Frequency of Th17 CD4+ T cells in early rheumatoid arthritis: a marker of anti-CCP seropositivity

Immuno-metabolic reprogramming of T cell: a new frontier for pharmacotherapy of Rheumatoid arthritis

Rheumatoid arthritis (RA) is a persistent autoimmune condition characterized by ongoing inflammation primarily affecting the synovial joint. This inflammation typically arises from an increase in immune cells such as neutrophils, macrophages, and T cells (TC). TC is recognized as a major player in RA pathogenesis. The involvement of HLA-DRB1 and PTPN-2 among RA patients confirms the TC involvement in RA. Metabolism of TC is maintained by various other factors like cytokines, mitochondrial proteins & other metabolites. Different TC subtypes utilize different metabolic pathways like glycolysis, oxidative phosphorylation and fatty acid oxidation for their activation from naive TC (T0). Although all subsets of TC are not deleterious for synovium, some subsets of TC are involved in joint repair using their anti-inflammatory properties. Hence artificially reprogramming of TC subset by interfering with their metabolic status poised a hope in future to design new molecules against RA.

Increased gene expression of CCR6 and RORγt in peripheral blood cells of rheumatoid arthritis patients and their correlation with anti-cyclic citrullinated peptide and disease activity

OBJECTIVES

The significance of T helper 17 (Th17) cells in the pathogenesis of rheumatoid arthritis (RA) has recently been demonstrated in many studies. Retinoic acid receptor-related orphan receptor γt (RORγt) is a transcription factor that is specifically involved in the generation of Th17 cells. Besides, the chemokine receptor CCR6, the receptor for CCL20, is characteristically expressed by these cells. Considering the pivotal roles of Th17 cells in RA pathogenesis, in this study, we assessed the gene expression of CCR6 and RORγt in the peripheral blood leukocytes of new case RA patients. Also, we evaluated their association with anticyclic citrullinated peptide (anti-CCP) antibodies and disease activity.

METHODS

Forty-five new case RA patients and 45 healthy persons have been recruited in this investigation. The gene expression of CCR6 and RORγt was evaluated by quantitative real-time PCR (qRT-PCR), and anti-CCP antibodies plasma levels were measured using the enzyme-linked immunosorbent assay (ELISA) technique. Disease activity was measured according to the disease activity score-28 (DAS-28) formula.

RESULTS

The gene expression of CCR6 and RORγt increased remarkably in new case RA patients compared to healthy controls (p < .05 and p < .01, respectively). Moreover, there was a positive correlation between RORγt gene expression and parameters, including gene expression of CCR6 (p = .001, r = .461), plasma levels of CCL20 (p = .0009, r = .477), ESR (p = .004, r = .419), DAS-28 (p = .006, r = .402), anti-CCP (p = .019, r = .346), and RF (p = .001, r = .451). Also, CCR6 gene expression was positively associated with the DAS-28 (p = .037, r = .310), plasma levels of anti-CCP (p = .037, r = .312), and ESR (p = .029, r = .327).

CONCLUSION

Increased gene expression of CCR6 and RORγt in peripheral blood leukocytes of new case RA patients may contribute to the exacerbation and pathogenesis of RA.

Stratified distribution of Th17 and Treg cells in patients with multi-stage rheumatoid arthritis

OBJECTIVE

Rheumatoid arthritis (RA) is a typical, progressive autoimmune disease. Its occurrence and development are associated with dysregulation of T and B cell numbers. However, the specific immune characteristics of different RA courses remain incompletely defined. Here, we describe the peripheral blood lymphocyte subsets, particularly CD4 + T subsets, of different RA courses with a focus on early RA (Ea-RA).

METHODS

In all, 131 patients with Ea-RA, 117 with advanced RA (Ad-RA), and 109 with treated RA (Tr-RA) were enrolled. We collected general clinical data. Whole blood samples obtained from the patients and 97 healthy controls (HCs) were analysed via flow cytometry.

RESULTS

Decreased absolute NK cell numbers and increased CD4/CD8 T cell ratios were observed in different RA groups, including Ea-RA, compared to healthy controls. In Ea-RA patients, the Th17 and Treg cell numbers were similar to those in HCs. We performed k-means clustering based on the profiles of Th17 and Treg cells for patients with multi-stage of RA. We identified three patient types: type A characterised by relatively low Treg and Th17 cell numbers, type B with moderate levels of Treg cells and levels of Th17 cells similar to that of type C patients, and type C with high levels of Treg cells and levels of Th17 cells similar to that of type B patients.

CONCLUSION

The immune characteristics of Ea-RA patients differ from those of HCs; an immune system disorder is apparent although no differences in Th17 and Treg levels were evident between Ea-RA patients and HCs. We found distributional heterogeneities of Th17 and Treg cells in patients with multi-stage of RA. Stratified management based on such heterogeneity may serve as a useful novel immunotherapy allowing of early intervention.

