Targeting the programmed cell death-1 pathway in rheumatoid arthritis

Insufficient PD-1 expression during active autoimmune responses: a deep single-cell proteomics analysis in inflammatory arthritis

Objectives

Programmed cell death protein-1 (PD-1) maintains peripheral immune tolerance by preventing T cell continuous activation. Aiming to understand the extent of PD-1 expression in inflammatory arthritis beyond its involvement with T cells, we assess its presence on various circulating single cells.

Methods

Mass cytometry analysis of patients with active seropositive/seronegative rheumatoid (RA; n=9/8) and psoriatic (PsA; n=9) arthritis versus healthy controls (HC; n=13), re-evaluating patients after 3 months of anti-rheumatic treatment.

Results

PD-1 was expressed in all leukocyte subpopulations, with the highest PD-1+ cell frequencies in eosinophils (59-73%) and T cells (50-60%), and the lowest in natural-killer cells (1-3%). PD-1+ cell frequencies and PD-1 median expression were comparable between patient subgroups and HC, in the majority of cell subsets. Exceptions included increases in certain T cell/B cell subsets of seropositive RA and specific monocyte subsets and dendritic cells of PsA; an expanded PD-1+CD4+CD45RA+CD27+CD28+ T subset, denoting exhausted T cells, was common across patient subgroups. Strikingly, significant inverse correlations between individual biomarkers of systemic inflammation (ESR and/or serum CRP) and PD-1+ cell frequencies and/or median expression were evident in several innate and adaptive immunity cell subsets of RA and PsA patients. Furthermore, all inverse correlations noted in individuals with active arthritis were no longer discernible in those who attained remission/low disease activity post-treatment.

Conclusion

PD-1 expression may be insufficient, relative to the magnitude of the concomitant systemic inflammatory response on distinct leukocyte subsets, varying between RA and PsA. Our results point to the potential therapeutic benefits of pharmacological PD-1 activation, to rebalance the autoimmune response and reduce inflammation.

Immune checkpoint inhibitors in Cancer patients with rheumatologic preexisting autoimmune diseases: a systematic review and meta-analysis

BACKGROUND

Patients with rheumatologic preexisting autoimmune disease (PAD) have not been enrolled in clinical trials of immune checkpoint inhibitors (ICIs). Therefore, the risks and benefits of ICI therapy in such patients are unclear. Herein, we investigated the safety and efficacy of ICIs in rheumatologic PAD patients through a meta-analysis.

METHODS

The PubMed, Cochrane Library, Embase and Web of Science databases were searched for additional studies. We analyzed the following data through Stata software: incidence of total irAEs (TirAEs), rate of flares, incidence of new on-set irAEs, rate of discontinuation, objective response rate (ORR) and disease control rate (DCR).

RESULTS

We identified 23 articles including 643 patients with rheumatologic PAD. The pooled incidences of TirAEs, flares and new-onset irAEs were 64% (95% CI 55%-72%), 41% (95% CI 31%-50%), and 33% (95% CI 28%-38%), respectively. In terms of severity, the incidences were 7% (95% CI 2%-14%) for Grade 3-4 flares and 12% (95% CI 9%-15%) for Grade 3-4 new-onset irAEs. Patients with RA had a greater risk of flares than patients with other rheumatologic PADs did (RR = 1.35, 95% CI 1.03-1.77). The ORR and DCR were 30% and 44%, respectively. Baseline anti-rheumatic treatment was not significantly associated with the frequency of flares (RR = 1.05, 95% CI 0.63-1.77) or the ORR (RR = 0.45, 95% CI 0.12-1.69).

CONCLUSIONS

Patients with rheumatologic PAD, particularly those with RA, are susceptible to relapse of their rheumatologic disease following ICI therapy. ICIs are also effective for treating rheumatologic PAD patients. PROSPECTIVE REGISTER OF SYSTEMATIC REVIEWS (PROSPERO): number CRD 42,023,439,702.

