Identification of biomarkers to stratify response to B-cell-targeted therapies in systemic lupus erythematosus: an exploratory analysis of a randomised controlled trial.

Background: Systemic lupus erythematosus (SLE) is a complex autoimmune disease associated with widespread immune dysregulation and diverse clinical features. Immune abnormalities might be differentially associated with specific organ involvement or response to targeted therapies. We aimed to identify biomarkers of response to belimumab after rituximab to facilitate a personalised approach to therapy. Methods: In this exploratory analysis of a randomised controlled trial (BEAT-LUPUS), we investigated immune profiles of patients with SLE recruited to the 52-week clinical trial, which tested the combination of rituximab plus belimumab versus rituximab plus placebo. We used machine learning and conventional statistics to investigate relevant laboratory and clinical biomarkers associated with major clinical response. BEAT LUPUS is registered at ISRCTN, 47873003, and is now complete. Findings: Between Feb 2, 2017, and March 28, 2019, 52 patients were recruited to BEAT-LUPUS, of whom 44 provided clinical data at week 52 and were included in this analysis. 21 (48%) of 44 participants were in the belimumab group (mean age 39·5 years [SD 12·1]; 17 [81%] were female, four [19%] were male, 13 [62%] were White) and 23 (52%) were in the placebo group (mean age 42·1 years [SD 10·5]; 21 [91%] were female, two [9%] were male, 16 [70%] were White). Ten (48%) of 21 participants who received belimumab after rituximab and eight (35%) of 23 who received placebo after rituximab had a major clinical response at 52 weeks (between-group difference of 13% [95% CI -15 to 38]). We found a predictive association between baseline serum IgA2 anti-double stranded DNA (dsDNA) antibody concentrations and clinical response to belimumab after rituximab, with a between-group difference in major clinical response of 48% (95% CI 10 to 70) in patients with elevated baseline serum IgA2 anti-dsDNA antibody concentrations. Moreover, among those who had a major clinical response, serum IgA2 anti-dsDNA antibody concentrations significantly decreased from baseline only in the belimumab group. Increased circulating IgA2 (but not total) plasmablast numbers, and T follicular helper cell numbers predicted clinical response and were both reduced only in patients who responded to belimumab after rituximab. Serum IgA2 anti-dsDNA antibody concentrations were also associated with active renal disease, whereas serum IgA1 anti-dsDNA antibody and IFN-α concentrations were associated with mucocutaneous disease activity but did not predict response to B-cell targeted therapy. Patients with a high baseline serum interleukin-6 concentration were less likely to have a major clinical response, irrespective of therapy. Interpretation: This exploratory study revealed the presence of distinct molecular networks associated with renal and mucocutaneous involvement, and response to B-cell-targeted therapies, which, if confirmed, could guide precision targeting of advanced therapies for this heterogenous disease. Funding: Versus Arthritis, UCLH Biomedical Research Centre, LUPUS UK, and GSK.

Regulatory T cells enhance Th17 migration in psoriatic arthritis which is reversed by anti-TNF.

Regulatory T cells (Treg) prevent the migration of effector T cells toward sites of inflammation, thereby limiting disease progression. We investigated this aspect of Treg function using psoriatic arthritis (PsA) as an exemplar of chronic inflammation. Patients with PsA had an increased Th17:Treg ratio which was reversed by anti-tumor necrosis factor (TNF) therapy. Utilizing an in vitro migration assay, Treg from patients with PsA treated with conventional therapy paradoxically boosted CCR6+ effector T-cell (a surrogate for Th17) migration toward CCL20. In contrast, Treg from patients with PsA treated with anti-TNF suppressed CCL20-driven effector T-cell migration. The boosting effect of TNF blockade upon Treg suppression of migration was accompanied by increased effector T-cell CCL20 production and enhanced interaction between Treg and effector T cells. This study provides mechanistic insight into Treg modulation of effector T-cell migration in patients with chronic inflammation and how this can be targeted by therapy.

Clinical Remission of Sight-Threatening Non-Infectious Uveitis Is Characterized by an Upregulation of Peripheral T-Regulatory Cell Polarized Towards T-bet and TIGIT.