Levels of Pathogenic Th17 and Th22 Cells in Patients with Rheumatoid Arthritis

Rheumatoid arthritis (RA) is a chronic autoimmune condition characterized, among others, by tissue damage and activation/differentiation of proinflammatory lymphocytes. Accordingly, several studies have concluded that type 17 T helper (Th17) cells seem to have an important role in the pathogenesis of this condition. However, the strategy for the identification and analysis of proinflammatory Th17 cells in those studies has not been consistent and has usually been different from what was originally described. Therefore, we decided to evaluate the levels of Th17 cells in patients with RA employing an extended immune phenotype by using an eight-color multiparametric flow cytometry analysis. For this purpose, blood samples were obtained from 30 patients with RA and 16 healthy subjects, and the levels of Th17 and type 22 helper (Th22) lymphocytes were analyzed as well as the in vitro differentiation of peripheral blood mononuclear cells into Th17 lymphocytes induced by interleukin-23 (IL-23) and IL-1β. We found significant enhanced levels of total Th17 lymphocytes (defined as CD4⁺IL-17⁺) as well as enhanced numbers of their pathogenic (defined as CD4⁺CXCR3⁺IL-17⁺IL-22⁺CD243⁺CD161⁺IFN-γ⁺IL-10⁻) and nonpathogenic (CD4⁺CXCR3⁺IL-17⁺IL-22⁻CD243⁻CD161⁻IFN-γ⁻IL-10⁺) cell subsets in patients with RA. Likewise, the number of Th22 (CD4⁺CXCR3^+/-IL-17⁻IL-22⁺) was also increased in these patients compared to healthy controls. However, the in vitro induction/differentiation of pathogenic Th17 cells showed similar results in controls and patients with RA. Likewise, no significant associations were detected in patients with RA between the levels of Th17 or Th22 cells and clinical or laboratory parameters. Our data indicate that patients with RA show enhanced blood levels of the different subsets of Th17 cells and Th22 lymphocytes tested in this study and suggest that these levels are not apparently associated with clinical or laboratory parameters.

Therapeutic Effects of Hypoxic and Pro-Inflammatory Priming of Mesenchymal Stem Cell-Derived Extracellular Vesicles in Inflammatory Arthritis

Mesenchymal stem cells (MSCs) immunomodulate inflammatory responses through paracrine signalling, including via secretion of extracellular vesicles (EVs) in the cell secretome. We evaluated the therapeutic potential of MSCs-derived small EVs in an antigen-induced model of arthritis (AIA). EVs isolated from MSCs cultured normoxically (21% O₂, 5% CO₂), hypoxically (2% O₂, 5% CO₂) or with a pro-inflammatory cytokine cocktail were applied into the AIA model. Disease pathology was assessed post-arthritis induction through swelling and histopathological analysis of synovial joint structure. Activated CD4+ T cells from healthy mice were cultured with EVs or MSCs to assess deactivation capabilities prior to application of standard EVs in vivo to assess T cell polarisation within the immune response to AIA. All EVs treatments reduced knee-joint swelling whilst only normoxic and pro-inflammatory primed EVs improved histopathological outcomes. In vitro culture with EVs did not achieve T cell deactivation. Polarisation towards CD4+ helper cells expressing IL17a (Th17) was reduced when normoxic and hypoxic EV treatments were applied in vitro. Normoxic EVs applied into the AIA model reduced Th17 polarisation and improved Regulatory T cell (Treg):Th17 homeostatic balance. Normoxic EVs present the optimal strategy for broad therapeutic benefit. EVs present an effective novel technology with the potential for cell-free therapeutic translation.

Recent Advances in Understanding the Pathogenesis of Rheumatoid Arthritis: New Treatment Strategies

Rheumatoid arthritis (RA) is considered a chronic systemic, multi-factorial, inflammatory, and progressive autoimmune disease affecting many people worldwide. While patients show very individual courses of disease, with RA focusing on the musculoskeletal system, joints are often severely affected, leading to local inflammation, cartilage destruction, and bone erosion. To prevent joint damage and physical disability as one of many symptoms of RA, early diagnosis is critical. Auto-antibodies play a pivotal clinical role in patients with systemic RA. As biomarkers, they could help to make a more efficient diagnosis, prognosis, and treatment decision. Besides auto-antibodies, several other factors are involved in the progression of RA, such as epigenetic alterations, post-translational modifications, glycosylation, autophagy, and T-cells. Understanding the interplay between these factors would contribute to a deeper insight into the causes, mechanisms, progression, and treatment of the disease. In this review, the latest RA research findings are discussed to better understand the pathogenesis, and finally, treatment strategies for RA therapy are presented, including both conventional approaches and new methods that have been developed in recent years or are currently under investigation.

High serum IgA and activated Th17 and Treg predict the efficacy of abatacept in patients with early, seropositive rheumatoid arthritis

OBJECTIVE

To identify the predictive biomarkers for achieving remission with abatacept in patients with seropositive rheumatoid arthritis (RA).

METHODS

We enrolled patients with RA who were treated with abatacept. We compared the baseline laboratory results and longitudinal immune-phenotyping data between patients who achieved remission and those who did not achieve remission at 6 months according to the clinical disease activity index.

RESULTS

One hundred and twenty RA patients were enrolled. In the seropositive patients with early RA (n = 24), high serum IgA levels, anti-citrullinated peptide (CCP) titers, and neutrophil counts before treatment were predictors of remission (area under the curve [AUC], 0.659, 0.741, and 0.704, respectively). Additionally, activated Th17 (aTh17) cells and activated Treg (aTreg) cells before treatment were found to be significantly higher in patients with remission compared to those without remission (2.9% vs 1.1%, P = 0.02; 34.3% vs 17%, P = 0.03, respectively). The measurement of longitudinal cell subpopulation revealed a decrease in the effector CD4 T cell population after abatacept treatment, which correlated with anti-CCP titers and neutrophil counts, and was associated with remission achievement. In seropositive patients with established RA (n = 79), high RF titers and low IFN-γ levels were associated with the good response to abatacept.

CONCLUSION

Our study has shown that serum IgA levels, anti-CCP titer, and neutrophil counts are predictive biomarkers for predicting the response to abatacept in patients with seropositive and early RA and may reflect the inhibition of effector CD4 T cell subpopulations by abatacept. Key Points • Serum IgA levels and neutrophil counts are novel biomarkers for predicting the efficacy of abatacept. • Those may reflect the inhibition of effector CD4 T cell subpopulations by abatacept.

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.

