The Proportion of Regulatory T Cells in Patients with Ankylosing Spondylitis: A Meta-Analysis

Peripheral Th17/Treg imbalance in Chinese patients with untreated antisynthetase syndrome associated interstitial lung disease

Interstitial lung disease (ILD) is a common and fatal manifestation of antisynthetase syndrome (ASS). The aim of this study was to provide new insight into investigate peripheral blood lymphocytes, CD4+ T cells, cytokine levels and their relation to the clinical profile of untreated patients with ASS-ILD. The retrospective study population included thirty patients diagnosed with ASS-ILD and 30 healthy controls (HCs). Baseline clinical and laboratory data were collected for all subjects, including peripheral blood lymphocyte, CD4+ T cell subsets measured by flow cytometry, and serum cytokine levels measured by multiple microsphere flow immunofluorescence. Their correlations with clinical and laboratory findings were analyzed by Pearson's or Spearman's correlation analysis. In addition, the Benjamini-Hochberg method was used for multiple correction to adjust the p-values. Patients with ASS-ILD had lower CD8+ T cells, higher proportion of Th17 cells and Th17/Treg ratio than HCs. Serum cytokine levels (IL-1β, IL-6, IL-12, IL-17, IL-8, IL-2, IL-4, IL-10, TNF-α and IFN-γ) were higher in patients with ASS-ILD than HCs. Moreover, Th17/Treg ratio was negatively correlated with diffusing capacity of carbon monoxide (DLCO)%. Our study demonstrated abnormalities of immune disturbances in patients with ASS-ILD, characterized by decreased CD8+ T cells and an increased Th17/Treg ratio, due to an increase in the Th17 cells. These abnormalities may be the immunological mechanism underlying the development of ILD in ASS.

Dysregulated Non-Coding RNA Expression in T Cells from Patients with Ankylosing Spondylitis Contributes to Its Immunopathogenesis

Ankylosing spondylitis (AS) is a chronic inflammatory disorder characterized by inflammatory back pain and bony fusion of vertebral joints. Genetic associations and environmental factors have been proposed to explain the immunopathogenesis of AS. In the past few years, there have been major advances in understanding T cell dysfunction in AS. Clinically, targeting interleukin-17A, a major cytokine secreted by T helper 17 cells, has been approved for treating patients with active AS. Non-coding RNAs (ncRNAs) are RNA transcripts that do not translate into proteins. The ncRNAs regulate both innate and adaptive immunity and participate in the pathogenesis of autoimmune diseases, including AS. The main purpose of this article is to review the up-to-date studies investigating the aberrant expression of ncRNAs in T cells from patients with AS and to summarize their roles in its pathogenesis. After searching PubMed for studies published between January 2013 and June 2024, nine studies investigating the expression of ncRNAs in AS T cells were included. We found that aberrantly expressed ncRNAs in AS T cells could cause abnormal cytokine release, cell signaling abnormalities, and dysregulated cell proliferation and death, which contribute to the immunopathogenesis of AS. We discussed some limitations of these studies and suggested several research fields for further investigation.

T cells in the pathogenesis of axial spondyloarthritis

Axial spondyloarthritis (axSpA) is the prototype of the spondyloarthritis spectrum. The involvement of T cells in its pathogenesis has long been suspected on the basis of the association with the major histocompatibility complex I molecule HLA-B27 and the pivotal role of interleukin 17 in the inflammatory mechanisms associated with the disease. Moreover, the presence of unconventional or "innate-like" T cells within the axial enthesis suggests an important role for these cells in the pathophysiology of the disease. In this review, we describe the characteristics and the interleukin 17 secretion capacity of the T-cell subsets identified in axSpA. We discuss the genetic and epigenetic mechanisms that support the alteration of T-cell functions and promote their activation in axSpA. We also discuss recent data on T cells that could explain the extra-articular manifestations of the SpA spectrum.

The proportion of regulatory T cells in peripheral blood of patients with autoimmune hepatitis: A systematic review and meta-analysis

BACKGROUND

Many researches have reported the impairment of regulatory T cells (Tregs) in autoimmune hepatitis (AIH), whilst the change of Tregs in peripheral blood remains controversial. We performed this systematic review and meta-analysis to clarify the numerical change of circulating Tregs in AIH patients compared with healthy individuals.

