The number of circulating monocytes as biomarkers of the clinical response to methotrexate in untreated patients with rheumatoid arthritis

Target Role of Monocytes as Key Cells of Innate Immunity in Rheumatoid Arthritis

Rheumatoid arthritis (RA) is a chronic, systemic, and inflammatory autoimmune condition characterized by synovitis, pannus formation (with adjacent bone erosion), and joint destruction. In the perpetuation of RA, fibroblast-like synoviocytes (FLSs), macrophages, B cells, and CD4+ T-cells-specifically Th1 and Th17 cells-play crucial roles. Additionally, dendritic cells, neutrophils, mast cells, and monocytes contribute to the disease progression. Monocytes, circulating cells primarily derived from the bone marrow, participate in RA pathogenesis. Notably, CCR2 interacts with CCL2, and CX3CR1 (expressed by monocytes) cooperates with CX3CL1 (produced by FLSs), facilitating the migration involved in RA. Canonical "classical" monocytes predominantly acquire the phenotype of an "intermediate" subset, which differentially expresses proinflammatory cytokines (IL-1β, IL-6, and TNF) and surface markers (CD14, CD16, HLA-DR, TLRs, and β1- and β2-integrins). However, classical monocytes have greater potential to differentiate into osteoclasts, which contribute to bone resorption in the inflammatory milieu; in RA, Th17 cells stimulate FLSs to produce RANKL, triggering osteoclastogenesis. This review aims to explore the monocyte heterogeneity, plasticity, antigenic expression, and their differentiation into macrophages and osteoclasts. Additionally, we investigate the monocyte migration into the synovium and the role of their cytokines in RA.

Pathophysiology and stratification of treatment-resistant rheumatoid arthritis

Early diagnosis and timely therapeutic intervention are clinical challenges of rheumatoid arthritis (RA), especially for treatment-resistant or difficult-to-treat patients. Little is known about the immunological mechanisms involved in refractory RA. In this review, we summarize previous research findings on the immunological mechanisms of treatment-resistant RA. Genetic prediction of treatment-resistant RA is challenging. Patients with and without anti-cyclic citrullinated peptide autoantibodies are considered part of distinct subgroups, especially regarding long-term clinical prognosis and treatment responses. B cells, T cells and other immune cells and fibroblasts are of pathophysiological importance and are associated with treatment responses. Finally, we propose a new hypothesis that stratifies patients with RA into two subgroups with distinct immunological pathologies based on our recent immunomics analysis of RA. One RA subgroup with a favorable prognosis is characterized by increased interferon signaling. Another subgroup with a worse prognosis is characterized by enhanced acquired immune responses. Increases in dendritic cell precursors and diversified autoreactive anti-modified protein antibodies may have pathophysiological roles, especially in the latter subgroup. These findings that improve treatment response predictions might contribute to future precision medicine for RA.

Identification of gene expression biomarkers to predict clinical response to methotrexate in patients with rheumatoid arthritis

OBJECTIVES

To identify biomarkers at the gene expression level to predict response to methotrexate (MTX) in patients with rheumatoid arthritis (RA).

METHODS

MTX-naïve patients with RA were started on MTX and followed up over three months. The disease activity score 28 (DAS28) was used to classify patients into responders and non-responders. Genome-wide gene expression analysis was performed in CD4 + and CD14 + mononuclear cells sampled from whole blood at baseline to identify differentially expressed genes in responders versus non-responders. Gene selection methods and prediction modelling obtained the most relevant differentially expressed genes. A logistic regression prediction model was subsequently constructed and validated via bootstrapping. The area under the receiver operating characteristic (AUC) curve was calculated to judge model quality.

RESULTS

Seventy-nine patients with RA (53.4 ± 13.9 years, 74.7% females) were enrolled, and 70 finished the study with a documented treatment EULAR response (77.1% responders). Forty-six differentially expressed genes were found. The most promising genes were KRTAP4-11, LOC101927584, and PECAM1 in CD4 + cells and PSMD5 and ID1 in CD14 + cells. The final prediction model using these genes reached an AUC of 90%; the validation set's AUC was 82%.

CONCLUSIONS

Our prediction model constructed via genome-wide gene expression analysis in CD4 + and CD14 + mononuclear cells yielded excellent predictions. Our findings necessitate confirmation in other cohorts of MTX-naïve RA patients. Especially if used in conjunction with previously identified clinical and laboratory (bio)markers, our results could help predict response to MTX in RA to guide treatment decisions. Key Points • Patients with rheumatoid arthritis may or may not respond to treatment with methotrexate, which is the recommended first-line drug in guidelines around the world. • In non-responders, valuable time is lost until second-line treatments are started. • This study aimed at predicting response to methotrexate by identifying differentially expressed genes from peripheral blood samples. • The final prediction model yielded excellent prognostic values, but validation in other cohorts is necessary to corroborate these findings.

Circulating and Synovial Monocytes in Arthritis and Ex-Vivo Model to Evaluate Therapeutic Modulation of Synovial Monocytes

Monocytes are innate immune cells that play a dual role in protection of host against pathogens and initiation and perpetuation of inflammatory disorders including joint diseases. During inflammation, monocytes migrate from peripheral blood to tissues via chemokine receptors where they produce inflammatory factors. Monocytes are classified into three subsets, namely: classical, intermediate and non-classical, each subset has particular function. Synovium of patients with inflammatory joint diseases, such as rheumatoid arthritis and psoriatic arthritis as well as osteoarthritis, is enriched by monocytes that differ from circulatory ones by distinct subsets distribution. Several therapeutic agents used systemically or locally through intra-articular injections in arthritis management modulate monocyte subsets. This scoping review summarized the existing literature delineating the effect of common therapeutic agents used in arthritis management on circulating and synovial monocytes/macrophages. As certain agents have an inhibitory effect on monocytes, we propose to test their potential to inhibit synovial monocytes via an ex-vivo platform based on cultured synovial fluid mononuclear cells derived from patients with rheumatic diseases. Information obtained from the ex-vivo platform can be applied to explore the therapeutic potential of medications in clinical practice.

