly enriched for renal criteria compared to the CCP- EA subgroup and enriched for immunologic criteria compared to the CCP- EA and CCP- NA subgroups. In both the CCP+ and CCP- AA subgroups, discoid rash was enriched compared to the EA and NA subgroups and anti-Sm positivity was enriched compared to the EA subgroups. Among the CCP- subgroups, SS-B (La) was enriched in the NA subgroup compared to the AA subgroup and Cent B was enriched in the NA subgroup compared to the AA and EA subgroups. All RNP autoantibodies were enriched in the CCP- AA subgroup, but not the CCP+ AA subgroup.

Conclusion: Race contributes to variations in the frequency of ACR criteria and antinuclear autoantibodies which were observed between the CCP+ and CCP- SLE patients.

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ACR Meeting Abstracts - https://acrabstracts.org/abstract/ccp-autoantibody-positive-sle-patients-show-unique-enrichments-in-sle-criteria-and-autoantibody-biomarkers-that-vary-by-race/