Quantifying circulating Th17 cells by qPCR: potential as diagnostic biomarker for rheumatoid arthritis

OBJECTIVE

The diagnosis of RA patients remains a challenge, especially in ACPA-negative disease. Novel T-cell subsets, particularly Th17 may be useful, although data on Th17 frequency using flow cytometry in RA are conflicting. We investigated whether a novel epigenetic qPCR assay for the quantification of Th17 could differentiate patients with RA from those with symptoms evolving towards an alternative diagnosis.

METHODS

We used a qPCR assay measuring the extent of the methylation at a key position in the IL-17 and CD4 genes. Assays were performed on whole blood from 49 healthy controls (HC) and 165 early arthritis clinic patients. Flow cytometry was further used to detect the expression of CXCR4 on Th17 cells.

RESULTS

In 75 inflammatory arthritis patients who progressed to RA, the qPCR assays showed significantly fewer Th17 cells compared with 90 patients who did not (P<0.0001). Regression models demonstrated a high predictive value for RA development (75.8% correct prediction), and particularly for the ACPA-negative group (n = 125) where Th17 and swollen joint count (SJC) were the only predictors (73% correct prediction). The chemokine receptor CXCR4 had significantly higher expression on Th17 from early RA patients (n = 11) compared with HC (n = 15).

CONCLUSION

The results of the epigenetic qPCR assay showed that low levels of Th17 cells were predictive of developing RA, particularly in the ACPA-negative patients. This could have value for insights into pathogenesis and management. The results suggest the recruitment of Th17 to the inflammatory disease site, consistent with high CXCR4 expression.

Dendritic cells, T cells and their interaction in rheumatoid arthritis

Dendritic cells (DCs) are the key professional antigen-presenting cells which bridge innate and adaptive immune responses, inducing the priming and differentiation of naive to effector CD4+ T cells, the cross-priming of CD8+ T cells and the promotion of B cell antibody responses. DCs also play a critical role in the maintenance of immune homeostasis and tolerance. DC-T cell interactions underpin the generation of an autoimmune response in rheumatoid arthritis (RA). Here we describe the function of DCs and review evidence for DC and T cell involvement in RA pathogenesis, in particular through the presentation of self-peptide by DCs that triggers differentiation and activation of autoreactive T cells. Finally, we discuss the emerging field of targeting the DC-T cell interaction for antigen-specific immunotherapy of RA.

Effector Functions of CD4+ T Cells at the Site of Local Autoimmune Inflammation-Lessons From Rheumatoid Arthritis

Infiltration of memory CD4+ T cells in synovial joints of Rheumatoid Arthritis (RA) patients has been reported since decades. Moreover, several genome wide association studies (GWAS) pinpointing a key genetic association between the HLA-DR locus and RA have led to the generally agreed hypothesis that CD4+ T cells are directly implicated in the disease. Still, RA is a heterogeneous disease and much effort has been made to understand its different facets. T cell differentiation is driven by mechanisms including antigen stimulation, co-stimulatory signals and cytokine milieu, all of which are abundant in the rheumatic joint, implying that any T cells migrating into the joint may be further affected locally. In parallel to the characterization and classification of T-cell subsets, the contribution of different effector T cells to RA has been investigated in numerous studies though sometimes with contradictory results. In particular, the frequency of Th1 and Th17 cells has been assessed in the synovial joints with various results that could, at least partly, be explained by the stage of the disease. For regulatory T cells, it is largely accepted that they accumulate in RA synovial fluid and that the equilibrium between regulatory T cells and effector cells is a key factor in controlling inflammation processes involved in RA. Recent phenotypic studies describe the possible implication of a novel subset of peripheral T helper cells (Tph) important for T-B cell cross talk and plasma cell differentiation in the RA joint of ACPA+ (autoantibodies against citrullinated proteins) RA patients. Finally, cytotoxic CD4+ T cells, historically described as increased in the peripheral blood of RA patients have attracted new attention in the last years. In view of the recently identified peripheral T-cell subsets, we will integrate immunological data as well as information on genetic variants and therapeutic strategy outcomes into our current understanding of the width of effector T cells. We will also integrate tissue-resident memory T cell aspects, and discuss similarities and differences with inflammatory conditions in skin (psoriasis) and mucosal organs (Crohn's disease).

Expansion and activation of monocytic-myeloid-derived suppressor cell via STAT3/arginase-I signaling in patients with ankylosing spondylitis

Background

Ankylosing spondylitis (AS) is a chronic inflammatory rheumatic disease. The dysregulated immune system plays an important role in the pathogenesis of AS. Myeloid-derived suppressor cells (MDSCs) play a key immunoregulatory role in autoimmune arthritis. The aim of this study was to clarify the underlying immunoregulatory mechanism of MDSCs in patients with AS.

Methods

Flow cytometry was used to analyze the phenotype of MDSCs among peripheral blood mononuclear cells (PBMCs) from 46 patients with AS and 46 healthy control subjects. The correlation between MDSC frequency and the disease index of patients with AS was evaluated. A T cell proliferation experiment was used to evaluate the immunosuppressive function of MDSCs.

Results

Polymorphonuclear (PMN) and monocytic (M)-MDSCs were significantly elevated in the PBMCs of patients with AS, when compared with levels in healthy controls. Additionally, M-MDSC levels correlated positively with the clinical index of AS, including the Bath ankylosing spondylitis disease activity index (BASDAI) score, erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) levels. M-MDSCs derived from patients with AS suppressed T cell responses, and this effect was dependent on the induction of arginase-I. Furthermore, AS-derived M-MDSCs showed high levels of phosphorylated STAT3. Stattic, a STAT3-specific inhibitor, and STAT3-targeted siRNA abrogated the immunosuppressive function of M-MDSCs. Inhibition of STAT3 signaling also resulted in decreased arginase-I activity.

Conclusions

STAT3/arginase-I signaling plays an important role in both the expansion and activation of M-MDSCs in patients with AS. This information may be beneficial in developing novel therapeutic strategies for preventing AS.