Methotrexate Provokes Disparate Folate Metabolism Gene Expression and Alternative Splicing in Ex Vivo Monocytes and GM-CSF- and M-CSF-Polarized Macrophages

Macrophages constitute important immune cell targets of the antifolate methotrexate (MTX) in autoimmune diseases, including rheumatoid arthritis. Regulation of folate/MTX metabolism remains poorly understood upon pro-inflammatory (M1-type/GM-CSF-polarized) and anti-inflammatory (M2-type/M-CSF-polarized) macrophages. MTX activity strictly relies on the folylpolyglutamate synthetase (FPGS) dependent intracellular conversion and hence retention to MTX-polyglutamate (MTX-PG) forms. Here, we determined FPGS pre-mRNA splicing, FPGS enzyme activity and MTX-polyglutamylation in human monocyte-derived M1- and M2-macrophages exposed to 50 nmol/L MTX ex vivo. Moreover, RNA-sequencing analysis was used to investigate global splicing profiles and differential gene expression in monocytic and MTX-exposed macrophages. Monocytes displayed six-eight-fold higher ratios of alternatively-spliced/wild type FPGS transcripts than M1- and M2-macrophages. These ratios were inversely associated with a six-ten-fold increase in FPGS activity in M1- and M2-macrophages versus monocytes. Total MTX-PG accumulation was four-fold higher in M1- versus M2-macrophages. Differential splicing after MTX-exposure was particularly apparent in M2-macrophages for histone methylation/modification genes. MTX predominantly induced differential gene expression in M1-macrophages, involving folate metabolic pathway genes, signaling pathways, chemokines/cytokines and energy metabolism. Collectively, macrophage polarization-related differences in folate/MTX metabolism and downstream pathways at the level of pre-mRNA splicing and gene expression may account for variable accumulation of MTX-PGs, hence possibly impacting MTX treatment efficacy.

Pharmacokinetics of oral and subcutaneous methotrexate in red and white blood cells in patients with early rheumatoid arthritis: the methotrexate monitoring trial

OBJECTIVE

To investigate the pharmacokinetics of methotrexate polyglutamate (MTX-PG) accumulation in red blood cells (RBCs) and peripheral blood mononuclear cells (PBMCs) in patients with early rheumatoid arthritis (RA) after oral and subcutaneous MTX treatment.

METHODS

In a clinical prospective cohort study (Methotrexate Monitoring study), newly diagnosed patients with RA were randomised for oral or subcutaneous MTX. At 1, 2, 3 and 6 months after therapy initiation, blood was collected and RBCs and PBMCs were isolated. MTX-PG1-6 concentrations were determined by mass spectrometry methods using stable isotopes of MTX-PG1-6 as internal standards.

RESULTS

43 patients (mean age: 58.5 years, 77% female) were included. PBMCs and RBCs revealed disparate pharmacokinetic profiles in both absolute MTX-PG accumulation levels and distribution profiles. Intracellular MTX-PG accumulation in PBMCs was significantly (p<0.001) 10-fold to 20-fold higher than RBCs at all time points, regardless of the administration route. MTX-PG distribution in PBMCs was composed of mostly MTX-PG1 (PG1>PG2>PG3). Remarkably, the distribution profile in PBMCs remained constant over 6 months. RBCs accumulated mainly MTX-PG1 and lower levels of MTX-PG2-5 at t=1 month. After 3 months, MTX-PG3 was the main PG-moiety in RBCs, a profile retained after 6 months of MTX therapy. Subcutaneous MTX administration results in higher RBC drug levels than after oral administration, especially shortly after treatment initiation.

CONCLUSIONS

This is the first study reporting disparate MTX-PG accumulation profiles in RBCs versus PBMCs in newly diagnosed patients with RA during 6 months oral or subcutaneous MTX administration. This analysis can contribute to improved MTX therapeutic drug monitoring for patients with RA.

TRIAL REGISTRATION NUMBER

NTR 7149.

Molecular signature of methotrexate response among rheumatoid arthritis patients

Background

Methotrexate (MTX) is the first line treatment for rheumatoid arthritis (RA), but failure of satisfying treatment response occurs in a significant proportion of patients. Here we present a longitudinal multi-omics study aimed at detecting molecular and cellular processes in peripheral blood associated with a successful methotrexate treatment of rheumatoid arthritis.

Methods

Eighty newly diagnosed patients with RA underwent clinical assessment and donated blood before initiation of MTX, and 3 months into treatment. Flow cytometry was used to describe cell types and presence of activation markers in peripheral blood, the expression of 51 proteins was measured in serum or plasma, and RNA sequencing was performed in peripheral blood mononuclear cells (PBMC). Response to treatment after 3 months was determined using the EULAR response criteria. We assessed the changes in biological phenotypes during treatment, and whether these changes differed between responders and non-responders with regression analysis. By using measurements from baseline, we also tried to find biomarkers of future MTX response or, alternatively, to predict MTX response.

Results

Among the MTX responders, (Good or Moderate according to EULAR treatment response classification, n = 60, 75%), we observed changes in 29 partly overlapping cell types proportions, levels of 13 proteins and expression of 38 genes during treatment. These changes were in most cases suppressions that were stronger among responders compared to non-responders. Within responders to treatment, we observed a suppression of FOXP3 gene expression, reduction of immunoglobulin gene expression and suppression of genes involved in cell proliferation. The proportion of many HLA-DR expressing T-cell populations were suppressed in all patients irrespective of clinical response, and the proportion of many IL21R+ T-cells were reduced exclusively in non-responders. Using only the baseline measurements we could not detect any biomarkers or prediction models that could predict response to MTX.

Conclusion

We conclude that a deep molecular and cellular phenotyping of peripheral blood cells in RA patients treated with methotrexate can reveal previously not recognized differences between responders and non-responders during 3 months of treatment with MTX. This may contribute to the understanding of MTX mode of action and explain non-responsiveness to MTX therapy.

Clinical, imaging, and blood biomarkers to assess 1-year progression risk in fibrotic interstitial lung diseases-Development and validation of the honeycombing, traction bronchiectasis, and monocyte (HTM)-score

INTRODUCTION

Progression of fibrotic interstitial lung disease (ILD) leads to irreversible loss of lung function and increased mortality. Based on an institutional ILD registry, we aimed to evaluate biomarkers derived from baseline patient characteristics, computed tomography (CT), and peripheral blood for prognosis of disease progression in fibrotic ILD patients.

METHODS

Of 209 subsequent ILD-board patients enregistered, 142 had complete follow-up information and were classified fibrotic ILD as defined by presence of reticulation or honeycombing using a standardized semi-quantitative CT evaluation, adding up typical ILD findings in 0-6 defined lung fields. Progression at 1 year was defined as relative loss of ≥10% in forced vital capacity, of ≥15% in diffusion capacity for carbon monoxide, death, or lung transplant. Two-thirds of the patients were randomly assigned to a derivation cohort evaluated for the impact of age, sex, baseline lung function, CT finding scores, and blood biomarkers on disease progression. Significant variables were included into a regression model, its results were used to derive a progression-risk score which was then applied to the validation cohort.

