Photo Credit: Toa55

The following is a summary of “High serum levels of CXCL₁₃ predict lower response to csDMARDs in both ACPA-positive and ACPA-negative early rheumatoid arthritis,” published in the October 2024 issue of Rheumatology by Stefano et al. 

In patients with rheumatoid arthritis (RA), increased circulating levels of C-X-C motif chemokine ligand 13 (CXCL₁₃) reflect synovial production and suggest immune system dysregulation. 

Researchers conducted a prospective study to assess if CXCL₁₃ predicts response to methotrexate (MTX) in patients with early RA, alone or with anti-citrullinated protein antibodies (ACPA) and rheumatoid factor (RF). 

They assessed 243 patients with early RA on treat-to-target MTX therapy, measuring baseline CXCL₁₃, ACPA, and IgM-RF levels, with follow-up at 2 months. High CXCL₁₃ (≥100 pg/ml) was evaluated for links to 6-month remission and second-line (2L) therapy needs within 2 years. 

The results showed high CXCL13 levels in 53.6% of ACPA-positive and 31.5% of ACPA-negative patients, with minimal association with disease activity and RF. Serum CXCL₁₃ remained stable after 2 months. High baseline CXCL₁₃ independently predicted failure to achieve remission and a higher frequency of 2L treatment in patients who are ACPA-positive, with adjusted odds ratios (ORs) between 0.17–0.49 for remission and 6.75 for 2L treatment. In patients who are ACPA-negative with high CXCL₁₃ , remission required higher MTX doses, and CXCL13 levels predicted MTX escalation with an adjusted OR (95% CI) of 2.69 (1.35–5.34). 

The study concluded that high serum CXCL₁₃ levels identify patients with RA more resistant to first-line (1L) MTX treatment, making CXCL₁₃ a promising biomarker for MTX response in both ACPA-positive and -negative early RA. 

Source: academic.oup.com/rheumatology/advance-article-abstract/doi/10.1093/rheumatology/keae596/7848463