Cytokines and Regulatory T Cells in Rheumatoid Arthritis and Their Relationship with Response to Corticosteroids

Revisiting steroidogenesis and its role in immune regulation with the advanced tools and technologies

Historically tools and technologies facilitated scientific discoveries. Steroid hormone research is not an exception. Unfortunately, the dramatic advancement of the field faded this research area and flagged it as a solved topic. However, it should have been the opposite. The area should glitter with its strong foundation and attract next-generation scientists. Over the past century, a myriad of new facts on biochemistry, molecular biology, cell biology, physiology and pathology of the steroid hormones was discovered. Several innovations were made and translated into life-saving treatment strategies such as synthetic steroids, and inhibitors of steroidogenesis and steroid signaling. Steroid molecules exhibit their diverse effects on cell metabolism, salt and water balance, development and function of the reproductive system, pregnancy, and immune-cell function. Despite vigorous research, the molecular basis of the immunomodulatory effect of steroids is still mysterious. The recent excitement on local extra-glandular steroidogenesis in regulating inflammation and immunity is revitalizing the topic with a new perspective. Therefore, here we review the role of steroidogenesis in regulating inflammation and immunity, discuss the unresolved questions, and how this area can bring another golden age of steroid hormone research with the development of new tools and technologies and advancement of the scientific methods.

TGFB1 (rs1800470 and rs1800469) variants are independently associated with disease activity and autoantibodies in rheumatoid arthritis patients

To evaluate the association between TGFB1 + 869 T > C (rs1800470) and TGFB1-509 C > T (rs1800469) variants with susceptibility for rheumatoid arthritis (RA), disease activity, presence of rheumatoid factor (RF), anti-cyclic citrullinated peptide (anti-CCP) and TGF-β1 plasma levels. A total of 262 patients with RA and 168 control individuals were tested for the TGFB1 variants using a TaqMan genotyping assay. Disease activity score in 28 joints (DAS28) classified RA patients into two groups of disease activity: remission/mild (DAS28 < 3.2) and moderate/severe (DAS28 ≥ 3.2). TGFB1 + 869 T > C and -509 C > T variants, independently or in haplotype combination, were not associated with RA's susceptibility. Patients with the TGFB1-509 TT genotype had a higher frequency of DAS28 ≥ 3.2 (OR 2.58, 95% CI 1.04-6.42, p = 0.041). The TGFB1 + 869 CC genotype in seropositive patients for RF or anti-CCP was associated with decreased TGF-β1 levels (p = 0.032 and p = 0.039, respectively). Patients with the TGFB1 + 869 C allele and elevated RF titles demonstrated a higher frequency of DAS28 ≥ 3.2 (p = 0.037). The TGFB1 + 869 T > C variant was associated with diminished TGF-β1 plasma levels and moderate/severe activity disease only in seropositive RF patients. This is the first study showing that TGF-β1 plasma levels can be modulated by the interaction between the TGFB1 + 869 T > C variant and autoantibodies. However, the TGFB1-509 C > T variant was associated with moderate/severe activity disease, independently of autoantibodies positivity. Thus, our findings suggest that TGFB1 + 869 T > C and -509 C > T variants can predict activity disease in different RA patient subgroups.

Elevated circulating IL-17 level is associated with inflammatory arthritis and disease activity: A meta-analysis

OBJECTIVES

Previous studies found that the interleukin (IL)-17 level was elevated in inflammatory arthritis, but results were inconsistent. This meta-analysis aimed to investigate the association of IL-17 cytokine with osteoarthritis (OA), rheumatoid arthritis (RA), ankylosing spondylitis (AS) and psoriatic arthritis (PsA).

METHODS

Relevant studies were searched using databases. Standardized mean difference (SMD) was calculated. Correlation coefficient was utilized to evaluate the relationship between IL-17 and disease activity of AS and RA. Subgroup analysis, sensitivity analysis and meta-regression were applied to explore the sources of heterogeneity.

