Peripheral Treg Cells Research Articles

Efficient IL-2R signaling differentially affects the stability, function, and composition of the regulatory T-cell pool

Signaling via interleukin-2 receptor (IL-2R) is a requisite for regulatory T (Treg) cell identity and function. However, it is not completely understood to what degree IL-2R signaling is required for Treg cell homeostasis, lineage stability and function in both resting and inflammatory conditions. Here, we characterized a spontaneous mutant mouse strain endowed with a hypomorphic Tyr129His variant of CD25, the α-chain of IL-2R, which resulted in diminished receptor expression and reduced IL-2R signaling. Under noninflammatory conditions, Cd25Y129H mice harbored substantially lower numbers of peripheral Treg cells with stable Foxp3 expression that prevented the development of spontaneous autoimmune disease. In contrast, Cd25Y129H Treg cells failed to efficiently induce immune suppression and lost lineage commitment in a T-cell transfer colitis model, indicating that unimpaired IL-2R signaling is critical for Treg cell function in inflammatory environments. Moreover, single-cell RNA sequencing of Treg cells revealed that impaired IL-2R signaling profoundly affected the balance of central and effector Treg cell subsets. Thus, partial loss of IL-2R signaling differentially interferes with the maintenance, heterogeneity, and suppressive function of the Treg cell pool.

Changes in the Peripheral Treg Cell Proportion and Immune Function in Hepatocellular Carcinoma Patients After Transarterial Chemoembolization with Gelatin Sponge Microparticles

Object: Observe the effect of gelatin sponge microparticles-transarterial chemoembolization (GSMs-TACE) on the immune function of patients with liver cancer by detecting the proportion of Treg cells in the peripheral blood.

High-Dose Neonatal Vitamin A Supplementation to Bangladeshi Infants Increases the Percentage of CCR9-Positive Treg Cells in Infants with Lower Birthweight in Early Infancy, and Decreases Plasma sCD14 Concentration and the Prevalence of Vitamin A Deficiency at Two Years of Age

Vitamin A (VA) stores are low in early infancy and may impair development of the immune system. This study determined if neonatal VA supplementation (VAS) affects the following: 1) development of regulatory T (Treg) cells; 2) chemokine receptor 9 (CCR9) expression, which directs mucosal targeting of immune cells; and 3) systemic endotoxin exposure as indicated by changed plasma concentrations of soluble CD14 (sCD14). Secondarily, VA status, growth, and systemic inflammation were investigated. In total, 306 Bangladeshi infants were randomly assigned to receive 50,000 IU VA or placebo (PL) within 48h of birth, and immune function was assessed at 6 wk, 15 wk, and 2 y. Primary outcomes included the following: 1) peripheral blood Treg cells; 2) percentage of Treg, T, and B cells expressing CCR9; and 3) plasma sCD14. Secondary outcomes included the following: 4) VA status measured using the modified relative dose-response (MRDR) test and plasma retinol; 5) infant growth; and 6) plasma C-reactive protein (CRP). Statistical analysis identified group differences and interactions with sex and birthweight. VAS increased (P=0.004) the percentage of CCR9+ Treg cells (13.2± 1.37%) relative to PL (9.17± 1.15%) in children below the median birthweight but had the opposite effect (P=0.04) in those with higher birthweight (VA, 9.13± 0.89; PL, 12.1± 1.31%) at 6 and 15 wk (values are combined mean±SE). VAS decreased (P=0.003) plasma sCD14 (1.56± 0.025mg/L) relative to PL (1.67± 0.032mg/L) and decreased (P=0.034) the prevalence of VA deficiency (2.3%) relative to PL (9.2%) at 2 y. Neonatal VAS enhanced mucosal targeting of Treg cells in low-birthweight infants. The decreased systemic exposure to endotoxin and improved VA status at 2 y may have been due to VA-mediated improvements in gut development resulting in improved barrier function and nutrient absorption. This trial was registered at clinicaltrials.gov as NCT01583972 and NCT02027610.

