High sensitivity of host Helios+/Neuropilin-1+ Treg to pretransplant conditioning hampers development of OX40bright/integrin-ß7+ regulatory cells in acute gastrointestinal GvHD.

This study sought to compare the behavior of Treg subsets displaying different coexpression patterns of Neuropilin-1 (Nrp1) and Helios, under the influence of gut stress unrelated to hematopoietic stem cell transplantation, pretransplantation conditioning, and posttransplant gastrointestinal acute graft versus host disease (GI-aGvHD). Host CD4+/CD25hi/Foxp3+ Treg cells, identified by flow cytometry, were isolated from various tissues of mice affected by these stressors. Expression of CD25, CTLA-4, CD39, OX40, integrin-ß7, LAG3, TGFß/LAP, granzyme-A, -B, and interleukin-10 was compared in four Treg subsets displaying Helios or Nrp1 only, both or none. Fluorescence-activated cell sorter-sorted Treg subsets, displaying markers affected in a conditioning- and GI-aGVHD-restricted manner, were further investigated by transcriptome profiling and T-cell suppression assays. We found that conditioning by irradiation greatly diminished the relative frequency of Helios+/Nrp1+ Treg, shifting the balance toward Helios-/Nrp1- Treg in the host. Upregulation of integrin-ß7 and OX40 occurred in GI-aGvHD-dependent manner in Helios+/Nrp1+ cells but not in Helios-/Nrp1- Treg. Sorted Treg subsets, confirmed to overexpress Nrp1, Helios, OX40, or integrin-ß7, displayed superior immunosuppressive activity and enrichment in activation-related messenger RNA transcripts. Our data suggest that conditioning-induced shrinkage of the Nrp1+/Helios+ Treg subset may contribute to the development of GI-GvHD by impairing gut homing and decreasing the efficiency of Treg-mediated immunosuppression.

Human small intestine contains 2 functionally distinct regulatory T-cell subsets.

BACKGROUND: Regulatory T (Treg) CD4 cells in mouse gut are mainly specific for intestinal antigens and play an important role in the suppression of immune responses against harmless dietary antigens and members of the microbiota. However, information about the phenotype and function of Treg cells in the human gut is limited. OBJECTIVE: We performed a detailed characterization of Foxp3+ CD4 Treg cells in human normal small intestine (SI) as well as from transplanted duodenum and celiac disease lesions. METHODS: Treg cells and conventional CD4 T cells derived from SI were subjected to extensive immunophenotyping and their suppressive activity and ability to produce cytokines assessed. RESULTS: SI Foxp3+ CD4 T cells were CD45RA-CD127-CTLA-4+ and suppressed proliferation of autologous T cells. Approximately 60% of Treg cells expressed the transcription factor Helios. When stimulated, Helios-negative Treg cells produced IL-17, IFN-γ, and IL-10, whereas Helios-positive Treg cells produced very low levels of these cytokines. By sampling mucosal tissue from transplanted human duodenum, we demonstrated that donor Helios-negative Treg cells persisted for at least 1 year after transplantation. In normal SI, Foxp3+ Treg cells constituted only 2% of all CD4 T cells, while in active celiac disease, both Helios-negative and Helios-positive subsets expanded 5- to 10-fold. CONCLUSION: The SI contains 2 subsets of Treg cells with different phenotypes and functional capacities. Both subsets are scarce in healthy gut but increase dramatically in active celiac disease.

Helios is a marker, not a driver, of human Treg stability.

Treg therapy holds promise as a potentially curative approach to establish immune tolerance in transplantation and autoimmune disease. An outstanding question is whether therapeutic Tregs have the potential to transdifferentiate into effector T-cells and, thus, exacerbate rather than suppress immune responses. In mice, the transcription factor Helios is thought to promote Treg lineage stability in a range of inflammatory contexts. In humans, the role of Helios in Tregs is less clear, in part, due to the inability to enrich and study subsets of Helios-positive versus Helios-negative Tregs. Using an in vitro expansion system, we found that loss of high Helios expression and emergence of an intermediate Helios (Heliosmid )-expressing population correlated with Treg destabilization. We used CRISPR/Cas9 to genetically ablate Helios expression in human naive or memory Tregs and found that Helios-KO and unedited Tregs were equivalent in their suppressive function and stability in inflammation. Thus, high Helios expression is a marker, but not a driver, of human Treg stability in vitro. These data highlight the importance of monitoring Helios expression in therapeutic Treg manufacturing and provide new insight into the biological function of this transcription factor in human T-cells.