RESULTS

83 records were enrolled. The IL-17 level was elevated in AS (SMD = 2.348, P < .001), RA (SMD = 1.502, P < .001), PsA (SMD = 1.710, P < .001) and OA (SMD = 1.192, P = .016), and similar results occurred in subgroup analysis. Furthermore, the IL-17 level was positively associated with disease activity of AS and RA.

CONCLUSION

Circulating IL-17 level is significantly elevated in inflammatory arthritis and is related to the disease activity of AS and RA, suggesting that it plays an important role in the pathogenesis and progression of inflammatory arthritis (especially in AS and RA).

Glucocorticoids, Sex Hormones, and Immunity

Glucocorticoid hormones regulate essential body functions in mammals, control cell metabolism, growth, differentiation, and apoptosis. Importantly, they are potent suppressors of inflammation, and multiple immune-modulatory mechanisms involving leukocyte apoptosis, differentiation, and cytokine production have been described. Due to their potent anti-inflammatory and immune-suppressive activity, synthetic glucocorticoids (GCs) are the most prescribed drugs used for treatment of autoimmune and inflammatory diseases. It is long been noted that males and females exhibit differences in the prevalence in several autoimmune diseases (AD). This can be due to the role of sexual hormones in regulation of the immune responses, acting through their endogenous nuclear receptors to mediate gene expression and generate unique gender-specific cellular environments. Given the fact that GCs are the primary physiological anti-inflammatory hormones, and that sex hormones may also exert immune-modulatory functions, the link between GCs and sex hormones may exist. Understanding the nature of this possible crosstalk is important to unravel the reason of sexual disparity in AD and to carefully prescribe these drugs for the treatment of inflammatory diseases. In this review, we discuss similarities and differences between the effects of sex hormones and GCs on the immune system, to highlight possible axes of functional interaction.

Prospects of IL-2 in Cancer Immunotherapy

IL-2 is a powerful immune growth factor and it plays important role in sustaining T cell response. The potential of IL-2 in expanding T cells without loss of functionality has led to its early use in cancer immunotherapy. IL-2 has been reported to induce complete and durable regressions in cancer patients but immune related adverse effects have been reported (irAE). The present review discusses the prospects of IL-2 in immunotherapy for cancer.

Characterization of T-cell subpopulations in patients with chronic rhinosinusitis with nasal polyposis

Background:

There is an ongoing discussion concerning the potential origins of chronic rhinosinusitis with nasal polyposis (CRSwNP).

Objective:

The aim of this study was to quantify subpopulations of T cells in peripheral blood and nasal polyps in CRSwNP to examine their influence on the etiology of this disease.

Methods:

Tissue and blood samples were collected from 11 patients who underwent nasal sinus surgery, and these samples were analyzed by multicolor flow cytometry.

Results:

There was a significantly lower frequency of CD4⁺ T-helper (Th) cells and a significantly higher frequency of CD8⁺ T cells among lymphocytes isolated from nasal polyps compared with peripheral blood mononuclear cells (PBMC). In both T-cell subpopulations, a shift mainly from naive T cells among peripheral blood lymphocytes toward an effector memory and terminally differentiated subtype predominance in nasal polyps was observed. Among CD4⁺ T cells, the frequencies of cluster of differentiation (CD) 45RA- Forkhead-Box-Protein P3high (FoxP3^high) cytotoxic T-lymphocyte-associated Protein 4high (CTLA-4^high) activated regulatory T (T_reg) cells, and CD45RA- Forkhead-Box-Protein P3low (FoxP3^low) memory T cells were significantly increased in nasal polyps compared with PBMC.

Conclusion:

In this study, we presented a detailed characterization of CD4⁺ and CD8⁺ T-cell subpopulations in patients with CRSwNP. CD8⁺ T cells were more prominent in nasal polyps than in CD4⁺ T cells. Both nasal CD8⁺ T cells and CD4⁺ T cells predominantly had an effector memory phenotype. Among CD4⁺ T cells, activated T_reg cells were increased in nasal polyps compared with PBMC. The data point toward a local regulation of T-cell composition within the microenvironment of nasal polyps, which might be further exploited in the future to develop novel immunotherapeutic strategies.