Characteristics and reference ranges of CD4+T cell subpopulations among healthy adult Han Chinese in Shanxi Province, North China

BackgroundImmunophenotyping of blood lymphocytes is an essential tool to evaluate the immune function of patients with immunodeficiency or autoimmunity. Predominately identified CD4+T cell subsets, Th1, Th2, Th17, as well as regulatory T (Treg) cells, play crucial roles in several immunological and pathological conditions. Considering the variations in cell counts among populations and ethnicities, specific CD4+T cell subset reference values need to be locally established to enable meaningful comparisons and accurate data interpretation in clinical and research settings. Therefore, the aim of this study was to establish distributions and reference ranges for blood CD4+T cell subpopulations in age- and sex-balanced healthy adults of a Han Chinese population in Shanxi Province, North China.MethodsPeripheral blood CD4+T cell subsets were examined in 150 healthy volunteers (75 males, 75 females) aged 20–70 years with a four-color FACSCalibur flow cytometer.ResultsReference value percentages (absolute counts, cells/μl) were defined as 95% of the population for cell types as follows: CD4+T, 23.78–51.07 (360–1127); Th1, 0.43–39.62 (2.64–276.21); Th2, 0.27–3.57 (1.80–27.14); Th17, 0.22–2.62 (1.10–19.54); and Treg, 2.17–7.94 (13.47–64.58). The ranges for the Th1:Th2 and Th17:Treg ratios were 0.59–52.37 and 0.04–0.76, respectively. Notably, a significant increase was observed in the values of Treg cells in older individuals, and the numbers of Treg cells in females also tended to decrease when compared to those in males. Therefore, we established the distribution and reference range of CD4+T cell subsets based on age and sex, demonstrating the lowest values of Treg cells in younger females.ConclusionsCollectively, our data provide population-, age-, and sex-specific distributions and reference ranges of circulating CD4+T cell subpopulations, which can be adopted to guide clinical decisions and interpretation of immunophenotyping data in the Han Chinese population in Taiyuan, Shanxi Province, China. In addition, the low expression of peripheral Treg cells in younger females may be associated with the predisposition of females to autoimmune diseases.

Two of a kind? Immunological and clinical risk factors differ between recurrent implantation failure and recurrent miscarriage

Recurrent miscarriage (RM) and recurrent implantation failure (RIF) are unsolved challenges in reproductive medicine. Whether RIF patients share the same risk factors as RM patients is a matter of debate. Besides clinical factors, immune alterations are discussed in both conditions. The scope of this study was to compare the prevalence of clinical and immunological risk factors in a large cohort of RM and RIF patients. Between 11/2011 and 02/2019, 613 RM and 185 RIF patients were included. A screening for anatomical malformations, endocrine, autoimmune, prothrombotic and parental chromosomal disorders was performed. The immune status was assessed using flow cytometry analysis of peripheral lymphocyte subpopulations and uterine natural killer cells (uNK cells) using immunohistochemistry. RM patients showed a higher rate of intrauterine adhesions and elevated antinuclear antibodies ≥ 1:160 (p < 0.05). A higher prevalence of submucous fibroids and increased factor VIII levels were observed in RIF patients (p < 0.05). The prevalence of an antiphospholipid syndrome (APLS) was low and did not differ between the two groups. RIF patients had higher numbers of peripheral regulatory T-cells (p < 0.05). Significant more RIF patients were diagnosed with elevated uNK cells (p < 0.05). Differences in clinical and immunological risk factors of RM and RIF patients reflect different entities. Lower Tregs in RM and higher uNK cells in RIF patients might be related to the previous exposure of the immune system to fetal cells. The low prevalence of an APLS indicates a potential overestimation of this factor in the pathophysiology of RM and RIF.