CD4+ regulatory T cells lacking Helios and Eos.

The transcriptional regulators that drive regulatory T (Treg) cell development and function remain partially understood. Helios (Ikzf2) and Eos (Ikzf4) are closely-related members of the Ikaros family of transcription factors. They are highly expressed in CD4+ Treg cells and functionally important for Treg cell biology, as mice deficient for either Helios or Eos are susceptible to autoimmune diseases. However, it remains unknown if these factors exhibit specific or partially redundant functions in Treg cells. Here we show that mice with germline deletions of both Ikzf2 and Ikzf4 are not very different from animals with single Ikzf2 or Ikzf4 deletions. Double knockout Treg cells differentiate normally, and efficiently suppress effector T cell proliferation in vitro. Both Helios and Eos are required for optimal Foxp3 protein expression. Surprisingly, Helios and Eos regulate different, largely non-overlapping, sets of genes. Only Helios is required for proper Treg cell aging, as Helios deficiency results in reduced Treg cell frequencies in the spleen of older animals. These results indicate that Helios and Eos are required for distinct aspects of Treg cell function.

Temporal changes in regulatory T cell subsets defined by the transcription factor Helios in stroke and their potential role in stroke-associated infection: a prospective case-control study.

BACKGROUND: Regulatory T cells (Tregs) are involved in the systemic immune response after ischemic stroke. However, their role remains unclear, and the effect appears to be both neuroprotective and detrimental. Treg suppressor function may result in immunodepression and promote stroke-associated infection (SAI). Thus we assume that the bidirectional effects of Tregs may be in part attributed to the intracellular transcription factor Helios. Tregs with Helios expression (H+ Tregs) constitute 70-90% of all Treg cells and more frequently than Helios-negative Tregs (H- Tregs) express molecules recognized as markers of Tregs with suppressor abilities. METHODS AND RESULTS: We prospectively assessed the circulating Treg population with flow cytometry in 52 subjects on days 1, 3, 10 and 90 after ischemic stroke and we compared the results with those obtained in concurrent age-, sex- and vascular risk factor-matched controls. At all studied time points the percentage of H+ Tregs decreased in stroke subjects-D1: 69.1% p < 0.0001; D3: 62.5% (49.6-76.6), p < 0.0001; D10: 60.9% (56.5-72.9), p < 0.0001; D90: 79.2% (50.2-91.7), p = 0.014 vs. controls: 92.7% (81.9-97.0) and the percentage of H- Tregs increased accordingly. In patients with SAI the percentage of pro-suppressor H+ Tregs on post-stroke day 3 was higher than in those without infection (p = 0.03). After adjustment for confounders, the percentage of H+ Tregs on day 3 independently correlated with SAI [OR 1.29; CI 95%: 1.08-1.27); p = 0.02]. Although the percentage of H+ Tregs on day 3 correlated positively with NIHSS score on day 90 (rS = 0.62; p < 0.01) and the infarct volume at day 90 (rS = 0.58; p < 0.05), in regression analysis it was not an independent risk factor. CONCLUSIONS: On the first day after stroke the proportion of H+ vs. H- Tregs changes in favor of pro-inflammatory H- Tregs, and this shift continues toward normalization when assessed on day 90. A higher percentage of pro-suppressive H+ Tregs on day 3 independently correlates with SAI and is associated positively with NIHSS score, but it does not independently affect the outcome and stroke area in the convalescent phase of stroke.

Helios as a Potential Biomarker in Systemic Lupus Erythematosus and New Therapies Based on Immunosuppressive Cells.

