Advances in CTLA-4-Ig-mediated modulation of inflammatory cell and immune response activation in rheumatoid arthritis

Non-TNFi biologic and targeted synthetic DMARDs in rheumatoid arthritis-associated interstitial lung disease: A propensity score-matched, active-comparator, new-user study

OBJECTIVES

This study aimed to compare treatment outcomes in rheumatoid arthritis-associated interstitial lung disease (RA-ILD) between initiators of rituximab, abatacept, tocilizumab, and tofacitinib using the Target Trial Emulation Framework.

METHODS

We emulated three trials comparing abatacept, tocilizumab, and tofacitinib with rituximab (reference). Patients fulfilling validated RA-ILD algorithms initiating one of these non-TNFi b/tsDMARDs were propensity score (PS)-matched (1:1) using national Veterans Affairs (VA) data from 2006 to 2020. PS models included demographics, comorbidities, general health status indicators, and several RA- and ILD-related severity measures. Composite study outcomes were death and respiratory-related hospitalization, ascertained by VA data and linkages to the National Death Index and Medicare, over three-year (primary) and one-year follow-up periods (secondary). Cox regression models were used to analyze study outcomes adjusting for any unbalanced variables. Several sensitivity and subgroup analyses were performed.

RESULTS

In the primary cohort, we 1:1 matched abatacept (n = 150), tocilizumab (n = 73), and tofacitinib (n = 94) with equal numbers of rituximab initiators (mean age 68.1-69.4 years, 88-92 % male). There were no significant differences in the primary composite outcome among any of the comparisons (abatacept aHR: 1.03 [0.72, 1.47]; tocilizumab aHR: 1.15 [0.68, 1.93]; tofacitinib aHR: 0.89 [0.54, 1.46]). Secondary, subgroup, and sensitivity analyses supported the main findings.

CONCLUSIONS

We did not find significant differences in mortality or respiratory hospitalization between RA-ILD patients initiating different non-TNFi b/tsDMARDs, though estimates were imprecise, and residual confounding may be present. These findings emphasize the need for clinical trials of advanced immunomodulatory therapies in RA-ILD.

Activation of TGR5 in the injured nerve site according to a prevention protocol mitigates partial sciatic nerve ligation-induced neuropathic pain by alleviating neuroinflammation

ABSTRACT

Neuropathic pain is a pervasive medical challenge currently lacking effective treatment options. Molecular changes at the site of peripheral nerve injury contribute to both peripheral and central sensitization, critical components of neuropathic pain. This study explores the role of the G-protein-coupled bile acid receptor (GPBAR1 or TGR5) in the peripheral mechanisms underlying neuropathic pain induced by partial sciatic nerve ligation in male mice. TGR5 was upregulated in the injured nerve site and predominantly colocalized with macrophages. Perisciatic nerve administration of the TGR5 agonist, INT-777 according to a prevention protocol (50 μg/μL daily from postoperative day [POD] 0 to POD6) provided sustained relief from mechanical allodynia and spontaneous pain, whereas the TGR5 antagonist, SBI-115 worsened neuropathic pain. Transcriptome sequencing linked the pain relief induced by TGR5 activation to reduced neuroinflammation, which was further evidenced by a decrease in myeloid cells and pro-inflammatory mediators (eg, CCL3, CXCL9, interleukin [IL]-6, and tumor necrosis factor [TNF] α) and an increase in CD86-CD206+ anti-inflammatory macrophages at POD7. Besides, myeloid-cell-specific TGR5 knockdown in the injured nerve site exacerbated both neuropathic pain and neuroinflammation, which was substantiated by bulk RNA-sequencing and upregulated expression levels of inflammatory mediators (including CCL3, CCL2, IL-6, TNF α, and IL-1β) and the increased number of monocytes/macrophages at POD7. Furthermore, the activation of microglia in the spinal cord on POD7 and POD14 was altered when TGR5 in the sciatic nerve was manipulated. Collectively, TGR5 activation in the injured nerve site mitigates neuropathic pain by reducing neuroinflammation, while TGR5 knockdown in myeloid cells worsens pain by enhancing neuroinflammation.

Cell-based therapies for the treatment of rheumatoid arthritis

Autoimmune diseases, including rheumatoid arthritis that is the most prevalent rheumatic autoimmune disorder, affect autologous connective tissues caused by the breakdown of the self-tolerance mechanisms of the immune system. During the last two decades, cell-based therapy, including stem cells and none-stem cells has been increasingly considered as a therapeutic option in various diseases. This is partly due to the unique properties of stem cells that divide and differentiate from the specialized cells in the damaged tissue. Moreover, stem cells and none-stem cells, impose immunomodulatory properties affecting the diseases caused by immunological abnormalities such as rheumatic autoimmune disorders. In the present review, the efficacy of cell-based therapy with four main types of stem cells, including mesenchymal stem cells, hematopoietic stem cells, embryonic stem cells, and human amniotic membrane cells, as well as none-stem cells, including regulatory T cells, chimeric antigen receptor T cells, and tolerogenic dendritic cells will be evaluated. Moreover, other related issues, including safety, changes in immunological parameters, suitable choice of stem cell and none-stem cell origin, conditioning regimen, limitations, and complications will be discussed.

Migraine and risk of rheumatoid arthritis: A systematic review and meta-analysis of observational studies

Background

Exposure to Migraine may be one of the risk factors for the onset of rheumatoid arthritis (RA), while the relationship between the two is debatable. In this study, the connection between migraine and the risk of RA was investigated using a systematic review and meta-analysis of the pertinent literature.

Methods

Up to July 2022, the PubMed, EMBASE, Web of Science (WOS), and scopus databases were employed to search for observational studies on the risk of RA in migraineurs. The effect sizes were pooled using a random-effects model or a fixed-effects model.

Results

Out of 2345 records, 5 studies (3 case and control studies and 2 cohort studies) were identified and included in the meta-analysis. According to a pooled analysis, migraine sufferers had a higher chance of developing RA (pooled adjusted effect estimate: 1.94, 95% confidence interval: 1.74-2.17; p < 0.01).

Conclusions

Migraine can be legitimately regarded as a risk factor for RA since this study demonstrated a relationship between migraine and RA. This conclusion should be treated with caution due to low power and precision. Rigorous design and larger sample sizes of studies are needed to verify the findings.

Mechanism-driven strategies for prevention of rheumatoid arthritis

In seropositive rheumatoid arthritis (RA), the onset of clinically apparent inflammatory arthritis (IA) is typically preceded by a prolonged period of autoimmunity manifest by the presence of circulating autoantibodies that can include antibodies to citrullinated protein antigens (ACPA) and rheumatoid factor (RF). This period prior to clinical IA can be designated preclinical RA in those individuals who have progressed to a clinical diagnosis of RA, and an 'at-risk' status in those who have not developed IA but exhibit predictive biomarkers of future clinical RA. With the goal of developing RA prevention strategies, studies have characterized immune phenotypes of preclinical RA/at-risk states. From these studies, a model has emerged wherein mucosal inflammation and dysbiosis may lead first to local autoantibody production that should normally be transient, but instead is followed by systemic spread of the autoimmunity as manifest by serum autoantibody elevations, and ultimately drives the development of clinically identified joint inflammation. This model can be envisioned as the progression of disease development through serial 'checkpoints' that in principle should constrain or resolve autoimmunity; however, instead the checkpoints 'fail' and clinical RA develops. Herein we review the immune processes that are likely to be present at each step and the potential therapeutic strategies that could be envisioned to delay, diminish, halt or even reverse the progression to clinical RA. Notably, these prevention strategies could utilize existing therapies approved for clinical RA, therapies approved for other diseases that target relevant pathways in the preclinical/at-risk state, or approaches that target novel pathways.

