Methotrexate treatment affects effector but not regulatory T cells in juvenile idiopathic arthritis

Treg fitness signatures as a biomarker for disease activity in Juvenile Idiopathic Arthritis

Juvenile Idiopathic Arthritis (JIA) is an autoimmune condition characterised by flares of joint inflammation. However, no reliable biomarker exists to predict the erratic disease course. Normally, regulatory T cells (Tregs) maintain tolerance, with altered Tregs associated with autoimmunity. Treg signatures have shown promise in monitoring other conditions, therefore a Treg gene/protein signature could offer novel biomarker potential for predicting disease activity in JIA. Machine learning on our nanoString Treg 48-gene signature on peripheral blood (PB) Tregs generated a model to distinguish active JIA (active joint count, AJC≥1) Tregs from healthy controls (HC, AUC = 0.9875 on test data). Biomarker scores from this model successfully differentiated inactive (AJC = 0) from active JIA PB Tregs. Moreover, scores correlated with clinical activity scores (cJADAS), and discriminated subclinical disease (AJC = 0, cJADAS≥0.5) from remission (cJADAS<0.5). To investigate altered protein expression as a surrogate measure for Treg fitness in JIA, we utilised spectral flow cytometry and unbiased clustering analysis. Three Treg clusters were of interest in active JIA PB, including TIGIThighCD226highCD25low Teff-like Tregs, CD39-TNFR2-Helioshigh, and a 4-1BBlowTIGITlowID2intermediate Treg cluster predominated in inactive JIA PB (AJC = 0). The ratio of these Treg clusters correlated to cJADAS, and higher ratios could potentially predict inactive individuals that flared by 9-month follow-up. Thus, we demonstrate altered Treg signatures and subsets as an important factor, and useful biomarker, for disease progression versus remission in JIA, revealing genes and proteins contributing to Treg fitness. Ultimately, PB Treg fitness measures could serve as routine biomarkers to guide disease and treatment management to sustain remission in JIA.

The 'Treg paradox' in inflammatory arthritis

Classic regulatory T (Treg) cells expressing CD4 and the hallmark transcription factor FOXP3 are integral to the prevention of multi-system autoimmunity. However, immune-mediated arthritis is often associated with increased numbers of Treg cells in the inflamed joints. To understand these seemingly conflicting observations, which we collectively describe as 'the Treg paradox', we provide an overview of Treg cell biology with a focus on Treg cell heterogeneity, function and dysfunction in arthritis. We discuss how the inflamed environment constrains the immunosuppressive activity of Treg cells while also promoting the differentiation of TH17-like Treg cell, exTreg cell (effector T cells that were formerly Treg cells), and osteoclastogenic Treg cell subsets that mediate tissue injury. We present a new framework to understand Treg cells in joint inflammation and define potential strategies for Treg cell-directed interventions in human inflammatory arthritis.

Gene association analysis to determine the causal relationship between immune cells and juvenile idiopathic arthritis

BACKGROUND

Juvenile idiopathic arthritis (JIA) is a type of chronic childhood arthritis with complex pathogenesis. Immunological studies have shown that JIA is an acquired self-inflammatory disease, involving a variety of immune cells, and it is also affected by genetic and environmental susceptibility. However, the precise causative relationship between the phenotype of immune cells and JIA remains unclear to date. The objective of our study is to approach this inquiry from a genetic perspective, employing a method of genetic association analysis to ascertain the causal relationship between immune phenotypes and the onset of JIA.

METHODS

In this study, a two-sample Mendelian randomization (MR) analysis was used to select single nucleotide polymorphisms (SNPs) significantly associated with immune cells as instrumental variables to analyze the bidirectional causal relationship between 731 immune cells and JIA. There were four types of immune features (median fluorescence intensity (MFI), relative cellular (RC), absolute cellular (AC), and morphological parameters (MP)). Finally, the heterogeneity and horizontal reproducibility of the results were verified by sensitivity analysis, which ensured more robust results.

