The Synergistic Immunoregulatory Effects of Culture-Expanded Mesenchymal Stromal Cells and CD4+25+Foxp3+ Regulatory T Cells on Skin Allograft Rejection

Mesenchymal stromal cells (MSCs) are seen as an ideal source of cells to induce graft acceptance; however, some reports have shown that MSCs can be immunogenic rather than immunosuppressive. We speculate that the immunomodulatory effects of regulatory T cells (Tregs) can aid the maintenance of immunoregulatory functions of MSCs, and that a combinatorial approach to cell therapy can have synergistic immunomodulatory effects on allograft rejection. After preconditioning with Fludarabine, followed by total body irradiation and anti-asialo-GM-1(ASGM-1), tail skin grafts from C57BL/6 (H-2k^b) mice were grafted onto the lateral thoracic wall of BALB/c (H-2k^d) mice. Group A mice (control group, n = 9) did not receive any further treatment after preconditioning, whereas groups B and C (n = 9) received cell therapy with MSCs or Tregs, respectively, on days −1, +6 and +13 relative to the skin transplantation. Group D (n = 10) received cell therapy with MSCs and Tregs on days −1, +6 and +13. Cell suspensions were obtained from the spleens of five randomly chosen mice from each group on day +7, and the immunomodulatory effects of the cell therapy were evaluated by flow cytometry and real-time PCR. Our results show that allograft survival was significantly longer in group D compared to the control group (group A). Flow cytometric analysis and real-time PCR for splenocytes revealed that the Th2 subpopulation in group D increased significantly compared to the group B. Also, the expression of Foxp3 and STAT 5 increased significantly in group D compared to the conventional cell therapy groups (B and C). Taken together, these data suggest that a combined cell therapy approach with MSCs and Tregs has a synergistic effect on immunoregulatory function in vivo, and might provide a novel strategy for improving survival in allograft transplantation.     

肝移植急性排斥反应时外周血Th17细胞的特征及意义

目的:观测肝移植患者术前及术后急性排斥时外周血中Th17细胞频率变化特征,探讨其与肝移植术后急性排斥发生的关系。方法:对18例于我院进行肝移植手术的患者进行随访研究,应用流式细胞仪检测各随访点外周血中Th17细胞频率。随访期间发生急性排斥反应的患者为急排组(n=7,男女比为5/2),未发生急性排斥反应者为非急排组(n=11,男女比为8/3),比较两组患者肝移植前后外周血中Th17细胞频率的变化规律。结果:急排组与非急排组患者肝移植术前外周血中Th17细胞频率无统计学差异(P=0.672),而急排组患者发生急性排斥反应时与非急排组患者相比Th17细胞频率明显升高(P=0.002)。在随访研究中,急排组患者在发生急性排斥反应时外周血中Th17细胞频率较未发生急性排斥反应时增高,且Th17细胞频率与ALT变化趋势一致,呈明显正性相关。而非急排组患者术后随访期间外周血中Th17细胞频率无统计学差异。结论:肝移植患者术后发生急性排斥反应时外周血中Th17细胞频率明显升高,变化趋势与ALT水平一致,呈正性相关,可能成为诊断急性排斥反应的潜在指标。     

Increased Numbers of Circulating CD8 Effector Memory T Cells before Transplantation Enhance the Risk of Acute Rejection in Lung Transplant Recipients

The effector and regulatory T cell subpopulations involved in the development of acute rejection episodes in lung transplantation remain to be elucidated. Twenty-seven lung transplant candidates were prospectively monitored before transplantation and within the first year post-transplantation. Regulatory, Th17, memory and naïve T cells were measured in peripheral blood of lung transplant recipients by flow cytometry. No association of acute rejection with number of peripheral regulatory T cells and Th17 cells was found. However, effector memory subsets in acute rejection patients were increased during the first two months post-transplant. Interestingly, patients waiting for lung transplant with levels of CD8⁺ effector memory T cells over 185 cells/mm³ had a significant increased risk of rejection [OR: 5.62 (95% CI: 1.08-29.37), p=0.04]. In multivariate analysis adjusted for age and gender the odds ratio for rejection was: OR: 5.89 (95% CI: 1.08-32.24), p=0.04. These data suggest a correlation between acute rejection and effector memory T cells in lung transplant recipients. The measurement of peripheral blood CD8⁺ effector memory T cells prior to lung transplant may define patients at high risk of acute lung rejection.     