The mechanism of dendritic cell-T cell crosstalk in rheumatoid arthritis

Rheumatoid arthritis (RA) is a chronic inflammatory disease characterised by joint pain and swelling, synovial hyperplasia, cartilage damage, and bone destruction. The mechanisms of dendritic cell (DC) and T cell-mediated crosstalk have gradually become a focus of attention. DCs regulate the proliferation and differentiation of CD4+ T cell subtypes through different cytokines, surface molecules, and antigen presentation. DC-T cell crosstalk also blocks antigen presentation by DCs, ultimately maintaining immune tolerance. DC-T cell crosstalk mainly involves chemokines, surface molecules (TonEBP, NFATc1), the PD-L1/PD-1 signalling axis, and the TGF-β signalling axis. In addition, DC-T cell crosstalk in RA is affected by glycolysis, reactive oxygen species, vitamin D, and other factors. These factors lead to the formation of an extremely complex regulatory network involving various mechanisms. This article reviews the key immune targets of DC-T cell crosstalk and elucidates the mechanism of DC-T cell crosstalk in RA to provide a basis for the treatment of patients with RA.

Intra-articular delivery of AAV vectors encoding PD-L1 attenuates joint inflammation and tissue damage in a mouse model of rheumatoid arthritis

Objective

Rheumatoid arthritis (RA) is the most common form of autoimmune inflammatory arthritis. Intra-articular gene delivery to block proinflammatory cytokines has been studied in pre-clinical models and human clinical trials. It has been demonstrated that the level of programmed death-ligand 1 (PD-L1) is associated with rheumatoid arthritis (RA). This study examined the therapeutic role of PD-L1 by intra-articular delivery via adeno-associated virus (AAV) vectors in the mouse collagen-induced arthritis (CIA) model.

Methods

Mice were intra-articularly injected with AAV5 vectors encoding human PD-L1 on day 0 and immunized with bovine type II collagen to induce CIA simultaneously. On day 49 post AAV administration, joints were collected for histo-pathological and cytokine analysis. Additionally, the systemic impacts of intra-articular injection of AAV5/PD-L1 vectors were also studied. To study the therapeutic effect of PD-L1, AAV5/PD-L1 vectors were administered into the joints of RA mice on day 21.

Results

After administration of AAV5/PD-L1 vectors, strong PD-L1 expression was detected in AAV transduced joints. Joints treated with PD-L1 at the time of arthritis induction exhibited significantly less swelling and improved histopathological scores when compared to untreated joints. Additionally, the infiltration of T cells and macrophages was decreased in joints of CIA mice that received AAV5/PD-L1 vectors (P<0.05). The levels of pro-inflammatory cytokines, including IL-1, IL-6, IL-17 and TNFα, were lower in AAV5/PD-L1 treated than untreated joints (P<0.05). Furthermore, the administration of AAV5/PD-L1 vectors into the joints of CIA mice did not impact serum cytokine levels and the antibody titers to type II collagen. Biodistribution of AAV vectors after intra-articular injection showed undetectable AAV genomes in other tissues except for a low level in the liver. Similar to the results of AAV5/PD-L1 vector administration on day 0, decreased joint swelling and lower histopathological damage were observed in joints treated with AAV5/PD-L1 vectors on day 21.

Conclusion

The results from this study demonstrate that local AAV mediated PD-L1 gene delivery into the joints is able to prevent the development and block the progression of arthritis in CIA mice without impacting systemic immune responses. This study provides a novel strategy to effectively treat inflammatory joint diseases using local AAV gene therapy by interference with immune checkpoint pathways.

Immune-related adverse events in patients with pre-existing autoimmune rheumatologic disease on immune checkpoint inhibitor therapy

Introduction

Immune checkpoint inhibitors (ICIs) enhance the immune system’s ability to target and destroy cancer cells, but this non-specific immune overactivation can result in immune-related adverse events (irAEs). Patients with underlying autoimmune diseases were excluded from the original ICI clinical trials because of the theoretical risk of irAEs. This study aimed to evaluate the risk of irAEs in patients with pre-existing rheumatologic diseases on ICIs, impact of anti-rheumatic therapy on irAEs, and malignancy outcomes.

Methods

We performed a retrospective chart review of patients with a pre-existing rheumatologic diagnosis receiving ICIs at the University of North Carolina from 2014 to 2019. Risk differences (RD) and asymptotic 95% confidence intervals (95% CIs) using a continuity correction along with odds ratios (OR) and exact 95% CIs were produced between pre-specified risk factors and flares of the underlying rheumatologic disease and/or irAEs. Kaplan–Meier survival estimates for time to unfavorable cancer response between subsets of patients were compared using the log-rank test.