RESULTS

In the derivation cohort, age, monocyte count ≥0.65 G/L, honeycombing and traction bronchiectasis extent had significant impact. Multivariate analyses revealed the variables monocyte count ≥0.65 G/L (1 point) and combined honeycombing or traction bronchiectasis score [0 vs. 1-4 (1 point) vs. 5-6 lung fields (2 points)] as significant, so these were used for score development. In the derivation cohort, resulting scores of 0, 1, 2, and 3 accounted for 1-year progression rates of 20, 25, 46.9, and 88.9%, respectively. Similarly, in the validation cohort, progression at 1 year occurred in 0, 23.8, 53.9, and 62.5%, respectively. A score ≥2 showed 70.6% sensitivity and 67.9% specificity, receiver operating characteristic analysis for the scoring model had an area under the curve of 71.7%.

CONCLUSION

The extent of honeycombing and traction bronchiectasis, as well as elevated blood monocyte count predicted progression within 1 year in fibrotic ILD patients.

CD169+ Monocyte and Regulatory T Cell Subsets Are Associated with Disease Activity in Rheumatoid Arthritis

Disease activity in rheumatoid arthritis (RA) is influenced by activation of circulating and synovial immune cells. Regulatory T cells (Tregs) and monocytes are key cells that drive inflammation in RA. This study investigated if a relationship exists between disease activity in RA and circulating Treg and monocyte numbers and phenotypes. A potential sialic acid (Sia) mediated link between Tregs and monocytes was also probed in vitro. Peripheral blood mononuclear cells (PBMCs) were isolated from RA patient (n = 62) and healthy control (n = 21) blood using density gradient separation. Flow cytometry was used to count and phenotype Treg and monocyte subsets, and to sort healthy control Tregs for Sia cell culture experiments. The effects of Sia on activated Treg FoxP3 and NFκB expression was assessed by flow cytometry and concentrations of secreted TNFα, IL-10 and IFNγ determined by ELISA. High disease activity RA patients who were unresponsive to disease modifying anti-rheumatic drugs (n = 31), have significantly lower relative numbers (percentages) of CD4+CD25+CD127− Tregs (p < 0.01) and memory CD45RA−FoxP3+ Tregs (p < 0.01), compared to low disease activity responders (n = 24). Relative numbers of non-classical CD169+ monocytes are associated with disease activity in RA (p = 0.012). Sia reduced Treg expression of FoxP3, NFκB and cytokines in vitro. A strong association has been identified between non-classical CD169+ monocytes and post-treatment disease activity in RA. This study also indicates that Sia can reduce Treg activation and cytokine release. We postulate that such a reduction could be mediated by interaction with sialyted proteins captured by CD169+ monocytes.

Methotrexate Treatment Suppresses Monocytes in Nonresponders to Pneumococcal Conjugate Vaccine in Rheumatoid Arthritis Patients

Patients with rheumatoid arthritis (RA) have an increased risk of infections; therefore, immunization against vaccine-preventable diseases is important. Methotrexate (MTX) impairs the antibody response to pneumococcal conjugate vaccine (PCV) in patients with arthritis, and the underlying mechanism is largely unknown. Here, we investigate the potential role of the innate immune system in the faltering antibody response following PCV vaccination in RA patients treated with MTX. Phenotypes of circulating granulocytes and monocytes were analyzed in 11 RA patients treated with MTX, 13 RA patients without disease-modifying antirheumatic drug treatment (0DMARD), and 13 healthy controls (HC). Peripheral blood samples were collected before and 7 days after vaccination. In addition, the MTX group was sampled before initiating treatment. Frequencies of granulocyte and monocyte subsets were determined using flow cytometry. Serotype-specific IgG were quantified using a multiplex bead assay, pre- and 4-6 weeks after vaccination. At baseline, no differences in granulocyte and monocyte frequencies were observed between the groups. Within the MTX group, the frequency of basophils increased during treatment and was higher compared to the HC and 0DMARD groups at the prevaccination time point. MTX patients were categorized into responders and nonresponders according to the antibody response. Before initiation of MTX, there were no differences in granulocyte and monocyte frequencies between the two subgroups. However, following 6-12 weeks of MTX treatment, both the frequency and concentration of monocytes were lower in PCV nonresponders compared to responders, and the difference in monocyte frequency remained after vaccination. In conclusion, the suppressive effect of MTX on monocyte concentration and frequency could act as a biomarker to identify nonresponders to PCV vaccination.

Human Bone Marrow Mesenchymal Stromal/Stem Cells Regulate the Proinflammatory Response of Monocytes and Myeloid Dendritic Cells from Patients with Rheumatoid Arthritis

Rheumatoid arthritis (RA) is a disabling autoimmune disease whose treatment is ineffective for one-third of patients. Thus, the immunomodulatory potential of mesenchymal stromal/stem cells (MSCs) makes MSC-based therapy a promising approach to RA. This study aimed to explore the immunomodulatory action of human bone marrow (BM)-MSCs on myeloid dendritic cells (mDCs) and monocytes, especially on cytokines/chemokines involved in RA physiopathology. For that, LPS plus IFNγ-stimulated peripheral blood mononuclear cells from RA patients (n = 12) and healthy individuals (n = 6) were co-cultured with allogeneic BM-MSCs. TNF-α, CD83, CCR7 and MIP-1β protein levels were assessed in mDCs, classical, intermediate, and non-classical monocytes. mRNA expression of other cytokines/chemokines was also evaluated. BM-MSCs effectively reduced TNF-α, CD83, CCR7 and MIP-1β protein levels in mDCs and all monocyte subsets, in RA patients. The inhibition of TNF-α production was mainly achieved by the reduction of the percentage of cellsproducing this cytokine. BM-MSCs exhibited a remarkable suppressive action over antigen-presenting cells from RA patients, potentially affecting their ability to stimulate the immune adaptive response at different levels, by hampering their migration to the lymph node and the production of proinflammatory cytokines and chemokines. Accordingly, MSC-based therapies can be a valuable approach for RA treatment, especially for non-responder patients.

Molecular and Cellular Heterogeneity in Rheumatoid Arthritis: Mechanisms and Clinical Implications

Rheumatoid arthritis is an autoimmune disease that exhibits significant clinical heterogeneity. There are various treatments for rheumatoid arthritis, including disease-modifying anti-rheumatic drugs (DMARDs), glucocorticoids, non-steroidal anti-inflammatory drugs (NSAIDs), and inflammatory cytokine inhibitors (ICI), typically associated with differentiated clinical effects and characteristics. Personalized responsiveness is observed to the standard treatment due to the pathophysiological heterogeneity in rheumatoid arthritis, resulting in an overall poor prognosis. Understanding the role of individual variation in cellular and molecular mechanisms related to rheumatoid arthritis will considerably improve clinical care and patient outcomes. In this review, we discuss the source of pathophysiological heterogeneity derived from genetic, molecular, and cellular heterogeneity and their possible impact on precision medicine and personalized treatment of rheumatoid arthritis. We provide emphasized description of the heterogeneity derived from mast cells, monocyte cell, macrophage fibroblast-like synoviocytes and, interactions within immune cells and with inflammatory cytokines, as well as the potential as a new therapeutic target to develop a novel treatment approach. Finally, we summarize the latest clinical trials of treatment options for rheumatoid arthritis and provide a suggestive framework for implementing preclinical and clinical experimental results into clinical practice.