RESULTS

We found that CD3 on CM CD8br was causally associated with JIA at the level of 0.05 significant difference (95% CI = 0.630 ~ 0.847, P = 3.33 × 10-5, PFDR = 0.024). At the significance level of 0.20, two immunophenotypes were causally associated with JIA, namely: HLA DR on CD14+ CD16- monocyte (95% CI = 0.633 ~ 0.884, P = 6.83 × 10-4, PFDR = 0.16) and HLA DR on CD14+ monocyte (95% CI = 0.627 ~ 0.882, P = 6.9 × 10-4, PFDR = 0.16).

CONCLUSION

Our study assessed the causal effect of immune cells on JIA from a genetic perspective. These findings emphasize the complex and important role of immune cells in the pathogenesis of JIA and lay a foundation for further study of the pathogenesis of JIA.

Immunosuppressive treatments selectively affect the humoral and cellular response to SARS-CoV-2 in vaccinated patients with vasculitis

OBJECTIVES

To analyse humoral and cellular immune response to mRNA COVID-19 vaccines in patients with GCA.

METHODS

Consecutive patients with a diagnosis of GCA receiving two doses of BNT162b2 vaccine were assessed at baseline and 3 weeks from the second vaccine dose. Healthy subjects (n = 51) were included as controls (HC). Humoral response was assessed with Spike-specific IgG antibody response (S-IgG) and neutralizing antibodies (NtAb). Specific T cell response was assessed by enzyme linked immunosorbent spot (ELISpot).

RESULTS

Of 56 included patients with GCA, 44 were eligible after exclusion of previous evidence of COVID-19 and incomplete follow-up. A significant proportion of patients with GCA (91%) demonstrated antibody (S-IgG) response, but this was significantly lower than HCs (100%); P < 0.0001. Neutralizing activity was not detected in 16% of patients with GCA. Antibody titres (S-IgG and NtAb) were significantly lower compared with HCs. Humoral response (S-IgG and NtAb) was significantly hampered by treatment with MTX. Cellular response was lacking in 30% of patients with GCA (vs 0% in HCs; P < 0.0001). Cellular response was significantly influenced by the levels of baseline peripheral T-lymphocytes and by glucocorticoid treatment. Treatment with tocilizumab did not affect any level of the immune response elicited by vaccination.

CONCLUSIONS

Although patients with GCA apparently achieve a robust antibody seroconversion, there is a significant impairment of the neutralizing activity. MTX significantly reduced all levels of the humoral response. Up to one-third of patients do not develop a cellular immune protection in response to COVID-19 vaccination.

Short term, low dose alpha-ketoglutarate based polymeric nanoparticles with methotrexate reverse rheumatoid arthritis symptoms in mice and modulate T helper cell responses

Activated effector T cells induce pro-inflammatory responses in rheumatoid arthritis (RA) which then lead to inflammation of the joints. In this report, we demonstrate that polymeric nanoparticles with alpha keto-glutarate (aKG) in their polymer backbone (termed as paKG NPs) modulate T cell responses in vitro and in vivo. Impressively, a low dose of only three administrations of methotrexate, a clinically and chronically administered drug for RA, in conjunction with two doses of paKG NPs, reversed arthritis symptoms in collagen-induced arthritis (CIA) mice. This was further followed by significant decreases in pro-inflammatory antigen-specific T helper type 17 (TH17) responses and a significant increase in anti-inflammatory regulatory T cell (TREG) responses when CIA treated splenic cells were isolated and re-exposed to the CIA self-antigen. Overall, this study supports the concurrent and short term, low dose of paKG NPs and methotrexate for the reversal of RA symptoms.

Application and pharmacological mechanism of methotrexate in rheumatoid arthritis

Methotrexate (MTX) has been used for the treatment of rheumatoid arthritis (RA) for about forty years and to date MTX remains the part of global standard of treatment for RA. The efficacy of MTX in RA is the result of multiple mechanisms of action. In order to summarize the possible pharmacological mechanisms of MTX in the treatment of RA, this review will elaborate on folate antagonism, promotion of adenosine accumulation, regulation of inflammatory signaling pathways, bone protection and maintenance of immune system function.

