Decrease In Treg Cells Research Articles

The Effect of TGF-β on Treg Cells in Adverse Pregnancy Outcome upon Toxoplasma gondii Infection.

Toxoplasma gondii (T. gondii) is a ubiquitous intracellular protozoan parasite that causes adverse pregnancy outcomes. Its infection downregulates the Treg cell population and TGF-β level, which may contribute to adverse pregnancy outcomes. TGF-β plays a critical role in Treg cell development, but whether TGF-β treatment can affect the number and function of Treg cells and hence alleviate adverse pregnancy outcomes caused by T. gondii infection remains elusive. In this study, T. gondii-infected pregnant mice were treated with TGF-β or TGF-β-neutralizing antibody. The pregnancy outcomes were observed on gestational day 14. The numbers of Treg cells and pSmad3, programmed death 1 (PD-1), and Cytotoxic T lymphocyte-associated antigen-4 (CTLA-4) expression of Treg cells were analyzed by flow cytometry. Histological changes were assessed using HE staining, while IL-10 and TNF-α levels were measured using ELISA. The results indicated that TGF-β treatment improved the T. gondii-induced adverse pregnancy outcomes, with alleviation of hemorrhage, restoration of uterine spiral arteries of the placenta, and increased Treg cell numbers; meanwhile, TGF-β neutralization resulted in more serious adverse pregnancy outcomes, with serious hemorrhage, more dilated uterine spiral arteries, and decreased Treg cell numbers. pSmad3 expression in CD4+ cells and CTLA-4 and PD-1 levels on Treg cells were upregulated by TGF-β treatment, but downregulated by TGF-β neutralization. The ratio of IL-10/TNF-α also increased after TGF-β treatment, but decreased after TGF-β neutralization. Our data indicate that TGF-β treatment could improve adverse pregnancy outcomes caused by T. gondii infection by upregulating Treg cell differentiation and function via the TGF-β/Smad3 signaling pathway, but not the proliferation of Treg cells.

Molecular chaperone is required for gut tolerogenic dendritic cell development and function

Abstract The intestinal mucosa is continuously inundated with foreign antigens. Therefore, immune cells need to be tightly regulated to maintain tolerance against harmless dietary antigens and microbiota while responding to pathogens. Intestinal dendritic cells (DCs) play an integral role in regulating immunity and tolerance because of their unique position at the interface of innate and adaptive immunity. Multiple populations of intestinal DCs have been reported based on the expression of CD103, CD11b, and CX3CR1. However, the mechanism by which different DC subsets regulate intestinal homeostasis is still unclear. Heat shock protein gp96 is an essential chaperone for most TLRs, integrins, and other proteins important for DC functions. However, the role of DC-intrinsic gp96 in regulating gut tolerance has not been studied. By a genetic strategy, we discovered that selective deletion of gp96 from CD11c+ cells in mice results in alteration of DC and T cell subsets in the gut as well as the loss of antigen-specific regulatory T cell (Treg) induction. Strikingly DC-specific gp96 knockout mice develop spontaneous colitis by 24 weeks of age. Furthermore, differentiation of murine bone marrow-derived DCs revealed that gp96 depletion selectively decreased cell maturation in response to FLT3L compared to CSF2. Also, gp96 depletion reduced DC migration and cross-presentation. Taken together, our results demonstrated that gp96 depletion from CD11c+ cells selectively inhibits tolerogenic DCs in the gut leading to decreased Treg cells, which indicates that DC-intrinsic gp96 plays essential roles in maintaining gut tolerance.

NKG2D+CD4+ T Cells Kill Regulatory T Cells in a NKG2D-NKG2D Ligand- Dependent Manner in Systemic Lupus Erythematosus