Effects of Biological/Targeted Therapies on Bone Mineral Density in Inflammatory Arthritis

Inflammatory arthritis has been reported to be associated with the development of osteoporosis. Recent research has investigated the mechanisms of bone metabolism in chronic inflammatory arthritis such as rheumatoid arthritis (RA) and spondyloarthritis (SpA). Progress in both animal and clinical studies has provided a better understanding of the osteoclastogenesis-related pathways regarding the receptor activator of nuclear factor-κB ligand (RANKL), anti-citrullinated protein antibodies (ACPAs), and Wnt signaling and Dickkopf-related protein 1 (Dkk-1). The complex interplay between inflammatory cytokines and bone destruction has been elucidated, especially that in the interleukin-17/23 (IL-17/23) axis and Janus kinase and signal transducer and activator of transcription (JAK-STAT) signaling. Moreover, advances in biological and targeted therapies have achieved essential modifications to the bone metabolism of these inflammatory arthritis types. In this narrative review, we discuss recent findings on the pathogenic effects on bone in RA and SpA. Proinflammatory cytokines, autoantibodies, and multiple signaling pathways play an essential role in bone destruction in RA and SpA patients. We also reviewed the underlying pathomechanisms of bone structure in biological and targeted therapies of RA and SpA. The clinical implications of tumor necrosis factor inhibitors, abatacept, rituximab, tocilizumab, Janus kinase inhibitors, and inhibitors of the IL-17/23 axis are discussed. Since these novel therapeutics provide new options for disease improvement and symptom control in patients with RA and SpA, further rigorous evidence is warranted to provide a clinical reference for physicians and patients.

HLA-DRB1 risk alleles for RA are associated with differential clinical responsiveness to abatacept and adalimumab: data from a head-to-head, randomized, single-blind study in autoantibody-positive early RA

Background

Certain risk alleles associated with autoantibody-positive rheumatoid arthritis (RA) have been linked to poorer prognoses. In patients with autoantibody-positive RA, abatacept shows differential efficacy to tumor necrosis factor inhibitors. Our aim was to investigate the relationship between clinical response to abatacept and to adalimumab and presence of risk alleles encoding human leukocyte antigen (HLA)-DRB1 shared epitope (SE) in RA.

Methods

In this head-to-head study, biologic-naïve adults with early (≤ 12 months), moderate-to-severe RA and inadequate response to methotrexate (MTX-IR), autoantibody-positive for both anti-cyclic citrullinated peptide 2 and rheumatoid factor, were randomized 1:1 to receive subcutaneous abatacept 125 mg weekly or subcutaneous adalimumab 40 mg every 2 weeks for 24 weeks with stable, weekly oral MTX. An open-label period to 48 weeks followed, during which adalimumab-treated patients were switched to abatacept. Patients were genotyped for HLA-DRB1 alleles and classified as SE-positive (≥ 1 SE allele) or SE-negative (no SE alleles). Efficacy was assessed at weeks 24 and 48.

Results

Forty patients each received abatacept (9 SE-negative, 30 SE-positive, one unknown) or adalimumab (9 SE-negative, 31 SE-positive). Mean age and disease duration were 46.0 years and 5.5 months, respectively. At week 24, a greater percentage of abatacept patients achieved 50% improvement in ACR criteria (ACR50) compared with adalimumab patients (73% vs 45%, respectively) and estimate of difference (95% confidence interval [CI]), 28 (5, 48). In SE-positive patients, ACR50 estimate of difference (95% CI) was 32 (7, 55). During the open-label period, responses were sustained in the abatacept non-switch group and showed trends toward further improvement in the adalimumab-to-abatacept switch group at week 48, in both the overall and the SE-positive subpopulation. No new safety signals were identified.

Conclusions

In MTX-IR patients with early, autoantibody-positive RA, abatacept resulted in numerically higher efficacy responses versus adalimumab after 24 weeks, with more pronounced treatment differences in SE-positive patients. After 48 weeks, responses were sustained in patients who continued abatacept while those who switched to abatacept showed further clinical improvement, overall, and in SE-positive patients. This supports co-stimulation blockade as an effective treatment strategy for patients with early, autoantibody-positive RA, particularly among SE-positive patients.

Trial registration

NIH US National Library of Medicine, NCT02557100. Registered on September 23, 2015.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13075-021-02607-7.

Tuning Monocytes and Macrophages for Personalized Therapy and Diagnostic Challenge in Rheumatoid Arthritis

Monocytes/macrophages play a central role in chronic inflammatory disorders, including rheumatoid arthritis (RA). Activation of these cells results in the production of various mediators responsible for inflammation and RA pathogenesis. On the other hand, the depletion of macrophages using specific antibodies or chemical agents can prevent their synovial tissue infiltration and subsequently attenuates inflammation. Their plasticity is a major feature that helps the switch from a pro-inflammatory phenotype (M1) to an anti-inflammatory state (M2). Therefore, understanding the precise strategy targeting pro-inflammatory monocytes/macrophages should be a powerful way of inhibiting chronic inflammation and bone erosion. In this review, we demonstrate potential consequences of different epigenetic regulations on inflammatory cytokines production by monocytes. In addition, we present unique profiles of monocytes/macrophages contributing to identification of new biomarkers of disease activity or predicting treatment response in RA. We also outline novel approaches of tuning monocytes/macrophages by biologic drugs, small molecules or by other therapeutic modalities to reduce arthritis. Finally, the importance of cellular heterogeneity of monocytes/macrophages is highlighted by single-cell technologies, which leads to the design of cell-specific therapeutic protocols for personalized medicine in RA in the future.

Systemic administration of cytotoxic T lymphocyte-associated antigen 4 (CTLA-4)-Ig abrogates alveolar bone resorption in induced periodontitis through inhibition of osteoclast differentiation and activation: An experimental investigation

BACKGROUND/OBJECTIVES

Cytotoxic T lymphocyte-associated antigen 4 (CTLA-4) is a critical immunoregulatory molecule expressed on T cells. CTLA-4 also binds to the surfaces of monocytes and macrophages, precursors of osteoclasts. Research on rheumatoid arthritis demonstrated that CTLA-4 suppresses inflammation and bone resorption. However, its effects on alveolar bone have yet to be understood. The purpose of this study was to investigate the role and potential mechanism of CTLA-4 in bone resorption in periodontitis.

MATERIALS AND METHODS

In vivo, the effects of systemic administration of CTLA-4 immunoglobulin fusion protein (CTLA-4-Ig) on alveolar bone resorption were investigated using a periodontitis mouse model. A total of 20 C57BL/6J mice were randomly assigned to two groups according to the administration modes. Periodontitis was induced by placing a ligature around the left maxillary second molar. The contralateral tooth was left un-ligated. In the CTLA-4-Ig (+) group, CTLA-4-Ig was administered by intraperitoneal injection at 1 and 3 days after ligature placement. Animals in the CTLA-4-Ig (-) group were given only phosphate-buffered saline each time. At 5 days after ligature placement, bone resorption was assessed by micro-computed tomography and histological examination, and the prevalence of osteoclast-like cells was assessed by tartrate-resistant acid phosphatase (TRAP) staining. In vitro, the effects of CTLA-4-Ig on osteoclasts were evaluated. Viability of RAW 264.7 cells treated with receptor activator of nuclear factor-κB ligand (RANKL) and CTLA-4-Ig was tested by WST-1 assay. Osteoclast-like cells were enumerated by TRAP staining, and osteoclast activity was evaluated by resorption pit assay. Gene expression levels of osteoclast differentiation markers (macrophage-colony stimulating factor receptor, carbonic anhydrase II, cathepsin K, and Trap) and protein phosphatase 2A (PP2A), a major serine-threonine phosphatase, were assessed by quantitative real-time polymerase chain reaction. The effect of CTLA-4-Ig on the nuclear factor-κB (NF-κB) activation was assessed by enzyme-linked immunosorbent assay.

