Expression of T follicular helper lymphocytes with different subsets and analysis of serum IL-6, IL-17, TGF-β and MMP-3 contents in patients with rheumatoid arthritis

T follicular helper cells and T follicular regulatory cells in autoimmune diseases

T follicular helper (Tfh) cells are heterogeneous and mainly characterized by expressing surface markers CXCR5, ICOS, and PD-1; cytokine IL-21; and transcription factor Bcl6. They are crucial for B-cell differentiation into long-lived plasma cells and high-affinity antibody production. T follicular regulatory (Tfr) cells were described to express markers of conventional T regulatory (Treg) cells and Tfh cells and were able to suppress Tfh-cell and B-cell responses. Evidence has revealed that the dysregulation of Tfh and Tfr cells is positively associated with the pathogenic processes of autoimmune diseases. Herein, we briefly introduce the phenotype, differentiation, and function of Tfh and Tfr cells, and review their potential roles in autoimmune diseases. In addition, we discuss perspectives to develop novel therapies targeting Tfh/Tfr balance.

Transplantation of IL‑1β siRNA‑modified bone marrow mesenchymal stem cells ameliorates type II collagen‑induced rheumatoid arthritis in rats

Rheumatoid arthritis (RA) is a chronic autoimmune disease that causes erosion of articular cartilage and bone and has adverse effects on both patients and livestock animals. The aim of the present study was to investigate the role of interleukin-1β (IL-1β) in the pathogenesis of RA, and to further determine whether injection of IL-1β small interfering RNA (siRNA) or transplantation of IL-1β siRNA + bone marrow mesenchymal stem cells (BMSCs) can ameliorate RA in rats. A collagen-induced arthritis (CIA) rat model was established by injecting type II collagen for 4 weeks. Next, CIA rats were randomly divided into three groups and injected or transplanted with PBS, IL-1β siRNA and IL-1β siRNA + BMSCs for another 4 weeks. The CIA rat model was successfully established, as demonstrated by the higher toe swelling value, thymus and spleen/body weight, immobility time and serum IL-1β concentration, as well as lower body weight, climbing time and mRNA expression of programmed death-1 (PD-1), transforming growth factor-β1 (TGF-β1) and forkhead box protein 3 (Foxp3) in the spleen, compared with control rats. Furthermore, histopathology results demonstrated that joint swelling and redness were observed in the knee joints of CIA rats. H&E results revealed that CIA rats presented erosive destruction of the bone and ulceration of the articular cartilage. In addition, in vitro results demonstrated that IL-1β expression was successfully silenced after IL-1β siRNA transfection in lipopolysaccharide-stimulated BMSCs. When compared with the results of PBS rats, both IL-1β siRNA injection and IL-1β siRNA + BMSC transplantation significantly increased the body weight, climbing time and mRNA expression of PD-1, TGF-β1 and Foxp3 in the spleen, while significantly reduced the immobility time and serum IL-1β concentration. In addition, when compared with that of IL-1β siRNA injection, IL-1β siRNA + BMSC transplantation exhibited markedly higher therapeutic efficacy against CIA. These results demonstrated that higher IL-1β contributed to the pathogenesis of CIA, and that IL-1β siRNA injection ameliorated CIA, while its combination with BMSCs exerted synergistic effects, which may be beneficial against RA.

T-Cell Immune Imbalance in Rheumatoid Arthritis Is Associated with Alterations in NK Cells and NK-Like T Cells Expressing CD38

BACKGROUND

CD38+ NK (CD3- CD16+ CD38+ CD56+) cells were increased in rheumatoid arthritis (RA), which suppressed Treg cell differentiation. This study explored how CD38+ NK cells regulated CD4+ T-cell differentiation into Treg cells in RA.

METHODS

Proportions of CD38+ NK cells and their counterpart CD38+ NK-like T (CD3+ CD16+ CD38+ CD56+) cells were measured in RA and rats with collagen-induced arthritis (CIA). CD38+ NK cells and CD38+ NK-like T cells were cocultured with CD4+ T cells, respectively.

RESULTS

A significantly increased proportion of CD38+ NK cells and a decreased proportion of CD38+ NK-like T cells were detected in RA and CIA blood and synovial fluids. When CD4+ T cells were cocultured with CD38+ NK cells, mammalian target of rapamycin (mTOR) signaling was activated, and Th1/Th2 and Th17/Treg ratios were increased. When CD38+ NK cells were pretreated with anti-CD38 antibody, Treg cell proportion was increased, and Th1/Th2 and Th17/Treg ratios were decreased. CD38+ NK-like T cells showed the opposite results. CD38+ NK cells and CD38+ NK-like-T cells activated differential gene expressions and pathways in CD4+ T cells and initiated Th1 and Th2 cell differentiation by differential gene nodes.