Research progress in drug therapy of juvenile idiopathic arthritis

BACKGROUND

Juvenile idiopathic arthritis (JIA) is the most common chronic rheumatic disease in children. With the gradual expansion of the incidence of JIA in the population, the pathogenesis and treatment of JIA were further explored and analyzed, and JIA has achieved some success in drug therapy.

DATA SOURCES

A systemic literature search was conducted on PubMed, Cochrane Library, EMBASE, ISI Web of Science, the US National Institutes of Health Ongoing Trials Register, and the EU Clinical Trials Register. Through the searching of clinical trials of JIA in recent years, we summarized the progress of the clinical treatment of JIA.

RESULTS

The main treatment drugs for JIA include non-steroidal anti-inflammatory drugs, glucocorticoids, disease-modifying antirheumatic drugs and biological agents. So far, a variety of biological agents targeting the cytokines and receptors involved in its pathogenesis have been gradually approved for JIA in many countries. The application of biological agents in JIA showed good efficacy and safety, bringing unprecedented experience to children and adolescents with JIA.

CONCLUSIONS

The potential and advantages of biologic agents in the treatment of JIA are significant, and the application of biologic agents in the treatment of JIA will be more and more common.

Efficacy and safety of low-dose interleukin-2 in combination with methotrexate in patients with active rheumatoid arthritis: a randomized, double-blind, placebo-controlled phase 2 trial

Rheumatoid arthritis (RA) is an aggressive autoimmune arthritis, and current therapies remain unsatisfactory due to low remission rate and substantially adverse effects. Low-dose interleukin-2 (Ld-IL2) is potentially a therapeutic approach to further improve the disease. This randomized, double-blind, placebo-controlled trial was undertaken to evaluate the efficacy and safety of Ld-IL2 in patients with active RA. Patients were randomly assigned (1:1) to receive Ld-IL2, defined as a dose of 1 million IU, or placebo in a 12-week trial with a 12-week follow-up. Three cycles of Ld-IL2 or placebo were administered subcutaneously every other day for 2 weeks (a total of 7 doses), followed by a 2-week break. All patients received a stable dose of methotrexate (MTX). The primary outcomes were the proportion of patients achieving the ACR20, DAS28-ESR <2.6, and the change from baseline in CDAI or SDAI at week 24. Secondary endpoints included other clinical responses and safety. The primary outcomes were achieved in the per-protocol population. The improvements from baseline in CDAI and SDAI were significantly greater across time points for the Ld-IL2 + MTX group (n = 17) than for the placebo+MTX group (n = 23) (P = 0.018 and P = 0.015, respectively). More patients achieved ACR20 response in the Ld-IL2 + MTX group than those in the placebo+MTX group at week 12 (70.6% vs 43.5%) and at week 24 (76.5% vs 56.5%) (P = 0.014). In addition, low Treg and high IL-21 were associated with good responses to Ld-IL2. Ld-IL-2 treatment was well-tolerated in this study. These results suggested that Ld-IL2 was effective and safe in RA. ClinicalTrials.gov number: NCT 02467504.

Juvenile idiopathic arthritis

Juvenile idiopathic arthritis (JIA) is an umbrella term for arthritis of unknown origin, lasting for >6 weeks with onset before 16 years of age. JIA is the most common chronic inflammatory rheumatic condition of childhood. According to the International League Against Rheumatism (ILAR) classification, seven mutually exclusive categories of JIA exist based on disease manifestations during the first 6 months of disease. Although the ILAR classification has been useful to foster research, it has been criticized mainly as it does not distinguish those forms of chronic arthritis observed in adults and in children from those that may be unique to childhood. Hence, efforts to provide a new evidence-based classification are ongoing. Similar to arthritis observed in adults, pathogenesis involves autoimmune and autoinflammatory mechanisms. The field has witnessed a remarkable improvement in therapeutic possibilities of JIA owing to the availability of new potent drugs and the possibility to perform controlled trials with support from legislative interventions and large networks availability. The goal of drug therapy in JIA is to rapidly reduce disease activity to inactive disease or clinical remission, minimize drug side effects and achieve a quality of life comparable to that of healthy peers. As JIA can influence all aspects of a child's and their family's life, researchers increasingly recognize improvement of health-related quality of life as a key treatment goal.

