Identification, frequency, activation and function of CD4+ CD25(high)FoxP3+ regulatory T cells in children with juvenile idiopathic arthritis

The 'Treg paradox' in inflammatory arthritis

Classic regulatory T (Treg) cells expressing CD4 and the hallmark transcription factor FOXP3 are integral to the prevention of multi-system autoimmunity. However, immune-mediated arthritis is often associated with increased numbers of Treg cells in the inflamed joints. To understand these seemingly conflicting observations, which we collectively describe as 'the Treg paradox', we provide an overview of Treg cell biology with a focus on Treg cell heterogeneity, function and dysfunction in arthritis. We discuss how the inflamed environment constrains the immunosuppressive activity of Treg cells while also promoting the differentiation of TH17-like Treg cell, exTreg cell (effector T cells that were formerly Treg cells), and osteoclastogenic Treg cell subsets that mediate tissue injury. We present a new framework to understand Treg cells in joint inflammation and define potential strategies for Treg cell-directed interventions in human inflammatory arthritis.

Peripheral blood regulatory T cells and disease activity, quality of life, and outcomes in children with juvenile idiopathic arthritis

OBJECTIVES

To measure regulatory T cell (Treg) levels in the peripheral blood of children with juvenile idiopathic arthritis (JIA) and analyse the association of this measure with disease activity, quality of life, adjustment of treatment, and hospitalisation.

METHODS

We conducted a two-phase study (cross-sectional and prospective), including consecutive children with a JIA diagnosis according to ILAR criteria. Our independent variables were Tregs, Th1, Th2, and cytokines in peripheral blood, and our dependent variables in the cross-sectional phase were arthritis category, JIA activity, and patient-reported outcomes. To test associations, we used Spearman's correlation coefficient and the Mann-Whitney U test. In the prospective phase, we explored the probability of treatment adjustment and hospitalisation for JIA during follow-up according to Tregs levels at baseline, using Cox proportional regression.

RESULTS

Our sample included 87 participants (median age 11 years, 63.2% girls). Tregs were not associated with most variables of interest. However, we found that higher Tregs concentration was associated with lower erythrocyte sedimentation rate (ESR) and better subjective disease status and course, while higher IL-10 and TGF-β levels were associated with lower ESR, less pain, and better subjective disease status We found no association between Tregs and treatment adjustments or hospitalisation.

CONCLUSIONS

Higher baseline Treg levels in the peripheral blood of children with JIA may be associated with reduced disease activity and better quality of life, though were not informative on the inflammatory progression on the follow-up.

Th17/1 and ex-Th17 cells are detected in patients with polyarticular juvenile arthritis and increase following treatment

BACKGROUND

A better understanding of the pathogenesis of polyarticular juvenile idiopathic arthritis (polyJIA) is needed to aide in the development of data-driven approaches to guide selection between therapeutic options. One inflammatory pathway of interest is JAK-STAT signaling. STAT3 is a transcription factor critical to the differentiation of inflammatory T helper 17 cells (Th17s). Previous studies have demonstrated increased STAT3 activation in adult patients with rheumatoid arthritis, but less is known about STAT3 activation in polyJIA. We hypothesized that Th17 cells and STAT3 activation would be increased in treatment-naïve polyJIA patients compared to pediatric controls.

METHODS

Blood from 17 patients with polyJIA was collected at initial diagnosis and again if remission was achieved (post-treatment). Pediatric healthy controls were also collected. Peripheral blood mononuclear cells were isolated and CD4 + T cell subsets and STAT activation (phosphorylation) were evaluated using flow cytometry. Data were analyzed using Mann-Whitney U and Wilcoxon matched-pairs signed rank tests.

RESULTS

Treatment-naïve polyJIA patients had increased Th17 cells (CD3 + CD4 + interleukin(IL)-17 +) compared to controls (0.15% v 0.44%, p < 0.05), but Tregs (CD3 + CD4 + CD25 + FOXP3 +) from patients did not differ from controls. Changes in STAT3 phosphorylation in CD4 + T cells following ex vivo stimulation were not significantly different in patients compared to controls. We identified dual IL-17 + and interferon (IFN)γ + expressing CD4 + T cells in patients, but not controls. Further, both Th17/1 s (CCR6 + CD161 + IFNγ + IL-17 +) and ex-Th17s (CCR6 + CD161 + IFNγ + IL-17neg) were increased in patients' post-treatment (Th17/1: 0.3% v 0.07%, p < 0.05 and ex-Th17s: 2.3% v 1.4%, p < 0.05). The patients with the highest IL-17 expressing cells post-treatment remained therapy-bound.