Vitamin D in rheumatoid arthritis-towards clinical application

In addition to its well-documented involvement in mineral homeostasis, vitamin D seems to have broad effects on human health that go beyond the skeletal system. Prominent among these so-called nonclassical effects of vitamin D are its immunomodulatory properties. In vitro studies have shown anti-inflammatory effects of 1,25-dihydroxyvitamin D (1,25(OH)2D), the active form of vitamin D. In addition, epidemiological analysis of patients with established inflammatory disease identified associations between vitamin D deficiency (low serum concentrations of inactive 25-hydroxyvitamin D, abbreviated to 25(OH)D) and inflammatory conditions, including rheumatoid arthritis (RA). The association of vitamin D deficiency with RA severity supports the hypothesis of a role for vitamin D in the initiation or progression of the disease, or possibly both. However, whether 25(OH)D status is a cause or consequence of RA is still incompletely understood and requires further analysis in prospective vitamin D supplementation trials. The characterization of factors that promote the transition from preclinical to clinical phases of RA has become a major focus of research, with the aim to facilitate earlier diagnosis and treatment, and improve therapeutic outcomes. In this Review, we aim to describe the current knowledge of vitamin D and the immune system specifically in RA, and discuss the potential benefits that vitamin D might have on slowing RA progression.

Glucocorticoid pharmacogenetics in pediatric idiopathic nephrotic syndrome

Idiopathic nephrotic syndrome represents the most common type of primary glomerular disease in children: glucocorticoids (GCs) are the first-line therapy, even if considerable interindividual differences in their efficacy and side effects have been reported. Immunosuppressive and anti-inflammatory effects of these drugs are mainly due to the GC-mediated transcription regulation of pro- and anti-inflammatory genes. This mechanism of action is the result of a complex multistep pathway that involves the glucocorticoid receptor and several other proteins, encoded by polymorphic genes. Aim of this review is to highlight the current knowledge on genetic variants that could affect GC response, particularly focusing on children with idiopathic nephrotic syndrome.

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.

Complex Primary Human Cell Systems for Drug Discovery

Phenotypic or biofunctional assays play an important role in drug discovery by helping to bridge the gap between high-throughput, target-based screening assays used for compound identification and more physiologically relevant in vivo disease models used for preclinical development. We have developed a standardised panel of phenotypic assays using primary human cells and co-cultures that model tissue and disease biology for characterization of drug leads. Here we show application of these assays for characterisation of clinical stage kinase inhibitors for rheumatoid arthritis, the recently approved JAK kinase inhibitor, tofacitinib, and the SYK kinase inhibitor, fostamatinib. We demonstrate how profiling in this assay panel can relate to clinical effects, both efficacy and safety related.

Low-dose interleukin-2 therapy: a driver of an imbalance between immune tolerance and autoimmunity

For many years, the role of interleukin-2 (IL-2) in autoimmune responses was established as a cytokine possessing strong pro-inflammatory activity. Studies of the past few years have changed our knowledge on IL-2 in autoimmune chronic inflammation, suggesting its protective role, when administered at low-doses. The disrupted balance between regulatory and effector T cells (Tregs and Teffs, respectively) is a characteristic of autoimmune diseases, and is dependent on homeostatic cytokines, including IL-2. Actually, inherent defects in the IL-2 signaling pathway and/or levels leading to Treg compromised function and numbers as well as Th17 expansion have been attributed to autoimmune disorders. In this review, we discuss the role of IL-2 in the pathogenesis of autoimmune diseases. In particular, we highlight the impact of the dysregulated IL-2 pathway on disruption of the Treg/Th17 balance, reversal of which appears to be a possible mechanism of the low-dose IL-2 treatment. The negative effects of IL-2 on the differentiation of follicular helper T cells (Tfh) and pathogenic Th17 cells, both of which contribute to autoimmunity, is emphasized in the paper as well. We also compare the current IL-2-based therapies of animal and human subjects with immune-mediated diseases aimed at boosting the Treg population, which is the most IL-2-dependent cell subset desirable for sufficient control of autoimmunity. New perspectives of therapeutic approaches focused on selective delivery of IL-2 to inflamed tissues, thus allowing local activity of IL-2 to be combined with its reduced systemic and pleiotropic toxicity, are also proposed in this paper.