CONCLUSIONS

This study suggest that the high CD38+ NK cell proportion and low CD38+ NK-like T cell proportion in RA suppress Treg cell differentiation by stimulating mTOR signaling in CD4+ T cells, which consequentially disturbs the immune tolerance.

Altered Distribution of Circulating T Follicular Helper-Like Cell Subsets in Rheumatoid Arthritis Patients

Objective: Recent studies on follicular regulatory T (Tfr) and follicular helper T (Tfh) cells suggest that they may participate in the pathogenesis of rheumatoid arthritis (RA). Here, we examine Tfr-like and Tfh-like cells and their subsets in RA and assess the correlations between these subsets with B cells and cytokines related to the pathogenesis of RA and their clinical significance.

Methods: The study population consisted of 18 healthy controls and 47 RA patients (17 new onset, 57.00 ± 11.73 years; 30 treated RA patients, 57.56 ± 1.97 years). Disease activity scores in 28 joints were calculated. The positive rates of rheumatoid factor (RF) and anticyclic citrullinated peptide antibodies (anti-CCP) were 82.9 and 89.4%, respectively. Cell subsets were analyzed using flow cytometry, and serum cytokine levels were measured using cytometric bead array.

Results: Tfh-like and PD-1⁺ Tfh-like cells were elevated, and the distribution of Tfh-like cell subsets was altered with increased Tfh17-like and Tfh1/17-like cells in RA patients. The receiver operating characteristics curves for Tfh-like, Tfh17-like, Tfh1/17-like, and PD-1⁺ Tfh-like cells indicate improved RA diagnostic potential. RA patients had decreased regulatory T (Treg), Tfr-like, and memory Tfr-like (mTfr-like) cells and increased Tfh-like/Treg, Tfh-like/Tfr-like, and Tfh-like/mTfr-like cell ratios. Tfh-like cells and their subsets, including Tfh1-like, Tfh2-like, Tfh1/17-like, and PD-1⁺ Tfh-like cells, were positively correlated with B cells. Tfh-like/Treg, Tfh-like/Tfr-like, and Tfh-like/mTfr-like cell ratios were positively correlated with B cells in new-onset RA. Interleukin (IL)-2, IL-4, IL-17, interferon-γ, and tumor necrosis factor-α were positively correlated with Tfr-like and mTfr-like cells. IL-2 and IL-10 were positively correlated with Tfh-like and Tfh2-like cells. IL-4 was positively correlated with Tfh-like cells.

Conclusions: Tfh-like and PD-1⁺ Tfh-like cells are increased, whereas Treg, Tfr-like, and mTfr-like cells are decreased in RA, leading to an imbalance in Tfh-like/Treg, Tfh-like/Tfr-like, and Tfh-like/mTfr-like cell ratios. Tfh-like cells and a portion of their subsets as well as Tfh-like/Treg, Tfh-like/Tfr-like, and Tfh-like/mTfr-like cell ratios are closely related to B cells. Dysfunction of cell subsets leads to abnormal levels of cytokines involved in the pathogenesis of RA. The altered distributions of Tfh-like cell subsets, especially Tfh1/17-like cells, represent potential therapeutic targets for treatment of RA.

Follicular helper T cells: potential therapeutic targets in rheumatoid arthritis

Rheumatoid arthritis (RA) is a chronic autoimmune disease with joint and systemic inflammation that is accompanied by the production of autoantibodies, such as rheumatoid factor and anti-cyclic citrullinated peptide (anti-CCP) antibodies. Follicular helper T (Tfh) cells, which are a subset of CD4+ T cells, facilitate germinal center (GC) reactions by providing signals required for high-affinity antibody production and the generation of long-lived antibody-secreting plasma cells. Uncontrolled expansion of Tfh cells is observed in various systemic autoimmune diseases. Particularly, the frequencies of circulating Tfh-like (cTfh-like) cells, their subtypes and synovial-infiltrated T helper cells correlate with disease activity in RA patients. Therefore, reducing autoantibody production and restricting excessive Tfh cell responses are ideal ways to control RA pathogenesis. The present review summarizes current knowledge of the involvement of Tfh cells in RA pathogenesis and highlights the potential of these cells as therapeutic targets.

Pathogenesis and Function of Interleukin-35 in Rheumatoid Arthritis

It is well known that RA (Rheumatoid arthritis) is an autoimmune disease characterized by multiple and symmetric arthropathy. The main pathological features of RA are synovial hyperplasia, angiogenesis, pannus formation, inflammatory cell infiltration, articular cartilage, bone destruction, and ultimately joint dysfunction, even deformity. IL-35 (Interleukin-35) is a new member of the IL-12 (Interleukin-12) family, which is an immunosuppressive and anti-inflammatory cytokine secreted mainly by Treg (T regulatory cells). There is evidence suggested that IL-35 can attenuate the progression of RA through influencing the immune and pathological process. It suggests that IL-35 played an important role in the pathogenesis of RA, and can be used as a potential target for the future treatment of RA. This review summarizes the recent advances of IL-35 in the pathological roles and the therapeutic potential roles in RA.