Tdap booster to adolescents with juvenile idiopathic arthritis on and off anti-TNF agents is safe and immunogenic

INTRODUCTION

The response to vaccines in juvenile idiopathic arthritis (JIA) patients on and off anti-tumor necrosis factor (anti-TNF) agents remains highly discussed. There are no published studies on the immune response following a Tdap booster dose in JIA patients so far.

OBJECTIVE

To evaluate the immune response and safety after a Tdap booster in JIA patients and in healthy adolescents.

METHODS

Nineteen adolescents with JIA according to the ILAR criteria on anti-TNF medication, 19 adolescents with JIA off anti-TNF medication, and 27 healthy adolescents (control group) were compared after a Tdap booster. Adverse events and disease activity were evaluated. Lymphocyte immunophenotyping was performed by flow cytometry. Tetanus, diphtheria and pertussis toxin antibodies were assessed by ELISA; whole blood was stimulated with whole-cell pertussis, and supernatants were assessed for cytokines by xMAP.

RESULTS

The three groups showed a similar frequency of adverse events. There was no disease reactivation after the Tdap booster. Tetanus, diphtheria and pertussis antibodies showed a significant response when D0 and D14 concentrations were compared in both JIA groups and controls. Over time, a different pattern of response to the Tdap booster was observed among the groups for tetanus antibodies (p = 0.005) but not for diphtheria and pertussis antibodies. In contrast to the protection attained for tetanus and diphtheria, in the three groups, not all individuals showed pertussis seroconversion at either D14 or D28. In addition, the seroconversion of three subjects with JIA on anti-TNF medication was not maintained at D28. JIA patients off anti-TNF showed a higher percentage of naive CD8 + T cells (p = 0.007) and central memory CD8 + cells (p = 0.003) and a lower percentage of effector CD8 + T cells (p = 0.003) and NK cell numbers (p = 0.018) than the control group. The JIA group off anti-TNF medication had fewer B lymphocytes than both the JIA group on anti-TNF medication and the control group (p = 0.016). Cellular immunity to Bordetella pertussis showed that IFNγ levels were significantly lower in both JIA groups than in the control group (p = 0.003), IL10 levels were higher in the JIA off anti-TNF group (p = 0.009), IL17A and IL5 levels were lower in the JIA on anti-TNF group than in the control group (p = 0.018 and p = 0.016, respectively); however, an increase in IFNγ (p = 0.008), IL17A (p = 0.030) and TNFα (p = 0.041) levels was observed at D14 in both patient groups. Both JIA groups showed higher levels of IL21 than the control group (p = 0.023).

CONCLUSION

We conclude that individuals with JIA on or off anti-TNF agents showed a good response to a booster dose for the three antigens studied in the absence of major adverse events and without the reactivation of the disease.

Peripheral Blood Lymphocyte Analysis in Oligo- and Polyarticular Juvenile Idiopathic Arthritis Patients Receiving Methotrexate or Adalimumab Therapy: A Cross-Sectional Study