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.

Expansion of inflammatory monocytes in periphery and infiltrated into thyroid tissue in Graves' disease

Monocytes are important mediators of immune system and are reported to be altered in autoimmune disorders. Little is known about the pathological role of monocytes in Graves' disease (GD). Thus, we investigated monocytes in periphery and thyroid tissue in GD. Untreated GD patients were enrolled and followed up until remission. Monocytes were significantly increased and positively correlated with anti-thyrotropin receptor antibody (TRAb) in untreated GD (r_counts = 0.269, P < 0.001; r_percentage = 0.338, P < 0.001). Flow cytometry showed CD14++ CD16+ monocytes were increased and CD14++ CD16- monocytes were decreased in untreated GD (both P < 0.001). Skewed monocyte subsets were recovered in GD with remission. Serum B cell-activating factor (BAFF) was positively correlated with TRAb (r = 0.384 and P = 0.001). CD14++ CD16+ monocytes expressed higher level of BAFF in untreated GD (P < 0.05). The frequency of CD14+ monocytes and CD14+ CD16+ monocytes were significantly higher in GD thyroid tissue than in normal thyroid tissue (both P < 0.001). Our study suggested CD14++ CD16+ monocytes were significantly expanded and involved in the production of TRAb via secreting a higher level of BAFF in periphery. Besides, monocytes infiltrated into thyroid tissue and thus could serve as an important participant in GD pathogenesis.

Potential clinical biomarkers in rheumatoid arthritis with an omic approach

Objective

To aid in the selection of the most suitable therapeutic option in patients with diagnosis of rheumatoid arthritis according to the phase of disease, through the review of articles that identify omics biological markers.

Methods

A systematic review in PubMed/Medline databases was performed. We searched articles from August 2014 to September 2019, in English and Spanish, filtered by title and full text; and using the terms "Biomarkers" AND “Rheumatoid arthritis".

Results

This article supplies an exhaustive review from research of objective measurement, omics biomarkers and how disease activity appraise decrease unpredictability in treatment determinations, and finally, economic, and clinical outcomes of treatment options by biomarkers’ potential influence. A total of 122 articles were included. Only 92 met the established criteria for review purposes and 17 relevant references about the topic were included as well. Therefore, it was possible to identify 196 potential clinical biomarkers: 22 non-omics, 20 epigenomics, 33 genomics, 21 transcriptomics, 78 proteomics, 4 glycomics, 1 lipidomics and 17 metabolomics.

Conclusion

A biomarker is a measurable indicator of some, biochemical, physiological, or morphological condition; evaluable at a molecular, biochemical, or cellular level. Biomarkers work as indicators of physiological or pathological processes, or as a result of a therapeutic management. In the last five years, new biomarkers have been identified, especially the omics, which are those that proceed from the investigation of genes (genomics), metabolites (metabolomics), and proteins (proteomics). These biomarkers contribute to the physician choosing the best therapeutic option in patients with rheumatoid arthritis.

Intermediate monocytes correlate with CXCR3+ Th17 cells but not with bone characteristics in untreated early rheumatoid arthritis

BACKGROUND

Rheumatoid arthritis (RA) is associated with development of generalized osteoporosis. Bone-degrading osteoclasts are derived from circulating precursor cells of monocytic lineage, and the intermediate monocyte population is important as osteoclast precursors in inflammatory conditions. T cells of various subsets are critical in the pathogenesis of both RA and associated osteoporosis, but so far, no studies have examined associations between circulating intermediate monocytes, T cell subsets and bone characteristics in patients with RA. The aim of this study was to investigate the frequency of intermediate monocytes in patients with untreated early rheumatoid arthritis (ueRA) compared to healthy controls (HC), and to explore the correlation between intermediate monocytes and a comprehensive panel of T helper cell subsets, bone density and bone microarchitecture in ueRA patients.

METHODS

78 patients with ueRA fulfilling the ACR/EULAR 2010 criteria were included and compared to 29 age- and sex-matched HC. Peripheral blood samples were obtained before start of treatment and proportions of monocyte subsets and CD4+ helper and regulatory T cell subsets were analyzed by flow cytometry. Bone densitometry was performed on 46 of the ueRA patients at inclusion using DXA and HR-pQCT.

RESULTS

Flow cytometric analyses showed that the majority of ueRA patients had frequencies of intermediate monocytes comparable to HC. The intermediate monocyte population correlated positively with CXCR3+ Th17 cells in ueRA patients but not in HC. However, neither the proportions of intermediate monocytes nor CXCR3+ Th17 cells were associated with bone density or bone microarchitecture measurements.

CONCLUSIONS

Our findings suggest that in early RA, the intermediate monocytes do not correlate with bone characteristics, despite positive correlation with circulating CXCR3+ Th17 cells. Future longitudinal studies in patients with longer disease duration are required to fully explore the potential of intermediate monocytes to drive bone loss in RA.

Rheumatoid arthritis CD14+ monocytes display metabolic and inflammatory dysfunction, a phenotype that precedes clinical manifestation of disease

Introduction

This study investigates the metabolic activity of circulating monocytes and their impact on pro‐inflammatory responses in RA and explores whether this phenotype is already primed for inflammation before clinical manifestations of disease.

Methods

Blood was collected and CD14⁺ monocytes isolated from healthy control donors (HC), individuals at‐risk (IAR) and RA patients. Monocyte frequency in blood and synovial tissue was assessed by flow cytometry. Inflammatory responses and metabolic analysis ± specific inhibitors were quantified by RT‐PCR, Western blot, migration assays, Seahorse‐XFe‐technology, mitotracker assays and transmission electron microscopy. Transcriptomic analysis was performed on HC, IAR and RA synovial tissue.

Results

CD14⁺ monocytes from RA patients are hyper‐inflammatory following stimulation, with significantly higher expression of cytokines/chemokines than those from HC. LPS‐induced RA monocyte migratory capacity is consistent with increased monocyte frequency in RA synovial tissue. RA CD14⁺ monocytes show enhanced mitochondrial respiration, biogenesis and alterations in mitochondrial morphology. Furthermore, RA monocytes display increased levels of key glycolytic enzymes HIF1α, HK2 and PFKFB3 and demonstrate a reliance on glucose consumption, blockade of which abrogates pro‐inflammatory mediator responses. Blockade of STAT3 activation inhibits this forced glycolytic flux resulting in metabolic reprogramming and resolution of inflammation. Interestingly, this highly activated monocytic phenotype is evident in IAR of developing disease, in addition to an enhanced monocyte gene signature observed in synovial tissue from IAR.