The Helios protein (encoded by the IKZF2 gene) is a member of the Ikaros transcription family and it has recently been proposed as a promising biomarker for systemic lupus erythematosus (SLE) disease progression in both mouse models and patients. Helios is beginning to be studied extensively for its influence on the T regulatory (Treg) compartment, both CD4+ Tregs and KIR+/Ly49+ CD8+ Tregs, with alterations to the number and function of these cells correlated to the autoimmune phenomenon. This review analyzes the most recent research on Helios expression in relation to the main immune cell populations and its role in SLE immune homeostasis, specifically focusing on the interaction between T cells and tolerogenic dendritic cells (tolDCs). This information could be potentially useful in the design of new therapies, with a particular focus on transfer therapies using immunosuppressive cells. Finally, we will discuss the possibility of using nanotechnology for magnetic targeting to overcome some of the obstacles related to these therapeutic approaches.

Helios expressing regulatory T cells are correlated with decreased IL-2 producing CD8 T cells and antibody diversity in Mozambican individuals living chronically with HIV-1.

BACKGROUND: Human immunodeficiency virus type 1 (HIV-1) causes impairment of T and B cell responses, which begins during the acute phase of infection and is not completely restored by antiretroviral treatment. Regulatory T cell (Tregs) can improve overall disease outcome by controlling chronic inflammation but may also suppress beneficial HIV-1 specific immune responses. We aimed to analyze the profile of Tregs and their correlation with the status of T cells activation, the expression of IL-2 and IFNγ and the profile of HIV-1 specific antibodies response in Mozambican people living chronically with HIV-1 (PLWH-C). RESULTS: In PLWH-C, the proportion of total Tregs was positively correlated with the proportion of IL-2+CD4 T cells (r = 0.647; p = 0.032) and IL-2+IFNγ+CD8 T cells (r = 0.551; p = 0.014), while the proportions of Helios+Tregs correlated inversely with levels of IL-2+CD8 T cells (r = - 0.541; p = 0.017). Overall, PLWH-C, with (82%) or without virologic suppression (64%), were seronegative for at least HIV-1 p31, gp160 or p24, and the breadth of antibody responses was positively correlated with proportions of CD38+HLA-DR+CD8 T cells (r = 0.620; p = 0.012), viral load (r = 0.452; p = 0.040) and inversely with absolute CD4 T cells count (r = - 0.481; p = 0.027). Analysis of all individuals living HIV-1 showed that the breadth of HIV-1 antibody responses was inversely correlated with the proportion of Helios+Tregs (r = - 0.45; p = 0.02). CONCLUSION: Among Mozambican people living with HIV-1, seronegativity to some HIV-1 proteins is common, particularly in virologically suppressed individuals. Furthermore, lower diversity of HIV-specific antibodies is correlated to lower immune activation, lower viral replication and higher CD4 counts, in PLWH-C. Elevation in the proportion of Helios+Tregs is related to a reduction of CD8 T expressing intracellular IL-2, in PLWH-C, but may contribute to impairment of B cell function.

Associations of different immune checkpoints-expressing CD4+ Treg/ T cell subsets with disease-free survival in colorectal cancer patients.

There are different subsets of T regulatory cells (Tregs), orchestrating critical roles in the regulation of anti-tumor immunity in colorectal cancer (CRC). In this study, we report that a high frequency of circulating CD4+FoxP3+ Tregs was associated with poorer disease-free survival (DFS), while their higher frequencies in tumor-infiltrating CD4+ Tregs was associated with better DFS. We further investigated such associations with four Tregs/T cells expressing or lacking FoxP3 and Helios (FoxP3±Helios±). For the first time, we report that a high frequency of circulating CD4+FoxP3+Helios+ Tregs was associated with poorer DFS, while a high frequency of tumor-infiltrating CD4+FoxP3-Helios- T cells was associated with poorer DFS. In the four FoxP3±Helios± T cell subsets expressing any of the immune checkpoints (ICs) investigated, we found that a high frequency of CD4+FoxP3+Helios-PD-1+ Tregs in circulation was associated with worse DFS. We also found that high frequencies of FoxP3+Helios+CTLA-4+ Tregs, FoxP3+Helios-CTLA-4+ Tregs, and FoxP3-Helios+CTLA-4+ CD4+ T cells in circulation were associated with worse DFS. In contrast, high frequencies of CD4+TIM-3+ T cells, FoxP3+Helios+TIM-3+ Tregs, and FoxP3-Helios+TIM-3+ CD4+ T cells in circulation were associated with longer DFS. Our data show that certain CD4+ Treg/T cell subsets could serve as independent predictive biomarkers in CRC patients. Identification of the exact subpopulations contributing to clinical outcomes is critical for prognoses and therapeutic targeting.