CONCLUSIONS

Patients with polyJIA have increased baseline Th17 cells, potentially reflecting higher tonic STAT3 activation in vivo. These quantifiable immune markers may identify patients that would benefit upfront from pathway-focused biologic therapies. Our data also suggest that inflammatory CD4 + T cell subsets not detected in controls but increased in post-treatment samples should be further evaluated as a tool to stratify patients in remission on medication. Future work will explore these proposed diagnostic and prognostic biomarkers.

Impact of FOXP3 gene polymorphisms and gene-environment interactions in asthma and atopy in a Brazilian population

BACKGROUND

Polymorphisms in genes related to the activation and development of regulatory T cells (Tregs), such as FOXP3, may be associated with asthma and atopy development. Additionally, environmental factors such as exposure to infections can modify the effect of these associations. This study evaluated the impact of polymorphisms in the FOXP3 on the risk of asthma and atopy as also gene-environment interactions in these outcomes.

METHODS

This study included 1,246 children from the SCAALA program, between 4 and 11 years of age. DNA was extracted from peripheral blood and eight SNPs (rs2280883, rs11465476, rs11465472, rs2232368, rs3761549, rs3761548, rs2232365 and rs2294021) were genotyped using the 2.5 HumanOmni Beadchip from Illumina (San Diego, California, USA) or TaqMan qRT-PCR.

RESULTS

The rs2232368 (Allele T) was positively associated with asthma symptoms (OR=1.95, CI=1.04 to 3.66, p = 0.040) and skin prick test (SPT) reactivity to aeroallergens (OR=2.31, CI=1.16 to 4.59, p = 0.017). The rs3761549 (Allele T) was positively associated with SPT reactivity (OR=1.44, CI=1.03 to 2.02, p = 0.034). The rs2280883 (Allele C) was negatively associated with specific IgE to aeroallergens (OR=0.83, CI=0.70 to 0.99, p = 0.040). Furthermore, the rs2280883 played a protective role in the development of atopy only in individuals seropositive to Epstein-Barr virus (EBV) infection (OR=0.74, CI=0.60 to 0.92, p = 0.003 and OR=0.74; 95% CI=0.61-0.91, p = 0.007 for SPT and slgE respectively), but not in individuals without EBV infection.

CONCLUSION

Polymorphisms in the FOXP3 gene were associated with the risk of atopy and asthma development in our population. In addition, EBV infection had an effect modifier of the observed association for rs2280883 variant.

New therapeutic strategies based on biasing IL-2 mutants for cancers and autoimmune diseases

Interleukin-2 (IL-2) is an immunomodulatory multifunctional cytokine. High-dose IL-2 was first approved by the U.S. Food and Drug Administration (FDA) in the 1990s for the treatment of metastatic renal cell carcinoma and metastatic melanoma. However, the short half-life of IL-2 and its toxicity caused by high-dose IL-2 limit the clinical use of IL-2. Recently, the development of cell-type-selective engineered IL-2 products become a hot research filed, mainly because IL-2 stimulates both regulatory T cells (Treg) and effector T cells (Teff) in vivo. The selective effect of IL-2 on Treg and Teff can be improved by designing biased IL-2 mutants, which showed reduced toxicity while being more effective in stimulating anti-tumor effector immunity or ameliorating autoimmune diseases. In this review we summarize the biological properties of IL-2 mutants reported so far. The design process and principle of IL-2 mutants, IL-2 mutant antibody complexes and IL-2 fusion proteins were discussed, which provided research basis for the design and application of IL-2 mutants in the future.

B Cells on the Stage of Inflammation in Juvenile Idiopathic Arthritis: Leading or Supporting Actors in Disease Pathogenesis?