METHODS

Relevant studies were identified from Medline, PubMed, Embase, Web of Science, the Cochrane Library, China National Knowledge Infrastructure, and WanFang Data. Twenty-nine studies involving 968 AIH patients and 583 healthy controls were included. Subgroup analysis stratified by Treg definition or ethnicity was performed, and analysis of active-phase AIH was conducted.

RESULTS

The proportions of Tregs among CD4 T cells and PBMCs were generally decreased in AIH patients compared with healthy controls. Subgroup analysis showed that circulating Tregs identified by CD4+CD25+/high, CD4+CD25+Foxp3+, CD4+CD25+/highCD127-/low, and Tregs in Asian population were decreased among CD4 T cells in AIH patients. No significant change of CD4+CD25+/highFoxp3+CD127-/low Tregs and Tregs in Caucasian population among CD4 T cells were found in AIH patients, whereas the number of studies was limited in these subgroups. Moreover, analysis of the active-phase AIH patients showed that Treg proportions were decreased generally, whereas no significant differences in Tregs/CD4 T cells were observed when markers CD4+CD25+Foxp3+, CD4+CD25+/highFoxp3+CD127-/low were used or in Caucasian population.

CONCLUSIONS

The proportions of Tregs among CD4 T cells and PBMCs were decreased in AIH patients compared with healthy controls generally, whereas Treg definition markers, ethnicity, and disease activity had influence on the results. Further large-scale and rigorous study is warranted.

Identification of gut dysbiosis in axial spondyloarthritis patients and improvement of experimental ankylosing spondyloarthritis by microbiome-derived butyrate with immune-modulating function

Introduction

Dysbiosis is an environmental factor that affects the induction of axial spondyloarthritis (axSpA) pathogenesis. In the present study, we investigated differences in the gut microbiota of patients with axSpA and revealed an association between specific gut microbiota and their metabolites, and SpA pathogenesis.

Method

Using 16S rRNA sequencing data derived from feces samples of 33 axSpA patients and 20 healthy controls (HCs), we examined the compositions of their gut microbiomes.

Results

As a result, axSpA patients were found to have decreased α-diversity compared to HCs, indicating that axSpA patients have less diverse microbiomes. In particular, at the species level, Bacteroides and Streptococcus were more abundant in axSpA patients than in HCs, whereas Faecalibacterium (F). prausnitzii, a butyrate-producing bacteria, was more abundant in HCs. Thus, we decided to investigate whether F. prausnitzii was associated with health conditions by inoculating F. prausnitzii (0.1, 1, and 10 μg/mL) or by administrating butyrate (0.5 mM) into CD4+ T cells derived from axSpA patients. The levels of IL-17A and IL-10 in the CD4+ T cell culture media were then measured. We also assessed osteoclast formation by administrating butyrate to the axSpA-derived peripheral blood mononuclear cells. The CD4+ IL-17A+ T cell differentiation, IL-17A levels were decreased, whereas IL-10 was increased by F. prausnitzii inoculation. Butyrate reduced CD4+ IL-17A+ T cell differentiation and osteoclastogenesis.

Discussion

We found that CD4+ IL-17A+ T cell polarization was reduced, when F. prausnitzii or butyrate were introduced into curdlan-induced SpA mice or CD4+ T cells of axSpA patient. Consistently, butyrate treatment was associated with the reduction of arthritis scores and inflammation levels in SpA mice. Taken together, we concluded that the reduced abundance of butyrate-producing microbes, particularly F. prausnitzii, may be associated with axSpA pathogenesis.

Cytokines and regulatory T cells in ankylosing spondylitis

Aims

To investigate the correlations among cytokines and regulatory T cells (T-regs) in ankylosing spondylitis (AS) patients, and their changes after anti-tumour necrosis factor-α (TNF-α) treatment.