Total body irradiation of donors can alter the course of tolerance and induce acute rejection in a spontaneous tolerance rat liver transplantation model

Liver transplantation is an established therapy for end-stage liver diseases. Graft rejection occurs unless the recipient receives immunosuppression after transplantation. This study aimed to explore the mechanism of acute rejection of liver allografts in rats pre-treated with total body irradiation to eliminate passenger lymphocytes and to define the role of CD4⁺CD25⁺ regulatory T cells in the induction of immunotolerance in the recipient. Male Lewis rats were used as donors and male DA rats were recipients. Rats were randomly assigned to the following four groups: control group, homogeneity liver transplantation group, idio-immunotolerance group and acute rejection group. After transplantation, the survival time of each group, serum alanine aminotransferase, total bilirubin levels, number of Foxp3⁺CD4⁺CD25⁺ regulatory T cells, expression of glucocorticoid-induced tumor necrosis factor receptor on T cell subgroups, histopathology of the hepatic graft and spleen cytotoxic T lymphocyte lytic activity were measured. In the acute rejection group, where donors were preconditioned with total body irradiation before liver transplantation, all recipients died between day 17 and day 21. On day 14, serum alanine aminotransferase increased significantly to (459.2±76.9) U L^?1, total bilirubin increased to (124.1±33.7) ??mol L^?1 (P<0.05) and the ratio of Foxp3⁺CD4⁺CD25⁺ regulatory T cells decreased significantly to 1.50%±0.50% (P<0.05) compared with the other groups. Analysis of the T cell subpopulations in the acute rejection group varied from the other groups. Histological analysis showed typical changes of acute rejection in the acute rejection group only. Preconditioning of the donors with total body irradiation eliminated passenger lymphocytes of the liver graft, and thus affected the course of tolerance and induced acute rejection after liver transplantation.     

CD39+ Regulatory T cells suppress generation and differentiation of Th17 cells in human malignant pleural effusion via a LAP-dependent mechanism

Background

Both regulatory T cells (Tregs) and T helper IL-17-producing cells (Th17 cells) have been found to be involved in human malignancies, however, the possible implication of Tregs in regulating generation and differentiation of Th17 cells in malignant pleural effusion remains to be elucidated.

Methods

The numbers of both CD39⁺Tregs and Th17 cells in malignant pleural effusion and peripheral blood from patients with lung cancer were determined by flow cytometry. The regulation and mechanism of Tregs on generation and differentiation of Th17 cells were explored.

Results

Both CD39⁺Tregs and Th17 cells were increased in malignant pleural effusion when compared with blood, and the numbers of CD39⁺Tregs were correlated negatively with those of Th17 cells. It was also noted that high levels of IL-1β, IL-6, and TGF-β1 could be observed in malignant pleural effusion when compared the corresponding serum, and that pleural CD39⁺Tregs could express latency-associated peptide on their surface. When naïve CD4⁺ T cells were cocultured with CD39⁺Tregs, Th17 cell numbers decreased as CD39⁺Treg numbers increased, addition of the anti-latency-associated peptide mAb to the coculture reverted the inhibitory effect exerted by CD39⁺Tregs.

Conclusions

Therefore, the above results indicate that CD39⁺Tregs inhibit generation and differentiation of Th17 cells via a latency-associated peptide-dependent mechanism.     