Buprenorphine does not impact the inflammatory response in haemophilia A mice with experimentally-induced haemarthrosis

Haemarthrosis is the most common clinical manifestation of haemophilia and is responsible for significant morbidity in haemophilic patients. The murine experimentally-induced knee bleeding model is an important model in haemophilia research but it is currently unknown if the use of analgesia in this model might impact on the inflammatory response. The aim was to investigate the inflammatory response after a needle induced knee bleed in haemophilia A mice treated with buprenorphine or saline. One hundred and sixty mice were randomized into two groups to blindly receive buprenorphine or saline. All the mice were anaesthetized and knee injury was induced by inserting a 30 G needle into the right knee joint. At t = 6, 24, 48 and 72 h, 20 mice from each group were terminated and the following parameters were assessed: change in body weight and joint diameter, visual bleeding score (VBS), white blood counts, haematocrit, platelet concentrations, haemoglobin, plasma haptoglobin and plasma and synovial fluid levels of 23 cytokines. Twenty mice were terminated at t = 0 receiving no injury or treatment to provide baseline measures. Twenty-one cytokines in plasma and 22 cytokines in synovial fluid, joint diameter change, VBS and blood parameters were not significantly altered by the administration of buprenorphine. Slight alterations of plasma haptoglobin at t = 48 h, body weight, plasma and synovial eotaxin and plasma G-CSF were found in buprenorphine-treated mice. We demonstrated that buprenorphine does not overall impact on the inflammatory response, and the use of buprenorphine in the knee bleeding model in haemophilic mice should be continued.

Patients with the most advanced rheumatoid arthritis remain with Th1 systemic defects after TNF inhibitors treatment despite clinical improvement

Systemic immune defects might reflect severely dysregulated control of chronic inflammation related to disease progression. Th17/Treg cell imbalance has been demonstrated to be involved in rheumatoid arthritis (RA) pathogenesis. Despite controversial results, a growing anti-inflammatory role in this process has been recently attributed to Th1 responses. The aim of the study was to estimate the extent of Th1/Th17/Treg imbalance in peripheral blood (PB) of patients with short- and long-term RA in relation to cytokine milieu and its reversal after therapy with methotrexate and/or TNF inhibitors, respectively. Patients with different duration of RA (median 6 vs. 120 months) in the active phase of RA were enrolled in this study. We performed flow cytometric analysis of PB Th1, Th17, and Treg populations together with estimation of serum cytokine concentrations using cytometric bead array. Disease activity was calculated on the basis of clinical and biochemical indices of inflammation (DAS28, ESR, CRP). All parameters were measured and correlated with each other before and after 6 months therapy. Elevated levels of circulating Th17 cells and IL-6 were found in all active patients, of which Th17 cells were down-regulated by the treatment. Significantly reduced Th1 and functional CTLA-4+ Treg cell frequencies as well as Th1 cytokines observed only in progressive RA seemed to be irreversible. Although therapy induced clinical improvement in almost all patients, those with advanced RA remained with signs of inflammation. Our report demonstrates that both the extent of systemic immune abnormalities and their restoration are dependent on duration of the active RA.

Effects of periodontal therapy on disease activity and systemic inflammation in rheumatoid arthritis patients

OBJECTIVE

This observational prospective cohort study aimed to evaluate the effects of non-surgical periodontal treatment on clinical periodontal measurements and systemic inflammatory mediator levels in low or moderate to highly active rheumatoid arthritis (RA) patients with chronic periodontitis.