P1607CD 137 SIGNALING IN REGULATORY DENDRITIC CELLS IS REQUIRED FOR SUPPRESSING A SYSTEMIC INFLAMMATION IN THE BM12-INDUCIBLE MODEL OF SYSTEMIC LUPUS ERYTHEMATOSUS

Abstract Background and Aims Although CD137 is well known as a costimulatory receptor in T cells, limited information is available for its immunoregulatory function. Here, we report that CD137 signaling maintains CD11b+ regulatory dendritic cells (DCs) that can suppress activation of donor TH1 and TH17 CD4+ T cells in chronic graft-versus-host disease (GVHD). Method Chronic GVHD can be induced by mouse BMT models in which donor and recipient strain combination is MHC class I identical but MHC II mismatched. This chronic GVHD model recapitulates human SLE. Results : The deletion of CD137 in recipient mice shifted the disease phenotype toward acute GVHD, which was caused by the activation of donor T cells. CD137-/- recipients had had characteristic changes associated with acute GVHD: 1) there were defects in differentiation of T follicular helper (TFH) cells, germinal-center B cells, and plasma cells, and production of anti-DNA IgG1 autoantibody; 2) their splenic DCs showed dysregulated expression of DC-specific transcription factors and pro-inflammatory genes, and 3) there were strong activation of donor T cells but decreased Treg cells in the CD137-/- recipient spleen. CD11b+ splenic DCs stimulated with agnostic anti-CD137 antibody and CpG markedly increased expression of immunomodulatory genes, and such regulatory DCs inhibited acute GVHD in CD137-/- recipients. Their suppressive action was mediated through IL-10 that is indispensable for the induction and expansion of peripheral Treg cells. Conclusion Our study identifies CD137 signaling in DCs as an important braking point to prevent systemic inflammation, and this control system may be considered as a therapeutic strategy for a variety of inflammatory and autoimmune diseases.

Aged T cells shape neuronal autoimmune disease in a model of late-onset multiple sclerosis (Supported by NIH/NIAID R01AI121147)

Abstract Although multiple sclerosis (MS), a T cell-mediated autoimmune demyelinating disease, mainly develops in young people, late-onset has also been observed in aged people. The aged T cell immune system is different from the young. One of characteristics is disrupted thymocyte negative selection, and relatively enhanced thymic regulatory T (tTreg) cell generation and accumulated peripheral Treg (pTreg) cells. The relatively increased polyclonal Treg cells potentially shape the MS disease courses, and may even prevent remission stages of this disease. Using the mouse model experimental autoimmune encephalomyelitis (EAE) of human MS, we determined that a late-onset EAE has two types of disease courses. I: Onset of EAE in the aged group was later than the young group, but after onset, the disease became more severe than in their young counterparts; II: Alternatively, onset of EAE in the aged group never became severe until after a second antigen challenge was given, causing the symptoms to appear and progress to severe disease much faster than in their young counterparts. We also found that this late-onset of EAE was associated with a disparate distribution of Treg cells in lymph nodes versus in the central nervous system (CNS) during the disease. The aged mice had a high proportion of pTreg cells in the lymph nodes, but a low proportion in the CNS, compared to their young counterparts. We believe that accumulated pTreg cells in the elderly, which is one of hallmarks of aged T cell immune system, potentially results in their residing in the blood-brain barrier and/or choroid plexus, which hampers trafficking of monocytes and/or antigen-specific Treg cells into the CNS. Thus, it is detrimental for a CNS repairing processes in neuronal inflammation.

Propionate supplementation promotes the expansion of peripheral regulatory T-Cells in patients with end-stage renal disease