Increased Circulating Th17 Cells after Transarterial Chemoembolization Correlate with Improved Survival in Stage III Hepatocellular Carcinoma: A Prospective Study

Transarterial chemoembolization (TACE) has therapeutic effects in patients with unresectable hepatocellular carcinoma (HCC), but its impact on the cellular immune response during disease progression is largely unknown. Here we conducted a prospective study to evaluate the effect of TACE on immune status and to identify prognostic immune markers governing treatment success. In this study, 51 stage III HCC patients, 28 stage I HCC patients (TNM classification) and 20 healthy donors were enrolled. Flow cytometry and cytometric bead array were used to evaluate the circulating immune cell subsets, including CD4⁺ T cells (Th1, Th17 and Treg cells), CD8⁺ T cells, NK cells, and NKT cells, and plasma cytokines before TACE and 30 days after TACE. Interestingly, among those immune parameters, the frequency of circulating Th17 cells was higher in stage III HCC patients than in stage I HCC patients (P = 0.015) and healthy donors (P<0.001). Moreover, an increased frequency of circulating Th17 cells was observed 30 days after TACE (Th17_D30) compared with the baseline level (P = 0.036). Kaplan-Meier analysis demonstrated that Th17_D30 was positively associated with overall survival (OS; P = 0.007) and time to progression (TTP; P = 0.009). Multivariate Cox analysis revealed that Th17_D30 was an independent prognostic factor for OS (HR = 0.317, P = 0.032) and TTP (HR = 0.304, P = 0.010). These results provide a potential prognostic marker for stage III HCC patients undergoing TACE and may be useful for identifying patients who can benefit from adjuvant immunotherapies.     

Pretransplant Infusion of Donor B Cells Enhances Donor-Specific Skin Allograft Survival

Pretransplant donor lymphocyte infusion (DLI) has been shown to enhance donor-specific allograft survival in rodents, primates and humans. However, the cell subset that is critical for the DLI effect and the mechanisms involved remain elusive. In this study, we monitored donor cell subsets after DLI in a murine MHC class I L^d-mismatched skin transplantation model. We found that donor B cells, but not DCs, are the major surviving donor APCs in recipients following DLI. Infusing donor B, but not non-B, cells resulted in significantly enhanced donor-specific skin allograft survival. Furthermore, mice that had received donor B cells showed higher expression of Ly6A and CD62L on antigen-specific TCRαβ⁺CD3⁺CD4⁻CD8⁻NK1.1⁻ double negative (DN) regulatory T cells (Tregs). B cells presented alloantigen to DN Tregs and primed their proliferation in an antigen-specific fashion. Importantly, DN Tregs, activated by donor B cells, showed increased cytotoxicity toward anti-donor CD8⁺ T cells. These data demonstrate that donor B cells can enhance skin allograft survival, at least partially, by increasing recipient DN Treg-mediated killing of anti-donor CD8⁺ T cells. These findings provide novel insights into the mechanisms underlying DLI-induced transplant tolerance and suggest that DN Tregs have great potential as an antigen-specific immune therapy to enhance allograft survival.     

A Higher Frequency of Circulating IL-22+CD4+ T Cells in Chinese Patients with Newly Diagnosed Hashimoto’s Thyroiditis

Background

IL-22 and IL-17A are implicated in the pathogenesis of autoimmune diseases. However, the role of IL-22⁺ and IL-17A⁺ CD4⁺ T cells in the pathogenesis of Hashimoto’s thyroiditis (HT) is not fully understood. This study investigates serum IL-22 and IL-17A levels and determines the frequency of circulating IL-22⁺ CD4⁺ T cells in HT patients to understand their roles in the pathogenesis of HT.

Methods

The levels of serum IL-22, IL-17A and IFN-γ and the frequency of circulating IL-22⁺CD4⁺ and IL-17A⁺CD4⁺ T cells in 17 HT patients and 17 healthy controls (HC) were determined by enzyme-linked immunosorbent assay (ELISA) and flow cytometry. The levels of serum free triiodothyronine (FT4), free thyroxine (FT3), thyroid stimulating hormone (TSH), anti-thyroid peroxidase (TPO) and anti-thyroglobulin antibodies (TgAb) by chemiluminescent enzyme immunoassay and radioimmunoassay.