RESULTS

In vivo, ligature-induced bone resorption and the numbers of osteoclast-like cells were significantly decreased by the administration of CTLA-4-Ig. In vitro, treatment with RANKL and CTLA-4-Ig had no significant effect on cell viability. CTLA-4-Ig significantly reduced the prevalence and activation of osteoclast-like cells and decreased the expressions of osteoclast differentiation markers, compared with the RANKL-treated control. CTLA-4-Ig significantly suppressed RANKL-induced phosphorylation of NF-κB p65 but increased PP2A expression.

CONCLUSION

These results suggest that CTLA-4-Ig abrogates bone resorption in induced periodontitis, possibly via inhibition of osteoclast differentiation and activation. The regulation of the NF-κB pathway and PP2A expression may be one mechanism by which CTLA-4-Ig suppresses osteoclast behavior.

Risk of opportunistic infections in patients with rheumatoid arthritis initiating abatacept: cumulative clinical trial data

BACKGROUND

To evaluate incidence of opportunistic infections (OIs) in patients with rheumatoid arthritis (RA) treated with abatacept in clinical trials.

METHODS

This pooled analysis of 16 randomized, double-blind/open-label trials, with ≥ 1 abatacept (intravenous or subcutaneous) arm, and with/without placebo control covered cumulative (controlled short-term and open-label long-term) abatacept exposure periods. OIs were analyzed separately in controlled (abatacept and placebo individually) and cumulative periods. OIs were identified using a prespecified list; events were independently adjudicated. Unadjusted incidence rates (IRs; per 100 patient-years) with 95% confidence intervals (CIs) were calculated.

RESULTS

In cumulative periods, 7044 patients received abatacept, with a mean (standard deviation) duration of exposure of 36.9 (26.2) months (21,274 patient-years of exposure). IRs (95% CIs) of OIs were 0.17 (0.05-0.43) for abatacept and 0.56 (0.22-1.15) for placebo during the controlled periods and 0.21 (0.15-0.28) for abatacept during the cumulative periods. There was 1 case of tuberculosis in both the abatacept (IR [95% CI] 0.04 [0.00-0.24]) and placebo (IR [95% CI] 0.08 [0.00-0.44]) groups during the controlled periods; 13 verified tuberculosis cases (IR [95% CI] 0.06 [0.03-0.10]) were reported in the cumulative period. Herpes zoster was reported numerically more often with abatacept (IR 1.9 [1.4-2.5]), versus placebo (1.7 [1.1-2.6]) in the controlled periods; within the cumulative period, herpes zoster IR (95% CI) was 1.53 (1.36-1.71) for abatacept-treated patients.

CONCLUSION

In controlled periods of the clinical trials, abatacept-treated patients had similarly low rates of OIs compared with placebo-treated patients. Overall, OI rates were similar among abatacept-treated patients in the controlled and cumulative periods and consistent with the ranges reported in the literature.

CD80 Insights as Therapeutic Target in the Current and Future Treatment Options of Frequent-Relapse Minimal Change Disease

Minimal change disease (MCD) is the most common cause of idiopathic nephrotic syndrome in children, and it is well known for its multifactorial causes which are the manifestation of the disease. Proteinuria is an early consequence of podocyte injury and a typical sign of kidney disease. Steroid-sensitive patients react well with glucocorticoids, but there is a high chance of multiple relapses. CD80, also known as B7-1, is generally expressed on antigen-presenting cells (APCs) in steroid-sensitive MCD patients. Various glomerular disease models associated with proteinuria demonstrated that the detection of CD80 with the increase of urinary CD80 was strongly associated closely with frequent-relapse MCD patients. The role of CD80 in MCD became controversial because one contradicts finding. This review covers the treatment alternatives for MCD with the insight of CD80 as a potential therapeutic target. The promising effectiveness of CD20 (rituximab) antibody and CD80 inhibitor (abatacept) encourages further investigation of CD80 as a therapeutic target in frequent-relapse MCD patients. Therapeutic-based antibody towards CD80 (galiximab) had never been investigated in MCD or any kidney-related disease; hence, the role of CD80 is still undetermined. A new therapeutic approach towards MCD is essential to provide broader effective treatment options besides the general immunosuppressive agents with gruesome adverse effects.

Development of an intravital imaging system for the synovial tissue reveals the dynamics of CTLA-4 Ig in vivo

There have been many attempts to visualize the inflamed joints using multiphoton microscopy. However, due to the hypervascular and multilayered structure of the inflamed synovium, intravital imaging of the deep synovial tissue has been difficult. Here, we established original intravital imaging systems to visualize synovial tissue and pathological osteoclasts at the pannus–bone interface using multiphoton microscopy. Combined with fluorescence-labeling of CTLA-4 Ig, a biological agent used for the treatment of rheumatoid arthritis, we identified that CTLA-4 Ig was distributed predominantly within the inflamed synovium and bound to CX₃CR1⁺ macrophages and CD140a⁺ fibroblasts 6 h after injection, but not to mature osteoclasts. Intravital imaging of blood and lymphatic vessels in the inflamed synovium further showed that extravasated CTLA-4 Ig was immediately drained through lymphatic vessels under acute arthritic conditions, but the drainage activity was retarded under chronic conditions. These results indicate that this intravital synovial imaging system can serve as a platform for exploring the dynamics of immune cells, osteoclasts, and biological agents within the synovial microenvironment in vivo.

Poor prognostic factors in predicting abatacept response in a phase III randomized controlled trial in psoriatic arthritis

In ASTRAEA (NCT01860976), abatacept significantly increased American College of Rheumatology criteria 20% (ACR20) responses at Week 24 versus placebo in patients with psoriatic arthritis (PsA). This post hoc analysis explored relationships between prospectively identified baseline characteristics [poor prognostic factors (PPFs) ] and response to abatacept. Patients were randomized (1:1) to receive subcutaneous abatacept 125 mg weekly or placebo for 24 weeks; those without ≥ 20% improvement in joint counts at Week 16 switched to open-label abatacept. Potential predictors of ACR20 response were identified by treatment arm using multivariate analyses. Likelihood of ACR20 response to abatacept versus placebo was compared in univariate and multivariate analyses in subgroups stratified by the PPF, as defined by EULAR and/or GRAPPA treatment guidelines. Odds ratios (ORs) were generated using logistic regression to identify meaningful differences (OR cut-off: 1.2). 424 patients were randomized and treated (abatacept n = 213; placebo n = 211). In abatacept-treated patients, elevated C-reactive protein (CRP), high Disease Activity Score based on 28 joints (CRP), presence of dactylitis, and ≥ 3 joint erosions were identified as predictors of response (OR > 1.2). In placebo-treated patients, only dactylitis was a potential predictor of response. In the univariate analysis stratified by PPF, ACR20 response was more likely (OR > 1.2) with abatacept versus placebo in patients with baseline PPFs than in those without; multivariate analysis confirmed this finding. Response to abatacept versus placebo is more likely in patients with features indicative of high disease activity and progressive disease; these characteristics are recognized as PPFs in treatment guidelines for PsA.

Comparative risk of malignancies and infections in patients with rheumatoid arthritis initiating abatacept versus other biologics: a multi-database real-world study

Background

Patients with rheumatoid arthritis (RA) are at an increased risk of developing certain cancers and infections compared with the general population. Biologic and targeted synthetic disease-modifying antirheumatic drugs (b/tsDMARDs) are effective treatment options for RA, but limited evidence is available on the comparative risks among b/tsDMARDs. We assessed the risk of malignancies and infections in patients with RA who initiated abatacept versus other b/tsDMARDs in a real-world setting.