Patients with end-stage renal disease (ESRD) suffer from a progressively increasing low-grade systemic inflammation, which is associated with higher morbidity and mortality. Regulatory T cells (Tregs) play an important role in regulation of the inflammatory process. Previously, it has been demonstrated that short-chain fatty acids reduce inflammation in the central nervous system in a murine model of multiple sclerosis through an increase in tissue infiltrating Tregs. Here, we evaluated the effect of the short-chain fatty acid propionate on the chronic inflammatory state and T-cell composition in ESRD patients. Analyzing ESRD patients and healthy blood donors before, during, and 60 days after the propionate supplementation by multiparametric flow cytometry we observed a gradual and significant expansion in the frequencies of CD25highCD127− Tregs in both groups. Phenotypic characterization suggests that polarization of naïve T cells towards Tregs is responsible for the observed expansion. In line with this, we observed a significant reduction of inflammatory marker CRP under propionate supplementation. Of interest, the observed anti-inflammatory surroundings did not affect the protective pathogen-specific immunity as demonstrated by the stable frequencies of effector/memory T cells specific for tetanus/diphtheria recall antigens. Collectively, our data suggest that dietary supplements with propionate have a beneficial effect on the elevated systemic inflammation of ESRD patients. The effect can be achieved through an expansion of circulating Tregs without affecting the protective pathogen-reactive immunity.

Allergen alters IL-2/αIL-2-based Treg expansion but not tolerance induction in an allergen-specific mouse model.

BackgroundRegulatory T lymphocytes (Treg) play an important role in preventing allergic diseases. We characterized Treg expansion kinetics, marker profiles, and recirculation behavior in allergen‐challenged mice, which had been pretreated with IL‐2/αIL‐2 complexes in the presence or absence of allergen. Moreover, the ability of induced Treg to control airway hyperreactivity and effector functions of lung T cells was determined.MethodsHumanized TCR/HLA‐transgenic allergy mice were treated in vivo with recombinant IL‐2 complexed to the anti‐IL‐2 mAb JES6‐1 in the presence or absence of mugwort pollen extract (MPE) on days 0‐2. Afterward, they were intranasally challenged with MPE (days 13‐15) followed by determination of airway hyperreactivity and lung T cell effector functions. Multiparametric flow cytometry on peripheral blood T cells was performed on a daily basis.ResultsIL‐2/αIL‐2 complexes highly efficiently expanded peripheral Treg cells, while concomitant allergen exposure altered the phenotype of expanded Treg cells. Notably, application of allergen together with IL‐2/αIL‐2 complexes induced expression of Treg marker molecules CTLA4, NRP1, Helios, and GITR on conventional T cells. Apart from CD25, GARP was identified as the most reliable surface‐expressed lineage discrimination marker of Treg expanded in the presence of IL‐2/αIL‐2 complexes and allergen. Finally, IL‐2/αIL‐2 complex‐expanded Treg cells could be recalled upon allergen challenge, which was associated with suppression of lung‐specific Th2 responses long after initial treatment.ConclusionThe characterization of reliable surface and transcription markers of IL‐2/αIL‐2 complex‐expanded Treg along with their expansion kinetics and function will help to identify protocols for their long‐term expansion in vivo.

Immune checkpoint molecules in pregnancy: Focus on regulatory Tcells.

Regulatory T (Treg) cells are a specialized subpopulation of Tcells that plays critical roles in the maintenance of immune homeostasis. Although efforts have been done, their role in human pregnancy is not fully understood. Numerous studies reported the presence of Treg cells throughout gestation by promoting maternal-fetal tolerance and fetal development. Furthermore, Treg population is heterogeneous as it is expressing different immune checkpoint molecules favoring immune suppressive function. Therefore, better understanding of the heterogeneity and function of Treg cells during pregnancy is critical for an effective immune intervention. Latest evidence has shown that several immune checkpoint molecules are closely associated with pregnancy outcome via multiple inhibitory mechanisms. Majority of these studies demonstrated the modulatory effects of immune checkpoint molecules on effector T-cell immunity, but their effects on Treg activation and function are still an enigma. In this review, we emphasize the potential influence of multiple immune checkpoint molecules, including CTLA-4, PD-1, Tim-3, LAG-3, and TIGIT, either in membrane or soluble form, on the function of decidual and peripheral Treg cells during pregnancy. Additionally, we discuss the promising future of targeting Treg cells via immune checkpoint molecules for pregnancy maintenance and prevention of complicated pregnancies.