Results

We identified 45 patients receiving an ICI with an underlying rheumatologic diagnosis, including 22 with rheumatoid arthritis (RA). Overall, 13 patients (29%) had a flare of their autoimmune disease, 20 patients (44%) had a new-onset irAE, and 27 (60%) had either a flare or new-onset irAE. Patients with RA had higher risk of flares compared to those with other rheumatologic disorders (45% vs 13%, RD 32%, 95% CI 2.0–56.8); all RA flares were ≤ grade 2 and treated in the outpatient setting. Concurrent treatment of the rheumatologic disease at the start of ICI therapy was not associated with a reduced risk of flare (OR 0.86, 95% CI 0.19–3.76) or new onset irAE (OR 3.21, 95% CI 0.83–13.6) compared to those not on anti-rheumatic medications. Anti-rheumatic therapy did not impact time to unfavorable malignancy outcome (p = 0.52).

Conclusion

The majority of our study cohort experienced a flare or new onset irAE with ICI treatment. Treatment with anti-rheumatic therapy did not prevent disease flares or new onset irAEs, but did not negatively impact malignancy outcomes. Research is needed to determine safe anti-rheumatic therapy options to prevent flares and irAEs that do not interfere with malignancy outcomes.

Dual Costimulatory and Coinhibitory Targeting with a Hybrid Fusion Protein as an Immunomodulatory Therapy in Lupus Nephritis Mice Models

Systemic lupus erythematosus is a complex autoimmune disorder mostly mediated by B-cells in which costimulatory signals are involved. This immune dysregulation can cause tissue damage and inflammation of the kidney, resulting in lupus nephritis and chronic renal failure. Given the previous experience reported with CTLA4-Ig as well as recent understanding of the PD-1 pathway in this setting, our group was encouraged to evaluate, in the NZBWF1 model, a human fusion recombinant protein (Hybri) with two domains: CTLA4, blocking the CD28—CD80 costimulatory pathway, and PD-L2, exacerbating the PD-1–PD-L2 coinhibitory pathway. After achieving good results in this model, we decided to validate the therapeutic effect of Hybri in the more severe MRL/lpr model of lupus nephritis. The intraperitoneal administration of Hybri prevented the progression of proteinuria and anti-dsDNA antibodies to levels like those of cyclophosphamide and reduced the histological score, infiltration of B-cells, T-cells, and macrophages and immune deposition in both lupus-prone models. Additionally, Hybri treatment produced changes in both inflammatory-related circulating cytokines and kidney gene expression. To summarize, both in vivo studies revealed that the Hybri effect on costimulatory-coinhibitory pathways may effectively mitigate lupus nephritis, with potential for use as a maintenance therapy.

Checkpoint Inhibitors and Induction of Celiac Disease-like Condition

Immune checkpoint inhibitors herald a new era in oncological therapy-resistant cancer, thus bringing hope for better outcomes and quality of life for patients. However, as with other medications, they are not without serious side effects over time. Despite this, their advantages outweigh their disadvantages. Understanding the adverse effects will help therapists locate, apprehend, treat, and perhaps diminish them. The major ones are termed immune-related adverse events (irAEs), representing their auto-immunogenic capacity. This narrative review concentrates on the immune checkpoint inhibitors induced celiac disease (CD), highlighting the importance of the costimulatory inhibitors in CD evolvement and suggesting several mechanisms for CD induction. Unraveling those cross-talks and pathways might reveal some new therapeutic strategies.

Programmed Cell Death Ligand 1-Transfected Mouse Bone Marrow Mesenchymal Stem Cells as Targeted Therapy for Rheumatoid Arthritis

Programmed cell death 1 ligand (PD-L1) and its receptor (PD-1) are key molecules for immunoregulation and immunotherapy. PD-L1 binding PD-1 is an effective way to regulate T or B cell immunity in autoimmune diseases such as rheumatoid arthritis (RA). In our study, we overexpressed PD-L1 by constructing a recombinant of PD-L1-lentiviral vector, which was subsequently used to transfect mouse bone marrow mesenchymal stem cells (MBMMSCs) and significantly suppressed the development of collagen-induced arthritis (CIA) in DBA/1j mice. In addition, PD-L1-transfected MBMMSCs (PD-L1-MBMMSCs) ameliorated joint damage, reduced proinflammatory cytokine expression, and inhibited T and B cell activation. Furthermore, PD-L1-MBMMSCs decreased the number of dendritic cells and increased the numbers of regulatory T cells and regulatory B cells in joints of CIA mice. In conclusion, our results provided a potential therapeutic strategy for RA treatment with PD-L1-MBMMSC-targeted therapy.