Results

The percentages of circulating IL-22⁺CD4⁺ and IL-17⁺CD4⁺ T cells (p<0.0001, p<0.0001) and the levels of serum IL-22, IL-17A and IFN-γ (p<0.0001, p<0.0001, p = 0.0210) in the HT patients were significantly higher than that in the HC. The percentages of IL-22⁺CD4⁺ T cells were positively correlated with Th17 cells (r = 0.8815, p<0.0001) and IL-17A⁺IL-22⁺CD4⁺ T cells (r = 0.8914, p<0.0001), but were negatively correlated with Th1 cells (r = −0.6110, p<0.0092) in the HT patients. The percentages of Th22 cells, Th17 cells and IL-17A⁺IL-22⁺CD4⁺ T cells were negatively correlated with the levels of serum TSH in the HT patients (r = −0.8402, p<0.0001; r = −0.8589, p<0.0001; r = −0.8289 p<0.0001, respectively).

Conclusions

A higher frequency of circulating IL-22⁺CD4⁺ and IL-17A⁺CD4⁺ T cells may be associated with the development of HT in Chinese patients.     

Regulatory Phenotype,PD-1 and TLR3 Expression in T Cells and Monocytes from HCV Patients Undergoing Antiviral Therapy: A Randomized Clinical Trial

Background & Aims

The cellular immunity has a profound impact on the status of hepatitis C virus (HCV) infection. However, the response of cellular immunity on the virological response in patients with antiviral treatment remains largely unclear. We aimed to clarify the response of peripheral T cells and monocytes in chronic hepatitis C patients with antiviral treatment.

Methods

Patients with chronic hepatitis C were treated either with interferon alpha-2b plus ribavirin (n = 37) or with pegylated interferon alpha-2a plus ribavirin (n = 33) for up to 24 weeks. Frequencies of peripheral regulatory T-cells (Tregs), programmed death-1 (PD-1) expressing CD4⁺ T-cells or CD8⁺ T-cells and toll-like receptor (TLR) 3 expressing CD14⁺ monocytes were evaluated by flow cytometry in patients at baseline, 12 and 24 weeks following treatment and in 20 healthy controls.

Results

Frequencies of Tregs, PD-1 and TLR3 expressing cells were higher in patients than those in control subjects (P<0.05). Patients with complete early virological response (cEVR) showed lower Tregs, PD-1 expressing CD4⁺ or CD8⁺ T-cells than those without cEVR at 12 weeks (P<0.05). Patients with low TLR3 expressing CD14⁺ monocytes at baseline had a high rate of cEVR (P<0.05).

Conclusions

Low peripheral TLR3 expressing CD14⁺ monocytes at baseline could serve as a predictor for cEVR of antiviral therapy in chronic HCV-infected patients. The cEVR rates were significantly increased in the patients with reduced circulating Tregs, PD-1 expressing CD4⁺ or CD8⁺ T-cells.

Trial Registration

Chinese Clinical Trial Registry ChiCTR10001090.     

Loss of CD28 on Peripheral T Cells Decreases the Risk for Early Acute Rejection after Kidney Transplantation

Background

End-stage renal disease patients have a dysfunctional, prematurely aged peripheral T-cell system. Here we hypothesized that the degree of premature T-cell ageing before kidney transplantation predicts the risk for early acute allograft rejection (EAR).

Methods

222 living donor kidney transplant recipients were prospectively analyzed. EAR was defined as biopsy proven acute allograft rejection within 3 months after kidney transplantation. The differentiation status of circulating T cells, the relative telomere length and the number of CD31⁺ naive T cells were determined as T-cell ageing parameters.

Results

Of the 222 patients analyzed, 30 (14%) developed an EAR. The donor age and the historical panel reactive antibody score were significantly higher (p = 0.024 and p = 0.039 respectively) and the number of related donor kidney transplantation was significantly lower (p = 0.018) in the EAR group. EAR-patients showed lower CD4⁺CD28null T-cell numbers (p<0.01) and the same trend was observed for CD8⁺CD28null T-cell numbers (p = 0.08). No differences regarding the other ageing parameters were found. A multivariate Cox regression analysis showed that higher CD4⁺CD28null T-cell numbers was associated with a lower risk for EAR (HR: 0.65, p = 0.028). In vitro, a significant lower percentage of alloreactive T cells was observed within CD28null T cells (p<0.001).