Methods

We included 72 AS patients with detailed medical records, disease activity score (Bath Ankylosing Spondylitis Disease Activity Index), functional index (Bath Ankylosing Spondylitis Functional Index), and laboratory data (interleukin (IL)-2, IL-4, IL-10, TNF-α, interferon (IFN)-γ, transforming growth factor (TGF)-β, ESR, and CRP). Their peripheral blood mononuclear cells (PBMCs) were marked with anti-CD4, anti-CD25, and anti-FoxP3 antibodies, and triple positive T cells were gated by flow cytometry as T-regs. Their correlations were calculated and the changes after anti-TNF-α therapy were compared.

Results

The frequency of T-regs in PBMCs was positively correlated to ESR and CRP in AS (r = 0.35 and 0.43; p = 0.032 and 0.027, respectively), and there was also a significant correlation between serum level of TNF-α and CRP (p = 0.041). The frequency of T-regs in PBMCs positively correlated to serum levels of TNF-α, IL-10, and TGF-β, while IL-2, IL-4, and IFN-γ showed opposite results. After anti-TNF-α treatment, there were significantly lower serum levels of TNF-α, IL-10, TGF-β, and frequency of T-regs in PBMCs among these AS patients (p = 0.026, 0.032, 0.029, and 0.037, respectively).

Conclusion

In AS patients, proinflammatory cytokine may give positive feedback to induce more T-reg production and anti-inflammatory cytokine secretion to suppress this inflammatory status, and they can be reversed by anti-TNF-α therapy. However, the detailed interactions among T-regs and complex cytokine networks in autoinflammatory diseases still need more studies and further functional assay.

Cite this article: Bone Joint Res 2023;12(2):133–137.

Peripheral Treg Levels and Transforming Growth Factor-β (TGFβ) in Patients with Psoriatic Arthritis: A Systematic Review Meta-Analysis

INTRODUCTION

Studies on the level of regulatory T (T_reg) cells in psoriatic arthritis (PsA) have been controversial, leading to disagreement regarding the role T_reg cells play in the pathogenesis of the disease. To clarify the status of T_reg cells in patients with PsA, we performed a meta-analysis to determine the levels of T_reg cells and serum T_reg-associated cytokines in PsA patients.

METHODS

According to published data from PubMed, Web of Science, Embase, Clinical Trials.gov, MEDLINE, Web of Knowledge, Cochrane Library, and FDA.gov, we determined the T_reg and T_reg cytokine levels in patients with PsA. The effect estimates were pooled using a random-effects model.

RESULTS

This meta-analysis included 12 studies. Compared to healthy controls (HCs), the proportions of T_reg cells had no significant difference in patients with PsA (based on standardized means[SMD] = - 1.038, 95% confidence intervals[CI] =  - 2.165 to 0.089, p = 0.071). On the basis of subgroup analysis, patients with PsA had a lower percentage of CD4⁺ T_reg cells (SMD = - 1.501, 95% CI - 2.799 to - 0.202, p = 0.023) than OKT8⁺ T_reg (SMD = 0.568, 95% CI - 2.127 to 3.263, p = 0.679). Besides, CD4⁺CD25⁺FoxP3⁺ T_reg cells and CD4⁺CD25^highCD127^low T_reg cells were both significantly decreased on the levels of PBMCs in patients with PsA (SMD = - 0.764, 95% CI - 1.404 to - 0.125, p = 0.019; SMD = - 5.184, 95% CI - 6.955 to - 3.412, p < 0.001). CD4⁺CD25⁺FoxP3⁺ T_reg cells were particularly more abundant in the synovial fluid thanin peripheral blood (SMD = 3.288, 95% CI 2.127 to 4.449, p < 0.001). No significant difference was observed in the proportion of CD4⁺CD25⁺ T_reg cells in peripheral blood and CD4⁺CD25⁺FoxP3⁺ T_reg cells in CD4⁺ T cells (SMD = - 2.498, 95% CI - 7.720 to 2.725, p = 0.349; SMD = - 0.719, 95% CI - 2.525 to 1.086, p = 0.435). PsA patients had decreased cytokines such as transforming growth factor-β (TGFβ) (SMD = - 2.199, 95% CI - 3.650 to - 0.749, p = 0.003).