Conclusion

RA CD14⁺ monocytes are metabolically re‐programmed for sustained induction of pro‐inflammatory responses, with STAT3 identified as a molecular regulator of metabolic dysfunction. This phenotype precedes clinical disease onset and may represent a potential pathway for therapeutic targeting early in disease.

Methrotexate Treatment Inmunomodulates Abnormal Cytokine Expression by T CD4 Lymphocytes Present in DMARD-Naïve Rheumatoid Arthritis Patients

CD4⁺T-lymphocytes are relevant in the pathogenesis of rheumatoid arthritis (RA), however, their potential involvement in early RA remains elusive. Methotrexate (MTX) is a commonly used disease-modifying antirheumatic drug (DMARD), but its mechanism has not been fully established. In 47 new-onset DMARD-naïve RA patients, we investigated the pattern of IFNγ, IL-4 and IL-17A expression by naïve (T_N), central (T_CM), effector memory (T_EM) and effector (T_E) CD4⁺ subsets; their STAT-1, STAT-6 and STAT-3 transcription factors phosphorylation, and the circulating levels of IFNγ, IL-4 and IL-17. We also studied the RA patients after 3 and 6 months of MTX treatment and according their clinical response. CD4⁺T-lymphocyte subsets and cytokine expression were measured using flow cytometry. New-onset DMARD-naïve RA patients showed a significant expansion of IL-17A⁺, IFNγ⁺ and IL-17A⁺IFNγ⁺ CD4⁺T-lymphocyte subsets and increased intracellular STAT-1 and STAT-3 phosphorylation. Under basal conditions, nonresponder patients showed increased numbers of circulating IL-17A producing T_N and T_MC CD4⁺T-lymphocytes and IFNγ producing T_N, T_CM, T_EM CD4⁺T-lymphocytes with respect to responders. After 6 months, the numbers of CD4⁺IL-17A⁺T_N remained significantly increased in nonresponders. In conclusion, CD4⁺T-lymphocytes in new-onset DMARD-naïve RA patients show IL-17A and IFNγ abnormalities in T_N, indicating their relevant role in early disease pathogenesis. Different patterns of CD4⁺ modulation are identified in MTX responders and nonresponders.

TLR expression in peripheral monocyte subsets of patients with idiopathic inflammatory myopathies: association with clinical and immunological features

BACKGROUND

Monocytes and toll-like receptors (TLR) have been found in the inflammatory infiltrate of muscle biopsies in patients with idiopathic inflammatory myopathies (IIM), suggesting an important role of these cells in the pathogenesis of myositis. The monocyte subsets, their TLR expression in peripheral blood and their relationship with the clinical characteristics of patients with IIM has not been addressed.

METHODS

We recruited 45 patients with IIM diagnosis and 15 age and sex-adjusted healthy controls. We assessed the disease activity and damage, performed a nailfold capillaroscopy and registered the cardio-pulmonary parameters from the medical charts. Monocyte subsets, their expression of TLR2 and TLR4 and the serum Th1/Th2/Th17 cytokines levels were evaluated by flow cytometry. We expressed quantitative variables as medians and interquartile ranges (IQR) or minimum and maximum (min-max). Differences between groups were assessed with Mann-Whitney U and the Kruskal-Wallis tests. Correlation between quantitative variables was assessed with Spearman Rho.

RESULTS

Twenty-nine patients were women (64.4%) and 32 (71.1%) had dermatomyositis. In comparison to healthy controls, patients with active IIM had a higher percentage of intermediate monocytes and lower amounts of classical monocytes. Patients with IIM had a higher expression of TLR4 in all their monocyte subsets, regardless of disease activity and prednisone treatment. Serum IL-6 correlated with the TLR2 expression in every monocyte subset and the expression of TLR2 in intermediate monocytes was higher among patients with dysphagia. Subjects with nailfold capillaroscopy abnormalities had a higher amount of TLR2+ classical and non-classical monocytes and those with interstitial lung disease (ILD) had a higher percentage of TLR4+ non-classical monocytes. The classical and intermediate monocytes from patients with anti Mi2 antibodies had a higher expression of TLR4. The percentage of intermediate monocytes and the expression of TLR4 in all monocyte subsets showed a good diagnostic capacity in patients with IIM.

CONCLUSION

Patients with IIM have a differential pool of monocyte subsets with an enhanced expression of TLR2 and TLR4, which correlates with disease activity and distinctive clinical features including dysphagia, ILD, vasculopathy, and pro-inflammatory cytokines. These immunological features might be useful as a potential diagnostic tool as well as novel disease activity biomarkers in IIM.

Using the Immunophenotype to Predict Response to Biologic Drugs in Rheumatoid Arthritis

Tumour necrosis factor (TNF)-α is a key mediator of inflammation in rheumatoid arthritis, and its discovery led to the development of highly successful anti-TNF therapy. Subsequently, other biologic drugs targeting immune pathways, namely interleukin-6 blockade, B cell depletion, and T cell co-stimulation blockade, have been developed. Not all patients respond to a biologic drug, leading to a knowledge gap between biologic therapies available and the confident prediction of response. So far, genetic studies have failed to uncover clinically informative biomarkers to predict response. Given that the targets of biologics are immune pathways, immunological study has become all the more pertinent. Furthermore, advances in single-cell technology have enabled the characterization of many leucocyte subsets. Studying the blood immunophenotype may therefore, define biomarker profiles relevant to each individual patient's disease and treatment outcome. This review summarises our current understanding of how immune biomarkers might be able to predict treatment response to biologic drugs.