Methods

This retrospective, observational study used administrative data from three large US healthcare databases (MarketScan, PharMetrics, and Optum) to identify patients treated with abatacept or other b/tsDMARDs. In both groups, age-stratified incidence rates (IRs) with 95% confidence intervals (CIs) were calculated for total malignancy and hospitalized infections; propensity score matching and Cox proportional hazards regression models were used to estimate hazard ratios (HRs) with 95% CIs for total malignancy, lung cancer, lymphoma, breast cancer, non-melanoma skin cancer (NMSC), hospitalized infections, opportunistic infections, and tuberculosis (TB), both within individual databases and in meta-analyses across the three databases.

Results

A rounded total of 19.2, 13.6, and 4.2 thousand patients initiating abatacept and 55.3, 40.8, and 13.8 thousand initiating other b/tsDMARDs were identified in the MarketScan, PharMetrics, and Optum databases, respectively. The IRs for total malignancy and hospitalized infections were similar between the two groups in each age stratum. In meta-analyses, total malignancy risk (HR [95% CI] 1.09 [1.02–1.16]) of abatacept versus other b/tsDMARDs was slightly but statistically significantly increased; small, but not statistically significant, increases were seen for lung cancer (1.10 [0.62–1.96]), lymphoma (1.27 [0.94–1.72]), breast cancer (1.15 [0.92–1.45]), and NMSC (1.10 [0.93–1.30]). No significant increase in hospitalized infections (0.96 [0.84–1.09]) or opportunistic infections (1.06 [0.96–1.17]) was seen. For TB, low event counts precluded meta-analysis.

Conclusions

In this real-world multi-database study, the risks for specific cancers and infections did not differ significantly between patients in the abatacept and other b/tsDMARDs groups. The slight increase in total malignancy risk associated with abatacept needs further investigation. These results are consistent with the established safety profile of abatacept.

Synthesis and Structure-Affinity Relationship of Small Molecules for Imaging Human CD80 by Positron Emission Tomography

The costimulatory molecule CD80 is an early marker for immune activation. It is upregulated on activated antigen-presenting cells. We aimed at developing a tracer for imaging CD80 by positron emission tomography (PET). Novel CD80 ligands were synthesized and tested by SPR for affinity to human CD80 (hCD80) and displacement of endogenous ligands. Several compounds bound with one-digit nanomolar affinity to hCD80 and displaced CTLA-4 and CD28 at nanomolar concentrations. A structure-affinity relationship study revealed relevant moieties for strong affinity to hCD80 and positions for further modifications. Lead compound MT107 (7f) was radiolabeled with carbon-11. In vitro, [¹¹C]MT107 showed specific binding to hCD80-positive tissue and high plasma protein binding. In vivo, [¹¹C]MT107 accumulated in liver, gall bladder, and intestines but only scarcely in hCD80-positive xenografts. The unfavorable in vivo performance may result from high plasma protein binding and extensive biliary excretion.

Differential gene expression in articular cartilage between rheumatoid arthritis and endemic Kashin-Beck disease

Kashin-beck disease (KBD) is endemic chronic osteoarthrosis and its pathogenesis is still unclear. The present study aimed to explore differential gene expression in articular cartilage between patients with rheumatoid arthritis (RA) and KBD. Articular cartilages were collected from KBD and RA patients, and differentially expressed genes (DEGs) were analyzed by RNA-seq. The signaling pathway and biological process (BP) of the DEGs were identified by enrichment analysis. The protein-protein interaction (PPI) network of DEGs and the key genes of KBD were identified by network analysis with STRING and cytoscape software. We identified 167 immune-related DEGs in articular cartilage samples from KBD patients compared with RA. The up-regulation of MAPK signaling pathway and the down-regulation of signaling pathways such as toll-like receptor, janus kinase-signal transducers and activators of transcription, leukocyte migration, T-cell receptor and chemokine, and antigen processing and presentation were involved in KBD. We identified 137 genes nodes related with immune and mapped the PPI network diagram. BP analysis revealed that immune response, calcium ion homeostasis, blood vessel morphogenesis, inflammatory response, lymphocyte proliferation, and MAPK activation were involved in KBD. In conclusion, gene expression profiling can be used to identify the different mechanism of pathogenesis between KBD and RA.

Improved patient-reported outcomes in patients with psoriatic arthritis treated with abatacept: results from a phase 3 trial

BACKGROUND

To explore the effect of abatacept treatment on patient-reported outcomes (PROs) in psoriatic arthritis (PsA).

METHODS

Patients with PsA were randomised (1:1) to subcutaneous abatacept 125 mg weekly/placebo for 24 weeks with early escape (EE) to open-label abatacept (week 16). Adjusted mean changes from baseline to weeks 16 (all patients) and 24 (non-EE responders) in Health Assessment Questionnaire-Disability Index (HAQ-DI), Short Form-36 (SF-36; physical and mental component summary and domains), Dermatology Life Quality Index and Functional Assessment of Chronic Illness Therapy-Fatigue (FACIT-F) were evaluated. Subpopulations were analysed by baseline C-reactive protein (CRP) level (> vs ≤ upper limit of normal [ULN]) and prior tumour necrosis factor inhibitor (TNFi) exposure. Proportions of patients reporting improvements ≥ minimal clinically important differences (MCIDs) and ≥ normative values (NVs) in HAQ-DI, SF-36 and FACIT-F (week 16 before EE) were analysed.

RESULTS

In total population, numerically higher improvements in most PROs were reported with abatacept (n = 213) versus placebo (n = 211) at both time points (P > 0.05). Higher proportions of abatacept versus placebo patients reported PRO improvements ≥ MCID and ≥ NV at week 16. At week 16, all PRO improvements were numerically greater (P > 0.05) in patients with baseline CRP > ULN versus CRP ≤ ULN (all significant [95% confidence interval] for abatacept vs placebo); improvements in SF-36 component summaries and FACIT-F were greater in TNFi-naïve versus TNFi-exposed patients (abatacept > placebo). Week 24 subgroup data were difficult to interpret due to low patient numbers.

CONCLUSIONS

Abatacept treatment improved PROs in patients with PsA versus placebo, with better results in elevated baseline CRP and TNFi-naïve subpopulations.

TRIAL REGISTRATION

ClinicalTrials.gov number, NCT01860976 (funded by Bristol-Myers Squibb); date of registration: 23 May 2013.

Abatacept in combination with methotrexate in Japanese biologic-naive patients with active rheumatoid arthritis: a randomised placebo-controlled phase IV study

Objectives

To evaluate efficacy and safety of abatacept+methotrexate (MTX) in biologic-naive, anticitrullinated protein antibody (ACPA)-positive Japanese patients with active rheumatoid arthritis (RA) and early erosion versus placebo+MTX.

Methods

In this phase IV, multicentre, double-blind study (NCT01758198), patients were randomised (1:1) to receive intravenous abatacept (~10 mg/kg) or placebo, plus MTX (≥6 mg/week). Primary efficacy objectives were to compare American College of Rheumatology 20 (ACR20) response rates at week 16 and mean change from baseline in van der Heijde-modified total Sharp score (vdH-mTSS) at week 24 between abatacept+MTX and placebo+MTX groups.

Results

Overall, 203 and 202 patients received abatacept+MTX and placebo+MTX, respectively. At week 16, ACR20 response rates were higher in the abatacept (75.4%) versus placebo group (27.7%; p<0.001). Mean change from baseline in vdH-mTSS at week 24 was 0.84 in the abatacept and 1.26 in the placebo group (p=0.017). Radiographic non-progression rates (change in vdH-mTSS≤smallest detectable change (1.9)) were 88.1% and 75.4% in abatacept and placebo groups, respectively. Adjusted mean change from baseline in Disease Activity Score 28 (C-reactive protein) (DAS28 (CRP)) at week 16 demonstrated a numerically greater reduction in the abatacept versus placebo group. Proportions of patients with DAS28 (CRP), Simplified Disease Activity Index and Clinical Disease Activity Index remission up to week 52 were higher in the abatacept versus placebo group. The abatacept safety profile was consistent with previous observations.