Helios-Negative Regulatory T Cells as a Key Factor of Immune Tolerance in Nonallergic Beekeepers.

BACKGROUND AND OBJECTIVES: Although exposure to stings has been identified as the leading risk factor for anaphylaxis due to Hymenoptera venom allergy, professional beekeepers receive hundreds of stings yearly without developing systemic reactions. This study aims to analyze the mechanisms underlying bee venom tolerance in beekeepers. METHODS: A cross-sectional study was conducted. Participants were recruited and classified into 3 groups: allergic patients (APs), who experienced systemic reactions after bee stings, with a positive intradermal test and specific IgE (sIgE) to Apis mellifera venom (AmV); tolerant beekeepers (TBKs), who received ≥50 stings/year; and healthy nonexposed controls (HCs). We measured serum levels of sIgE and specific IgG4 (sIgG4) to AmV, rApi m 1, rApi m 2, rApi m 3, Api m 4, rApi m 5, and rApi m10, as well as AmV-induced basophil degranulation, percentage of T-cell subsets, regulatory T cells (Treg), and IL-10 production. RESULTS: Compared with TBKs, APs had high levels of sIgE to AmV and all its allergic components (P<.001), together with a high basophil activation rate (P<.001). Conversely, compared with APs, TBKs had higher levels of sIgG4 (P<.001) and IL-10 (P<.0001), as well as an enhanced CTLA-4+ Treg population (P=.001), expanded Helios- Treg (P<.003), and reduced type 1 helper T cells (TH1) (P=.008), TH2 (P=.004), and TH17 (P=.007) subsets. CONCLUSIONS: The profile of TBKs, which was strongly marked by Treg activity, differed from that of TBKs. This natural tolerance would be led by the expansion of inducible Helios- Treg cells at the peripheral level. The Helios- Treg population could be a novel candidate biomarker for monitoring tolerance.

Influenza virus infection selectively triggers the accumulation and persistence of more potent Helios-expressing Foxp3+ regulatory T cells in the lungs.

Foxp3+ regulatory T cells (Tregs) represent a special lineage of CD4+ T cells. Analysis of Treg response during primary and secondary influenza virus infection clearly demonstrates a robust accumulation of Tregs into the infected lungs and the existence of a population of long-lived antigen-specific memory Tregs in the same tissues after resolution of the infection. However, it remains unknown whether these Tregs co-express Helios, a member of the Ikaros transcription factor family. In this study, Foxp3+ Helios+ and Foxp3+ Helios- Tregs in the lungs, mLNs and spleens of influenza virus-infected and uninfected control mice were tracked. The data show that while there is a co-existence of Foxp3+ Helios+ and Foxp3+ Helios- Tregs in the tissues, the accumulated Tregs in the lungs and lung-draining mediastinal lymph nodes (mLNs) of the infected mice are highly enriched for Foxp3+ Helios+ cells. It was further demonstrated that, after the clearance of primary infection, Foxp3+ Helios+ cells have the ability to persist in the tissues over their Helios- counterparts. More importantly, Foxp3+ Helios+ Tregs accumulated in an accelerated kinetics during recall response to reinfection. In vitro analysis of Treg suppressive function revealed that Foxp3+ Helios+ Tregs are more capable of suppressing influenza virus-specific CD8+ T cell activation, cytokine production and proliferation. Together, the data provide new insights into Treg responses during primary and secondary influenza virus infection and suggest that Foxp3+ Helios+ Tregs predominantly drive the Treg responses.