Th17/Treg-Related Transcriptional Factor Expression and Cytokine Profile in Patients With Rheumatoid Arthritis

Objectives

The aim of our study was to determine whether there is a correlation between transcription factors expression and Th17/Treg ratio, cytokine profile in the RA phenotype as well as to identify transcription factors that could be a potential biomarker for RA.

Methods

The study was conducted on 45 patients with RA, 27 patients with OA and 46 healthy controls (HCs). Th17 and Treg frequency was determined by flow cytometry (15 patients with RA/OA and 15 subjects of HC). Gene expression was estimated by qPCR, and the serum cytokine levels were determined by ELISA.

Results

The percentage of Treg (CD4+CD25highCD127-) cells in RA patients was lower than in OA patients or HCs. Proportions of Th17 (CD4+CCR6+CXCR3-) cells were higher in RA and OA in comparison to HCs. STAT5 showed a very high expression in the blood of RA patients compared to healthy subjects. The expression of STAT5 and HELIOS was not detected in Th17 cells. A positive correlation between SMAD3 and STAT3 in RA patients was observed. Negative correlations between HIF-1A and SMAD2 in RA Treg cells and DAS-28 score were observed. The range of serum of IL-17 and IL-21 were higher in RA patients than in OA patients. Concentrations of serum IL-2 and IFN-γ were higher in RA and OA patients than in healthy subjects. Based on the ROC analysis, the diagnostic potential of the combination of HIF1A, SMAD3 and STAT3, was determined at AUC 0.95 for distinguishing RA patients from HCs. For distinguishing RA patients from OA patients the diagnostic potential of the combination of SMAD2, SMAD3, SMAD4 and STAT3, was determined at AUC 0.95.

Conclusion

Based on our study, we conclude that SMAD3 and STAT3 could be potential diagnostic biomarkers for RA.

Regulatory Effect of Sishen Pill on Tfh Cells in Mice With Experimental Colitis

The T follicular helper T (Tfh) cells play a significant role in the pathogenesis of inflammatory bowel disease (IBD), which is regulated by the Bcl-6/Blimp-1 pathway. Some studies have suggested that regulating activation of the Bcl-6/Blimp-1 pathway should be an effective method to treat IBD. Sishen Pill (SSP) has been used frequently to treat chronic colitis. Its mechanism is related to the downstream proteins in the Bcl-6/Blimp-1 pathway. However, it is unknown whether SSP regulates the function and differentiation of Tfh cells to treat IBD. In the present study, chronic colitis was induced by dextran sodium sulfate and treated with SSP for 7 days. SSP effectively treated chronic colitis, regulated the balance between Tfh10, Tfh17 and T follicular regulatory cells, while SSP increased the Blimp-1 level, inhibited expressions of Bcl-6, T-cell costimulator, programmed death (PD)-1 and PD-ligand 1 on the surface of Tfh cells. SSP inhibited activation of BcL-6, phosphorylated signal transducer and activator of transcription (p-STAT)3, signal lymphocyte activation molecule (SLAM)-associated protein but improved Blimp-1 and STAT3 expression in colonic tissues. The results indicated that SSP regulated the differentiation and function of Tfh cells to treat IBD, which was potentially related with inhibiting the Bcl-6/Blimp-1 pathway.

The role of follicular T helper cells in the humoral alloimmune response after clinical organ transplantation

Over the past decade, antibody‐mediated or humoral rejection in combination with development of de novo donor‐specific antibodies (DSA) has been recognized as a distinct and common cause of transplant dysfunction and is responsible for one‐third of the failed allografts. Detailed knowledge of the mechanisms that initiate and maintain B‐cell driven antidonor reactivity is required to prevent and better treat this antidonor response in organ transplant patients. Over the past few years, it became evident that this response largely depends on the actions of both T follicular helper (Tfh) cells and the controlling counterparts, the T follicular regulatory (Tfr) cells. In this overview paper, we review the latest insights on the functions of circulating (c)Tfh cells, their subsets Tfh1, Tfh2 and Tfh17 cells, IL‐21 and Tfr cells in antibody mediated rejection (ABMR). This may offer new insights in the process to reduce de novo DSA secretion resulting in a decline in the incidence of ABMR. In addition, monitoring these cell populations could be helpful for the development of biomarkers identifying patients at risk for ABMR and provide novel therapeutic drug targets to treat ABMR.