MicroRNA miR-155 is required for expansion of regulatory T cells to mediate robust pregnancy tolerance in mice.

The immune-regulatory microRNA miR-155 is reduced in recurrent miscarriage, suggesting that miR-155 contributes to immune tolerance in pregnancy. Here we show miR-155 is induced in the uterine mucosa and draining lymph nodes (dLN) during the female immune response to male seminal fluid alloantigens. Mice with null mutation in miR-155 (miR-155-/-) exhibited a reduced CD4+ T cell response after mating, with a disproportionate loss of CD25+FOXP3+ Treg cells. miR-155 deficiency impaired expansion of both peripheral and thymic Treg cells, distinguished by neuropilin-1 (NRP1), and fewer Treg cells expressed Ki67 proliferation marker and suppressive function marker CTLA4. Altered Treg phenotype distribution in miR-155-/- mice was confirmed by t-distributed neighbor embedding (tSNE) analysis. Fewer dendritic cells (DCs) and macrophages trafficked to the dLN of miR-155-/- mice, associated with lower CCR7 on DCs, and reduced uterine Ccl19 expression, implicating compromised antigen presentation in the stunted Treg cell response. miR-155-/- mice exhibited elevated susceptibility to inflammation-induced fetal loss and fetal growth restriction compared with miR-155+/+ controls, but outcomes were restored by transfer of wild-type Tregs. Thus miR-155 is a key regulator of immune adaptation to pregnancy and is necessary for sufficient Tregs to achieve robust pregnancy tolerance and protect against fetal loss.

Altered Frequency of NK Cells and Treg Cells by Astragalus Polysaccharide Combined with Budesonide in Asthma Model Mice

Objective. We investigated the efficacy of astragalus polysaccharide (APS) combined with budesonide and the effect on expressions of peripheral NK cells and Treg cells and the molecular mechanism in mice with bronchial asthma. Methods. In this study, we established a mouse model of asthma. Four groups of BaLB/C mice were developed; control group had no asthma induction, and the other three groups of mice were sensitized by OVA (Ovalbumin), OVA + budesonide, and OVA + APS + budesonide. Flow cytometry was used to determine the proportion of NK cells and Treg cells. Levels of cytokines IL-4 and IL-10 were detected using RT-PCR and ELISA. Results. Asthma mice treated with APS + budesonide showed alleviated airway resistance compared to model mice (P&lt;0.05). The percentage of dendritic cells (DCs) was reduced (P&lt;0.05), while anti-inflammatory NK cells and Treg cells significantly increased after APS + budesonide treatment (P&lt;0.05). Further, APS + budesonide treatment resulted in improvements in IL-4 and IL-10 mRNA and protein levels (P&lt;0.05). Conclusion. APS combined with budesonide medication may regulate expressions of DCs cells and related cytokines, reliving clinical symptom of bronchial asthma.

Impaired tumor necrosis factor-α secretion by CD4 T cells during respiratory syncytial virus bronchiolitis associated with recurrent wheeze.

BackgroundInfants with severe respiratory syncytial virus (RSV) bronchiolitis have an increased risk of recurrent wheezing and asthma. We aimed to evaluate the relationships between regulatory T cell (Treg) percentage and cytokine production of in vitro‐stimulated CD4+ T cells during acute bronchiolitis and the development of recurrent wheezing in the first 3 years of life.MethodsWe obtained peripheral blood from 166 infants hospitalized with their first episode of RSV‐confirmed bronchiolitis. Granzyme B (GZB) expression, and interleukin‐10, interferon‐γ, tumor necrosis factor‐α (TNF‐α), IL‐4, and IL‐5 production by in vitro anti‐CD3/CD28‐ and anti‐CD3/CD46‐activated CD4+ T cells, and percentage of peripheral Treg (CD4+CD25hiFoxp3hi) cells were measured by flow cytometry. Wheezing was assessed every 6 months. Recurrent wheezing was defined as three or more episodes following the initial RSV bronchiolitis.ResultsSixty‐seven percent (n = 111) of children had wheezing after their initial RSV infection, with 30% having recurrent wheezing. The percentage of peripheral Treg (CD4+CD25hiFoxp3hi) cells was not significantly different between the wheezing groups. Decreased TNF‐α production from anti‐CD3/CD28− and anti‐CD3/CD46− activated CD4+ T cells was observed in the recurrent wheezers, compared with nonwheezers (p = .048 and .03, respectively). There were no significant differences in the GZB+ CD4+ T cells and production of other inflammatory cytokines between these groups.ConclusionsWe demonstrated lower TNF‐α production by in vitro stimulated CD4+ T cells during severe RSV bronchiolitis in children that subsequently developed recurrent wheezing, compared with children with no subsequent wheeze. These findings support the role of CD4+ T cell immunity in the development of subsequent wheezing in these children.

