The imbalance between pathogenic and beneficial species of the intestinal microbiome and metabolism in rheumatoid arthritis (RA) remains unclarified. Here, using shotgun-based metagenome sequencing for a treatment-naïve patient cohort and a “quasi-paired cohort” method, we observed a deficiency of butyrate-producing species and an overwhelming number of butyrate consumers in RA patients. These outcomes mainly occurred in patients with positive ACPA, with a mean AUC of 0.94. This panel was also validated in established RA with an AUC of 0.986 in those with joint deformity. In addition, we showed that butyrate promoted T regs , while suppressing T convs and osteoclasts, due to potentiation of the reduction in HDAC expression and down-regulation of proinflammatory cytokine genes. Dietary butyrate supplementation conferred anti-inflammatory benefits in a mouse model by rebalancing T FH cells and T regs , as well as reducing antibody production. These findings reveal the critical role of butyrate-metabolizing species and suggest the potential of butyrate-based therapies for RA patients.

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Objective To investigate the regulation of T follicular regulatory (Tfr) and T follicular (Tfh) cell subtypes by low-dose IL-2 in systemic lupus erythematosus (SLE) in a randomized, double-blind, placebo-controlled clinical trial. Methods A post hoc analysis was performed in a randomized cohort of SLE patients (n=60) receiving low-dose IL-2 therapy (n=30) or placebo (n=30), along with the standard of care treatment. The primary endpoint was the attainment of SLE responder index-4 (SRI-4) at week 12 in the trial. Twenty-three healthy controls were enrolled for T cell subset detection at the same time as the trial. The t-stochastic neighbor embedding (tSNE) analysis of CD4 T subsets based on immune cells flow cytometry markers was performed to distinguish Tfh, Tfh1, Tfh2, Tfh17, and Tfr cell subsets. Results Compared with HC, the frequency of Tfr (CXCR5+PD-1low Treg and CXCR5+PD-1high Treg) cells was significantly reduced, while the pro-inflammatory Tfh cells were increased in patients with SLE. The imbalanced Tfh cell was associated with several pathogenic factors (anti-dsDNA antibodies (r=0.309, P=0.027) and serum IL-17 (r=0.328, P=0.021)) and SLE Disease Activity Index (SLEDAI) score (r=0.273, P=0.052). Decreased CXCR5+PD-1low Treg/Tfh and CXCR5+PD-1low Treg/Tfh17 were both associated with increased immunoglobulin M (IgM) (r=−0.448, P=0.002 and r=−0.336, P=0.024, respectively). Efficacy of low-dose IL-2 therapy was associated with a restored Tfr/Tfh cell balance. Conclusion These data support the hypothesis that promotion of Tfr is associated with decreased disease activities and that low-dose IL-2 therapy can recover Tfr/Tfh immune balance. Trial registration number ClinicalTrials.gov Registries (NCT02465580).

ImportancePrimary Sjögren syndrome (pSS) is a systemic autoimmune disease associated with dysregulated immune cells, with no efficient therapy. There is a need to study potential therapeutic approaches.ObjectiveTo investigate the efficacy, safety, and immune response of low-dose interleukin 2 (LD-IL-2) in the treatment of pSS.Design, Setting, and ParticipantsA double-blind, placebo-controlled randomized clinical trial was conducted with a 2-group superiority design from June 2015 to August 2017. Sixty patients, aged 18 to 70 years, were recruited from Peking University People’s Hospital. Efficacy analyses were based on the intention-to-treat (ITT) principle. Data were analyzed from December 2018 to March 2020.InterventionsPatients with pSS were treated with LD-IL-2 or placebo for 12 weeks and accompanied by 12 weeks of follow-up.Main Outcomes and MeasuresThe primary end point was defined as a 3-point or greater improvement on the European League Against Rheumatism Sjögren’s Syndrome Disease Activity Index (ESSDAI) by week 24. The secondary end points included other clinical responses, safety, and changes of immune cell subsets at week 12 and 24.ResultsSixty patients with pSS were recruited, with 30 in the LD-IL-2 group (mean [SD] age, 47.6 [12.8] years; 30 [100%] women) and 30 in the placebo group (mean [SD] age, 51.0 [11.9] years; 30 [100%] women), and 57 completed the trial. More patients in the LD-IL-2 group (20 [66.7%]) achieved ESSDAI score reduction of at least 3 points than in the placebo group (8 [26.7%]) at week 24 (P = .004). There were greater resolutions of dryness, pain, and fatigue in the LD-IL-2 group than placebo group at week 12 (dryness: difference, −18.33 points; 95% CI, −28.46 to −8.21 points; P = .001; pain: difference, −10.33 points; 95% CI, −19.38 to −1.29 points; P = .03; fatigue: difference, −11.67 points; 95% CI, −20.65 to −2.68 points; P = .01). No severe adverse events were observed in either group. In addition, the LD-IL-2 group showed a significant decrease in infection compared with the placebo group (1 [3.3%] vs 9 [30.0%]; P = .006). Immunological analysis revealed that LD-IL-2 promoted an expansion of regulatory T cells and regulatory CD24highCD27+ B cells.Conclusions and RelevanceIn this randomized clinical trial, LD-IL-2 was effective and well tolerated in patients with pSS, and it restored immune balance, with enhanced regulatory T cells and CD24highCD27+ B cells.Trial RegistrationClinicalTrials.gov Identifier: NCT02464319

Background To determine the diagnostic accuracy of major salivary gland ultrasonography (SGUS) in primary Sjögren’s syndrome (pSS) using the novel Outcome Measures in Rheumatology Clinical Trials (OMERACT) scoring system in a large-scale multicentre study. Methods SGUS was conducted for 246 pSS patients, 140 control subjects with conditions other than SS and 27 healthy control subjects. The echostructure features from the parotid and submandibular glands on both sides were graded using the novel OMERACT scoring system. Receiver operating characteristic curves were used to describe the diagnostic accuracy of the scoring system for pSS. The associations between the SGUS and disease characteristics were analysed to evaluate the clinical value of SGUS for pSS. Results The US scores in the pSS group were significantly higher than those in the non-pSS group (p < 0.001). The level of diagnostic accuracy was comparable with the scores of all four glands (AUC=0.908) when only the parotid and submandibular glands on either side were scored (AUC=0.910, 0.904, respectively). The optimal cut-off value for the left (right) parotid gland and the left (right) submandibular gland was 4, with maximal sensitivity (75.6% and 77.2%, respectively) and specificity (91.6% and 92.2%, respectively). The pSS patients with positive SGUS results presented a longer disease duration, parotid enlargement, dental loss and higher levels of serological markers, such as anti-SSA, anti-SSB, positive RF, IgG and γ-globulin%. Conclusions SGUS with the OMERACT scoring system yields high sensitivity and specificity, demonstrating high diagnostic feasibility for pSS. The SGUS may have implications for deciding disease severity and treatment efficacy.