PD-L1 expression in papillary thyroid cancer with and without lymphocytic thyroiditis: a cross sectional study

The impact of concurrent autoimmune thyroid disease on the tumour microenvironment and disease progression in papillary thyroid cancer (PTC) is not well understood. Studies evaluating the programmed cell death ligand 1 (PD-L1) tumour expression in PTC have shown variable results, and the effect of lymphocytic thyroiditis (LT) on tumour PD-L1 expression has not been adequately assessed. The main aim of this study was to determine expression of PD-L1 in PTC with and without LT. We examined 81 PTC cases; 28.5% of all reviewed PTC had presence of LT. In PTC specimens without LT, tumour PD-L1 expression was significantly lower compared to PD-L1 expression in PTC with LT, 6.9% vs 39.1%, respectively. Expression of PD-L1 did not differ with PTC stage, even when sub-categorised according to the presence and absence of LT. Utility of PD- L1 expression as a prognostic marker in thyroid cancer needs to be interpreted with caution.

A systematic review and meta-analysis of rituximab combined with methotrexate versus methotrexate alone in the treatment of rheumatoid arthritis

BACKGROUND

This meta-analysis aimed to explore the efficacy and safety of rituximab combined with methotrexate (MTX) versus MTX alone in the treatment of rheumatoid arthritis (RA).

METHODS

We performed an electronic search of PubMed (1950-January 2018), EMBASE (1974-January 2018), the Cochrane Library (January 2018 Issue 3), the Google database (1950-January 2018), and the Chinese Wanfang database (1950-January 2018). Only randomized controlled trials (RCTs) were included. The American College of Rheumatology 20% improvement criteria (ACR20), ACR50, ACR70, total complication rate, and infection rate were the outcomes. A fixed/random effects model was used according to the heterogeneity assessed by the I statistic. Data analysis was performed using Stata 12.0 software.

RESULTS

A total of five RCTs with 3299 patients (rituximab combined with MTX group = 1787, MTX only group = 1512) were included in the meta-analysis. The pooled risk ratio showed that the administration of rituximab combined with MTX was associated with more ACR20, ACR50, and ACR70 than the administration of MTX only (P < .05). There were no significant differences between the two groups in terms of the total complication rate and the infection rate (P > .05).

CONCLUSION

The administration of rituximab combined with MTX was effective and safe for RA patients. Additional high-quality RCTs with long-term follow-ups should be conducted in the future to identify the potential complications in the long term.

Different exercise modalities relieve pain syndrome in patients with knee osteoarthritis and modulate the dorsolateral prefrontal cortex: A multiple mode MRI study

OBJECTIVES

Knee osteoarthritis (KOA) is a common degenerative joint disease with no satisfactory intervention. Recently, both physical and mindfulness exercises have received considerable attention for their implications in KOA pain management, and the dorsolateral prefrontal cortex (DLPFC) has displayed a critical role in pain modulation. This study aimed to comparatively investigate the modulation effects of different exercises using multidisciplinary measurements.

METHODS

140 KOA patients were randomized into Tai Chi, Baduanjin, stationary cycling, or health education control groups for 12 weeks. Knee Injury and Osteoarthritis Outcome Score (KOOS), resting state functional magnetic resonance imaging (fMRI), structural MRI, and serum biomarkers were measured at baseline and at the end of the study.

RESULTS

We found: 1) increased KOOS pain subscores (pain reduction) and serum programmed cell death protein 1 (PD-1) levels in the three exercise groups compared to the control group; 2) decreased resting state functional connectivity (rsFC) of the DLPFC-supplementary motor area (SMA) and increased rsFC between the DLPFC and anterior cingulate cortex in all exercise groups compared to the control group; 3) significant associations between DLPFC-SMA rsFC with KOOS pain subscores and serum PD-1 levels at baseline; 4) significantly increased grey matter volume in the SMA in the Tai Chi and stationary cycling groups, and a trend toward significant increase in the Baduanjin group compared to the control group; 5) significant DLPFC rsFC differences among different exercise groups; and 6) that baseline DLPFC-SMA rsFC can predict the effect of mind-body exercise on pain improvement in KOA.