SUBJECTS AND METHODS

Rheumatoid arthritis activity was assessed with disease activity score test (DAS28). Thirty patients with RA with moderate to high disease activity (DAS28 ≥ 3.2) and chronic periodontitis (MHDA group) and thirty patients with RA with low disease activity (DAS28 < 3.2) and chronic periodontitis (LDA group) were enrolled in the study. The patients were monitored at the beginning and 3 months after undergoing periodontal therapy. Erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), tumour necrosis factor-alpha (TNF-α) levels in serum, DAS28 and periodontal parameters were evaluated.

RESULTS

Erythrocyte sedimentation rate, CRP, TNF-α levels in serum, DAS28 and periodontal parameters exhibited similar and significant reduction 3 months after the non-surgical periodontal treatment.

CONCLUSION

Non-surgical periodontal treatment may prove beneficial in reducing RA severity as measured by ESR, CRP, TNF-α levels in serum and DAS28 in low or moderate to highly active RA patients with chronic periodontitis.

Differential effects of decoy receptor- and antibody-mediated tumour necrosis factor blockage on FoxP3 expression in responsive arthritis patients

Our aim was to clarify if anti-tumour necrosis factor (TNF) drugs have effect on expression of three splice forms of FoxP3 mRNA in blood CD4+ T cells from rheumatoid arthritis (RA) patients compared with healthy controls. Forty-five rheumatoid arthritis patients treated with anti-TNF therapy were investigated in a 12-week prospective cohort study. FoxP3 isoforms, CD25 and CTLA-4 mRNA in blood CD4+ T cells were measured with quantitative real-time PCR. Patients benefitting from the treatment, based on changes in DAS28 scores, revealed a significant decrease in expression of full-length FoxP3 following 12 weeks treatment with TNF receptor 2 fusion protein (Etanercept), but not following treatment with anti-TNF antibodies (Adalimumab or Infliximab). A partial normalization of the CTLA-4/FoxP3fl ratio and a correlation between clinical improvement and change in FoxP3 mRNA expression were also seen in Etanercept responders. These changes were not observed in responsive patients treated with the antibody therapies. Our data suggest that TNF decoy receptor and anti-TNF antibodies differ in their effect on FoxP3 expression in responsive patients. As Etanercept binds both TNF-α and Lymphotoxin-α (LT-α), whereas the antibodies only target TNF-α, LT-α may regulate FoxP3 expression in a subset of RA patients. Our findings support the view that anti-TNF treatment is mainly symptomatic.

Effects of glucocorticoid treatment on CD25⁻FOXP3⁺ population and cytokine-producing cells in rheumatoid arthritis

OBJECTIVES

To investigate CD25(-)FOXP3(+) cells in RA patients and their possible relationship with disease features and response to glucocorticoids (GCs).

METHODS

Peripheral blood mononuclear cells were collected from 147 RA patients, 29 healthy controls and 75 SLE patients as disease controls. The proportion of CD4(+)FOXP3(+) cells with negative, low or high CD25 expression and the levels of IL-10-, TNF-α-, IL-17- and IFNγ-producing cells were assessed by flow cytometry. The presence of the high IL-10 genotype (-1082GG), associated with good response to GC, was determined by PCR amplification and hybridization with allele-specific fluorescently labelled probes. Data were related to treatment and clinical parameters.

RESULTS

The CD25(-)FOXP3(+) population was significantly increased in RA patients and negatively correlated with DAS-28 and other disease parameters. The IL-10 genotype did not influence the frequency of these cells in controls or the entire RA group; however, GC-treated patient carriers of the high IL-10 genotype presented significantly higher levels of this population in addition to an increased percentage of IL-10-secreting cells and relatively low amounts of TNF-α-, IFN-γ- and IL-17-positive cells. Finally, a prospective study confirmed that genetically high IL-10 producers significantly increase CD25(-)FOXP3(+) cells after 6 months of GC treatment.

CONCLUSION

The present study provides the first evidence of increased CD25(-)FOXP3(+) cells in RA patients, which were associated with disease activity and with GC treatment in carriers of the high IL-10 genotype, suggesting that this population plays a role in the clinical response to prednisone in RA.