Identification of regulatory T cell molecules associated with severity of multiple sclerosis.

BACKGROUND: Regulatory CD4+ T cells (Tregs) exhibit functional alterations in patients with multiple sclerosis (MS). Transforming growth factor (TGF)-ß is a key regulator of Treg development and function. OBJECTIVE: The objective of this study is to determine whether the expression of functionally relevant TGF-ß-regulated molecules is altered in Tregs from patients with MS. METHODS: Expression of nine Treg markers was analyzed by multi-color flow cytometry in CD4+ T cells and Treg subpopulations of 31 untreated MS patients and age- and sex-matched healthy donors (HDs). Correlations between Treg marker expression and clinical variables were sought. RESULTS: Expression of the transcription factor Helios, which defines thymic-derived Tregs, was decreased in this Treg subpopulation. The frequency of peripherally generated Tregs was increased in patients with MS, particularly in patients with progressive MS. Low frequencies of thymic-derived Tregs were associated with magnetic resonance imaging (MRI) lesion-burden and a high relapse rate. Four surface markers associated with TGF-ß signaling (ABCA1, BTLA, DNAM-1, and GARP) were differentially expressed on Tregs from patients with MS and HDs. Expression levels of CD73, CD103, ABCA1, and PAR2 showed strong correlations with disease severity. CONCLUSION: We have identified novel markers abnormally expressed on Tregs from patients with MS that could detect patients with severe disease.

Infection of Epstein-Barr Virus is Associated with the Decrease of Helios+FoxP3+Regulatory T Cells in Active Ulcerative Colitis Patients.

Background: Loss of immune homeostasis to enteric pathogens is considered to be involved in the pathogenesis of ulcerative colitis (UC), and regulatory T cells (Tregs) are key for this immune homeostasis. Helios exhibits an important effect on regulating the suppressive function of Tregs. Epstein-Barr virus (EBV) is more commonly detected in UC. However, whether there is an association between EBV infection and Helios+Tregs and its impact on disease activity of UC remain unclear. We aimed to explore the clinical significance of Helios+Tregs and their potential association with EBV infection in UC. Methods: Seventy-six UC patients and 38 controls were consecutively enrolled. Helios+FoxP3+Tregs were analyzed using flow cytometry and compared among groups. Eight active UC patients treated with 5-aminosalicylic acid were followed up. Correlation analyses were conducted between Helios+FoxP3+Tregs and disease activity indicators. In addition, EBV viral loads in the mucosal lesion were quantified in active UC by quantitative polymerase chain reaction and were comprehensively analyzed in subgroups of different disease severity, and their associations with Helios+FoxP3+Tregs were also analyzed. Results: Helios+FoxP3+Tregs were significantly decreased in active UC and were inversely correlated with serum C-reactive protein and Mayo score. Moreover, we observed the recovery of Helios+FoxP3+Tregs in followed-up active UC achieving remission after treatment. EBV loads were higher in active UC, and levels of Helios+FoxP3+Tregs in the EBV-positive subgroup were lower than the EBV-negative subgroup in moderate and severe active patients. Most importantly, we found that Helios+FoxP3+Tregs were significantly negatively correlated with EBV viral loads. Conclusion: Helios+FoxP3+Tregs are likely to play a pivotal role in disease activity of UC and may be influenced by EBV infection.

Helios+ and Helios- Treg subpopulations are phenotypically and functionally distinct and express dissimilar TCR repertoires.