Electronic supplementary material

The online version of this article (10.1186/s13075-018-1654-4) contains supplementary material, which is available to authorized users.

Sialylated Autoantigen-Reactive IgG Antibodies Attenuate Disease Development in Autoimmune Mouse Models of Lupus Nephritis and Rheumatoid Arthritis

Pro- and anti-inflammatory effector functions of IgG antibodies (Abs) depend on their subclass and Fc glycosylation pattern. Accumulation of non-galactosylated (agalactosylated; G0) IgG Abs in the serum of rheumatoid arthritis and systemic lupus erythematosus (SLE) patients reflects severity of the diseases. In contrast, sialylated IgG Abs are responsible for anti-inflammatory effects of the intravenous immunoglobulin (pooled human serum IgG from healthy donors), administered in high doses (2 g/kg) to treat autoimmune patients. However, whether low amounts of sialylated autoantigen-reactive IgG Abs can also inhibit autoimmune diseases is hardly investigated. Here, we explore whether sialylated autoantigen-reactive IgG Abs can inhibit autoimmune pathology in different mouse models. We found that sialylated IgG auto-Abs fail to induce inflammation and lupus nephritis in a B cell receptor (BCR) transgenic lupus model, but instead are associated with lower frequencies of pathogenic Th1, Th17 and B cell responses. In accordance, the transfer of small amounts of immune complexes containing sialylated IgG Abs was sufficient to attenuate the development of nephritis. We further showed that administration of sialylated collagen type II (Col II)-specific IgG Abs attenuated the disease symptoms in a model of Col II-induced arthritis and reduced pathogenic Th17 cell and autoantigen-specific IgG Ab responses. We conclude that sialylated autoantigen-specific IgG Abs may represent a promising tool for treating pathogenic T and B cell immune responses in autoimmune diseases.

The RORγt-CCR6-CCL20 axis augments Th17 cells invasion into the synovia of rheumatoid arthritis patients

OBJECTIVES

To clarify the pathogenic role of transcription factor expression of CD4 + T helper (Th) cell subsets in the development of rheumatoid arthritis (RA).

METHODS

We collected CD4 + T cells from peripheral blood mononuclear cells (PBMCs) and synovial fluid mononuclear cells (SFMCs) by magnetic cell sorting. The proportion of Th cell subsets were classified from cell surface markers (CD45RA, CXCR5, CXCR3, CCR6) and the expression of their transcription factors (T-bet, GATA3, RORγt) were analyzed by flow cytometry before and at 24 weeks after anti-rheumatic treatment. Chemotaxis assays quantified migratory ability.

RESULTS

The expression of CCR6 and RORγt in Th17 cells from PBMC of RA patients was significantly higher than in healthy control volunteers and osteoarthritis patients. The proportion of Th17 cells in SFMCs of RA patients was significantly higher than that in PBMCs. Chemotaxis assays revealed that the migration index of Th17 cells towards CCL20 was remarkably enhanced in RA patients. The expression of CCR6 and RORγt in Th17 cells at 24 weeks post-therapeutic intervention was significantly decreased compared to before treatment.

CONCLUSION

The high expression of RORγt might facilitate the migration of Th17 cells to inflamed joints via the enhanced expression of CCR6 and contribute to the pathology of RA.

Th17 pathway in recent-onset autoimmune diabetes

AIMS

Evaluate the participation of IL-17 pathway in T1D pathogenesis. T helper 17 cells are potent, highly inflammatory cells that produce interleukin 17A (IL-17A), considered a mediator of various immune disorders. However, their role in Type 1 diabetes (T1D) pathogenesis in humans is not totally elucidated.

METHODS

The expression of IL-17 Receptor A (IL-17RA) in peripheral T lymphocytes and IL-17A serum levels in recent-onset patients with T1D were compared with healthy controls. IL-17A gene variants were evaluated in a greater cohort.

RESULTS

Patients with recent-onset T1D (less than 6 months of diagnosis) exhibited lower expression of IL-17RA in CD3+ T (% of cells = 31.3% × 43.6%; p = .041) and CD4+ T cells (11.1% × 25.2%; p = .0019) and lower number of IL-17RA in CD4+ T cells (MFI = 1.16 × 4.56; p = .03) than controls. IL-17RA expression in CD8+ T cells and IL-17A serum levels were similar in both groups. The coding regions and boundary intron sequences of IL17A were sequenced. Seventeen allelic variants, including three novel variants in exon 3 (3'UTR n) were identified, but no one was associated with T1D susceptibility, as well as the resulting haplotypes and diplotypes. The expression of IL-17RA was not correlated with metabolic variables (glucose and HbA1c levels) or pancreatic autoantibodies titers.

CONCLUSIONS

The lower expression of IL-17RA in CD3+ and CD4+ T cells suggests a reduced effect of IL-17A in immune response of recent-onset T1D patients, at least at peripheral tissues. IL-17A allelic variants were not related with T1D susceptibility.

Peripheral blood T helper type 17 frequency shows an inverse correlation with disease activity and magnetic resonance imaging-based osteitis and erosions in disease-modifying anti-rheumatic drug- and steroid-naive established rheumatoid arthritis