Background: Non-infectious uveitis can cause chronic relapsing and remitting ocular inflammation, which may require high dose systemic immunosuppression to prevent severe sight loss. It has been classically described as an autoimmune disease, mediated by pro-inflammatory Th1 and Th17 T-cell subsets. Studies suggest that natural immunosuppressive CD4+CD25+FoxP3+ T-regulatory cells (Tregs) are involved in resolution of inflammation and may be involved in the maintenance of clinical remission. Objective: To investigate whether there is a peripheral blood immunoregulatory phenotype associated with clinical remission of sight-threatening non-infectious uveitis by comparing peripheral blood levels of Treg, Th1, and Th17, and associated DNA methylation and cytokine levels in patients with active uveitic disease, control subjects and patients (with previously active disease) in clinical remission induced by immunosuppressive drugs. Methods: Isolated peripheral blood mononuclear cells (PBMC) from peripheral blood samples from prospectively recruited subjects were analyzed by flow cytometry for CD3, CD4, FoxP3, TIGIT, T-bet, and related orphan receptor γt. Epigenetic DNA methylation levels of FOXP3 Treg-specific demethylated region (TSDR), FOXP3 promoter, TBX21, RORC2, and TIGIT loci were determined in cryopreserved PBMC using a next-generation sequencing approach. Related cytokines were measured in blood sera. Functional suppressive capacity of Treg was assessed using T-cell proliferation assays. Results: Fifty patients with uveitis (intermediate, posterior, and panuveitis) and 10 control subjects were recruited. The frequency of CD4+CD25+FoxP3+ Treg, TIGIT+ Treg, and T-bet+ Treg and the ratio of Treg to Th1 were significantly higher in remission patients compared with patients with active uveitic disease; and TIGIT+ Tregs were a significant predictor of clinical remission. Treg from patients in clinical remission demonstrated a high level of in vitro suppressive function compared with Treg from control subjects and from patients with untreated active disease. PBMC from patients in clinical remission had significantly lower methylation levels at the FOXP3 TSDR, FOXP3 promoter, and TIGIT loci and higher levels at RORC loci than those with active disease. Clinical remission was also associated with significantly higher serum levels of transforming growth factor ß and IL-10, which positively correlated with Treg levels, and lower serum levels of IFNγ, IL-17A, and IL-22 compared with patients with active disease. Conclusion: Clinical remission of sight-threatening non-infectious uveitis has an immunoregulatory phenotype characterized by upregulation of peripheral Treg, polarized toward T-bet and TIGIT. These findings may assist with individualized therapy of uveitis, by informing whether drug therapy has induced phenotypically stable Treg associated with long-term clinical remission.

Th17 cells are restrained by Treg cells via the inhibition of interleukin-6 in patients with rheumatoid arthritis responding to anti-tumor necrosis factor antibody therapy.

OBJECTIVE: The importance of interleukin-17 (IL-17) is underscored both by its resistance to control by Treg cells and the propensity of Treg cells to produce this highly inflammatory cytokine. This study sought to address whether Th17 cells are inhibited by Treg cells in rheumatoid arthritis (RA) patients responding to anti-tumor necrosis factor (anti-TNF) therapy, and if so defining the underlying mechanisms of suppression. METHODS: Inhibition of Th17 cell responses was determined by Treg cell suppression assays. The Treg cell phenotype was analyzed using flow cytometry and enzyme-linked immunosorbent assay. Mechanisms of suppression were tested by cytokine addition or antibody blockade. RESULTS: Th17 responses were inhibited by Treg cells from RA patients responding to the anti-TNF antibody adalimumab (Treg(ada) ), but not by Treg cells from healthy individuals or patients with active RA. Furthermore, Treg(ada) cells secreted less IL-17, even when exposed to proinflammatory monocytes from patients with active RA. Treg(ada) cells suppressed Th17 cells through the inhibition of monocyte-derived IL-6, but this effect was independent of IL-10 and transforming growth factor ß, which mediated the suppression of Th1 responses. Adalimumab therapy led to a reduction in retinoic acid receptor-related orphan nuclear receptor C-positive Th17 cells and an increase in FoxP3+ Treg cells lacking expression of the transcription factor Helios. However, this acquisition of IL-17-suppressor function was not observed in RA patients responding to treatment with etanercept, a modified TNF receptor-Fc fusion protein. Indeed, there was no alteration in Treg cell number, function, or phenotype in etanercept-treated patients, and Th17 responses remained unchecked. CONCLUSION: Th1 and Th17 responses are controlled through distinct mechanisms by Treg cells from patients responding to anti-TNF antibody therapy. Adalimumab therapy, but not etanercept therapy, induces a potent and stable Treg cell population with the potential to restrain the progression of IL-17-associated inflammation in RA via regulation of monocyte-derived IL-6.