Systemic lupus erythematosus (SLE) features a decreased pool of CD4+CD25+Foxp3+ T regulatory (Treg) cells. We had previously observed NKG2D+CD4+ T cell expansion in contrast to a decreased pool of Treg cells in SLE patients, but whether NKG2D+CD4+ T cells contribute to the decreased Treg cells remains unclear. In the present study, we found that the NKG2D+CD4+ T cells efficiently killed NKG2D ligand (NKG2DL)+ Treg cells in vitro, whereby the surviving Treg cells in SLE patients showed no detectable expression of NKG2DLs. It was further found that MRL/lpr lupus mice have significantly increased percentage of NKG2D+CD4+ T cells and obvious decreased percentage of Treg cells, as compared with wild-type mice. Adoptively transferred NKG2DL+ Treg cells were found to be efficiently killed in MRL/lpr lupus mice, with NKG2D neutralization remarkably attenuating this killing. Anti-NKG2D or anti-interferon-alpha receptor (IFNAR) antibodies treatment in MRL/lpr mice restored Treg cells numbers and markedly ameliorated the lupus disease. These results suggest that NKG2D+CD4+ T cells are involved in the pathogenesis of SLE by killing Treg cells in a NKG2D-NKG2DL-dependent manner. Targeting the NKG2D-NKG2DL interaction might be a potential therapeutic strategy by which Treg cells can be protected from cytolysis in SLE patients.

IL-7/IL-7R signaling pathway might play a role in recurrent pregnancy losses by increasing inflammatory Th17 cells and decreasing Treg cells.

We aim to investigate a possible role of IL-7/IL-7R signaling pathway in recurrent pregnancy losses (RPL). Using the abortion-prone (AP) and non-abortion-prone (NP) mice model, fetal resorption rates (FRR), Th17 and Treg cells-related factors, and the effect of IL-7 and IL-7R antagonist were investigated by flow cytometry, quantitative real-time PCR, and immunohistochemistry. IL-7 and IL-7R expressions in human decidua were investigated by immunohistochemistry. In the AP mice, IL-7R antagonist treatment significantly decreased FRR by downregulating Th17 and upregulating Treg-related factors. When the NP mice were treated with IL-7, FRR was significantly increased by upregulating Th17 and downregulating Treg-related factors. In decidual stromal cells of women with RPL, increased IL-7 and decreased IL-7R expressions were present when compared to normal controls. IL-7/IL-7R signaling pathway plays a possible role in RPL by upregulating Th17 immunity, meanwhile downregulating Treg immunity. Regulation of IL-7/IL-7R may be a new therapeutic strategy for RPL.

Proresolving lipid mediators resolvin D1, resolvin D2, and maresin 1 are critical in modulating T cell responses.

Resolution of inflammation is a finely regulated process mediated by specialized proresolving lipid mediators (SPMs), including docosahexaenoic acid (DHA)-derived resolvins and maresins. The immunomodulatory role of SPMs in adaptive immune cells is of interest. We report that D-series resolvins (resolvin D1 and resolvin D2) and maresin 1 modulate adaptive immune responses in human peripheral blood lymphocytes. These lipid mediators reduce cytokine production by activated CD8(+) T cells and CD4(+) T helper 1 (TH1) and TH17 cells but do not modulate T cell inhibitory receptors or abrogate their capacity to proliferate. Moreover, these SPMs prevented naïve CD4(+) T cell differentiation into TH1 and TH17 by down-regulating their signature transcription factors, T-bet and Rorc, in a mechanism mediated by the GPR32 and ALX/FPR2 receptors; they concomitantly enhanced de novo generation and function of Foxp3(+) regulatory T (Treg) cells via the GPR32 receptor. These results were also supported in vivo in a mouse deficient for DHA synthesis (Elovl2(-/-)) that showed an increase in TH1/TH17 cells and a decrease in Treg cells compared to wild-type mice. Additionally, either DHA supplementation in Elovl2(-/-) mice or in vivo administration of resolvin D1 significantly reduced cytokine production upon specific stimulation of T cells. These findings demonstrate actions of specific SPMs on adaptive immunity and provide a new avenue for SPM-based approaches to modulate chronic inflammation.

The immunomodulatory, antitumor and antimetastatic responses of melanoma-bearing normal and alcoholic mice to sunitinib and ALT-803: a combinatorial treatment approach.