An increased expansion of T helper type 17 (Th17) cells in the synovium has been shown to play a key role in cartilage and bone destruction in rheumatoid arthritis (RA). Because the correlation of the peripheral blood helper T cell subsets and various inflammatory cytokines with the magnetic resonance imaging (MRI)-based parameters have not been studied adequately to date, we sought to look for the same in this study. RA patients with disease duration less than 36 months, disease-modifying anti-rheumatic drugs (DMARDs) and steroid-naive, were recruited. MRI of the dominant hand and wrist was performed using a 0·2 Tesla MRI machine. Peripheral blood Th1 and Th17 were enumerated by flow cytometry and serum interleukin (IL)-6 and IL-17 by enzyme-linked immunosorbent assay (ELISA). Forty consecutive seropositive RA patients [33 females, mean disease duration 12·2 months, mean disease activity score (DAS)28 = 4·4] were included. MRI revealed erosions in 80% of these subjects. On subgroup analysis, prevalence of erosions (94 versus 68%) as well as mean erosion score (11·5 ± 18·9 versus 3·5 ± 6·0) were significantly higher in established RA (13-36 months' duration) compared to early RA (0-12 months). The median peripheral blood Th17 frequencies were significantly higher in patients (1·4%) compared to healthy controls (0·7%) and had a strong negative correlation with MRI parameters of erosion and osteitis as well as with DAS28 in the established RA subgroup. The frequency of peripheral blood Th17 subset was significantly expanded in established RA which correlated inversely with disease activity as well as MRI based erosions and osteitis.

The Relationship of Cytokines IL-13 and IL-17 with Autoantibodies Profile in Early Rheumatoid Arthritis

Aims. In the present study, we aimed to assess the concentrations of IL-13 and IL-17 in serum of patients with early rheumatoid arthritis (eRA), the investigation of correlation between the concentrations of these cytokines and disease activity score, and the concentration of some autoantibodies and the evaluation of the utility of IL-13 and -17 concentration measurements as markers of disease activity. Materials and Methods. Serum samples were collected from 30 patients and from 28 controls and analysed parameters. Results. The serum concentrations of IL-13, IL-17, anti-CCP, and IgM-RF were statistically significantly higher in patients with eRA, compared to the controls. IL-13 concentrations in the severe and moderate groups with eRA were statistically higher than in the mild and control groups. Also, in the case of IL-17, serum concentrations increased proportionally with the disease activity of eRA. We observe that concentrations of IL-13 and -17 did not correlate with autoantibodies. IL-17 concentration significantly positively correlated with CRP, while IL-13 concentration significantly negatively correlated with CRP. Disease activity score, DAS28, was strongly positively correlated with levels of ESR and weakly positively correlated with concentrations of anti-RA33 autoantibodies. IL-13 has a higher diagnostic utility than IL-17, CRP, ESR, IgM-RF, and anti-CCP as markers of disease activity. Conclusions. The presence of higher IL-13 and IL-17 serum levels in patients, compared with those of controls, confirms that these markers, found with high specificity, might be involved in the pathogenesis of eRA. IL-13 and IL-17 might be of better usefulness in the prediction of eRA activity status than IgM-RF and anti-CCP.

Major influence of CD4 count at the initiation of cART on viral and immunological reservoir constitution in HIV-1 infected patients

Background

A persistent immune activation is observed in gut during HIV-1 infection, which is not completely reversed by a combined antiretroviral therapy (cART). The impact of the time of cART initiation may highly influence the size of the viral reservoir and the ratio of CD4⁺/CD8⁺ T cells in the gut. In this study, we analyzed the characteristics of HIV rectal reservoir of long-term treated patients, regarding their blood CD4⁺ T cells count at the time of cART initiation.

Results

Twenty-four consenting men were enrolled: 9 exhibiting a CD4⁺ T cells count >350/mm³ (“high-level CD4 group”) and 15 < 350/mm³ (“low-level CD4 group”) in blood, at the start of cART. An immunophenotypical analysis of T and B cells subpopulations was performed in blood and rectal biopsies. HIV cell-associated DNA loads and qualitative intra-cellular RNA were determined in both compartments. The ratio of CD4⁺/CD8⁺ T cells was significantly decreased in the blood but not in the rectum of the “low-level CD4 group” of patients. The alteration in β7⁺ CD4⁺ T cells homing was higher in this group and was correlated to a low ratio of CD4⁺/CD8⁺ T cells in blood. An initiation of cART in men exhibiting a low-level CD4 count was also associated with an alteration of B cells maturation. HIV blood and gut DNA reservoirs were significantly lower in the “high-level CD4 group” of men. A high HIV DNA level was associated to a detectable intracellular HIV RNA in rectum.

Conclusions

An early initiation of cART could significantly preserve gut immunity and limit the viral reservoir constitution.

Electronic supplementary material

The online version of this article (doi:10.1186/s12977-016-0278-5) contains supplementary material, which is available to authorized users.

Ratio of Circulating IFNγ (+) "Th17 Cells" in Memory Th Cells Is Inversely Correlated with the Titer of Anti-CCP Antibodies in Early-Onset Rheumatoid Arthritis Patients Based on Flow Cytometry Methods of the Human Immunology Project

Rheumatoid arthritis (RA) is a systemic autoimmune disease with chronic joint inflammation characterized by activated T cells. IL-17 and Th17 cells play important roles in the pathogenesis of RA. Recently, plasticity in helper T cells has been demonstrated; Th17 cells can convert to Th1 cells. However, it remains to be elucidated whether this conversion occurs in the early phase of RA. Here, we validated the methods of the Human Immunology Project using only the cell-surface marker through measuring the actual expression of IL-17 and IFNγ. We also evaluated the expression of CD161 in human Th17 cells. We then tried to identify Th17 cells, IL-17⁺Th17 cells, and IFNγ⁺Th17 cells in the peripheral blood of early-onset RA patients using the standardized method of the Human Immunology Project. Our findings validated the method and the expression of CD161. The ratio of IFNγ⁺Th17 cells in memory T cells was inversely correlated to the titers of anti-CCP antibodies in the early-onset RA patients. These findings suggest that Th17 cells play important roles in the early phase of RA and that anti-IL-17 antibodies should be administered to patients with early phase RA, especially those with high titers of CCP antibodies.