CONCLUSION

Our results suggest that different exercises can modulate both common and unique DLPFC (cognitive control) pathways, and altered DLPFC-SMA rsFC is associated with serum biomarker levels. Our findings also highlight the potentials of neuroimaging biomarkers in predicting the therapeutic effect of mind-body exercises on KOA pain.

Two populations of circulating PD-1hiCD4 T cells with distinct B cell helping capacity are elevated in early rheumatoid arthritis

Objective

A novel population of B helper cells, phenotypically CD4+CXCR5−PD-1hi, has been described in the synovial tissues and peripheral blood of seropositive RA patients, and termed ‘peripheral helper T’ (Tph) cells. Contrary to CD4+CXCR5+PD-1hi follicular helper T (Tfh), Tph cells are not located in lymphoid organs but accumulate in inflamed tissues. Our objective was to study the frequency of circulating Tph (cTph) and circulating Tfh cell counterparts (cTfh) in patients with early RA (eRA).

Methods

Freshly isolated peripheral blood mononuclear cells from 56 DMARD-naïve eRA patients and 56 healthy controls were examined by flow cytometry. Autologous cocultures of naïve or memory B cells were established with isolated peripheral blood Tph or Tfh cells.

Results

Seropositive (RF+ and/or ACPA+, n = 38) but not seronegative eRA patients (n = 18) demonstrated increased frequencies and absolute numbers of cTph and cTfh cells. cTph but not cTfh cells expressed CCR2. Those eRA patients who experienced a significant clinical improvement at 12 months demonstrated a marked decrease of their cTph cell numbers whereas their cTfh cell numbers remained unchanged. Both isolated Tph and isolated Tfh cells were able to induce maturation of memory B cells, whereas only Tfh cells could differentiate naïve B cells.

Conclusion

Two populations of PD-1hiCD4 T cells with distinct phenotype and B cell helping capacity are increased in the peripheral blood of seropositive eRA patients. Whereas cTph cells are present only in patients with an active disease, cTfh cells seem to be constitutively elevated.

Checkpoint inhibitor-associated autoimmunity

Checkpoint inhibitors (CI) have revolutionized the management of many cancers but can result in immune-related adverse events (IRAE). In this chapter, we review the clinical manifestations and management of the most common IRAE, plus less common IRAE, such as inflammatory arthritis, of particular interest to rheumatologists. We review the mechanism of action of CI, predictors of IRAE, and the impact of IRAE on cancer outcomes. The study of IRAE is in its infancy; there are very few prospective studies and virtually no treatment trials. Where possible, we have drawn estimates of IRAE incidence from meta-analyses of randomized controlled trials. Clinical descriptions are derived from case series and case reports. Readers are encouraged to refer to consensus guidelines for IRAE management published by the American Society of Clinical Oncology and the Society for Immunotherapy of Cancer.

Inhibition of Glycolysis Reduces Disease Severity in an Autoimmune Model of Rheumatoid Arthritis

The K/BxN mouse is a spontaneous model of arthritis driven by T cell receptor transgenic CD4⁺ T cells from the KRN strain that are activated by glucose-6-phosphate isomerase (GPI) peptides presented by the H-2^g7 allele from the NOD strain. It is a model of autoimmune seropositive arthritis because the production of anti-GPI IgG is necessary and sufficient for joint pathology. The production of high levels of anti-GPI IgG requires on the expansion of CD4⁺ follicular helper T (Tfh) cells. The metabolic requirements of this expansion have never been characterized. Based on the therapeutic effects of the combination of metformin and 2-deoxyglucose (2DG) in lupus models that normalized the expansion of effector CD4⁺ T cells. We showed that the CD4⁺ T cells and to a lesser extent, the B cells from K/BxN mice are more metabolically active than the KRN controls. Accordingly, preventive inhibition of glycolysis with 2DG significantly reduced joint inflammation and the activation of both adaptive and innate immune cells, as well as the production of pathogenic autoantibodies. However, contrary to the lupus-prone mice, the addition of metformin had little beneficial effect, suggesting that glycolysis is the major driver of immune activation in this model. We propose that K/BxN mice are another model in which autoreactive Tfh cells are highly glycolytic and that their function can be limited by inhibiting glucose metabolism.