Juvenile idiopathic arthritis (JIA) is an umbrella term for seven distinct chronic immune-mediated diseases. Disease-modifying anti-rheumatic drugs (DMARD) are used to treat the underlying joint inflammation as well as extra-articular manifestations. Immunosuppression is a considerable side effect of the drugs. The main goal of this study was to investigate the effect of different JIA therapies on leukocyte subpopulations, which play a role in immune-defense. Three study groups were established. The first group consisted of JIA patients treated with methotrexate solely, the second one received a combination of methotrexate (MTX) and adalimumab (ADA). The control group was made up of the patients' healthy siblings. A total of 63 children were recruited. Fourty-one children with JIA and 22 healthy controls were included in the study. The absolute number of CD3+ T-cells was significantly elevated in patients treated with biological therapy compared to healthy controls (p2 = 0.017). In contrast, the number of CD56+ natural killer cells was significantly lower in children receiving biological therapy in comparison with healthy donors (p2 = 0.039). A significant alteration was also demonstrated between patients treated with MTX and MTX/ADA group concerning CD 19+ B-cells (p3 = 0.042). This is the first study that demonstrates significant alterations in the number of B-cells and T-cells with a relative decrease of NK-cell ratios in JIA patients receiving different DMARD therapy. Clinical Trial Registration: NCT03833271. 21.01.2019.

Early and Accurate Prediction of Clinical Response to Methotrexate Treatment in Juvenile Idiopathic Arthritis Using Machine Learning

Background and Aims: Accurately predicting the response to methotrexate (MTX) in juvenile idiopathic arthritis (JIA) patients before administration is the key point to improve the treatment outcome. However, no simple and reliable prediction model has been identified. Here, we aimed to develop and validate predictive models for the MTX response to JIA using machine learning based on electronic medical record (EMR) before and after administering MTX.

Materials and Methods: Data of 362 JIA patients with MTX mono-therapy were retrospectively collected from EMR between January 2008 and October 2018. DAS44/ESR-3 simplified standard was used to evaluate the MTX response. Extreme gradient boosting (XGBoost), support vector machine (SVM), random forest (RF), and logistic regression (LR) algorithms were applied to develop and validate models with 5-fold cross-validation on the randomly split training and test set. Data of 13 patients additionally collected were used for external validation.

Results: The XGBoost screened out the optimal 10 pre-administration features and 6 mix-variables. The XGBoost established the best model based on the 10 pre-administration variables. The performances were accuracy 91.78%, sensitivity 90.70%, specificity 93.33%, AUC 97.00%, respectively. Similarly, the XGBoost developed a better model based on the 6 mix-variables, whose performances were accuracy 94.52%, sensitivity 95.35%, specificity 93.33%, AUC 99.00%, respectively.

Conclusion: Based on common EMR data, we developed two MTX response predictive models with excellent performance in JIA using machine learning. These models can predict the MTX efficacy early and accurately, which provides powerful decision support for doctors to make or adjust therapeutic scheme before or after treatment.

Restoring T Cell Tolerance, Exploring the Potential of Histone Deacetylase Inhibitors for the Treatment of Juvenile Idiopathic Arthritis

Juvenile Idiopathic Arthritis (JIA) is characterized by a loss of immune tolerance. Here, the balance between the activity of effector T (Teff) cells and regulatory T (Treg) cells is disturbed resulting in chronic inflammation in the joints. Presently, therapeutic strategies are predominantly aimed at suppressing immune activation and pro-inflammatory effector mechanisms, ignoring the opportunity to also promote tolerance by boosting the regulatory side of the immune balance. Histone deacetylases (HDACs) can deacetylate both histone and non-histone proteins and have been demonstrated to modulate epigenetic regulation as well as cellular signaling in various cell types. Importantly, HDACs are potent regulators of both Teff cell and Treg cell function and can thus be regarded as attractive therapeutic targets in chronic inflammatory arthritis. HDAC inhibitors (HDACi) have proven therapeutic potential in the cancer field, and are presently being explored for their potential in the treatment of autoimmune diseases. Specific HDACi have already been demonstrated to reduce the secretion of pro-inflammatory cytokines by Teff cells, and promote Treg numbers and suppressive capacity in vitro and in vivo. In this review, we outline the role of the different classes of HDACs in both Teff cell and Treg cell function. Furthermore, we will review the effect of different HDACi on T cell tolerance and explore their potential as a therapeutic strategy for the treatment of oligoarticular and polyarticular JIA.