The transcription factor Helios is expressed in a large subset of Foxp3+ Tregs. We previously proposed that Helios is a marker of thymic derived Treg (tTreg), while Helios- Treg were induced from Foxp3- T conventional (Tconv) cells in the periphery (pTreg). To compare the two Treg subpopulations, we generated Helios-GFP reporter mice and crossed them to Foxp3-RFP reporter mice. The Helios+ Treg population expressed a more activated phenotype, had a slightly higher suppressive capacity in vitro and expressed a more highly demethylated TSDR but were equivalent in their ability to suppress inflammatory bowel disease in vivo. However, Helios+ Treg more effectively inhibited the proliferation of activated, autoreactive splenocytes from scurfy mice. When Helios+ and Helios- Treg were transferred to lymphoreplete mice, both populations maintained comparable Foxp3 expression, but Foxp3 expression was less stable in Helios- Treg when transferred to lymphopenic mice. Gene expression profiling demonstrated a large number of differentially expressed genes and showed that Helios- Treg expressed certain genes normally expressed in CD4+ Foxp3- T cells. TCR repertoire analysis indicated very little overlap between Helios+ and Helios- Treg. Thus, Helios+ and Helios- Treg subpopulations are phenotypically and functionally distinct and express dissimilar TCR repertoires.

Anti-IL1 treatment in colchicine-resistant paediatric FMF patients: real life data from the HELIOS registry.

OBJECTIVES: FMF is a prototype of autoinflammatory diseases associated with excess IL1 production. Anti-IL1 treatments are the first-line alternatives in colchicine-resistant/intolerant FMF patients. We aimed to investigate the efficacy and safety of anti-IL1 treatment in paediatric FMF patients in our local [Hacettepe univErsity eLectronIc research fOrmS (HELIOS)] registry. METHODS: HELIOS is a web-based biologic drug registry for paediatric rheumatology patients. We have analysed the clinical features, disease activity parameters, treatment responses and safety outcomes in FMF patients treated with anti-IL1 agents. RESULTS: Forty paediatric FMF patients (34 continuous and six on-demand use) were included. Among the continuously treated group (61.7% female), the mean age at the start of colchicine was 5.55 (3.87) years. Age at onset of the anti-IL1 treatment was 11.47 (5.41) years with a mean follow-up duration of 3.87 (1.96) years. Apart from two, all patients had biallelic exon-10 mutations. We also gave anti-IL1 treatment on an on-demand basis in six patients. Anakinra was used as the first-line anti-IL1 treatment. During the last visit, six patients were treated with anakinra and 28 patients with canakinumab. Anti-IL1 treatment decreased the CRP levels and number and severity of the attacks. There were three hospitalizations reported due to mild infections. Eleven patients had local skin reactions, two patients had leucopenia with anakinra and one patient had thrombocytopenia with canakinumab. There was no malignancy or other severe adverse reactions. CONCLUSION: Anakinra and canakinumab are efficient and safe alternatives in colchicine-resistant or -intolerant paediatric FMF patients. We also, for the first time, report on-demand use of anti-IL1 in paediatric FMF patients.

Increased proportion of functional subpopulations in circulating regulatory T cells in patients with chronic hepatitis B.

AIM: This study was designed to investigate the levels of circulating regulatory T cells (Tregs), and their functional subpopulations and related cytokines in chronic hepatitis B patients (CHB) and inactive hepatitis B surface antigen carriers. METHODS: The peripheral blood of 24 hepatitis B virus inactive carriers, 26 CHB patients, and 34 healthy controls was collected and analyzed by flow cytometry for Tregs and CD4+ CXCR5+ FoxP3+ follicular regulatory T cells. Interleukin (IL)-10, transforming growth factor-ß, and IL-21 levels in plasma were determined by enzyme-linked immunosorbent assay. Proportions of functional Treg subpopulations were analyzed by staining of Helios, CD45RA and FoxP3, TIGIT, and CD226, and the correlations between Treg subsets and clinical indicators were explored. RESULTS: CD4+ FoxP3+ levels in the peripheral blood of CHB patients were significantly increased, and the inhibitory ability of Tregs in CHB patients for cytokine secretion was stronger, and CD4+ CXCR5+ FoxP3+ follicular Tregs were also significantly higher than inactive carriers and healthy controls. Transforming growth factor-ß and IL-10 in the plasma of CHB patients were significantly higher than those of healthy controls, with IL-21 levels not significantly changed. Circulating CD4+ CXCR5-FoxP3+ Treg cells in CHB patients were positively correlated with hepatitis B surface antigen, hepatitis B e antigen, and hepatitis B virus DNA. The proportions of Helios+ FoxP3+ , CD45RA- FoxP3hi , and CD226- TIGIT+ functional subpopulations in CD4+ CXCR5- FoxP3+ Tregs in CHB patients were significantly increased, and they were significantly correlated with clinical indicators. CONCLUSIONS: Circulating Tregs in CHB patients not only have elevated levels, but their follicular Treg subpopulations are also increased, and Tregs tend to have stronger immunosuppressive functions.