The Abnormal CD4+T Lymphocyte Subset Distribution and Vbeta Repertoire in New-onset Rheumatoid Arthritis Can Be Modulated by Methotrexate Treament

Patients with long-term, treated, rheumatoid arthritis (RA) show abnormalities in their circulating CD4+ T-lymphocytes, but whether this occurs in recently diagnosed naïve patients to disease-modifying drugs (DMARDs) is under discussion. These patients show heterogeneous clinical response to methotrexate (MTX) treatment. We have examined the count of circulating CD4+ T-lymphocytes, and their naïve (TN), central memory (TCM), effector memory (TEM) and effector (TE) subsets, CD28 expression and Vβ TCR repertoire distribution by polychromatic flow cytometry in a population of 68 DMARD-naïve recently diagnosed RA patients, before and after 3 and 6 months of MTX treatment. At pre-treatment baseline, patients showed an expansion of the counts of CD4+ TN, TEM, TE and TCM lymphocyte subsets, and of total CD4+CD28- cells and of the TE subset with a different pattern of numbers in MTX responder and non-responders. The expansion of CD4+TEM lymphocytes showed a predictive value of MTX non-response. MTX treatment was associated to different modifications in the counts of the CD4+ subsets and of the Vβ TCR repertoire family distribution and in the level of CD28 expression in responders and non-responders. In conclusion, the disturbance of CD4+ lymphocytes is already found in DMARD-naïve RA patients with different patterns of alterations in MTX responders and non-responders.

A flow-through cell counting assay for point-of-care enumeration of CD4 T-cells

CD4 T-cell count is a priority for staging HIV disease and guiding clinical management as part of HIV care. Conventional CD4 T-cell enumeration methods based on flow cytometry are expensive, require well-trained personnel, and are challenging to use in rural, resource-scarce areas. A simple CD4 T-cell count test that can be used at point-of care, the Flow-Through cell Counting Assay (FTCA), is described in this article. The FTCA is based on the use of: 1) a special membrane that selectively retains white blood cells (WBCs); 2) a sample delivery system; and 3) optical signal detection. To show the feasibility of the FTCA, a proof-of-concept prototype of the FTCA cassette and digital camera or handheld reflectance meter were used for obtaining quantitative assay results within 30 min. The results show that the FTCA allows for quantitative enumeration of CD4 T-cells in the clinically relevant range of CD4 T-cell concentrations. The advantages of the FTCA technology, including simplicity, short analysis time, and portability, suggest that FTCA has great potential for use in clinical practice and wide applicability for other cell-based diagnostic tests.

Molecular Characterization of Monocyte Subsets Reveals Specific and Distinctive Molecular Signatures Associated With Cardiovascular Disease in Rheumatoid Arthritis

Objectives: This study, developed within the Innovative Medicines Initiative Joint Undertaking project PRECISESADS framework, aimed at functionally characterize the monocyte subsets in RA patients, and analyze their involvement in the increased CV risk associated with RA.

Methods: The frequencies of monocyte subpopulations in the peripheral blood of 140 RA patients and 145 healthy donors (HDs) included in the PRECISESADS study were determined by flow cytometry. A second cohort of 50 RA patients and 30 HDs was included, of which CD14⁺ and CD16⁺ monocyte subpopulations were isolated using immuno-magnetic selection. Their transcriptomic profiles (mRNA and microRNA), proinflammatory patterns and activated pathways were evaluated and related to clinical features and CV risk. Mechanistic in vitro analyses were further performed.

Results: CD14⁺⁺CD16⁺ intermediate monocytes were extended in both cohorts of RA patients. Their increased frequency was associated with the positivity for autoantibodies, disease duration, inflammation, endothelial dysfunction and the presence of atheroma plaques, as well as with the CV risk score. CD14⁺ and CD16⁺ monocyte subsets showed distinctive and specific mRNA and microRNA profiles, along with specific intracellular signaling activation, indicating different functionalities. Moreover, that specific molecular profiles were interrelated and associated to atherosclerosis development and increased CV risk in RA patients. In vitro, RA serum promoted differentiation of CD14⁺CD16⁻ to CD14⁺⁺CD16⁺ monocytes. Co-culture with RA-isolated monocyte subsets induced differential activation of endothelial cells.

Conclusions: Our overall data suggest that the generation of inflammatory monocytes is associated to the autoimmune/inflammatory response that mediates RA. These monocyte subsets, -which display specific and distinctive molecular signatures- might promote endothelial dysfunction and in turn, the progression of atherosclerosis through a finely regulated process driving CVD development in RA.

Inhibition of CCL3 abrogated precursor cell fusion and bone erosions in human osteoclast cultures and murine collagen-induced arthritis

Objective

Macrophage inflammatory protein 1-alpha (CCL3) is a chemokine that regulates macrophage trafficking to the inflamed joint. The agonistic effect of CCL3 on osteolytic lesions in patients with multiple myeloma is recognized; however, its role in skeletal damage during inflammatory arthritis has not been established. The aim of the study was to explore the role of osteoclast-associated CCL3 upon bone resorption, and to test its pharmacological blockade for protecting against bone pathology during inflammatory arthritis.

Methods

CCL3 production was studied during osteoclast differentiation from osteoclast precursor cells: human CD14-positive mononuclear cells. Mice with CIA were treated with an anti-CCL3 antibody. The effect of CCL3 blockade through mAb was studied through osteoclast number, cytokine production and bone resorption on ivory disks, and in vivo through CIA progression (clinical score, paw diameter, synovial inflammation and bone damage).

Results

Over time, CCL3 increased in parallel with the number of osteoclasts in culture. Anti-CCL3 treatment achieved a concentration-dependent inhibition of osteoclast fusion and reduced pit formation on ivory disks (P ⩽ 0.05). In CIA, anti-CCL3 treatment reduced joint damage and significantly decreased multinucleated tartrate-resistant acid phosphatase-positive osteoclasts and erosions in the wrists (P < 0.05) and elbows (P < 0.05), while also reducing joint erosions in the hind (P < 0.01) and fore paws (P < 0.01) as confirmed by X-ray.

Conclusion

Inhibition of osteoclast-associated CCL3 reduced osteoclast formation and function whilst attenuating arthritis-associated bone loss and controlling development of erosion in murine joints, thus uncoupling bone damage from inflammation. Our findings may help future innovations for the diagnosis and treatment of inflammatory arthritis.

Is prediction of clinical response to methotrexate in individual rheumatoid arthritis patients possible? A systematic literature review

OBJECTIVES

To identify, by a systematic literature review, predictors of clinical response to methotrexate treatment in rheumatoid arthritis patients, which would facilitate personalised treatment.

METHODS

PubMed and Embase databases were searched for original articles. Additionally, congress abstracts of European League Against Rheumatism and American College of Rheumatology annual meetings of the past 2 years were screened. Articles describing predictors of clinical response to methotrexate after 3 to 6 months were included, since this reflects the time span used to determine treatment effectiveness and decide on treatment changes in treat-to-target recommendations.

RESULTS

Thirty articles were included, containing 100 different predictors and 11 predictive models. Nineteen predictors and 2 predictive models were studied in multiple cohorts. Female gender was found to be a predictor of non-response in two studies (odds ratios 0.55 and 0.54), but these findings could not be replicated in two other studies. In two studies, smoking predicted non-response (adjusted odds ratios 0.35 and 0.60), although this was inconsistent over all response criteria assessed. Rheumatoid factor positivity predicted non-response in two studies (adjusted hazard ratio 0.61, adjusted odds ratio 0.4), but this was not found in three other studies. Heterogeneity in studies prohibited further comparison of predictive values between studies. Additionally, a validated epigenetic model was found (area under the curve 0.90 and 0.91).