Targeting Tregs in Juvenile Idiopathic Arthritis and Juvenile Dermatomyositis-Insights From Other Diseases

Regulatory T cells (Tregs) are believed to be dysfunctional in autoimmunity. Juvenile idiopathic arthritis (JIA) and juvenile dermatomyositis (JDM) result from a loss of normal immune regulation in specific tissues such as joints or muscle and skin, respectively. Here, we discuss recent findings in regard to Treg biology in oligo-/polyarticular JIA and JDM, as well as what we can learn about Treg-related disease mechanism, treatment and biomarkers in JIA/JDM from studies of other diseases. We explore the potential use of Treg immunoregulatory markers and gene signatures as biomarkers for disease course and/or treatment success. Further, we discuss how Tregs are affected by several treatment strategies already employed in the therapy of JIA and JDM and by alternative immunotherapies such as anti-cytokine or co-receptor targeting. Finally, we review recent successes in using Tregs as a treatment target with low-dose IL-2 or cellular immunotherapy. Thus, this mini review will highlight our current understanding and identify open questions in regard to Treg biology, and how recent findings may advance biomarkers and new therapies for JIA and JDM.

High rates of tuberculin skin test positivity due to methotrexate therapy: False positive results?

RATIONALE

The tuberculin skin test (TST) and interferon ? release assays (IGRAs) are commonly used for latent tuberculosis infection (LTBI) screening. Unexpectedly high TST positivity rates have been reported in patients with rheumatic diseases, and methotrexate is frequently used in this population. We hypothesized that methotrexate use could be associated with false-positive TST results.

OBJECTIVES

To investigate whether treatment with methotrexate and other factors are associated with false-positive TST results in patients with rheumatic diseases.

METHODS

Prospective single-center study conducted between April 2013 and March 2016. Adult patients with rheumatic diseases were evaluated with a TST and two IGRAs for LTBI screening. We compared TST and IGRA results in patients treated and not treated with methotrexate and analyzed for factors associated with positive TST results.

CONCLUSIONS

Our data suggest false-positive TST results associated with methotrexate therapy. Thus, we recommend against using the TST for LTBI screening in patients receiving methotrexate and the preferential use of IGRAs in such patients.

MEASUREMENTS AND MAIN RESULTS

We studied 393 patients with rheumatic diseases, including ankylosing spondylitis (ASP, n = 90), rheumatoid arthritis (RA; n = 120), psoriatic arthritis (PA, n = 126), and other disorders (n = 57). The rate of TST positivity varied across the groups: ASP 22.2%, RA 25%, PA 35.7%, and other disorders (22.8%). Positivity rates were lower with IGRAs. Methotrexate use was associated with a statistically significant two-fold increase in the risk of a positive TST and a dose\x96 response relationship was observed. We found no statistically significant associations between methotrexate use and IGRA test positivity.

CD8(+) T cells in human autoimmune arthritis: the unusual suspects

CD8(+) T cells are key players in the body's defence against viral infections and cancer. To date, data on the role of CD8(+) T cells in autoimmune diseases have been scarce, especially when compared with the wealth of research on CD4(+) T cells. However, growing evidence suggests that CD8(+) T-cell homeostasis is impaired in human autoimmune diseases. The contribution of CD8(+) T cells to autoimmune arthritis is indicated by the close association of MHC class I polymorphisms with disease risk, as well as the correlation between CD8(+) T-cell phenotype and disease outcome. The heterogeneous phenotype, resistance to regulation and impaired regulatory function of CD8(+) T cells - especially at the target organ - might contribute to the persistence of autoimmune inflammation. Moreover, newly identified populations of tissue-resident CD8(+) T cells and their interaction with antigen-presenting cells might have a key role in disease pathology. In this Review, we assess the link between CD8(+) T cells, autoimmune arthritis and the basis of their homeostatic changes under inflammatory conditions. Improved insight into CD8(+) T cell-specific pathogenicity will be essential for a better understanding of autoimmune arthritis and the identification of new therapeutic targets.