The Transcription Factor MAZR/PATZ1 Regulates the Development of FOXP3+ Regulatory T Cells

Forkhead box protein P3+ (FOXP3+) regulatory Tcells (Treg cells) play a key role in maintaining tolerance and immune homeostasis. Here, we report that a T cell-specific deletion of the transcription factor MAZR (also known as PATZ1) leads to an increased frequency of Treg cells, while enforced MAZR expression impairs Treg cell differentiation. Further, MAZR expression levels are progressively downregulated during thymic Treg cell development and during in-vitro-induced human Treg cell differentiation, suggesting that MAZR protein levels are critical for controlling Treg cell development. However, MAZR-deficient Treg cells show only minor transcriptional changes exvivo, indicating that MAZR is not essential for establishing the transcriptional program of peripheral Treg cells. Finally, the loss of MAZR reduces the clinical score in dextran-sodium sulfate (DSS)-induced colitis, suggesting that MAZR activity in Tcells controls the extent of intestinal inflammation. Together, these data indicate that MAZR is part of a Treg cell-intrinsic transcriptional network that modulates Treg cell development.

Absolute reduction of regulatory T cells and regulatory effect of short-term and low-dose IL-2 in polymyositis or dermatomyositis

AimThe study aimed to investigate the changes in peripherallymphocyte and CD4+T subsets and to observe the regulatory effect of low-dose interleukin-2 (ld-IL2) on these cells in polymyositis or dermatomyositis (PM/DM). MethodsLymphocyte subsets (CD3+T, CD4+T, CD8+T, B and natural killer (NK) cells), CD4+T subsets (Th1, Th2, Th17 and regulatory T (Treg) cells) and multiple cytokines of 71 patients after admission and treatment were measured by flow cytometry, as well as these indicators in 30 healthy controls (HCs). In DM, 35 cases were administrated with ld-IL2 combined with conventional therapy, the remaining 26 patients received conventional therapy only. ResultsThe numbers of CD3+T and CD4+T cells in PM/DM were markedly decreased. Meanwhile, the absolute number and percentage of peripheral Treg cells in PM/DM, as well as Th1 cells in DM, were significantly lower than those in HCs (P < 0.05), but Th2 and Th17 cells had no significant difference. The ratio of Th17/Treg in PM (P = 0.031) and in DM (P = 0.003) were obviously higher than that in HCs. The deficiency of Treg cells was associated with the occurrence of interstitial lung disease (ILD) in myositis patients. Meanwhile, reduced production of IL-2 was also observed in PM/DM (P < 0.001). ld-IL2 combination therapy could significantly increase the numbers of CD4+T subsets in DM, especially Treg cells (expanded 2.5 times). ConclusionsThe decline of peripheral Treg cells and serum IL-2 were found in PM/DM. ld-IL2 combination therapy could significantly increase the number of Treg cells.

Foxp3 Post-translational Modifications and Treg Suppressive Activity.