ALT-803, a novel IL-15/IL-15 receptor alpha complex, and the tyrosine kinase inhibitor, sunitinib, were examined for their single and combined effects on the growth of subcutaneous B16BL6 melanoma and on lymph node and lung metastasis. The study was conducted in immunocompetent C57BL/6 mice drinking water (Water mice) and in mice that chronically consumed alcohol (Alcohol mice), which are deficient in CD8(+) T cells. Sunitinib inhibited melanoma growth and was more effective in Alcohol mice. ALT-803 did not alter tumor growth or survival in Water or Alcohol mice. Combined ALT-803 and sunitinib inhibited melanoma growth and increased survival, and these effects were greater than sunitinib alone in Water mice. ALT-803 and alcohol independently suppressed lymph node and lung metastasis, whereas sunitinib alone or in combination with ALT-803 increased lymph node and lung metastasis in Water and Alcohol mice. Initially, ALT-803 increased IFN-γ-producing CD8(+)CD44(hi) memory T cells and CD8(+)CD44(hi)CD62L(lo) effector memory T cells and sunitinib decreased immunosuppressive MDSC and T regulatory cells (Treg). However, the impact of these treatments diminished with time. Subcutaneous tumors from Water mice showed increased numbers of CD8(+) T cells, CD8(+)CD44(hi) T cells, NK cells, and MDSC cells and decreased Treg cells after ALT-803 treatment.

Adjuvant effect of docetaxel on HPV16 L2E6E7 fusion protein vaccine in a mouse model

We previously demonstrated that the antineoplastic agent docetaxel enhanced the immune response to an influenza vaccine. This study evaluated the adjuvant effect of docetaxel (DOC) on the therapeutic efficacy of HPV16 L2E6E7 fusion protein (HPV-LFP) in mice inoculated with TC-1 cells. The results demonstrated that docetaxel significantly enhanced the therapeutic effect of HPV-LFP on TC-1 cell-induced tumors in mice. The injection of HPV-LFP in combination with docetaxel in TC-1 tumor-bearing mice significantly reduced tumor volume and weight, and a greater percent survival was detected than mice treated with HPV-LFP alone. The inhibition of tumors was associated with significantly increased serum antigen-specific IgG and isotypes, activated CTLs, increased IFN-γ-secreting T cells, and decreased Treg cells and IL-10-secreting cells in spleen. In addition, down-regulation of IL-10, VEGF and STAT3, up-regulation of IFN-γ and decreased Treg cells in the tumor microenvironment may also important contributing factors to the antitumor effect. It may be valuable to use a DOC-containing water to dilute HPV-LFP powder before injection in patients because of its excellent adjuvant effect on HPV-LFP and solubility in water.

IL-7/IL-7R signal pathway plays a major role in recurrent pregnancy losses by increasing inflammatory Th17 cells and decreasing Treg cells

IL-7/IL-7R signal pathway plays a major role in recurrent pregnancy losses by increasing inflammatory Th17 cells and decreasing Treg cells

Abnormalities of the bone marrow immune microenvironment in patients with immune thrombocytopenia.

Immune thrombocytopenia (ITP) is an acquired autoimmune disease. Although antiplatelet antibodies are considered as the primary immunologic defect in these patients, dysfunctional cellular immunity is also important in the pathophysiology of ITP. Peripheral T cell abnormalities have been demonstrated in patients with ITP; however, whether the impaired bone marrow (BM) microenvironment, specifically the BM immune microenvironment, is involved in the pathogenesis of ITP remains unknown. In this study, the compartments of the BM immune microenvironment and BM vascular microenvironment were analyzed in 26 untreated patients with ITP and 26 healthy donors (HD). Subsets of T cells in the BM immune microenvironment, including Th1, Th2, Tc1, Tc2, Th17, and Treg cells, were analyzed via flow cytometry. BM endothelial cells and perivascular cells, which are key elements of the vascular microenvironment, were analyzed via flow cytometry as well as hematoxylin-eosin (H&E) and immunohistochemical (IHC) staining in situ. Elements of the BM vascular microenvironment were found to be normal in patients with ITP, but abnormal characteristics of the BM immune microenvironment, including excessive polarization in Th1, Tc1, and Th17 cells and a remarkable decrease in Treg cells, were observed in patients with ITP. Therefore, a deregulated T cell response in the BM microenvironment might play an important role in the pathogenesis of ITP.

Th17/Treg cell expression in children with primary nephritic syndrome and the effects of ox-LDL on Th17/Treg cells.