CONCLUSIONS

No predictors were identified reliably predicting clinical response to methotrexate after 3 to 6 months in the individual patient: clinical predictors were weak. However, a promising epigenetic model was found that needs further validation.

Genetic and clinical markers for predicting treatment responsiveness in rheumatoid arthritis

Although many drugs and therapeutic strategies have been developed for rheumatoid arthritis (RA) treatment, numerous patients with RA fail to respond to currently available agents. In this review, we provide an overview of the complexity of this autoimmune disease by showing the rapidly increasing number of genes associated with RA.We then systematically review various factors that have a predictive value (predictors) for the response to different drugs in RA treatment, especially recent advances. These predictors include but are certainly not limited to genetic variations, clinical factors, and demographic factors. However, no clinical application is currently available. This review also describes the challenges in treating patients with RA and the need for personalized medicine. At the end of this review, we discuss possible strategies to enhance the prediction of drug responsiveness in patients with RA.

TNF, but not hyperinsulinemia or hyperglycemia, is a key driver of obesity-induced monocytosis revealing that inflammatory monocytes correlate with insulin in obese male mice

Inflammation contributes to obesity-related hyperinsulinemia and insulin resistance, which often precede type 2 diabetes. Inflammation is one way that obesity can promote insulin resistance. It is not clear if the extent of obesity, hyperinsulinemia, or hyperglycemia, underpins changes in cellular immunity during diet-induced obesity. In particular, the requirement for obesity or directionality in the relationship between insulin resistance and monocyte characteristics is poorly defined. Inflammatory cytokines such as tumor necrosis factor (TNF) can contribute to insulin resistance. It is unclear if TNF alters monocytosis or specific markers of cellular immunity in the context of obesity. We measured bone marrow and blood monocyte characteristics in WT and TNF-/- mice that were fed obesogenic, high fat (HF) diets. We also used hyperglycemic Akita mice and mice implanted with insulin pellets in order to determine if glucose or insulin were sufficient to alter monocyte characteristics. We found that diet-induced obesity in male mice increased the total number of monocytes in blood, but not in bone marrow. Immature, inflammatory (Ly6Chigh ) monocytes decreased within the bone marrow and increased within peripheral blood of HF-fed mice. We found that neither hyperinsulinemia nor hyperglycemia was sufficient to induce the observed changes in circulating monocytes in the absence of diet-induced obesity. In obese HF-fed mice, antibiotic treatment lowered insulin and insulin resistance, but did not alter circulating monocyte characteristics. Fewer Ly6Chigh monocytes were present within the blood of HF-fed TNF-/- mice in comparison to HF-fed wild-type (WT) mice. The prevalence of immature Ly6Chigh monocytes in the blood correlated with serum insulin and insulin resistance irrespective of the magnitude of adipocyte or adipose tissue hypertrophy in obese mice. These data suggest that diet-induced obesity instigates a TNF-dependent increase in circulating inflammatory monocytes, which predicts increased blood insulin and insulin resistance independently from markers of adiposity or adipose tissue expansion.

Monocytes in rheumatoid arthritis: Circulating precursors of macrophages and osteoclasts and, their heterogeneity and plasticity role in RA pathogenesis

Rheumatoid arthritis (RA) is a chronic systemic, autoimmune and inflammatory disease represented as synovitis, pannus formation, adjacent bone erosions, and joint destruction. The major cells involved in the perpetuation of RA pathogenesis are CD4⁺ T-cells (mainly Th1 cells and Th17 cells), fibroblasts like synoviocytes (FLS), macrophages and B cells. Other autoimmune cells such as dendritic cells, neutrophils, mast cells, and monocytes also contribute to RA pathogenesis. Monocytes are mainly bone marrow (BM) derived cells in the circulation. The chemokine receptors CCR2 and CX3CR1 expressed by monocytes interact with chemokine ligands CCL2 (MCP-1) and CX3CL1 (fractalkine) respectively produced by FLS and this interaction promotes their migration and recruitment into RA synovium. Activated monocytes on their surface exhibit upregulated antigenic expressions such as CD14, CD16, HLA-DR, toll-like receptors (TLRs), and adhesion molecules B1 and B2 integrins. RA monocytes interconnect with other cells in a positive loop manner in the propagation of the rheumatoid process. They skew towards mainly intermediate monocyte subsets (CD14⁺⁺ CD16⁺) which produce proinflammatory cytokines such as TNF-α, IL-1β, and IL-6. Moreover, the predominant intermediate monocytes in RA differentiate into M1-macrophages which play a major role in synovial inflammation. Demonstrations suggest monocytes with CD14⁺ and CD16^- expression (classical monocytes?) differentiate to osteoclasts which are the cells responsible for bone erosion in RA synovial joints. Th17 cells induce the production of RANKL by FLS which promotes osteoclastogenesis. Cytokines mainly TNF-α, IL-1β, and IL-6 amplify osteoclastogenesis. Hence, monocytes are the circulating precursors of macrophages and osteoclasts in RA. AIM OF THE REVIEW: To enlighten the identity of monocytes, the antigenic expression on monocyte surface and their cytokines role in RA. We also emphasize about the chemokine receptors expressed by monocytes subsets and chemotaxis of circulating monocytes into RA synovium. Additionally, we review monocytes as the circulating precursors of macrophages and osteoclasts in RA joints and their heterogeneity and plasticity role in RA.

Prediction of response to methotrexate in rheumatoid arthritis

INTRODUCTION

Methotrexate (MTX) is the first-line disease-modifying drug of choice in controlling active inflammation of the synovium that characterises rheumatoid arthritis, a chronic autoimmune inflammatory condition. However, many patients do not respond to treatment with MTX or cannot tolerate the medication. Pre-treatment characteristics that predict response to MTX are, therefore, of particular interest and potential clinical utility. Areas covered: This narrative review seeks to cover various genotypic and phenotypic characteristics that have been investigated as predictors of treatment response to MTX in RA. Ovid Medline searches (1946 to January 2018) were carried out for 'methotrexate' and 'rheumatoid arthritis', in combination with relevant terms. All papers identified were English language, with abstracts. Relevant references were also reviewed. Expert commentary: Despite the introduction of biologic medication and targeted therapies, MTX is likely to remain the mainstay of RA treatment, largely due to its much cheaper cost. Development of a multifactorial predictive algorithm for response to MTX may be of clinical utility, as well as routine MTX drug level testing to improve medication adherence and persistence.

