Photo Credit: Ilya Lukichev

The following is a summary of “In early rheumatoid arthritis, anticitrullinated peptide antibodies associate with low number of affected joints and rheumatoid factor associates with systemic inflammation,” published in the November 2023 issue of Rheumatology by Pertsinidou et al.

Researchers performed a retrospective study to examine the associations between specific rheumatoid arthritis (RA) autoantibodies and individual signs and symptoms at RA diagnosis.

They centrally analyzed IgA, IgG, IgM rheumatoid factor (RF), antibodies against cyclic citrullinated peptide version 2 (anti-CCP2), and 16 individual antibodies against citrullinated protein (ACPA) reactivities in baseline sera from 1,600 patients with RA classified according to the 1987 American College of Rheumatology (ACR) criteria. These analyses were correlated with baseline C-reactive protein (CRP), erythrocyte sedimentation rate (ESR), the number of swollen and tender joints (SJC and TJC), 28-joint disease activity scores (DAS28 and DAS28CRP), global disease activity assessed by patients, and Health Assessment Questionnaire.

The results showed individually, all autoantibodies, excluding IgG RF, were linked to a low number of SJC and TJC and elevated ESR. In IgM RF-negative patients, ACPA is specifically associated with a low count of swollen and tender joints. This association was held in multiple regression and stratified analyses, where IgM and IgA RF were associated with inflammation expressed as ESR. No association was observed between RF isotypes and ESR in those without ACPA peptide reactivity. The influence of RF on ESR increased with the number of ACPA reactivities, particularly for IgM RF. In patients meeting the 1987 ACR criteria without considering RF, IgM RF remained associated with elevated ESR, and ACPA remained associated with a low joint count.

They concluded that ACPA and RF have independent associations with early RA features, with ACPA linked to joints and RF linked to inflammation.

Source: ard.bmj.com/content/early/2023/11/23/ard-2023-224728