Conclusion

Immunological ageing-related expansion of highly differentiated CD28null T cells is associated with a lower risk for EAR.     

Imbalanced Frequencies of Th17 and Treg Cells in Acute Coronary Syndromes Are Mediated by IL-6-STAT3 Signaling

Aims

Extensive evidence suggests inflammatory components participate in the pathogenic processes of acute coronary syndromes (ACS). In this study, we aimed to elucidate the role and mechanism underlying the imbalance of Th17 and Treg cell peripheral populations in the pathogenesis of ACS.

Methods and Results

Using a flow cytometric analysis, we observed a significantly increased frequency of Th17 cells and a concurrently decreased CD4⁺CD25⁺Foxp3⁺ Treg cells in patients with ACS. To elucidate the mechanism of Th17/Treg imbalance in ACS, 22 inflammatory cytokines were measured using multiplexed immunobead-based assays. Of six elevated cytokines in ACS patients, only IL-6 was positively correlated with a higher Th17 cell level (r = 0.39, P<0.01). Relying on IL-6 stimulating and neutralizing studies, we demonstrated a direct role for IL-6 in sera from ACS patients with an increased frequency of Th17 cells. IL-6 induces the differentiation of Th17 cells from naïve CD4⁺ T cells through STAT3 activation and RORγt induction. However, we observed that high levels of TGF-β1 inhibited IL-6-dependent Th17 cell differentiation, indicating a complex interplay between the two cytokines in the control of Th17 and Treg cell populations.

Conclusions

Our results demonstrate the role of IL-6-STAT3 signaling in ACS through increased Th17 cell differentiation. These findings indicate that IL-6 neutralizing strategies could present novel therapeutic avenues in the treatment of ACS.     

The Ratio of Treg/Th17 Cells Correlates with the Disease Activity of Primary Immune Thrombocytopenia

Background

Primary immune thrombocytopenia (ITP) is an autoimmune heterogeneous disorder that is characterized by decreased platelet count. Regulatory T (Treg) cells and T helper type 17 (Th17) cells are two subtypes of CD4⁺ T helper (Th) cells. They play opposite roles in immune tolerance and autoimmune diseases, while they share a common differentiation pathway. The imbalance of Treg/Th17 has been demonstrated in several autoimmune diseases. In this study, we aimed to investigate the ratio of the number of Treg cells to the number of Th17 cells in ITP patients and evaluate the clinical implications of the alterations in this ratio.

Methods

Thirty adult patients with newly diagnosed ITP enrolled in this study. Twelve patients had been clinically followed up for 12 months. The percentages of CD4⁺CD25^hiFoxp3⁺ Treg cells and CD3⁺CD4⁺IL-17-producing Th17 cells in these patients and healthy controls (n = 17) were longitudinally analyzed by flow cytometry.

Results

The percentage of Treg cells in ITP patients was significantly lower than that of healthy controls, and the percentage of Th17 cells increased significantly at disease onset. The ratio of Treg/Th17 correlated with the disease activity.

Conclusion

The ratio of Treg/Th17 might be relevant to the clinical diversity of ITP patients, and this Treg/Th17 ratio might have prognostic role in ITP patients.     