Conclusions

Compared with MTX alone, abatacept+MTX improved clinical symptoms and inhibited structural damage progression in ACPA-positive, Japanese patients with RA, early erosion and inadequate response to MTX.

On-drug and drug-free remission by baseline symptom duration: abatacept with methotrexate in patients with early rheumatoid arthritis

Clinical outcomes in patients with early rheumatoid arthritis (RA) were assessed by baseline symptom duration in the Assessing Very Early Rheumatoid arthritis Treatment trial (ClinicalTrials.gov; NCT01142726). Patients with early, active RA were randomized to subcutaneous (SC) abatacept 125 mg/week plus methotrexate (MTX), SC abatacept alone, or MTX monotherapy for 12 months. All RA treatments were withdrawn after 12 months in patients with Disease Activity Score in 28 joints (C-reactive protein; DAS28-CRP) < 3.2. In this post hoc analysis, the proportion of patients achieving protocol-defined remission (DAS28-CRP < 2.6) or improvement in physical function at 12 and at both 12 and 18 months was assessed according to symptom duration (≤ 3 months, > 3 to ≤ 6 months, or > 6 months) and treatment group. No clinically significant differences were seen in baseline demographics or characteristics across symptom duration groups. Irrespective of baseline symptom duration, a numerically higher proportion of abatacept plus MTX-treated patients achieved DAS-defined remission at month 12 and sustained remission at month 18 compared with MTX monotherapy. A numerically higher proportion of abatacept plus MTX-treated patients with symptom duration ≤ 3 months maintained DAS-defined remission after complete treatment withdrawal from 12 to 18 months compared with longer symptom duration groups. This subgroup also had the fastest onset of clinical response (DAS28-CRP < 2.6) after initiation of treatment. Health Assessment Questionnaire-Disability Index response was similar regardless of baseline symptom duration. Overall, symptom duration of ≤ 3 months was associated with a faster onset of clinical response and higher rates of drug-free remission following treatment with abatacept plus MTX.

Molecular Mechanisms of T Cells Activation by Dendritic Cells in Autoimmune Diseases

The interaction between T cell and dendritic cells (DCs) that leads to T cell activation affects the progression of the immune response including autoimmune diseases. Antigen presentation on immune cell surface, formation of an immunological synapse (IS), and specific identification of complex by T cells including two activating signals are necessary steps that lead to T cell activation. The formation of stimulatory IS involves the inclusion of costimulatory molecules, such as ICAM-1/LFA-1 and CD28/B7-1, and so on. Some fusion proteins and monoclonal antibodies targeting costimulatory molecules have been developed and approved to treat autoimmune diseases, including rheumatoid arthritis (RA), systemic lupus erythematosus (SLE), multiple sclerosis (MS), type I diabetes (T1D), inflammatory bowel disease (IBD), and psoriasis. These biological agents, including CTLA-4- and LFA-3-Ig, anti-CD3 monoclonal antibody, could prevent the successful engagement of DCs by T cell with significant efficacy and safety profile. In this article, we reviewed the molecular mechanisms of T cell activation during the interaction between T cells and DCs, and summarized some biological agents that target costimulatory molecules involved in the regulation of T cell activation.

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.

The expression of mCTLA-4 in skin lesion inversely correlates with the severity of psoriasis

BACKGROUND

Psoriasis is a chronic inflammatory disease characterized by epidermal hyperplasia and increased T cell infiltration. Cytotoxic T lymphocyte antigen-4 (CTLA-4) is a key factor that affects T cell function and immune response. However, whether the expression of CTLA-4 affects the severity of psoriasis is still unknown.

OBJECTIVE

The aim of the project was to investigate the correlation between the expression of CTLA-4 and the severity of psoriasis.

METHODS

The plasma soluble CTLA-4 levels and membrane CTLA-4 expression were measured by enzyme-linked immunosorbent assay and immunohistochemistry analysis in mild, moderate and severe psoriasis patients, respectively. Imiquimod-induced mouse model of psoriasis was treated with CTLA-4 immunoglobulin fusion protein (CTLA-4 Ig) or anti-CTLA-4 antibody. Epidermal thickness and infiltrating CD3+ T cell counts were evaluated.

RESULTS

The plasma soluble CTLA-4 levels had no significant difference among mild, moderate, and severe patients (p > 0.05). However, the membrane CTLA-4 expression in skin was significantly higher in mild psoriasis patients compared to moderate and severe psoriasis patients (17652.86 ± 18095.66 vs 6901.36 ± 4400.77 vs 3970.24 ± 5509.15, p < 0.001). Furthermore, in imiquimod-induced mouse model of psoriasis, the results showed that mimicking CTLA-4 function improved the skin phenotype and reduced epidermal thickness (172.87 ± 28.25 vs 245.87 ± 36.61 μm, n = 6, p < 0.01) as well as infiltrating CD3+ T cell counts (5.09 ± 3.45 vs 13.45 ± 4.70, p < 0.01) compared to control group. However, blocking CTLA-4 function aggregated the skin phenotype including enhanced epidermal thickness and infiltrating CD3+ T cell counts compared to control group.

CONCLUSION

These results indicated that the expression of mCTLA-4 in skin lesion inversely correlated with the severity of psoriasis and CTLA-4 might play a critical role in the disease severity of psoriasis.

Genome-Wide Association Meta-Analysis Reveals Novel Juvenile Idiopathic Arthritis Susceptibility Loci

OBJECTIVE

Juvenile idiopathic arthritis (JIA) is the most common childhood rheumatic disease and has a strong genomic component. To date, JIA genetic association studies have had limited sample sizes, used heterogeneous patient populations, or included only candidate regions. The aim of this study was to identify new associations between JIA patients with oligoarticular disease and those with IgM rheumatoid factor (RF)-negative polyarticular disease, which are clinically similar and the most prevalent JIA disease subtypes.

METHODS

Three cohorts comprising 2,751 patients with oligoarticular or RF-negative polyarticular JIA were genotyped using the Affymetrix Genome-Wide SNP Array 6.0 or the Illumina HumanCoreExome-12+ Array. Overall, 15,886 local and out-of-study controls, typed on these platforms or the Illumina HumanOmni2.5, were used for association analyses. High-quality single-nucleotide polymorphisms (SNPs) were used for imputation to 1000 Genomes prior to SNP association analysis.

RESULTS

Meta-analysis showed evidence of association (P < 1 × 10^-6 ) at 9 regions: PRR9_LOR (P = 5.12 × 10^-8 ), ILDR1_CD86 (P = 6.73 × 10^-8 ), WDFY4 (P = 1.79 × 10^-7 ), PTH1R (P = 1.87 × 10^-7 ), RNF215 (P = 3.09 × 10^-7 ), AHI1_LINC00271 (P = 3.48 × 10^-7 ), JAK1 (P = 4.18 × 10^-7 ), LINC00951 (P = 5.80 × 10^-7 ), and HBP1 (P = 7.29 × 10^-7 ). Of these, PRR9_LOR, ILDR1_CD86, RNF215, LINC00951, and HBP1 were shown, for the first time, to be autoimmune disease susceptibility loci. Furthermore, associated SNPs included cis expression quantitative trait loci for WDFY4, CCDC12, MTP18, SF3A1, AHI1, COG5, HBP1, and GPR22.

CONCLUSION

This study provides evidence of both unique JIA risk loci and risk loci overlapping between JIA and other autoimmune diseases. These newly associated SNPs are shown to influence gene expression, and their bounding regions tie into molecular pathways of immunologic relevance. Thus, they likely represent regions that contribute to the pathology of oligoarticular JIA and RF-negative polyarticular JIA.