Lung Regulatory T Cells Express Adiponectin Receptor 1: Modulation by Obesity and Airway Allergic Inflammation.

Regulatory T cells (Tregs) decrease in the adipose tissue upon weight gain, contributing to persistent low-grade inflammation in obesity. We previously showed that adipose tissue Tregs express the adiponectin receptor 1 (AdipoR1); however, the expression in lung Tregs is still unknown. Here, we aimed to determine whether Helios+ and Helios- Treg subsets expressed AdipoR1 in the lungs of obese mice and whether different obesity grades affected the expression upon allergic lung inflammation. For diet-induced obesity (DIO), mice were fed a high-fat diet (HFD) for up to 15 weeks (overweight), 21 weeks (obesity), and 26 weeks (morbid obesity). Overweight and morbidly obese mice were sensitized and challenged with ovalbumin (OVA) to induce allergic lung inflammation. The AdipoR1 expression was reduced significantly in the lung Helios+ and Helios- Tregs of obese mice compared with lean mice. Airway allergic inflammation showed reduced AdipoR1 expression in lung Foxp3+ Tregs. Obesity significantly exacerbated the eosinophilic airway inflammation and reduced the number of Helios+ Tregs in lung and adipose tissue in the obesity-associated asthma model. Upon further weight gain, AdipoR1-expressing Tregs in the lungs of allergic mice were increased, whereas AdipoR1-expressing Tregs in adipose tissue were reduced. These data suggest that obesity-associated adipose tissue inflammation may exacerbate allergic inflammation by downregulating the AdipoR1+ Tregs in the lungs.

Foxp3+Helios+ regulatory T cells are associated with monocyte subsets and their PD-1 expression during acute HIV-1 infection.

BACKGROUND: Helios has been reported to stabilize regulatory T (Treg) suppressive function. Programmed cell death protein 1 (PD-1) expression in three human monocyte subsets modulates immune responses. Recently, our team reported that three monocyte subsets are associated with T helper cell differentiation in HIV-1-infected patients. Until now, the effects of monocyte subsets and their PD-1 expression on Foxp3+Helios+ Treg cells have not been fully characterized, especially during acute HIV-1 infection. RESULTS: The frequency of Foxp3+Helios+CD45RA+ Treg cells is significantly higher in patients with acute HIV-1 infection than those of healthy controls and chronic HIV-1-infected patients undergoing combined antiretroviral therapy. The frequency of Foxp3+Helios+CD45RA+ Treg cells is inversely correlated with CD4 T-cell counts and the CD4/CD8 ratio in chronic HIV-1-infected patients. During acute HIV-1 infection, the frequency of Foxp3+Helios+CD45RA+ Treg cells is inversely correlated with the frequency of the intermediate CD14++CD16+ monocyte subset, but positively correlated with PD-1 expression in both intermediate CD14++CD16+ and non-classical CD14+CD16++ monocyte subsets. CONCLUSIONS: In this study, the perturbations of Foxp3+Helios+ Treg cells were characterized, and the association between monocyte subsets and their PD-1 expression and Foxp3+Helios+ Treg cells was evaluated during HIV-1 infection. Our observations provide new evidence of the roles for Foxp3+Helios+ Treg cells and PD-1 expression on monocyte subsets in HIV pathogenesis.

Helios but not CD226, TIGIT and Foxp3 is a Potential Marker for CD4+ Treg Cells in Patients with Rheumatoid Arthritis.