CD146+ mesenchymal stem cells display greater therapeutic potential than CD146- cells for treating collagen-induced arthritis in mice

Background

The characteristics and therapeutic potential of subtypes of mesenchymal stem cells (MSCs) are largely unknown. In this study, CD146⁺ and CD146^– MSCs were separated from human umbilical cords, and their effects on regulatory T cells (Tregs), Th17 cells, chondrogenesis, and osteogenesis were investigated.

Methods

Flow cytometry was used to quantify IL-6 and TGF-β1 expressed on CD146⁺ and CD146^– MSCs. The therapeutic potential of both subpopulations was determined by measuring the clinical score and joint histology after intra-articular (IA) transfer of the cells into mice with collagen-induced arthritis (CIA).

Results

Compared with CD146^– MSCs, CD146⁺ MSCs expressed less IL-6 and had a significantly greater effect on chondrogenesis. After T lymphocyte activation, Th17 cells were activated when exposed to CD146^– cells but not when exposed to CD146⁺ cells both in vitro and in vivo. IA injection of CD146⁺ MSCs attenuated the progression of CIA. Immunohistochemistry showed that only HLA-A⁺ CD146⁺ cells were detected in the cartilage of CIA mice. These cells may help preserve proteoglycan expression.

Conclusions

This study suggests that CD146⁺ cells have greater potency than CD146^– cells for cartilage protection and can suppress Th17 cell activation. These data suggest a potential therapeutic application for CD146⁺ cells in treating inflammatory arthritis.

The Role of IL-17 and Th17 Lymphocytes in Autoimmune Diseases

The end of twentieth century has introduced some changes into T helper (Th) cells division. The identification of the new subpopulation of T helper cells producing IL-17 modified model of Th1-Th2 paradigm and it was named Th17. High abilities to stimulate acute and chronic inflammation made these cells ideal candidate for crucial player in development of autoimmune disorders. Numerous publications based on animal and human models confirmed their pivotal role in pathogenesis of human systemic and organ-specific autoimmune diseases. These findings made Th17 cells and pathways regulating their development and function a good target for therapy. Therapies based on inhibition of Th17-dependent pathways are associated with clinical benefits, but on the other hand are frequently inducing adverse effects. In this review, we attempt to summarize researches focused on the importance of Th17 cells in development of human autoimmune diseases as well as effectiveness of targeting IL-17 and its pathways in pre-clinical and clinical studies.

The IL-23-IL-17 axis in inflammatory arthritis

The discovery that the IL-23-IL-17 immune pathway is involved in many models of autoimmune disease has changed the concept of the role of T-helper cell subsets in the development of autoimmunity. In addition to TH17 cells, IL-17 is also produced by other T cell subsets and innate immune cells; which of these IL-17-producing cells have a role in tissue inflammation, and the timing, location and nature of their role(s), is incompletely understood. The current view is that innate and adaptive immune cells expressing the IL-23 receptor become pathogenic after exposure to IL-23, but further investigation into the role of IL-23 and IL-17 at different stages in the development and progression of chronic (destructive) inflammatory diseases is needed. Rheumatoid arthritis (RA) and spondyloarthritis (SpA) are the two most common forms of chronic immune-mediated inflammatory arthritis, and the IL-23-IL-17 axis is thought to have a critical role in both. This Review discusses the basic mechanisms of these cytokines in RA and SpA on the basis of findings from disease-specific animal models as well as human ex vivo studies. Promising therapeutic applications to modulate this immune pathway are in development or have already been approved. Blockade of IL-17 and/or TH17-cell activity in combination with anti-TNF therapy might be a successful approach to achieving stable remission or even prevention of chronic immune-mediated inflammatory diseases.

Altered immunoregulation in rheumatoid arthritis: the role of regulatory T cells and proinflammatory Th17 cells and therapeutic implications

In recent years several studies investigated the role of T lymphocyte subpopulations in the pathogenesis of rheumatoid arthritis (RA). Pathogenic Th17 cells mediate pannus growth, osteoclastogenesis, and synovial neoangiogenesis; hence they are key players in the development of the disease. On the other hand, regulatory T (Treg) cells are a T cell subset whose peculiar function is to suppress autoreactive lymphocytes. The imbalance between Th17 and Treg cells has been identified as a crucial event in the pathogenesis of RA. In addition, the effects of currently employed RA therapeutic strategies on these lymphocyte subpopulations have been extensively investigated. This review article aims to discuss current knowledge on Treg and Th17 cells in RA and possible implications of their therapeutic targeting in this disorder.

The pathogenic Th profile of human activated memory Th cells in early rheumatoid arthritis can be modulated by VIP

Our aim is to study the behavior of memory Th cells (Th17, Th17/1, and Th1 profiles) from early rheumatoid arthritis (eRA) patients after their in vitro activation/expansion to provide information about its contribution to RA chronicity. Moreover, we analyzed the potential involvement of vasoactive intestinal peptide (VIP) as an endogenous healing mediator. CD4(+)CD45RO(+) T cells from PBMCs of HD and eRA were activated/expanded in vitro in the presence/absence of VIP. FACS, ELISA, RT-PCR, and immunocytochemistry analyses were performed. An increase in CCR6(+)/RORC(+) cells and in RORC-proliferating cells and a decrease in T-bet-proliferating cells and T-bet(+)/RORC(+) cells were shown in eRA. mRNA expression of IL-17, IL-2, RORC, RORA, STAT3, and Tbx21 and protein secretion of IL-17, IFNγ, and GM-CSF were higher in eRA. VIP decreased the mRNA expression of IL-22, IL-2, STAT3, Tbx21, IL-12Rβ2, IL-23R, and IL-21R in HD and it decreased IL-21, IL-2, and STAT3 in eRA. VIP decreased IL-22 and GM-CSF secretion and increased IL-9 secretion in HD and it decreased IL-21 secretion in eRA. VPAC2/VPAC1 ratio expression was increased in eRA. All in all, memory Th cells from eRA patients show a greater proportion of Th17 cells with a pathogenic Th17 and Th17/1 profile compared to HD. VIP is able to modulate the pathogenic profile, mostly in HD. Our results are promising for therapy in the early stages of RA because they suggest that targeting molecules involved in the pathogenic Th17, Th17/1, and Th1 phenotypes and targeting VIP receptors could have a therapeutic effect modulating these subsets.