Efficacy and safety of abatacept, a T-cell modulator, in a randomised, double-blind, placebo-controlled, phase III study in psoriatic arthritis

OBJECTIVES

To assess the efficacy and safety of abatacept, a selective T-cell costimulation modulator, in a phase III study in psoriatic arthritis (PsA).

METHODS

This study randomised patients (1:1) with active PsA (~60% with prior exposure to a tumour necrosis factor inhibitor) to blinded weekly subcutaneous abatacept 125 mg (n=213) or placebo (n=211) for 24 weeks, followed by open-label subcutaneous abatacept. Patients without ≥20% improvement in joint counts at week 16 were switched to open-label abatacept. The primary end point was the proportion of patients with ≥20% improvement in the American College of Rheumatology (ACR20) criteria at week 24.

RESULTS

Abatacept significantly increased ACR20 response versus placebo at week 24 (39.4% vs 22.3%; p<0.001). Although abatacept numerically increased Health Assessment Questionnaire-Disability Index response rates (reduction from baseline ≥0.35) at week 24, this was not statistically significant (31.0% vs 23.7%; p=0.097). The benefits of abatacept were seen in ACR20 responses regardless of tumour necrosis factor inhibitor exposure and in other musculoskeletal manifestations, but significance could not be attributed due to ranking below Health Assessment Questionnaire-Disability Index response in hierarchical testing. However, the benefit on psoriasis lesions was modest. Efficacy was maintained or improved up to week 52. Abatacept was well tolerated with no new safety signals.

CONCLUSIONS

Abatacept treatment of PsA in this phase III study achieved its primary end point, ACR20 response, showed beneficial trends overall in musculoskeletal manifestations and was well tolerated. There was only a modest impact on psoriasis lesions.

TRIAL REGISTRATION NUMBER

ClinicalTrials.gov number, NCT01860976 (funded by Bristol-Myers Squibb).

Abatacept: A Review in Rheumatoid Arthritis

The biological DMARD (bDMARD) abatacept (Orencia^®), a recombinant fusion protein, selectively modulates a co-stimulatory signal necessary for T-cell activation. In the EU, abatacept is approved for use in patients with highly active and progressive rheumatoid arthritis (RA) not previously treated with methotrexate. Abatacept is also approved for the treatment of moderate to severe active RA in patients with an inadequate response to previous therapy with at least one conventional DMARD (cDMARD), including methotrexate or a TNF inhibitor. In phase III trials, beneficial effects on RA signs and symptoms, disease activity, structural damage progression and physical function were seen with intravenous (IV) or subcutaneous (SC) abatacept regimens, including abatacept plus methotrexate in methotrexate-naive patients with early RA and poor prognostic factors, and abatacept plus methotrexate or other cDMARDs in patients with inadequate response to methotrexate or TNF inhibitors. Benefits were generally maintained during longer-term follow-up. Absolute drug-free remission rates following withdrawal of all RA treatments were significantly higher with abatacept plus methotrexate than with methotrexate alone. Both IV and SC abatacept were generally well tolerated, with low rates of immunogenicity. Current evidence therefore suggests that abatacept is a useful treatment option for patients with RA.

T cell costimulation blockade blunts pressure overload-induced heart failure

Heart failure (HF) is a leading cause of mortality. Inflammation is implicated in HF, yet clinical trials targeting pro-inflammatory cytokines in HF were unsuccessful, possibly due to redundant functions of individual cytokines. Searching for better cardiac inflammation targets, here we link T cells with HF development in a mouse model of pathological cardiac hypertrophy and in human HF patients. T cell costimulation blockade, through FDA-approved rheumatoid arthritis drug abatacept, leads to highly significant delay in progression and decreased severity of cardiac dysfunction in the mouse HF model. The therapeutic effect occurs via inhibition of activation and cardiac infiltration of T cells and macrophages, leading to reduced cardiomyocyte death. Abatacept treatment also induces production of anti-inflammatory cytokine interleukin-10 (IL-10). IL-10-deficient mice are refractive to treatment, while protection could be rescued by transfer of IL-10-sufficient B cells. These results suggest that T cell costimulation blockade might be therapeutically exploited to treat HF.

Abatacept is an FDA-approved drug used for treatment of rheumatoid arthritis. Here the authors show that abatacept reduces cardiomyocyte death in a mouse model of heart failure by inhibiting activation and heart infiltration of T cells and macrophages, an effect mediated by IL-10, suggesting a potential therapy for heart failure.

Biologic therapies and bone loss in rheumatoid arthritis

INTRODUCTION

Rheumatoid arthritis (RA) is a common systemic autoimmune disease of unknown cause, characterized by a chronic, symmetric, and progressive inflammatory polyarthritis. One of the most deleterious effects induced by the chronic inflammation of RA is bone loss. During the last 15 years, the better knowledge of the cytokine network involved in RA allowed the development of potent inhibitors of the inflammatory process classified as biological DMARDs. These new drugs are very effective in the inhibition of inflammation, but there are only few studies regarding their role in bone protection. The principal aim of this review was to show the evidence of the principal biologic therapies and bone loss in RA, focusing on their effects on bone mineral density, bone turnover markers, and fragility fractures.

METHODS

Using the PICOST methodology, two coauthors (PC, LM-S) conducted the search using the following MESH terms: rheumatoid arthritis, osteoporosis, clinical trials, TNF- antagonists, infliximab, adalimumab, etanercept, certolizumab, golimumab, IL-6 antagonists, IL-1 antagonists, abatacept, tocilizumab, rituximab, bone mineral density, bone markers, and fractures. The search was conducted electronically and manually from the following databases: Medline and Science Direct. The search period included articles from 2003 to 2015. The selection included only original adult human research written in English. Titles were retrieved and the same two authors independently selected the relevant studies for a full text. The retrieved selected studies were also reviewed completing the search for relevant articles. The first search included 904 titles from which 253 titles were selected. The agreement on the selection among researchers resulted in a Kappa statistic of 0.95 (p < 0.000). Only 248 abstracts evaluated were included in the acronym PICOST. The final selection included only 28 studies, derived from the systematic search. Additionally, a manual search in the bibliography of the selected articles was made and included into the text and into the section of "small molecules of new agents."

CONCLUSION

Treatment with biologic drugs is associated with the decrease in bone loss. Studies with anti-TNF blocking agents show preservation or increase in spine and hip BMD and also a better profile of bone markers. Most of these studies were performed with infliximab. Only three epidemiological studies analyzed the effect on fractures after anti-TNF blocking agent's treatment. IL-6 blocking agents also showed improvement in localized bone loss not seen with anti-TNF agents. There are a few studies with rituximab and abatacept. Although several studies reported favorable actions of biologic therapies on bone protection, there are still unmet needs for studies regarding their actions on the risk of bone fractures.

Long-term safety and efficacy of treatment with subcutaneous abatacept in Japanese patients with rheumatoid arthritis who are methotrexate inadequate responders

OBJECTIVE

To assess the long-term safety, immunogenicity, and efficacy of subcutaneous (SC) abatacept in combination with methotrexate (MTX) in Japanese patients with rheumatoid arthritis who were MTX inadequate responders, in a long-term extension (LTE) to a double-dummy, double-blind study (NCT01001832).

METHODS

Patients, who had previously received SC or intravenous (IV) abatacept with MTX (6-8 mg/week) for 24 weeks, received SC abatacept (125 mg/week) with MTX for an additional 52 weeks. Safety, immunogenicity, and efficacy were assessed.

RESULTS

The LTE included 112 patients. SC abatacept was generally well tolerated in the LTE, with no new safety signals. American College of Rheumatology 20, 50, and 70 response rates, disease activity score 28 (C-reactive protein) remission rates (< 2.6), and Health Assessment Questionnaire-Disability Index response rates (≥ 0.3 improvement from baseline) achieved at the end of the double-blind period were maintained over the LTE and were comparable in patients who received SC or IV abatacept in the double-blind period. Seropositivity for immunogenicity occurred in 4 (3.6%) patients. Self-injection of SC abatacept was well controlled and not associated with additional safety events.