Rheumatic manifestations among cancer patients treated with immune checkpoint inhibitors

BACKGROUND

The use of immune checkpoint inhibitors (ICI) has grown incessantly since they were first approved in 2014. These monoclonal antibodies inhibit T cell activation, yielding a dramatic tumor response with improved survival. However, immunotherapy is frequently hampered by immune adverse events (iAE) such as hypophysitis, colitis, hepatitis, pneumonitis and rash. Until recently, rheumatic side effects were only infrequently reported.

AIM

To describe the rheumatic manifestations encountered among patients treated with ICIs in a large tertiary cancer center in Israel METHODS: The cancer center's patient registry was screened for patients who had ever been treated with ipilimumab, pembrolizumab and/or nivolumab with relevant data gathered from clinical charts.

RESULTS

Rheumatic manifestations were encountered in 14 of 400 patients (3.5%) who had received immunotherapy between January 1st 2013 and April 30th, 2017. The most common rheumatic manifestation was inflammatory arthritis (85%) for which a third (4/11) had a clear cut predisposing factor such as a personal or family history of psoriasis, a prior episode of uveitis or ACPA positivity. Pulmonary sarcoidosis and biopsy-proven eosinophilic fasciitis were diagnosed in two additional patients. Treatment with NSAIDS was mostly unsuccessful while steroid therapy was beneficial in doses ≥20 mg/d. Methotrexate enabled steroid tapering without an excess of side effects or tumor progression in the short follow-up available. Overall, rheumatic manifestations tended to occur later in the course of immunotherapy as compared to other iAE.

CONCLUSIONS

Our findings underscore that rheumatic iAE are part of the side effect profile of ICIs and require heightened awareness as these therapies are becoming the standard of care for various malignancies. We show that these appear later in the course of iAEs and respond preferentially to high dose steroids. MTX appears effective as a steroid sparing agent.

Physical activity and autoimmune diseases: Get moving and manage the disease

Physical activity, by definition, is any skeletal muscle body movement that results in energy expenditure. In the last few decades, a plethora of scientific evidences have accumulated and confirmed the beneficial role of physical activity as a modifiable risk factor for a wide variety of chronic diseases including cardiovascular diseases (CVDs), diabetes mellitus and cancer, among others. Autoimmune diseases are a heterogeneous group of chronic diseases, which occur secondary to loss of self-antigen tolerance. With the advent of biological therapies, better outcomes have recently been noted in the management of autoimmune diseases. Nonetheless, recent research highlights the salient role of modifiable behaviors such as physical inactivity on various aspects of the immune system and autoimmune diseases. Physical activity leads to a significant elevation in T-regulatory cells, decreased immunoglobulin secretion and produces a shift in the Th1/Th2 balance to a decreased Th1 cell production. Moreover, physical activity has been proven to promote the release of IL-6 from muscles. IL-6 released from muscles functions as a myokine and has been shown to induce an anti-inflammatory response through IL-10 secretion and IL-1β inhibition. Physical activity has been shown to be safe in most of autoimmune diseases including systemic lupus erythematosus (SLE), rheumatoid arthritis (RA), multiple sclerosis (MS), inflammatory bowel diseases (IBD), as well as others. Additionally, the incidence of RA, MS, IBD and psoriasis has been found to be higher in patients less engaged in physical activity. As a general trend, patients with autoimmune diseases tend to be less physically active as compared to the general population. Physically active RA patients were found to have a milder disease course, better cardiovascular disease (CVD) profile, and improved joint mobility. Physical activity decreases fatigue, enhances mood, cognitive abilities and mobility in patients with MS. In SLE patients, enhanced quality of life and better CVD profile were documented in more physically active patients. Physically active patients with type 1 diabetes mellitus have a decreased risk of autonomic neuropathy and CVD. Both fibromyalgia and systemic sclerosis patients report decreased disease severity, pain, as well as better quality of life with more physical activity. Further, SSc patients improve their grip strength, finger stretching and mouth opening with increased level of exercise. The purpose of this paper is to review the clinical evidence regarding the safety, barriers to engagement, and impact of physical activity on autoimmune diseases.