Regulatory T cells (Tregs) are engaged in maintaining immune homeostasis and preventing autoimmunity. Treg cells include thymic Treg cells and peripheral Treg cells, both of which can suppress the immune response via multiple distinct mechanisms. The differentiation, proliferation, suppressive function and survival of Treg cells are affected by distinct energy metabolic programs. Tissue-resident Treg cells hold unique features in comparison with the lymphoid organ Treg cells. Foxp3 transcription factor is a lineage master regulator for Treg cell development and suppressive activity. Accumulating evidence indicates that the activity of Foxp3 protein is modulated by various post-translational modifications (PTMs), including phosphorylation, O-GlcNAcylation, acetylation, ubiquitylation and methylation. These modifications affect multiple aspects of Foxp3 function. In this review, we define features of Treg cells and roles of Foxp3 in Treg biology, and summarize current research in PTMs of Foxp3 protein involved in modulating Treg function. This review also attempts to define Foxp3 dimer modifications relevant to mediating Foxp3 activity and Treg suppression. Understanding Foxp3 protein features and modulation mechanisms may help in the design of rational therapies for immune diseases and cancer.

Applying Circulating CD4CD25FOXP3 T Regulatory Cells and Interleukin 10 as a Measurable Clinical Predictor of Immune Status in Cancer Patients

Infection is a major cause of death in cancer patients. Most cancer patients have deregulated immune responses. Immune tolerance to cancer cells occurs mainly in the peripheral immune system which are regulated by Treg cells. Peripheral Treg cell counts increase with advancing tumor stage in head, neck, and lung squamous cell carcinomas (SCC). CD4CD25FOXP3 Treg cells are a subset of Treg cells that decrease IL-2 levels, secrete IL-10 and suppress CD8 T cells. We aim to determine the relationship between circulating CD4CD25FOXP3 Treg cells and the ability of patients with SCC of the head, neck, and lungs to mount an immune response. We hypothesize that compromised immune status in cancer patients are mediated through increased level of Treg cells and baseline IL-10 level. All patients with unresectable SCC of the head, neck and lungs requiring chemotherapy and/or radiation were included in this prospective observational study. Blood samples to measure levels of Treg cells, IL-2, and IL-10 were collected at the beginning of study enrollment and at the end of therapy or 6 months post enrollment, whichever occurred first. Subjects were followed for 12 months to track number of infections and treatment days. Although 23 eligible patients were enrolled, 2 patients died before the 12 month set of labs were obtained. Correlation analysis was conducted on 21 subjects who survived. Survival (COX regression) and ROC curve analysis were conducted on the 23 subjects. Correlation analysis showed that values for baseline CD4 T cells, baseline IL-10, and end of treatment IL-10 had a positive correlation with patient status (p = 0.05, 0.04, 0.04 respectively). Additionally, IL-10 baseline had a positive correlation with number of infections at 12 months (p=0.05). COX regression analysis revealed that IL-10 at baseline increases the risk of infection (p= 0.02; OR = 1.3). An IL-10 baseline level of 8.5 or greater demonstrates a 67% sensitivity and 89% specificity for predicting infection (AUC = 0.856). Currently there is no established measurable clinical indicator to assess a cancer patient’s immune status. Thus, making it difficult to predict which subset of cancer patients are at a higher risk of infection. The analysis of patients with SCC of the head, neck, and lungs in our study identified IL-10 levels, not Treg cell count to be a better reflection of immune status. An IL-10 baseline level of 8.5 may be an acceptable cut off point to predict risk of infection in this patient population who are undergoing cancer treatment.

IL-17A Can Promote Propionibacterium acnes-Induced Sarcoidosis-Like Granulomatosis in Mice.