CONCLUSIONS

SC abatacept had acceptable safety and was well tolerated and effective over the LTE (76 weeks in total), with low rates of immunogenicity in Japanese patients.

Delayed Cytotoxic T Lymphocyte-Associated Protein 4-Immunoglobulin Treatment Reverses Ongoing Alloantibody Responses and Rescues Allografts From Acute Rejection

Antibody-mediated rejection has emerged as the leading cause of late graft loss in kidney transplant recipients, and inhibition of donor-specific antibody production should lead to improved transplant outcomes. The fusion protein cytotoxic T lymphocyte-associated protein 4-immunoglobulin (CTLA4-Ig) blocks T cell activation and consequently inhibits T-dependent B cell antibody production, and the current paradigm is that CTLA4-Ig is effective with naïve T cells and less so with activated or memory T cells. In this study, we used a mouse model of allosensitization to investigate the efficacy of continuous CTLA4-Ig treatment, initiated 7 or 14 days after sensitization, for inhibiting ongoing allospecific B cell responses. Delayed treatment with CTLA4-Ig collapsed the allospecific germinal center B cell response and inhibited alloantibody production. Using adoptively transferred T cell receptor transgenic T cells and a novel approach to track endogenous graft-specific T cells, we demonstrate that delayed CTLA4-Ig minimally inhibited graft-specific CD4(+) and T follicular helper responses. Remarkably, delaying CTLA4-Ig until day 6 after transplantation in a fully mismatched heart transplant model inhibited alloantibody production and prevented acute rejection, whereas transferred hyperimmune sera reversed the effects of delayed CTLA4-Ig. Collectively, our studies revealed the unexpected efficacy of CTLA4-Ig for inhibiting ongoing B cell responses even when the graft-specific T cell response was robustly established.

Effects of type II collagen epitope carbamylation and citrullination in human leucocyte antigen (HLA)-DR4(+) monozygotic twins discordant for rheumatoid arthritis

The aim of this study is to investigate the effect of the native, citrullinated or carbamylated type II human collagen T cell- and B cell-epitopes on the adaptive immune response in rheumatoid arthritis (RA). Peripheral blood T and B cells obtained from a human leucocyte D4-related (antigen DR4(-) HLA-DR4)(+) woman with early RA, her healthy monozygotic twin and an unrelated HLA-DR3(+) woman with early RA were analysed for activation (CD154/CD69), apoptosis (annexin/7-aminoactinomycin), cytokine production [interferon (IFN)γ/interleukin (IL)-17/IL-4/IL-10/IL-6] and functional phenotype (CD45Ra/CCR7) after stimulation with the collagen native T cell epitope (T261-273), the K264 carbamylated T cell epitope (carT261-273), the native B cell epitope (B359-369) or the R360 citrullinated B cell epitope (citB359-369), and the combinations of these. The T cell memory compartment was activated by T cell epitopes in both discordant DR4(+) twins, but not in the DR3(+) RA. The collagen-specific activation of CD4(+) T cells was induced with both the native and carbamylated T cell epitopes only in the RA twin. Both T cell epitopes also induced IL-17 production in the RA twin, but a greater IL-4 and IL-10 response in the healthy twin. The citrullinated B cell epitope, particularly when combined with the carbamylated T cell epitope, induced B cell activation and an increased IL-6/IL-10 ratio in the RA twin compared to a greater IL-10 production in the healthy twin. Our data suggest that circulating collagen-specific T and B cells are found in HLA-DR4(+) subjects, but only RA activated cells express co-stimulatory molecules and produce proinflammatory cytokines. Carbamylation and citrullination further modulate the activation and cytokine polarization of T and B cells.

Antigen Presentation and T-Cell Activation Are Critical for RBP4-Induced Insulin Resistance

Adipose tissue (AT) inflammation contributes to impaired insulin action, which is a major cause of type 2 diabetes. RBP4 is an adipocyte- and liver-derived protein with an important role in insulin resistance, metabolic syndrome, and AT inflammation. RBP4 elevation causes AT inflammation by activating innate immunity, which elicits an adaptive immune response. RBP4-overexpressing mice (RBP4-Ox) are insulin resistant and glucose intolerant and have increased AT macrophages and T-helper 1 cells. We show that high-fat diet-fed RBP4(-/-) mice have reduced AT inflammation and improved insulin sensitivity versus wild type. We also elucidate the mechanism for RBP4-induced macrophage antigen presentation and subsequent T-cell activation. In RBP4-Ox, AT macrophages display enhanced c-Jun N-terminal kinase, extracellular signal-related kinase, and p38 phosphorylation. Inhibition of these pathways and of NF-κB reduces activation of macrophages and CD4 T cells. MyD88 is an adaptor protein involved in proinflammatory signaling. In macrophages from MyD88(-/-) mice, RBP4 fails to stimulate secretion of tumor necrosis factor, IL-12, and IL-6 and CD4 T-cell activation. In vivo blockade of antigen presentation by treating RBP4-Ox mice with CTLA4-Ig, which blocks costimulation of T cells, is sufficient to reduce AT inflammation and improve insulin resistance. Thus, MyD88 and downstream mitogen-activated protein kinase and NF-κB pathways are necessary for RBP4-induced macrophage antigen presentation and subsequent T-cell activation. Also, blocking antigen presentation with CTLA4-Ig improves RBP4-induced insulin resistance and macrophage-induced T-cell activation.

Effect of abatacept on the immunogenicity of 23-valent pneumococcal polysaccharide vaccination (PPSV23) in rheumatoid arthritis patients

Introduction

Patients with rheumatoid arthritis (RA) treated with abatacept (ABT) are at increased risk for vaccine-preventable infections. The aim of the present study is to evaluate the humoral response to 23-valent pneumococcal polysaccharide (PPSV23) vaccination in RA patients receiving ABT.

Methods

The immunogenicity study was nested within a randomized, double-blind placebo-controlled study, designed to evaluate the efficacy of the PPSV23. PPSV23 was given to 111 RA patients, who were classified into three groups: RA control (n = 35), methotrexate (MTX) alone (n = 55), and ABT (n = 21). Before and 4–6 weeks after vaccination, we measured the patients’ concentrations of antibodies against pneumococcal serotypes 6B and 23F using an enzyme-linked immunosorbent assay and determined their antibody functionality using a multiplexed opsonophagocytic killing assay, reported as the opsonization index (OI).

Results

The pneumococcal serotype-specific IgG concentrations and OIs were both significantly increased in all treatment groups in response to PPSV23 vaccination. In the ABT group, the IgG responses for the 6B serotype were lower compared with those in the MTX alone or control groups, whereas the OI responses were similar to those in the other two groups. In a subgroup analysis, the pneumococcal serotype-specific IgG responses were significantly lower in both serotypes (6B and 23F) in the ABT/MTX group; however, the OI responses in the ABT group were not different from the control group. There was no association between the pneumococcal serotype-specific IgG and OI responses for the 6B serotype in patients receiving ABT in contrast to the control or MTX alone patients. No severe adverse effects were observed in any of the treatment groups.

Conclusions

OI responses indicate antibody functionality rather than simply their amount, so the similarity of these measurements between all three groups suggests that RA patients receiving ABT still benefit from receiving the PPSV23 vaccination, even though they produce less IgG in response to it. The results suggest an influence of ABT on the humoral response to PPSV23 vaccination under MTX treatment; however, preserved opsonin responses are expected in RA patients treated with ABT plus MTX.

Trial registration

University Hospital Medical Information Network Clinical Trials Registry: UMIN000009566. Registered 12 December 2012.