Juvenile idiopathic arthritis (JIA) is a term that collectively refers to a group of chronic childhood arthritides, which together constitute the most common rheumatic condition in children. The International League of Associations for Rheumatology (ILAR) criteria define seven categories of JIA: oligoarticular, polyarticular rheumatoid factor (RF) negative (RF-), polyarticular RF positive (RF+), systemic, enthesitis-related arthritis, psoriatic arthritis, and undifferentiated arthritis. The ILAR classification includes persistent and extended oligoarthritis as subcategories of oligoarticular JIA, but not as distinct categories. JIA is characterized by a chronic inflammatory process affecting the synovia that begins before the age of 16 and persists at least 6 weeks. If not treated, JIA can cause significant disability and loss of quality of life. Treatment of JIA is adjusted according to the severity of the disease as combinations of non-steroidal anti-inflammatory drugs (NSAIDs), synthetic and/ or biological disease modifying anti-rheumatic drugs (DMARDs). Although the disease etiology is unknown, disturbances in innate and adaptive immune responses have been implicated in JIA development. B cells may have important roles in JIA pathogenesis through autoantibody production, antigen presentation, cytokine release and/ or T cell activation. The study of B cells has not been extensively explored in JIA, but evidence from the literature suggests that B cells might have indeed a relevant role in JIA pathophysiology. The detection of autoantibodies such as antinuclear antibodies (ANA), RF and anti-citrullinated protein antibodies (ACPA) in JIA patients supports a breakdown in B cell tolerance. Furthermore, alterations in B cell subpopulations have been documented in peripheral blood and synovial fluid from JIA patients. In fact, altered B cell homeostasis, B cell differentiation and B cell hyperactivity have been described in JIA. Of note, B cell depletion therapy with rituximab has been shown to be an effective and well-tolerated treatment in children with JIA, which further supports B cell intervention in disease development.

Immunological Profile and Predisposition to Autoimmunity in Girls With Turner Syndrome

OBJECTIVE

The risk of autoimmune diseases (AD) in patients with Turner Syndrome (TS) is twice higher than in the general female population and four times higher than in the male population. The causes of the increased incidence of AD in TS are still under discussion. We hypothesized the presence of a specific humoral, cellular, and regulatory T cell (Treg) immunity profile which predisposes to AD, disorders of immunity, and disorders of immune regulation.

METHODS

The study encompassed 37 girls with TS and with no signs of infection. The control group included 11 healthy girls with no hormonal disorders. A medical history focused on AD and immunity disorders was taken from all participants. The levels of: immunoglobulins IgG, IgA, IgM, total lymphocytes, lymphocytes subpopulations CD3+, CD4+, CD8+, CD19+, natural killer cells, Treg cells (CD4+ CD25+ CD127- FOXP3+), anti-inflammatory cytokines (interleukin-10, transforming growth factor-β), anti-nuclear antibodies, glutamic acid decarboxylase (GAD65 Abs), anti-thyroid peroxidase (anti-TPO Ab), and anti-thyroglobulin (anti-TG Ab) autoantibodies were determined in each participant.

RESULTS

The mean age and BMI in the TS group and in controls were comparable (11.9 ± 4.1 vs. 12.5 ± 4.0 years; 19.2 ± 3.4 vs. 19.7 ± 4.6, p > 0.05). Mean hSDS was significantly higher in controls (-2.2 ± 0.9 vs. -0.4 ± 1.5, p < 0.0001). AD and recurrent otitis media with complications were previously confirmed in 9 (24.3%) and 10 (27.0%) girls with TS. The TS group had significantly lower levels of IgG (p = 0.02), lower%CD4 (p < 0.001) and a significantly lower CD4:CD8 ratio than the controls (p < 0.001). There were no differences in mean Treg% between girls with TS and healthy controls. However, comparing Treg% between the TS group with coexisting autoimmunity and the remaining participants, a statistically significant difference was observed (2.09 ± 0.5 vs. 2.77 ± 1.6, p = 0.048). Patients with iXq had lower CD4% and more frequently had positive anti-TPO Ab and anti-TG Ab compared to the remaining girls with TS and controls (p = 0.001, p < 0.001, p = 0.01).

CONCLUSION

TS predisposes to AD, especially if associated with coexisting iXq. Our preliminary findings show that patients with TS may present a specific profile of humoral and cellular immunity markers, different from healthy girls.