BACKGROUND/AIMS: Rheumatoid arthritis (RA) is a progressive, chronic, even disabling systemic autoimmune disease. Imbalance between pathogenic immune cells and immunosuppressive cells is associated with the pathogenesis and development of RA and other autoimmune diseases. As Foxp3 is also expressed on activated CD4+ cells in the presence of inflammation, the identification of Treg cells in patients with RA remains a challenge. METHODS: Comprehensive analyses were carried out by Flow cytometry. Expression of Helios, CD226, T cell immunoreceptor with Ig and ITIM domains clinical samples and healthy controls. RESULTS: We have systemically examined three potential markers, Helios, CD226 and TIGIT, that are possibly related to Treg identification, and found that Helios expression on CD4+Foxp3+cells was decreased and negatively correlated with the disease activity of RA patients, while CD226 and TIGIT both showed elevated expression levels in CD4+Foxp3+cells in RA patients and they were not associated with disease activity of RA patients. CONCLUSION: Taken together, our findings indicate that CD4+CD25hiCD127low/-Foxp3+Helios+ may represent the real Treg cell population in patients with RA.

Soluble glucocorticoid-induced tumor necrosis factor receptor regulates Helios expression in myasthenia gravis.

BACKGROUND: Helios is important for functional and phenotype stability of regulatory T cells (Tregs). However, the role of Helios in autoimmune diseases and its regulation remains unclear. This study aimed to investigate the role of Helios+ Tregs in myasthenia gravis (MG) and glucocorticoid-induced tumor necrosis factor receptor (GITR) and its ligand (GITRL) in the modulation of Helios. METHOD: Multicolor flow cytometry was performed to analyze Helios+ Tregs in peripheral blood from MG patients and healthy donors (HDs). Enzyme-linked immunosorbent assay (ELISA) was used to determine the levels of soluble GITRL/GITR in plasma. Tregs were isolated via magnetic separation and treated with recombinant GITRL and GITR-Fc. Membrane GITRL on Tregs and expression of Helios and other markers (FOXP3, CD25, CD39, CTLA-4, PD-L1 and IL-10) involved in immunosuppressive activity were determined by flow cytometry. RESULT: Both Helios+ Tregs and soluble GITR were decreased in generalized MG (GMG) patients (n = 14), compared with HDs (n = 14) and ocular MG (OMG) patients (n = 16). Helios+ Tregs possessed greater immunosuppressive capacity compared to Helios- Tregs. Further analysis indicates soluble GITR was negatively correlated with quantitative MG score and promoted Helios expression and enhanced function of Tregs independently of membrane GITRL. CONCLUSION: This work demonstrates abnormal changes in Helios+ Tregs and soluble GITR in MG, as well as direct regulation of Helios by GITR in the context of Tregs. This work provides new insight into the role of GITR in the regulatory pathway of Helios and pathogenesis of MG.

Kinetics of Helios(+) and Helios(-) T regulatory cell subsets in the circulation of healthy pregnant women.

Regulatory T cells (Tregs) play a critical role in the maintenance of a pregnancy. While the kinetics of the number of peripheral blood Tregs has been satisfactorily described in mouse models, analysis of these cell populations in human pregnancy is complicated by high variability in the quantity of Tregs and inconsistencies in the markers used for detecting different types of Treg. In the light of this, we set out to investigate the kinetics of various types of Treg, including CD45RA, GARP and PD-1(+) Tregs, in the peripheral blood of pregnant women in the first, second and third trimester, and at the time of delivery. Tregs, defined as a CD4(+)CD25(++)CD127(dim)Foxp3(+) population of leucocytes, were detected using flow cytometry. Natural thymus-derived Tregs and induced Tregs in the peripheral blood were distinguished by the expression or absence of a Helios marker, respectively. Our results showed that during normal pregnancy the sizes of various Treg subpopulations varied across women and also in an individual woman did not remain constant but varied significantly, most notable being the decrease observed at the time of delivery. Helios(-) cells were significantly less frequent in the peripheral blood of healthy pregnant women than Helios(+) cells, and the majority of Tregs were Helios(+)PD-1(+) Tregs.