Association of anti-CarP levels with clinical activity and serological profile in rheumatoid arthritis

Abstract

Objective

To analyze the association of anti-CarP levels with clinical activity, manifestations, and serological profile in rheumatoid arthritis (RA) patients.

Methods

Cross-sectional study including RA patients and healthy controls (HC). Clinical and analytical data were collected, and anti-CarP levels were measured by ELISA.

Results

A total of 101 patients (79% female, mean age 45), and 98 HC (67% female, mean age 55) were included. RA patients had significantly higher anti-CarP levels than HC (p < 0.001), increasing with age (p = 0.004). Anti-CarP correlated with RF and ACPA positivity (p < 0.001). Those patients with RF/ACPA positive showed the highest anti-CarP levels compared to other groups (p < 0.001).

The threshold for elevated anti-CarP was set at 17.2 ng/mL. Among 35 patients with elevated anti-CarP, 32 were RF/ACPA double-positive (p = 0.006), and 3 were seronegative. Elevated anti-CarP levels were associated to clinical activity, tender joints (p = 0.002), the presence of rheumatoid nodules and interstitial lung disease, but not with Sharp/van der Heijde score, joint damage progression or Sjögren syndrome.

Conclusions

RA patients exhibit higher anti-CarP levels, especially those with RF/ACPA double-positivity. Elevated levels correlate with higher disease activity and extra-articular involvement.