[Quantity of Treg cells and Th17 cells in spleen of primary immune thrombocytopenic purpura patients]

Objective: To observe the quantity of Treg cells and Th17 cells in spleen of adult primary immune thrombocytopenic purpura (ITP) patients. Methods: 43 ITP cases with splenectomy treatment were enrolled from December 2008 to June 2016 at Union Hospital of Fujian Medical University, including 20 males and 23 females with a median age of 36 (18-76) years. The controls were thirty patients who underwent splenectomy because of pancreatic diseases or splenic impairment, including 21 males and 9 females with a median age of 47 (21-69) years. The quantity and ratio of Treg cells and Th17 cells were examined by immunohistochemistry between ITP patients and controls. Results: ①The quantity of Treg cells in ITP were less than controls[ (11.3±4.7) /mm(2) vs (59.0±15.0) /mm(2), t=-22.894, P<0.001], but Th17 cells were more than controls[ (235.2±69.4) /mm(2) vs (181.1±23.7) /mm(2), t=13.768, P<0.001]. So the ratio of Treg/Th17 in ITP was lower than controls (0.048±0.027 vs 0.328±0.086, t=19.522, P<0.001) . ② The quantity of Treg cells in cases without response after splenectomy were less than cases with response[ (9.5±5.0) /mm(2) vs (11.6±4.7) /mm(2), t=2.723, P=0.010], and there is no statistical differences between the two groups about the quantity of Th17 cells and the ratio of Treg/Th17 cells[ (232.3±80.8) /mm(2) vs (239.6±66.9) /mm(2), t=1.108, P=0.277; 0.040±0.024 vs 0.053±0.027, t=0.540, P=0.592]. Conclusions: There is a significant difference about the quantity of Treg cells and Th17 cells in spleen between ITP patients and healthy controls, and they are relevant to the response after splenectomy.

The Etiology of Juvenile Idiopathic Arthritis

Over the years, the commonly used term to describe juvenile idiopathic arthritis (JIA) has changed. By definition, JIA includes all types of arthritis with no apparent cause, lasting more than 6 weeks, in patients aged less than 16 years at onset. JIA pathogenesis is still poorly understood: the interaction between environmental factors and multiple genes has been proposed as the most relevant working mechanism to the development of JIA. The concept that various microbes that colonize or infect not only the mucosal surfaces, like the oral cavity, but also the airways and gut might trigger autoimmune processes, resulting in chronic arthritides, and JIA was first drafted at the outset of last century. JIA development might be initiated and sustained by the exposure to environmental factors, including infectious agents which affect people at a young age, depending on the underlying genetic predisposition to synovial inflammation. Many data from patients with JIA suggest a scenario in which different external antigens incite multiple antigen-specific pathways, cytotoxic T cell responses, activation of classical complement cascade, and production of proinflammatory cytokines. In this review, emphasis is paid not only to the potential role of parvovirus B19 and Epstein-Barr virus in primis but also to the general involvement of different bacteria as Salmonella spp., Shigella spp., Campylobacter spp., Mycoplasma pneumoniae, Chlamydophila pneumoniae, Bartonella henselae, and Streptococcus pyogenes for the development of immune-mediated arthritides during childhood. No unequivocal evidence favoring or refuting these associations has been clearly proved, and today, the strict definition of JIA etiology remains unknown. The infection can represent a random event in a susceptible individual, or it can be a necessary factor in JIA development, always in combination with a peculiar genetic background. Further studies are needed in order to address the unsolved questions concerning this issue.

Genetic polymorphisms of Foxp3 in patients with rheumatoid arthritis

OBJECTIVE

The aim of the study was to identify 2 polymorphic variants in the promoter region of the Foxp3 gene and their possible association with susceptibility to and severity of rheumatoid arthritis (RA). The association between genetic factors and pathogenesis suggests that T cells take part in the induction of RA. The CD4+CD25highFoxp3+ subset of regulatory T cells plays an essential role in preventing autoimmunity and maintaining immune homeostasis.

METHODS

Patients with RA (n = 274) and healthy individuals (n = 295) were examined for -3279 C/A and -924 A/G Foxp3 gene polymorphisms by the polymerase chain reaction-restriction fragment-length polymorphism method. Serum Foxp3 levels in patients with RA and controls were measured with ELISA.

