Macrophages contribute to the pathogenesis of rheumatoid arthritis (RA). They can display different states of activation or “polarization,” notably the so-called inflammatory “M1” and the various alternative “M2” polarizations, characterized by distinct functions. Data regarding the effects of RA anti-cytokine biological disease-modifying anti-rheumatic drugs (bDMARDs) on macrophage polarization are scarce. We aimed to assess in vitro modulation of macrophage polarization by bDMARDs targeting pro-inflammatory cytokines in RA. We generated monocyte derived macrophages using blood samples from 20 RA patients with active RA and 30 healthy controls. We evaluated in vitro the impact on M1 inflammatory macrophages of: etanercept (ETA), adalimumab (ADA), certolizumab (CZP), tocilizumab (TCZ), and rituximab (RTX). We assessed the impact on macrophage polarization using flow cytometry and RTqPCR to study the expression of surface markers and perform functional studies of cytokine production, phagocytosis, and negative feedback control of inflammation. Among evaluated bDMARDs, anti-TNF agents modulated the polarization of inflammatory macrophages by decreasing inflammatory surface markers (CD40, CD80) and favoring alternative markers (CD16, CD163, MerTK). Anti-TNF agents also induced alternative functions in macrophages activated in inflammatory condition with (i) the inhibition of inflammatory cytokines (TNF, IL-6, IL-12), (ii) an increase in phagocytosis. These findings were mechanistically related to an increase in early IL-10 production, responsible for higher negative feedback control of inflammation involving SOCS3 and Gas6. This IL-10 effect was STAT3-dependent. Anti-TNF agents not only inhibit in vitro inflammatory functions of macrophages, but also favor resolution of inflammation through polarization toward alternative features specifically involving the IL-10/STAT3 axis.

Objectives To assess the risk of losing remission, low disease activity (LDA) or radiographic progression in the case of (1) discontinuing or (2) tapering doses of biological disease-modifying antirheumatic drugs (bDMARDs) compared with continuation of the initial treatment regimen in rheumatoid arthritis (RA) patients with remission or LDA. Materials and methods A systematic literature analysis was carried out through May 2017 on the PubMed, Embase, Cochrane and international congress databases, selecting controlled trials comparing bDMARDs discontinuation/tapering versus continuation in RA patients with remission or LDA. The meta-analysis assessed the risk ratio (RR) and 95% CI of losing remission or LDA and the risk of radiographic progression after (1) discontinuing and (2) tapering doses of bDMARDs versus continuing the initial treatment. Results The meta-analysis comparing bDMARDs discontinuation versus continuation performed on nine trials showed an increased risk of losing remission (RR (95% CI)=1.97(1.43 to 2.73), P<0.0001) or LDA (RR (95% CI)=2.24(1.52 to 3.30), P<0.0001) and an increased risk of radiographic progression (RR (95% CI)=1.09(1.02 to 1.17), P=0.01) in case of bDMARD discontinuation. The meta-analysis comparing bDMARDs tapering versus continuation performed on 11 trials showed an increased risk of losing remission (RR (95% CI)=1.23(1.06 to 1.42), P=0.006) but no increased risk of losing LDA (RR (95% CI)=1.02 (0.85 to 1.23), P=0.81) nor any increased risk of radiographic progression (RR (95% CI)=1.09(0.94 to 1.26), P=0.26) in case of bDMARD tapering. Conclusion Discontinuation of bDMARDs leads to an increased risk of losing remission or LDA and radiographic progression, while tapering doses of bDMARDs does not increase the risk of relapse (LDA) or radiographic progression, even though there is an increased risk of losing remission.