Tolerogenic Dendritic Cells on Transplantation: Immunotherapy Based on Second Signal Blockage

Dendritic cells (DCs), the most important professional antigen-presenting cells (APC), play crucial role in both immunity and tolerance. It is well known that DCs are able to mount immune responses against foreign antigens and simultaneously tolerate self-antigens. Since DCs can be modulated depending on the surrounding microenvironment, they can act as a bridge between innate and adaptive immunity. However, the mechanisms that support this dual role are not entirely clear. Recent studies have shown that DCs can be manipulated ex vivo in order to trigger their tolerogenic profile, what can be a tool to be used in clinical trials aiming the treatment of various diseases and the prevention of transplant rejection. In this sense, the blockage of costimulatory molecules on DC, in the attempt of inhibiting the second signal in the immunological synapse, can be considered as one of the main strategies under development. This review brings an update on current therapies using tolerogenic dendritic cells modulated with costimulatory blockers with the aim of reducing transplant rejection. However, although there are current clinical trials using tolerogenic DC to treat allograft rejection, the actual challenge is to modulate these cells in order to maintain a permanent tolerogenic profile.

Increased risk of thyroid autoimmunity in rheumatoid arthritis: a systematic review and meta-analysis

Thyroid autoimmunity, which is the most common immune-mediated disease, is frequently together with other organ- as well as nonorgan-specific autoimmune disorders. Meanwhile, rheumatoid arthritis (RA) is a chronic immune-mediated inflammatory disorder that mainly results in cartilage destruction as well as synovial joint inflammation, and both the adaptive and innate immune responses involve in the progression of this disease. Considering that autoimmune elements may be common characteristics of thyroid autoimmunity and RA, it is likely that both disorders may coexist within some patients. A great number of studies have researched whether an association between thyroid autoimmunity and RA exists; however, the results of these studies have been inconsistent. Most of these studies have included relatively small sample sizes, which have rendered them insufficiently powerful to determine whether there is a relationship between RA and thyroid autoimmunity. The main objective of this meta-analysis was to provide reliable estimates of the extent of any association between thyroid autoimmunity and RA by combining the primary data from all related studies. Literature databases, including the Embase, Medline, Web of Science, Chinese Wanfang, and CBM databases, were searched for studies published from January 1980 to May 2014, with a language restriction of English and Chinese. A total of 1,021 RA cases and 1,500 healthy controls were included in this study. From these data, the odds ratios (OR) and the corresponding 95 % confidence intervals (95 % CI) were calculated. The results of the meta-analysis showed that the prevalence of thyroid autoantibody positivity in patients with RA was higher than that in healthy controls (TgAb: OR 3.17, 95 % CI 2.24-4.49; TPOAb: OR 2.33, 95 % CI 1.24-4.39). The results of this meta-analysis suggest that thyroid autoimmunity is more prevalent in patients with RA than in the control population.

Unique topics and issues in rheumatology and clinical immunology

Clinicians are facing unexpected issues in everyday practice, and these may become counterintuitive or challenging. Illustrative examples are provided by the hypersensitivity to universally used immunosuppressants such as corticosteroids or antibiotics such as beta-lactam. Secondly, additional issues are represented by the discovery of new pathogenetic mechanisms involved in rheumatoid and psoriatic arthritis or other chronic inflammatory diseases, genomic susceptibility to enigmatic diseases such as giant cell arteritis, or the shared role of specific mediators such as semaphorins. Third, the therapeutic armamentarium has dramatically changed over the past decade following the introduction of biotechnological drugs, and new mechanisms are being proposed to reduce adverse events or increase the drug effectiveness, particularly on cardiovascular comorbidities. Finally, rare diseases continue to represent difficult cases, as for Cogan's syndrome, with limited literature available for clinical recommendations. For these reason, the present issue of Clinical Reviews in Allergy and Immunology is timely and dedicated to these and other unique topics in clinical immunology and allergy. The aim of this issue is thus to help clinicians involved in internal medicine as well as allergists and clinical immunologists while discussing new pathways that will prove important in the near future.

Autoimmunity in 2013

The peer-reviewed publications in the field of autoimmunity published in 2013 represented a significant proportion of immunology articles and grew since the previous year to indicate that more immune-mediated phenomena may recognize an autoimmune mechanism and illustrated by osteoarthritis and atherosclerosis. As a result, our understanding of the mechanisms of autoimmunity is becoming the paradigm for translational research in which the progress in disease pathogenesis for both tolerance breakdown and inflammation perpetuation is rapidly followed by new treatment approaches and clinical management changes. The similarities across the autoimmune disease spectrum outnumber differences, particularly when treatments are compared. Indeed, the therapeutics of autoimmune diseases are based on a growing armamentarium that currently includes monoclonal antibodies and small molecules which act by targeting molecular markers or intracellular mediators with high specificity. Among the over 100 conditions considered as autoimmune, the common grounds are well illustrated by the data reported for systemic lupus erythematosus and rheumatoid arthritis or by the plethora of studies on Th17 cells and biomarkers, particularly serum autoantibodies. Further, we are particularly intrigued by studies on the genomics, epigenetics, and microRNA at different stages of disease development or on the safe and effective use of abatacept acting on the costimulation of T and B cells in rheumatoid arthritis. We are convinced that the data published in 2013 represent a promising background for future developments that will exponentially impact the work of laboratory and clinical scientists over the next years.

Abatacept decreases disease activity in a absence of CD4(+) T cells in a collagen-induced arthritis model

Introduction

Abatacept is a fusion protein of human cytotoxic T-lymphocyte–associated protein (CTLA)-4 and the Fc portion of human immunoglobulin G1 (IgG1). It is believed to be effective in the treatment of rheumatoid arthritis by inhibiting costimulation of T cells via blocking CD28–B7 interactions as CTLA-4 binds to both B7.1 (CD80) and B7.2 (CD86). However, the interaction of CD28 with B7 molecules is crucial for activation of naive cells, whereas it is unclear whether the action of already activated CD4⁺ T cells, which are readily present in established disease, also depends on this interaction. The aim of this study was to determine whether the mode of action of abatacept depends solely on its ability to halt T cell activation in established disease.

Methods

Arthritis was induced in thymectomized male DBA/1 mice by immunisation with bovine collagen type II. The mice were subsequently depleted for CD4⁺ T cells. Abatacept or control treatment was started when 80 % of the mice showed signs of arthritis. Arthritis severity was monitored by clinical scoring of the paws, and anti-collagen antibody levels over time were determined by enzyme-linked immunosorbent assay.

Results

Treatment with abatacept in the absence of CD4⁺ T cells resulted in lower disease activity. This was associated with decreasing levels of collagen-specific IgG1 and IgG2a antibodies, whereas the antibody levels in control or CD4⁺ T cell–depleted mice increased over time.

Conclusions

These results show that abatacept decreased disease activity in the absence of CD4⁺ T cells, indicating that the mode of action of abatacept in established arthritis does not depend entirely on its effects on CD4⁺ T cell activation.

Rheumatoid arthritis therapy reappraisal: strategies, opportunities and challenges

Rheumatoid arthritis (RA) is considered a chronic disease that cannot be cured. Biologic agents have enabled good therapeutic successes; however, the response to biologic therapy depends on treatment history and, especially, disease duration. In general, the more drug-experienced the patients, the lower the response rates, although this limitation can be overcome by promptly adjusting or switching treatment in a treat-to-target approach. Another challenge is the question of how long therapy should be continued once the treatment target, which should be remission or at least a state of low disease activity, has been reached. The data available suggest that, in most patients with established disease, cessation of biologic therapy will be followed by disease flares, whereas a reduction of dose or an increase in the interval between doses enables maintenance of treatment success. Induction therapy very early in the disease course followed by withdrawal of the biologic agent might also be a feasible approach to attain sustained good outcomes, but currently available data are not strong enough to allow for such a conclusion to be reached. Taken together, this underscores the importance of research into the cause(s) of RA so that curative therapies can be developed.