Activating and inhibitory Fc gamma receptors in rheumatoid arthritis: from treatment to targeted therapies

Expression of the myeloid inhibitory receptor CLEC12A correlates with disease activity and cytokines in early rheumatoid arthritis

The myeloid inhibitory receptor CLEC12A negatively regulates inflammation. Reduced CLEC12A expression enhances inflammation in CLEC12A knock-out mice with collagen antibody-induced arthritis. Moreover, CLEC12A internalisation augments human neutrophil activation. We thus postulated that CLEC12A expression on circulating myeloid cells of rheumatoid arthritis patients is associated with disease manifestations. Cell-surface, CLEC12A receptor expression was determined on circulating neutrophils and monocytes of eRA patients and of healthy donors. Generalized estimating equations model, Student’s t-test and Spearman’s correlations were performed to compare CLEC12A expression between groups and test its association with disease activity and clinical parameters. Plasma cytokines were measured by multiplex immunoassay. Patients with reduced neutrophil or monocyte CLEC12A expression at baseline and at 3 months have an increased simple disease activity index. Low baseline CLEC12A expression also correlates with a higher SDAI at 6 months. In contrast, positive correlations were observed between baseline CLEC12A expression and several cytokines. Moreover, neutrophil and monocyte CLEC12A expression is significantly higher in early rheumatoid arthritis patients at baseline than healthy controls. Circulating neutrophil and monocyte CLEC12A expression correlates with disease activity at baseline and is predictive of SDAI at later stages of the disease indicative of a regulatory role for CLEC12A in RA.

Association of Fcgamma receptor type 2A and 3A genotypes with rheumatoid arthritis in Chinese population

AIM

SNPs of FcγRs were implicated in pathogenesis of rheumatoid arthritis (RA) and treatment efficacy of TNF inhibitors (TNFi). This study aims to investigate the associations of FcγRIIa and FcγRIIIa genotypes with autoantibody production and treatment response to TNFi in Chinese patients with RA.

PATIENTS & METHODS

FcγRIIa and FcγRIIIa polymorphisms were genotyped in 158 RA patients. Response to TNFi was evaluated in 18 patients at 3 and 6 months after treatment.

RESULTS

FcγRIIa-131H allele was significantly increased in autoantibody-negative RA patients. FcγRIIa-131H/H+H/R was closely associated with differences in 28-joint disease activity score in patients at months 3 and 6 of TNFi treatment.

CONCLUSION

FcγRIIa-131H allele may have a protective role in autoantibody production and might be a biomarker for predicting good response to TNFi in Chinese RA patients.