CONCLUSIONS

T_reg definition markers influence the scale of T_reg cells in patients with PsA. Pathogenesis of PsA may be attributed to an insufficient or malfunctioning T_reg population.

Joint together: The etiology and pathogenesis of ankylosing spondylitis

Spondyloarthritis (SpA) refers to a group of diseases with inflammation in joints and spines. In this family, ankylosing spondylitis (AS) is a rare but classic form that mainly involves the spine and sacroiliac joint, leading to the loss of flexibility and fusion of the spine. Compared to other diseases in SpA, AS has a very distinct hereditary disposition and pattern of involvement, and several hypotheses about its etiopathogenesis have been proposed. In spite of significant advances made in Th17 dynamics and AS treatment, the underlying mechanism remains concealed. To this end, we covered several topics, including the nature of the immune response, the microenvironment in the articulation that is behind the disease's progression, and the split between the hypotheses and the evidence on how the intestine affects arthritis. In this review, we describe the current findings of AS and SpA, with the aim of providing an integrated view of the initiation of inflammation and the development of the disease.

The Potential Role of Genetics, Environmental Factors, and Gut Dysbiosis in the Aberrant Non-Coding RNA Expression to Mediate Inflammation and Osteoclastogenic/Osteogenic Differentiation in Ankylosing Spondylitis

Ankylosing spondylitis (AS) or radiographic axial spondyloarthritis is a chronic immune-mediated rheumatic disorder characterized by the inflammation in the axial skeleton, peripheral joints, and soft tissues (enthesis, fascia, and ligament). In addition, the extra-skeletal complications including anterior uveitis, interstitial lung diseases and aortitis are found. The pathogenesis of AS implicates an intricate interaction among HLA (HLA-B27) and non-HLA loci [endoplasmic reticulum aminopeptidase 1 (ERAP1), and interleukin-23 receptor (IL23R), gut dysbiosis, immune plasticity, and numerous environmental factors (infections, heavy metals, stress, cigarette smoking, etc.) The latter multiple non-genetic factors may exert a powerful stress on epigenetic regulations. These epigenetic regulations of gene expression contain DNA methylation/demethylation, histone modifications and aberrant non-coding RNAs (ncRNAs) expression, leading to inflammation and immune dysfunctions. In the present review, we shall discuss these contributory factors that are involved in AS pathogenesis, especially the aberrant ncRNA expression and its effects on the proinflammatory cytokine productions (TNF-α, IL-17 and IL-23), T cell skewing to Th1/Th17, and osteoclastogenic/osteogenic differentiation. Finally, some potential investigatory approaches are raised for solving the puzzles in AS pathogenesis.

Cellular and molecular diversity in spondyloarthritis

The spondyloarthritides are a cluster of inflammatory rheumatic diseases characterized by different diagnostic entities with heterogeneous phenotypes. The current classification system groups spondyloarthritis patients in two main categories, axial and peripheral spondyloarthritis, providing a framework wherein the clinical picture guides the treatment. However, the heterogeneity of the clinical manifestations of the pathologies, even when residing in the same group, highlights the importance of analyzing the smallest features of each entity to understand how different cellular subsets evolve, what the underlying mechanisms are and what biological markers can be identified and validated to evaluate the stage of disease and the corresponding efficacy of treatments. In this review, we will focus mostly on axial spondyloarthritis, report current knowledge concerning the cellular populations involved in its pathophysiology, and their molecular diversity. We will discuss the implications of such a diversity, and their meaning in terms of patients' stratification.