To investigate the role of T-helper cells/Treg (Th17/Treg) and morbidity factors related to primary nephritic syndrome (PNS) in children, as well as the influence of ox-low density lipoprotein (ox-LDL) on Th17/Treg expression in children with PNS. To clarify the pathogenesis of PNS in children, 50 children with PNS treated in our hospital were enrolled in the study group. Additionally, 20 healthy children who came to our hospital for physical examination during the same period were enrolled in the control group. Th17 and Treg cells in children belonging to the two groups were detected by flow cytometry; the numbers of Th17/Treg cells in peripheral blood mononuclear cells at different concentrations of ox-LDL were detected simultaneously. Ox-LDL can affect the number of Th17/Treg cells in peripheral blood mononuclear cells, and both cell types decreased with increasing concentration of ox-LDL, with the numbers being significantly lower in the control group. However, the decrease in the number of Th17 cells was statistically insignificant (P > 0.05), whereas the decrease in Treg cells was more obvious and statistically significant (P < 0.05). The effect of ox-LDL the number of Treg cells was stronger than that on Th17 cells. We concluded that the imbalance of Th17/Treg cells influenced by high and low ox-LDL concentrations in children with PNS might be the immunological basis of the disease.

Emergence of Photosensitivity with Decreased Treg Cells in a Patient with Mycosis Fungoides Treated with Anti-CC Chemokine Receptor 4 Antibody Mogamulizumab

Mogamulizumab is a therapeutic monoclonal antibody that targets the CC chemokine receptor 4 (CCR4). The treatment exhibits strong cytotoxicity for adult T-cell leukaemia/lymphoma (ATLL) cells via antibody-dependent cellular cytotoxicity (ADCC), although it carries the risk of serious adverse reactions to the skin, such as StevensJohnson syndrome (1, 2). We report here a patient with mycosis fungoides (MF) at tumour stage treated with mogamulizumab, who developed a photosensitivity reaction during the course of treatment. At the onset of photosensitivity, a reduction in both circulating and skin infiltrating regulatory T cells (Tregs) was observed.

Circulating FoxP3+ Regulatory T and Interleukin17-Producing Th17 Cells Actively Influence HBV Clearance in De Novo Hepatitis B Virus Infected Patients after Orthotopic Liver Transplantation

ObjectiveTo longitudinally investigate the role of FoxP3+ Regulatory T cells (Treg) and interleukin17-producing T helper 17 cells (Th17) in De Novo Hepatitis B Virus infection after orthotopic Liver Transplantation (DNHB-OLT), and analyze the possible correlation between these cells and HBV clearance of the disease.MethodsWe enrolled 12 control cases after orthotopic Liver Transplantation (OLT) and 24 patients, including 12 diagnosed with DNHB-OLT and 12 diagnosed with Acute Hepatitis B Virus infection (AHB), into the study from the liver transplantation and research center at Beijing 302 Hospital. Flow cytometry was used to detect the frequencies of Treg and Th17, and ELISA was applied to detect the concentration of IL6, IL22, TGF-β and IL2 in peripheral blood. We also measured the gene expression level by real time-quantitative PCR and protein expression using immunohistochemistry and western-blot. Furthermore, we divided DNHB-OLT patients into the clearance and non-clearance groups and examined longitudinally Th17, Treg cells at different times.ResultsThe percentage of Treg cells, expression of FoxP3 mRNA and related anti-inflammatory cytokines such as IL2 and TGF-β1 in the DNHB-OLT group were significantly higher than that in the AHB and OLT groups. The percentage of Th17 cells, expression of RORγt mRNA and related pro-inflammatory cytokines such as IL17 and IL22 in the DNHB-OLT group were significantly lower than that in the AHB group, but the levels of these cytokines are very similar to the OLT group. The ratios of Treg to Th17 in the DNHB-OLT group were significantly higher than that in the OLT and AHB groups. Treg frequencies significantly correlated with HBV DNA, whereas IL17 frequencies didn’t significantly correlate with ALT. In DNHB-OLT patients, the clearance group was accompanied by a rapid increase in the Th17 cells during the first 4th week and afterwards continuously decrease to the control group, together with a continuously decrease in Treg cells from the onset time point, which lead to a significant reduction in the ratios of Treg to Th17. The non-clearance group was accompanied by an increase in the Treg cells during the first 4th week and afterwards sharply decrease, together with a relatively stable and unchanged Th17 cells, which lead to a significant change in the ratios. In addition, compared to clearance group, the ratios of Treg to Th17 in non-clearance group were significantly higher at the onset point, 4th and 12th week, but no difference at 24th week.ConclusionDNHB-OLT patients possessed a favorable Treg differentiation environment, accompanied by a sustained higher preferentially Treg frequencies and up-regulation of related anti-inflammatory cytokines. The immune imbalance of the ratios between Treg and Th17 existed in DNHB-OLT patients. The changes of the ratios during the DNHB-OLT events were associated with HBV clearance, which suppressed immune inflammation reaction as well as inhibited ability of specific HBV clearance and led to immune escape and chronicity.