Fasting Enhances TRAIL-Mediated Liver Natural Killer Cell Activity via HSP70 Upregulation

Acute starvation, which is frequently observed in clinical practice, sometimes augments the cytolytic activity of natural killer cells against neoplastic cells. In this study, we investigated the molecular mechanisms underlying the enhancement of natural killer cell function by fasting in mice. The total number of liver resident natural killer cells in a unit weight of liver tissue obtained from C57BL/6J mice did not change after a 3-day fast, while the proportions of tumor necrosis factor–related apoptosis-inducing ligand (TRAIL)⁺ and CD69⁺ natural killer cells were significantly elevated (n = 7, p <0.01), as determined by flow cytometric analysis. Furthermore, we found that TRAIL⁻ natural killer cells that were adoptively transferred into Rag-2^−/− γ chain^−/− mice could convert into TRAIL⁺ natural killer cells in fasted mice at a higher proportion than in fed mice. Liver natural killer cells also showed high TRAIL-mediated antitumor function in response to 3-day fasting. Since these fasted mice highly expressed heat shock protein 70 (n = 7, p <0.05) in liver tissues, as determined by western blot, the role of this protein in natural killer cell activation was investigated. Treatment of liver lymphocytes with 50 µg/mL of recombinant heat shock protein 70 led to the upregulation of both TRAIL and CD69 in liver natural killer cells (n = 6, p <0.05). In addition, HSP70 neutralization by intraperitoneally injecting an anti- heat shock protein 70 monoclonal antibody into mice prior to fasting led to the downregulation of TRAIL expression (n = 6, p <0.05). These findings indicate that acute fasting enhances TRAIL-mediated liver natural killer cell activity against neoplastic cells through upregulation of heat shock protein 70.     

Th1 to Th2 immune deviation facilitates,but does not cause,islet allograft tolerance in mice

It has been reported that Th1 to Th2 immune deviation effectively promotes peripheral tolerance in situations involving a limited T cell clone size, such as T cell-dependent autoimmunity and transplantation across minor, but not major, histocompatibility barriers. In this study, we tested the hypothesis that while Th1 to Th2 immune deviation fails to induce tolerance in the MHC-mismatched islet allograft model, it may promote a state that is permissive for tolerance induction. Here, we report that anti-IL-12 did not prevent acute rejection of islet allografts when administered alone. In conjunction with CTLA4/Fc, however, anti-IL-12 greatly facilitated long-term engraftment in three MHC-mismatched strain combinations. Similarly, while non-cytolytic IL-4/Fc, a long-lasting form of IL-4, did not prevent acute graft rejection when administered alone, a low, but not a high, dose of IL-4/Fc synergized with CTLA4/Fc in inducing significant levels of islet allograft tolerance. Moreover, by using a skin allograft adoptive transfer model, we show that these effects induced by anti-IL-12 and IL-4/Fc treatment were associated with an enhancement of the suppressive properties of CD4⁺CD25⁺ regulatory T cells. Thus, anti-IL-12 and low-dose IL-4/Fc facilitate, but do not cause, islet allograft tolerance in mice by increasing the immunosuppressive potency of CD4⁺CD25⁺ regulatory T cells.     

Human Hepatocyte Growth Factor (hHGF)-Modified Hepatic Oval Cells Improve Liver Transplant Survival

Despite progress in the field of immunosuppression, acute rejection is still a common postoperative complication following liver transplantation. This study aims to investigate the capacity of the human hepatocyte growth factor (hHGF) in modifying hepatic oval cells (HOCs) administered simultaneously with orthotopic liver transplantation as a means of improving graft survival. HOCs were activated and isolated using a modified 2-acetylaminofluorene/partial hepatectomy (2-AAF/PH) model in male Lewis rats. A HOC line stably expressing the HGF gene was established following stable transfection of the pBLAST2-hHGF plasmid. Our results demonstrated that hHGF-modified HOCs could efficiently differentiate into hepatocytes and bile duct epithelial cells in vitro. Administration of HOCs at the time of liver transplantation induced a wider distribution of SRY-positive donor cells in liver tissues. Administration of hHGF-HOC at the time of transplantation remarkably prolonged the median survival time and improved liver function for recipients compared to these parameters in the other treatment groups (P<0.05). Moreover, hHGF-HOC administration at the time of liver transplantation significantly suppressed elevation of interleukin-2 (IL-2), tumor necrosis factor-α (TNF-α) and interferon-γ (IFN-γ) levels while increasing the production of IL-10 and TGF-β1 (P<0.05). HOC or hHGF-HOC administration promoted cell proliferation, reduced cell apoptosis, and decreased liver allograft rejection rates. Furthermore, hHGF-modified HOCs more efficiently reduced acute allograft rejection (P<0.05 versus HOC transplantation only). Our results indicate that the combination of hHGF-modified HOCs with liver transplantation decreased host anti-graft immune responses resulting in a reduction of allograft rejection rates and prolonging graft survival in recipient rats. This suggests that HOC-based cell transplantation therapies can be developed as a means of treating severe liver injuries.     