KEY MESSAGES

Th17 cells are more important than Th1 in the contribution to pathogenesis in eRA patients. Pathogenic Th17 and Th17/1 profile are abundant in activated/expanded memory Th cells from eRA patients. VIP decreases the pathogenic Th17, Th1, and Th17/1 profiles, mainly in healthy donors. The expression of VIP receptors is reduced in eRA patients respect to healthy donors, whereas the ratio of VPAC2/VPAC1 expression is higher.

Heterogeneous expression pattern of interleukin 17A (IL-17A), IL-17F and their receptors in synovium of rheumatoid arthritis, psoriatic arthritis and osteoarthritis: possible explanation for nonresponse to anti-IL-17 therapy?

Introduction

Accumulating evidence suggests an important role for interleukin 17 (IL-17) in the pathogenesis of several inflammatory diseases, including rheumatoid arthritis (RA) and psoriatic arthritis (PsA). Accordingly, clinical trials aimed at blocking IL-17 have been initiated, but clinical results between patients and across different diseases have been highly variable. The objective was to determine the variability in expression of IL-17A, IL-17F and their receptors IL-17RA and IL-17RC in the synovia of patients with arthritis.

Methods

Synovial biopsies were obtained from patients with RA (n = 11), PsA (n = 15) and inflammatory osteoarthritis (OA, n = 14). For comparison, synovia from noninflamed knee joints (n = 7) obtained from controls were included. Frozen sections were stained for IL-17A, IL-17F, IL-17RA and IL-17RC and evaluated by digital image analysis. We used confocal microscopy to determine which cells in the synovium express IL-17A and IL-17F, double-staining with CD4, CD8, CD15, CD68, CD163, CD31, von Willebrand factor, peripheral lymph node address in, lymphatic vessel endothelial hyaluronan receptor 1, mast cell tryptase and retinoic acid receptor–related orphan receptor γt (RORγt).

Results

IL-17A, IL-17F, IL-17RA and IL-17RC were abundantly expressed in synovial tissues of all patient groups. Whereas IL-17RA was present mostly in the synovial sublining, IL-17RC was abundantly expressed in the intimal lining layer. Digital image analysis showed a significant (P < 0.05) increase of only IL-17A in arthritis patients compared to noninflamed control tissues. The expression of IL-17A, IL-17F and their receptors was similar in the different patient groups, but highly variable between individual patients. CD4+ and CD8+ cells coexpressed IL-17A, and few cells coexpressed IL-17F. IL-17A and IL-17F were not expressed by CD15+ neutrophils. Mast cells were only occasionally positive for IL-17A or IL-17F. Interestingly, IL-17A and IL-17F staining was also observed in macrophages, as well as in blood vessels and lymphatics. This staining probably reflects receptor-bound cytokine staining. Many infiltrated cells were positive for the transcription factor RORγt. Colocalisation between RORγt and IL-17A and IL-17F indicates local IL-17 production.

Conclusions

Increased expression of IL-17A is not restricted to synovial tissues of RA and PsA patients; it is also observed in inflammatory OA. The heterogeneous expression levels may explain nonresponse to anti-IL-17 therapy in subsets of patients.

Electronic supplementary material

The online version of this article (doi:10.1186/s13075-014-0426-z) contains supplementary material, which is available to authorized users.

Emerging immunotherapies for rheumatoid arthritis

Novel treatments in development for rheumatoid arthritis target 3 broad areas: cytokines, cells, and signaling pathways. Therapies from each domain share common advantages (for example previously demonstrated efficacy, potential long-term immunomodulation, and oral administration respectively) that have stimulated research in each area but also common obstacles to their development. In this review recent progress in each area will be discussed alongside the factors that have impeded their path to clinical use.

Effect of intensive atorvastatin therapy on periprocedural PDCD4 expression in CD4+ T lymphocytes of patients with unstable angina undergoing percutaneous coronary intervention

OBJECTIVE

To investigate the effects of intensive atorvastatin therapy on programmed cell death 4 (PDCD4) expression by CD4+ T lymphocytes in patients with unstable angina who received percutaneous coronary intervention (PCI).

METHODS

Patients with unstable angina were randomized to pretreatment with either an intensive dose (80 mg/day, n = 33) or a conventional dose (20 mg/day, n = 33) of atorvastatin. Circulating CD4+ T cells were subsequently obtained prior to PCI, and also 18-24 h after PCI, using a magnetic cell sorting system. Fluorescence-based quantitative real-time PCR was then used to measure levels of PDCD4 mRNA in the isolated CD4+ T lymphocytes, and Western blot analysis was used to detect levels of PDCD4. Serum levels of interleukin (IL)-10 and TNF-α were quantified using enzyme-linked immunosorbent assays.

RESULTS

Of the 66 patients with unstable angina that were examined, levels of PDCD4 mRNA and protein were found to dramatically decrease in patients who received an intensive dose of atorvastatin following PCI (p < 0.05). In contrast, serum levels of TNF-α significantly increased following PCI in both the intensive dose group and the conventional dose group, with the latter being higher than the former (p < 0.05). Serum IL-10 levels also markedly increased following PCI for the two groups. However, higher values were associated with the intensive dose group (p < 0.05).

CONCLUSIONS

Intensive atorvastatin treatment reduced the post-PCI myocardial inflammatory response in patients with unstable angina, possibly by inhibiting PDCD4 expression in CD4+ T lymphocytes.

