Clinical significance of serum B cell chemokine (CXCL13) in early rheumatoid arthritis patients

Abstract

The diagnosis of early rheumatoid arthritis (RA) is challenging. B-cell chemokine (CXCL13) plays a critical role in the disease pathogenesis. To assess the diagnostic value of serum CXCL13 in early RA and compare it with rheumatoid factor (RF) and anti-cyclic citrullinated peptide (anti-CCP) antibodies. The study included 60 RA patients; 30 early, 30 established RA and 30 healthy controls. The modified health assessment questionnaire (MHAQ), modified Sharp-van der Heijde score (MSS) and disease activity score (DAS28) were assessed in RA patients. RF, anti-CCP and serum level of CXCL13 were measured. Patients had a mean age of 39 ± 7.4 years and disease duration of 4.4 ± 5.7 years; they were 46 females and 12 males (F:M 3.8:1). Serum CXCL13 was significantly higher in early (191.7 ± 74.4 pg/ml) compared to established (136.4 ± 79 pg/ml) RA (p = 0.007) which were not observed with RF and anti-CCP; both were higher than in control (30.4 ± 13.5 pg/ml) (p < 0.001). In early RA, the frequencies of CXCL13, RF and anti-CCP positivity were 90%, 73.3% and 56.7% while in the established cases the frequencies were 36.7%, 66.7% and 63.3% respectively. CXCL13 significantly correlated with DAS28 (early: 0.49, p = 0.006; established: r = 0.38, p = 0.04) but not with MHAQ or MSS. The CXCL13 significantly correlated with both the RF and anti-CCP in both early and established cases (p < 0.001). CXCL13 is an important for the diagnosis of early RA with a superior diagnostic performance compared to RF and anti-CCP. It may also be considered a potential biomarker of disease activity.