RESULTS

Foxp3 -3279 A and -924 G alleles were associated with significantly elevated risk of RA in the population tested (p = 0.003 and p = 0.004, respectively) compared to the wild-type alleles. Overall, -3279 C/A and -924 A/G Foxp3 gene polymorphisms were in indistinct linkage disequilibrium with D' = 0.481 and r(2) = 0.225. From 4 possible haplotypes, frequencies of 2 (AG and CA) showed significant differences between both examined groups (respectively, p < 0.001 and p = 0.007). After appropriate adjustment of Bonferroni correction for multiple testing, the genotype-phenotype analysis showed no significant correlation of the Foxp3 -3279 C/A and -924 A/G polymorphisms with the disease activity, joint damage, laboratory variables, and extraarticular manifestation in patients with RA. Serum Foxp3 level was significantly higher in patients than in controls (p < 0.0001).

CONCLUSION

Current findings indicated that the Foxp3 genetic polymorphism and the Foxp3 protein level may be associated with susceptibility to RA in the Polish population.

Imbalance of Th17 and T-regulatory cells in peripheral blood and synovial fluid in treatment naïve children with juvenile idiopathic arthritis

Objectives

The imbalance between Th17 and T regulatory cells (Tregs) may be a key event in development of autoimmunity. The problem is poorly explored in juvenile idiopathic arthritis (JIA) so far. In this study, peripheral blood (PB) and synovial fluid (SF) Tregs and Th17 cells from were assessed in untreated JIA children.

Material and methods

In 50 children with JIA the PB or SF percentages of Tregs and Th17 cells were assessed by flow cytometry, in comparison with PB Tregs and Th17 cells from 28 healthy controls. Additionally, in both groups the levels of proinfammatory cytokines, such as interleukin (IL)-1β, IL -6, IL -17, IL -21, IL -23 and tumor necrosis factor α (TN F-α) were assessed using ELI SA method.

Results

The proportion of JIA PB Th17 cells was significantly higher than in the controls (p = 0.01). Serum levels of IL -1β, IL -6, IL -17, IL -23 were also significantly higher in JIA (p = 0.011, p = 0.007, p = 0.008 and p = 0.023, respectively). The highest serum IL -6 levels were observed in oligoarthritis JIA (p = 0.031). Synovial fluid IL -21 concentration was distinctly higher in polyarticular JIA. Synovial fluid levels of TN F-α, IL -1β and IL -6 were significantly higher than in JIA PB (p = 0.038, p = 0.013 and p < 0.001, respectively). There was a significant correlation between IL -6 and PB Tregs (p = 0.02).

Conclusions

The results of this comprehensive analysis indicate a role of Th17 cell activation in the pathogenesis of JIA.

Human regulatory T cells with alloantigen specificity are more potent inhibitors of alloimmune skin graft damage than polyclonal regulatory T cells

Graft rejection by the immune system is a major cause of transplant failure. Lifelong immunosuppression decreases the incidence of graft rejection; however, nonspecific immunosuppression results in increased susceptibly to infection and cancer. Regulatory T cells (T(regs)), which suppress the activation of the immune system and induce tolerance, are currently under evaluation for use in clinical transplantation. Ex vivo expanded polyclonal T(regs) that are introduced into transplant recipients alter the balance of T effector cells to T(regs); however, experimental data suggest that alloantigen-specific T(regs) would be more effective at preventing graft rejection. We have developed a method to enrich alloantigen-specific human T(regs) based on the coexpression of activation markers, CD69 and CD71. These T(regs) could be readily expanded in vitro and demonstrated potent antigen-specific suppression. In a humanized mouse model of alloimmune-mediated injury of human skin grafts, alloantigen-specific T(regs) resulted in a significant reduction in clinically relevant indicators of dermal tissue injury when compared with polyclonal T(regs), restoring a histology comparable to healthy skin. This method of human allospecific T(reg) selection should be scalable to the clinic. The improved in vivo efficacy of alloantigen-specific T(regs) over polyclonal T(regs) shown here suggests that generating "customized" T(regs) with defined anti-donor allospecificities may improve current practice in clinical immunotherapy.