CXC ligand 13 in rheumatoid arthritis and its relation to secondary Sjögren’s syndrome

A systematic review of CXCL13 as a biomarker of disease and treatment response in rheumatoid arthritis

BACKGROUND

The B cell chemoattractant CXCL13 is a promising biomarker in rheumatoid arthritis (RA), with a plausible role in supporting diagnosis, monitoring disease activity and as a prognostic value. It is a key chemokine driving the formation of lymphoid follicles within the inflamed synovium. The objective of this systematic review was to evaluate the role of CXCL13 as a viable biomarker in RA.

METHODS

We conducted a systematic literature review of all published cohort and randomised controlled trials evaluating the role of CXCL13 in RA. The primary outcomes were; i) CXCL13 levels in RA patients compared to healthy controls, ii) the correlation between CXCL13 and markers of disease activity, and iii) the association between CXCL13 and treatment response.

RESULTS

The search produced 278 articles, of which 31 met the inclusion criteria. Of the 12 studies evaluating CXCL13 expression in early or established RA, all reported higher levels than that seen in healthy controls. Twelve of sixteen studies reported a weakly positive correlation between CXCL13 and markers of disease activity including DAS28 and swollen joint count, with rho values between 0.20-0.67. In 2 studies, CXCL13 levels correlated with ultrasonographic evidence of synovitis. Eighteen studies assessed CXCL13 in response to therapeutic intervention. The majority signified a fall in levels in response to treatment including biologics and Janus kinase (JAK) inhibition. In some, this reduction was only seen in treatment responders. High CXCL13 levels predicted failure to achieve disease remission with csDMARDs. The evidence for treatment prediction with biologics was conflicting.

CONCLUSION

Despite evidence to suggest a role in diagnosing RA and in detecting synovitis, the heterogeneity of studies included in this review limit our ability to draw robust conclusions. At present there are inadequate results to justify the routine use of CXCL13 as a biomarker in RA routine clinical practice.

Increased circulating CXCL13 levels in systemic lupus erythematosus and rheumatoid arthritis: a meta-analysis

OBJECTIVES

CXC ligand 13 (CXCL13) is known as B cell chemotactic factor (BLC), promoting the migration of B lymphocytes by communicating with its receptor CXCR5, which can be regarded as part of pathogenesis of systemic lupus erythematosus (SLE) and rheumatoid arthritis (RA). This meta-analysis was to evaluate the circulating CXCL13 levels in SLE and RA.

METHODS

All articles were respectively gathered from PubMed, Web of Science, and China National Knowledge Infrastructure (CNKI) (by the end of 10 April 2019). According to random effects model, standardized mean difference (SMD) and 95% confidence interval (CI) of CXCL13 levels in SLE and RA were calculated by Stata 12.0 software.

RESULTS

Totally, 15 studies were selected (981 SLE patients and 380 healthy controls, 332 RA patients and 147 healthy controls). SLE and RA patients were significantly increased in circulating CXCL13 levels (SMD = 1.851, 95% CI 0.604-3.098; SMD = 1.801, 95% CI = 1.145-2.457). Subgroup analyses showed that SLE patients from the Chinese group and systemic lupus erythematosus disease activity index (SLEDAI) score ≥ 6 group had higher circulating CXCL13 levels (SMD = 2.182, 95% CI 0.135-4.229; SMD = 0.767, 95% CI 0.503-1.030). However, there were no significant changes in CXCL13 concentrations in SLE patients from the English and SLEDAI score < 6 group. Similarly, subgroup analyses presented that RA patients from different classifications showed higher circulating CXCL13 levels. There was no publication bias.

CONCLUSIONS

This meta-analysis demonstrated increased circulating CXCL13 concentrations in SLE and RA patients. Circulating CXCL13 levels may act as biomarkers and therapy targets in the diagnosis and treatment of SLE and RA.Key Point• First, CXC ligand 13 (CXCL13) is closely related to the pathogenesis of systemic lupus erythematosus (SLE) and rheumatoid arthritis (RA), Second, this study may provide novel therapeutic targets for the treatment of SLE and RA patients. This meta-analysis provides a comprehensive analysis of circulating CXCL13 levels in patients with SLE and RA and also explores related influencing factors.