ICOS-Expressing Lymphocytes Promote Resolution of CD8-Mediated Lung Injury in a Mouse Model of Lung Rejection

Acute rejection, a common complication of lung transplantation, may promote obliterative bronchiolitis leading to graft failure in lung transplant recipients. During acute rejection episodes, CD8⁺ T cells can contribute to lung epithelial injury but the mechanisms promoting and controlling CD8-mediated injury in the lung are not well understood. To study the mechanisms regulating CD8⁺ T cell–mediated lung rejection, we used a transgenic model in which adoptively transferred ovalbumin (OVA)-specific cytotoxic T lymphocytes (CTL) induce lung injury in mice expressing an ovalbumin transgene in the small airway epithelium of the lungs (CC10-OVA mice). The lung pathology is similar to findings in humans with acute lung transplant. In the presence of an intact immune response the inflammation resolves by day 30. Using CC10-OVA.RAG^-/- mice, we found that CD4⁺ T cells and ICOS^+/+ T cells were required for protection against lethal lung injury, while neutrophil depletion was not protective. In addition, CD4⁺Foxp3 ⁺ ICOS⁺ T cells were enriched in the lungs of animals surviving lung injury and ICOS^+/+ Tregs promoted survival in animals that received ICOS^-/- T cells. Direct comparison of ICOS^-/- Tregs to ICOS^+/+ Tregs found defects in vitro but no differences in the ability of ICOS^-/- Tregs to protect from lethal lung injury. These data suggest that ICOS affects Treg development but is not necessarily required for Treg effector function.     

Elevated Peripheral Frequencies of Th22 Cells: A Novel Potent Participant in Obesity and Type 2 Diabetes

Objective

Chronic low-grade inflammation has long been recognized as the central link between obesity and type 2 diabetes (T2D). The novel subset of T helper (Th) cells, Th22, plays an emerging role in chronic inflammation. We investigated the potential association between Th22 and the pathogenesis of obesity and T2D.

Methods

Ninety T2D inpatients (T2D group), 30 healthy participants with BMI ranged from 19 to 23.9 kg/m2 (CTL group) and 30 metabolically healthy obese controls with BMI ≥ 30 kg/m2 (MHO group) were employed in our study. Peripheral frequencies of Th22 and Th1 and Th17 cells were determined by flow cytometry based on their specific cytokine patterns. Cytokine levels in fresh plasma were quantified by ELISA.

Results

Compared to that in CTL group (1.18±0.06%, n = 28), peripheral frequency of Th22 cells was significantly increased in MHO group (1.88±0.10%, n = 30) and in T2D group (2.247±0.10%, n = 89). There was a consistent notable increase in plasma interleukin (IL)-22 of T2D patients [47.56 (30.55–76.89) pg/mL] as compared with that of MHO group [36.65 (29.52–55.70) pg/ml; *P<0.0001] and CTLs [36.33 (31.93–40.62) pg/mL; *P<0.0001]. Furthermore, other than Th1/Th17, previously frequently described participants in obesity and T2D, there was a strong correlation between Th22 frequency and the homeostasis model of assessment for insulin resistance index (r = 0.6771, *P<0.0001) and HOMA for β-cell function (r = −0.7264, *P<0.0001).

Conclusions

There were increased Th22 frequencies and IL-22 levels in obesity and T2D. Elevated Th22 and IL-22 also aided in the differentiation of MHO from T2D patients. The notable correlation implied that Th22 might play a more determinant role in both insulin resistance and β-cell impairment.