CX3CR1 regulates osteoarthrosis chondrocyte proliferation and apoptosis via Wnt/β-catenin signaling

OBJECTIVE

The study was aimed to investigate the impact of CX3CR1 expression on the proliferation and apoptosis of osteoarthrosis (OA) chondrocytes through Wnt/ β-catenin pathway.

METHODS

The expression levels of CX3CR1 and Wnt/β-catenin pathway-related genes mRNA and protein in OA chondrocytes were examined by qRT-PCR and western blot. MTT and flow cytometry (FCM) assays were employed to assess cell proliferation, cell cycle and apoptosis. XAV-939, a Wnt/β-catenin pathway inhibitor, was used to inhibit the pathway.

RESULTS

CX3CR1 was significantly overexpressed in OA cartilages than that in normal articular cartilages (P < 0.05). After siCX3CR1 transfection, the expression level of Wnt 3, nuclear β-catenin, Cyclin D1, MMP-13 and phosphorylated GSK-3β significantly increased, while cytoplasm β-catenin, GSK-3β and phosphorylated β-catenin expression was inhibited (P<0.05). XAV-939abolished the effects of siCX3CR1 on proliferation, apoptosis and cell cycle progression of OA chondrocytes (P<0.05).

CONCLUSIONS

CX3CR1 regulated chondrocyte proliferation and apoptosis through Wnt/β-catenin signaling pathway. The overexpression of CX3CR1 in chondrocytes of OA may be closely related to the pathogenesis and progression of OA.

Monocyte alterations in rheumatoid arthritis are dominated by preterm release from bone marrow and prominent triggering in the joint

OBJECTIVE

Rheumatoid arthritis (RA) accompanies infiltration and activation of monocytes in inflamed joints. We investigated dominant alterations of RA monocytes in bone marrow (BM), blood and inflamed joints.

METHODS

CD14⁺ cells from BM and peripheral blood (PB) of patients with RA and osteoarthritis (OA) were profiled with GeneChip microarrays. Detailed functional analysis was performed with reference transcriptomes of BM precursors, monocyte blood subsets, monocyte activation and mobilisation. Cytometric profiling determined monocyte subsets of CD14⁺⁺CD16^-, CD14⁺⁺CD16⁺ and CD14⁺CD16⁺ cells in BM, PB and synovial fluid (SF) and ELISAs quantified the release of activation markers into SF and serum.

RESULTS

Investigation of genes differentially expressed between RA and OA monocytes with reference transcriptomes revealed gene patterns of early myeloid precursors in RA-BM and late myeloid precursors along with reduced terminal differentiation to CD14⁺CD16⁺monocytes in RA-PB. Patterns associated with tumor necrosis factor/lipopolysaccharide (TNF/LPS) stimulation were weak and more pronounced in RA-PB than RA-BM. Cytometric phenotyping of cells in BM, blood and SF disclosed differences related to monocyte subsets and confirmed the reduced frequency of terminally differentiated CD14⁺CD16⁺monocytes in RA-PB. Monocyte activation in SF was characterised by the predominance of CD14⁺⁺CD16⁺⁺CD163⁺HLA-DR⁺ cells and elevated concentrations of sCD14, sCD163 and S100P.

CONCLUSION

Patterns of less mature and less differentiated RA-BM and RA-PB monocytes suggest increased turnover with accelerated monocytopoiesis, BM egress and migration into inflamed joints. Predominant activation in the joint indicates the action of local and primary stimuli, which may also promote adaptive immune triggering through monocytes, potentially leading to new diagnostic and therapeutic strategies.

Pretransplant Numbers of CD16+ Monocytes as a Novel Biomarker to Predict Acute Rejection After Kidney Transplantation: A Pilot Study

Acute rejection is one of the major immunological determinants of kidney graft function and survival. Early biomarkers to predict rejection are lacking. Emerging evidence reveals a crucial role for the monocyte/macrophage lineage cells in the pathogenesis of rejection. We hypothesized that higher pretransplant numbers of proinflammatory CD16+ monocytes can predict rejection. The study cohort consisted of 104 kidney transplant recipients (58 with no rejection and 46 with biopsy-proven rejection) and 33 healthy persons. Posttransplant median follow-up time was 14.7 mo (interquartile range 0.3-34 mo). Pretransplantation blood samples were analyzed by flow cytometry for monocyte immunophenotypes. Groups were compared by Cox regression models for the occurrence of acute rejection. We documented a significantly increased absolute number of pretransplant CD16+ monocytes in patients who developed biopsy-proven rejection after transplantation compared with those with no rejection (hazard ratio [HR] 1.60, 95% CI 1.28-2.00, p < 0.001) and healthy persons (HR 1.47, 95% CI 1.18-1.82, p < 0.001). In parallel, significantly fewer absolute numbers of CD16- monocytes were observed at pretransplant time points in rejectors versus nonrejectors (HR 0.74, 95% CI 0.58-0.94, p < 0,014). A higher pretransplant number of CD16+ monocytes is significantly associated with a higher risk of acute rejection after kidney transplantation.

Allergens in red ginseng extract induce the release of mediators associated with anaphylactoid reactions

BACKGROUND

Anaphylactoid reactions induced by preparations containing red ginseng have been reported. The aim of this study is to evaluate the allergenicity and screen potential allergens in red ginseng extract thoroughly.

METHODS

Red ginseng extract (RGE) and different fractions of RGE were prepared and evaluated by measuring the degranulation and viability of rat basophilic leukemia 2H3 (RBL-2H3) cells. Potential allergens were screened by RBL-2H3 cell extraction and allergenicity verified in RBL-2H3 cells, mouse peritoneal mast cells, Laboratory of Allergic Disease 2 (LAD2) human mast cells and mice, respectively.

RESULTS

80% ethanol extract of red ginseng extract induced mast cell degranulation with less cytotoxicity, but 40% ethanol extract could not. Ginsenoside Rd and 20(S)-Rg3 could induce a significant increase in β-hexosaminidase release, histamine release and translocation of phosphatidylserine in RBL-2H3 cells. Ginsenoside Rd and 20(S)-Rg3 also increased β-hexosaminidase release and the intracellular Ca²⁺ concentration in mouse peritoneal mast cells and LAD2 cells. In addition, histamine levels in serum of mice were elevated dose-dependently.

CONCLUSIONS

Ginsenoside Rd and 20(S)-Rg3 are potential allergens that induce the release of mediators associated with anaphylactoid reactions. Our study could guide optimization of methods associated with Rd/20(S)-Rg3-containing preparations and establishment of quality standards for safe application of Traditional Chinese Medicines.