The etiology of sarcoidosis is unknown. In this study, Propionibacterium acnes (PA) was used to induce sarcoidosis-like granulomatous inflammation in a mouse model. Wild-Type (WT) C57BL/6 mice were divided into three groups: (1) WT-PA group; (2) WT-PA + Incomplete Freund's Adjuvant (IFA) group; and (3) WT-PBS group. Loose granuloma formation was observed in the lungs on day 56 in the WT-PA and WT-PA + IFA groups. The proportions of peripheral Th17 cells in the WT-PA (p = 0.0004) and WT-PA + IFA groups (p = 0.0005) were significantly higher than that in the WT-PBS group. The proportions of peripheral Treg cells in the WT-PA (p < 0.0001) and WT-PA + IFA groups (p < 0.0001) were lower than that in the WT-PBS group. Then, to explore the mechanism of IL-17, Wild-Type (WT) C57BL/6 mice were divided into three groups: (1) WT-PBS group (2) WT-PA group; (3) WT-PA + mouse IL-17A neutralizing antibody (IL-17Ab) group. IL-17A gene knockout mice (KO) were divided into two groups: (1) KO -PA group; (2) KO-PBS group. The KO-PA and WT-PA + IL-17Ab groups showed reduced inflammation and no loose granuloma formation on day 56. As compared to the WT-PA group, the ratio of peripheral Th17 in the KO-PA (p < 0.0001) and WT-PA + IL-17Ab groups (p < 0.0001) decreased, while the ratio of peripheral Treg in the KO-PA (p < 0.0001) and WT-PA + IL-17Ab (p = 0.0069) groups increased on day 56. Hence, PA can be used to establish a mouse model of sarcoidosis-like granuloma. IL-17A plays an important role in experimental sarcoidosis-like granuloma formation.

Helios Deficiency Predisposes the Differentiation of CD4+Foxp3- T Cells into Peripherally Derived Regulatory T Cells.

The transcription factor Helios is expressed in a large percentage of Foxp3+ regulatory T (Treg) cells and is required for the maintenance of their suppressive phenotype, as mice with a selective deficiency of Helios in Treg cells spontaneously develop autoimmunity. However, mice with a deficiency of Helios in all T cells do not exhibit autoimmunity, despite the defect in the suppressor function of their Treg cell population, suggesting that Helios also functions in non-Treg cells. Although Helios is expressed in a small subset of CD4+Foxp3- and CD8+ T cells and its expression is upregulated upon T cell activation, its function in non-Treg cells remains unknown. To examine the function of Helios in CD4+Foxp3- T cells, we transferred Helios-sufficient or -deficient naive CD4+Foxp3- TCR transgenic T cells to normal recipients and examined their capacity to respond to their cognate Ag. Surprisingly, Helios-deficient CD4+ T cells expanded and differentiated into Th1 or Th2 cytokine-producing effectors in a manner similar to wild-type TCR transgenic CD4+ T cells. However, the primed Helios-deficient cells failed to expand upon secondary challenge with Ag. The tolerant state of the Helios-deficient memory T cells was not cell-intrinsic but was due to a small population of Helios-deficient naive T cells that had differentiated into Ag-specific peripheral Treg cells that suppressed the recall response in an Ag-specific manner. These findings demonstrate that Helios plays a role in the determination of CD4+ T cell fate.

Connecting blood and intratumoral Treg cell activity in predicting future relapse in breast cancer.

Regulatory T (Treg) cells play a major role in the development of an immunosuppressive tumor microenvironment. The origin of intratumoral Treg cells and their relationship with peripheral blood Treg cells remain unclear. Treg cells consist of at least three functionally distinct subpopulations. Here we show that peripheral blood CD45RA-FOXP3hi Treg cells (Treg II cells) are phenotypically closest to intratumoral Treg cells, including in their expression of CCR8. Analyses of T cell antigen receptor repertoires further support the hypothesis that intratumoral Treg cells may originate primarily from peripheral blood Treg II cells. Moreover, the signaling responsiveness of peripheral blood Treg II cells to immunosuppressive, T helper type 1 (TH1) and T helper type 2 (TH2) cytokines reflects intratumoral immunosuppressive potential, and predicts future relapse in two independent cohorts of patients with breast cancer. Together, our findings give important insights into the relationship between peripheral blood Treg cells and intratumoral Treg cells, and highlight cytokine signaling responsiveness as a key determinant of intratumoral immunosuppressive potential and clinical outcome.