Enhanced and persistent levels of interleukin (IL)-17⁺ CD4⁺ T cells and serum IL-17 in patients with early inflammatory arthritis

Prognosis of patients with early inflammatory arthritis (EIA) is highly variable. The aim of this study was to compare, longitudinally and cross-sectionally, the levels of cytokine-expressing cells in peripheral blood (PB) from patients with EIA to those in established rheumatoid arthritis (RA) and healthy controls (HC). PB mononuclear cells from HC (n = 30), patients with EIA (n = 20) or RA (n = 38) were stimulated with phorbol myristate acetate (PMA)/ionomycin for 3 h, and stained for cell markers and cytokines. Serum cytokines and chemokines were measured by Luminex. Patients with EIA were reassessed at 6 and 12 months. The percentage of interleukin (IL)-17⁺ interferon (IFN)-γ⁻ CD4⁺ T cells [T helper type 17 (Th17)] was increased in RA and EIA versus HC. Serum IL-1β, IL-2, IL-4 IL-17 and macrophage inflammatory protein (MIP)-1α were increased in RA and EIA versus HC. IL-1Ra, IL-15 and IFN-α were increased in EIA versus HC. IL-6 and tumour necrosis factor (TNF)-α was increased in RA but not EIA versus HC. Disease activity scores in EIA patients improved over 12 months' treatment. Th17 percentage at baseline was correlated with both rheumatoid factor (RF) titre and functional deficit at 12 months. Baseline levels of serum granulocyte-macrophage colony-stimulating factor (GM-CSF), IL-6 and IL-8 were correlated with Larsen score at 12 months. There were no significant changes in cytokine-expressing CD4⁺ T cells over time, although the percentage of IL-6⁺monocytes increased. IL-17⁺ CD4⁺ T cells and serum IL-17 levels are increased in EIA. IL-6-expressing monocytes increase during the first year of disease, irrespective of disease-modifying anti-rheumatic drug (DMARD) therapy. We observed incomplete clinical responses, suggesting EIA patients need more intensive early therapy.

Induction of Th17 lymphocytes and Treg cells by monocyte-derived dendritic cells in patients with rheumatoid arthritis and systemic lupus erythematosus

Dendritic cells (DCs) have a key role in the regulation of immune response. We herein explored, in patients with inflammatory diseases, the role of monocyte derived DC's (mo-DCs) on the generation of Th17 and T regulatory (Treg) lymphocytes. Peripheral blood was obtained from thirty-five patients with rheumatoid arthritis (RA), twelve with systemic lupus erythematosus (SLE), and twenty healthy subjects. Mo-DCs were generated under standard (IL-4/GM-CSF) or tolerogenic (IL-4/GM-CSF plus recombinant P-selectin or PD-1 or IL-10) conditions, and their ability to induce Th17 and Treg lymphocytes was tested. We detected that mo-DCs from patients with RA showed an enhanced release of IL-6 and IL-23 as well as an increased capability to induce Th17 cells. Although mo-DCs from SLE patients also released high levels of IL-6/IL-23, it did not show an increased ability to induce Th17 lymphocytes. In addition, mo-DCs, from patients with RA and SLE generated under the engagement of PSGL-1, showed a defective capability to induce Foxp3+ Treg cells. A similar phenomenon was observed in SLE, when DC's cells were generated under PDL-1 engagement. Our data indicate that DCs from patients with rheumatic inflammatory disease show an aberrant function that may have an important role in the pathogenesis of these conditions.

IL-17 gene polymorphism is associated with chronic periodontitis and peri-implantitis in Iranian patients: a cross-sectional study

Periodontal disease (PD) and peri-implantitis (PI) are characterized by an immune response leading to destructive inflammation. The prominent impact of genetic factors on periodontitis has been previously evaluated and IL-17 has found to play a critical role in this process. This cytokine has a controversial behavior. This study aimed at finding out whether the polymorphism of this cytokine plays a significant role in chronic periodontitis (CP) and PI or it is just a pro-inflammatory regulatory cytokine. Fresh human blood samples were obtained and three main genotypes were traced carefully. The samples were transferred into 96-well plates and sent to KBioscience Institute in the United Kingdom for genotyping the polymorphism using Competitive Allele Specific PCR (KASP) technique. SPSS version19 software and chi-square and Kruskal-Wallis tests were used for statistical differences considering p-value less than 0.05. A significant difference was detected between the three groups in terms of specific SNP studied in this experiment (P = 0.00). The CC genotype of IL17 polymorphism (rs10484879) may contribute to the pathogenesis of peri-implantitis and periodontitis. The association of IL-17 polymorphism with PI and CP is a promising finding that may help in future similar studies on other ethnicities and larger study populations.

Targeting interleukin-17 in patients with active rheumatoid arthritis: rationale and clinical potential

Clinical and experimental evidence suggest that interleukin-17A (IL-17A; also known as IL-17) is an attractive therapeutic target in rheumatoid arthritis (RA). Rheumatoid synovial tissue produces IL-17A, which causes cartilage and bone degradation in synovial and bone explants. Overexpression of IL-17A induces synovial inflammation and joint destruction in animal RA models. These effects are attenuated in IL-17A-deficient animals and by agents that block IL-17A. Serum IL-17A levels and, to a greater extent, synovial fluid IL-17A levels are elevated in many patients with RA. In some RA cohorts, higher IL-17A levels have been associated with a more severe clinical course. Several IL-17A blockers, including the anti-IL-17A monoclonal antibodies secukinumab and ixekizumab, and the anti-IL-17 receptor subunit A monoclonal antibody brodalumab have been evaluated in phase II clinical trials. Of these, secukinumab is the most advanced with respect to clinical evaluation in RA, with phase III trials ongoing in patients on background methotrexate who had inadequate responses to previous tumor necrosis factor blocker therapy.