Imbalance of Peripheral Lymphocyte Subsets in Patients With Ankylosing Spondylitis: A Meta-Analysis

Ankylosing spondylitis is a complicated consequence of genetic predisposition and environmental factors. Enthesitis is believed to be the hallmark of ankylosing spondylitis, and the chronic inflammatory state of this disease is perpetuated by the disturbances of both the innate immune system and the acquired immune system. To clarify the alteration of immune system in patients with AS, we conducted a meta-analysis concerning the proportions of major lymphocyte subsets in the peripheral blood of AS patients. We systematically searched PubMed and China National Knowledge Infrastructure (CNKI) for articles related to this subject. A total of 95 articles involving 4,020 AS patients and 3,065 healthy controls were included in the analysis. This meta-analysis is performed on R platform using R package "meta", and Egger's tests were used to determine the presence of publication bias. Results showed that the percentages of T cells, NK cells and NKT cells were not significantly different between AS patients and healthy controls, but B cells were significantly increased. Among the subsets of T cells, the proportions of CD4+ T cells, Th17 cells, Tfh cells as well as Th1/Th2 ratio were significantly increased, while Tregs were significantly decreased. Subgroup analysis showed that the proportions of Th17 among both PBMCs, T cells and CD4+ T cells were significantly elevated, while Tregs were only significantly lower in PBMCs. Subgroup analysis also demonstrated that Tregs defined by "CD4+CD25+FoxP3+", "CD4+CD25+CD127low"or "CD4+CD25+CD127-"were significantly downregulated, indicating that the selection of markers could be critical. Further study is warranted in order to elucidate the complicated interactions between different lymphocyte subsets in AS patients. This study implied that the disequilibrium between Th17 and Tregs, as well as between Th1 and Th2 could contribute to the pathogenesis of ankylosing spondylitis, further cementing the understanding that ankylosing spondylitis is a consequence of disrupted balance of innate immune system and acquired immune system.

Novel immune cell phenotypes in spondyloarthritis pathogenesis

Spondyloarthritis (SpA) is a heterogeneous group of chronic inflammatory diseases of unknown etiology. Over time, the plethora of cellular elements involved in its pathogenesis has progressively enriched together with the definition of specific cytokine pathways. Recent evidence suggests the involvement of new cellular mediators of inflammation in the pathogenesis of SpA or new subgroups of known cellular mediators. The research in this sense is ongoing, and it is clear that this challenge aimed at identifying new cellular actors involved in the perpetuation of the inflammatory process in AxSpA is not a mere academic exercise but rather aims to define a clear cellular hierarchy. Such a definition could pave the way for new targeted therapies, which could interfere with the inflammatory process and specific pathways that trigger immune system dysregulation and stromal cell activity, ultimately leading to significant control of the inflammation and new bone formation in a significant number of patients. In this review, we will describe the recent advances in terms of new cellular actors involved in the pathogenesis of SpA, focusing our attention on stromal cells and innate and adaptive immunity cells.

Efficacy of alendronate for the treatment of ankylosing spondylitis: A protocol for systematic review and meta-analysis

BACKGROUND

Ankylosing spondylitis (AS) is a very tricky orthopedic disorder. If such condition cannot be managed fairly well, it may significantly affect quality of life and even leads to disability among such population. A variety of studies have reported that alendronate is utilized for the treatment of AS. However, their results are still contrary, and no systematic review has addressed on this topic. Thus, this study will systematically assess the efficacy and safety of alendronate for the treatment of patients with AS.

METHODS

A comprehensive literature search will be performed from the below electronic databases from their commencement to the January 31, 2020 without language and publication status limitations: PubMed, Embase, Cochrane Library, Web of Science, Allied and Complementary Medicine Database, WANGFANG, and China National Knowledge Infrastructure. Only randomized controlled trials focusing on the alendronate for the treatment of patients with AS will be considered for inclusion in this study. Two authors will independently select all identified records, extract essential data from all included studies, and appraise study quality for each eligible trial using Cochrane risk of bias. If any differences occur, another experienced author will be invited to solve them by discussion and a consensus decision will be made. We will implement RevMan 5.3 software to analyze the extracted data.

RESULTS

This study will summarize high-quality randomized controlled trials to assess the efficacy and safety of alendronate for the treatment of patients with AS through primary outcome of bone densitometry; and secondary outcomes of pain intensity, quality of life, disease activity, functional status, and adverse events.

CONCLUSION

This study will provide evidence to help determine whether alendronate is an effective and safe management for patient with AS or not.

STUDY REGISTRATION

INPLASY202040153.