Mo1733 Increased Ileal and Colonic Concentrations of Th1 and Th17 and Decreased Treg Cell Associated Cytokines in Crohn's Disease (CD) and Ulcerative Colitis (UC), but With Different Patterns

Mo1733 Increased Ileal and Colonic Concentrations of Th1 and Th17 and Decreased Treg Cell Associated Cytokines in Crohn's Disease (CD) and Ulcerative Colitis (UC), but With Different Patterns

Inactivation of Notch signaling reverses the Th17/Treg imbalance in cells from patients with immune thrombocytopenia

T helper 17 (Th17) cells and regulatory T (Treg) cells, along with Th1 and Th2 cells, may contribute to the development of immune thrombocytopenia (ITP). The imbalance of Th17/Treg toward Th17 cells has been shown to play a pivotal role in the peripheral immune response. Notch signaling has been implicated in peripheral T-cell activation and effector cell differentiation. However, the role of Th17/Treg in the pathogenesis of ITP and the effect of Notch signaling on Th17/Treg imbalances remain largely elusive in ITP. In vitro, we treated peripheral blood mononuclear cells (PBMCs) from ITP and healthy controls with γ-secretase inhibitor (DAPT). Th17 cells and Treg cells were measured by flow cytometry and IL-17, IL-21, and IL-10 secretion by enzyme immunoassay technique. The mRNA expression of Ntoch1, Hes1, Hey1, RORγt, and Foxp3 was investigated by RT-PCR. Cell proliferation and apoptosis were determined by the Cell Counting Kit-8 and apoptosis detection kit. We demonstrated that DAPT was effective in inhibiting mRNA expression of Notch signaling molecules. In untreated cultured PBMCs from ITP patients, we observed elevated Th17 cell and IL-21 levels and RORγt mRNA expression, decreased Treg cells and Foxp3 mRNA expression, and an increased ratio of Th17/Treg and RORγt/Foxp3. After inactivating Notch signal by DAPT, Th17 cells and Th17/Treg ratio were dose dependently decreased and accompanied by the reduction of IL-17 in culture supernatants and RORγt mRNA expression in ITP patients. However, no significant difference was found for Treg cells and Foxp3 mRNA expression, RORγt/Foxp3 ratio, and IL-21 and IL-10 levels after DAPT treatment in ITP patients. We also present evidence that the effect of DAPT inhibition on the Th17 cell response was associated with downregulation of RORγt and IL-17 transcription using human in vitro polarization. In conclusion, our findings highlight the importance of Notch signaling in Th17/Treg imbalances in ITP. Inactivation of Notch signaling might be a potential immunoregulatory strategy in ITP patients.

Correlation between Treg/Th17 and Traditonal Chinese Medicine syndrome differentiation classification in patients with immune thrombocytopenia

Objective To explore the role of Treg/Th17 cell ratio imbalance in the pathogenesis of idiopathic thrombocytopenic purpura(ITP)patients with different Traditional Chinese Medicine(TCM)syndrome differentiation classifications:bleeding due to blood-heat,Yin deficiency with fire hyperactivity and Qi deficiency-caused bleeding.Methods A total of 92 patients were divided into the bleeding due to blood-heat group(n=30),Yin deficiency with fire hyperactivity group(n=31)and Qi deficiency-caused bleeding group(n=31)according to the TCM syndrome differentiation classification.The peripheral blood samples were obtained from the patients and 30 volunteers served as healthy controls.The percentages of Treg cells and Th17 cells in the blood samples were analyzed by flow cytometry,and the mRNA levels of Foxp3 and ROR-γt were analyzed by RT-PCR.Results The percentages of Treg cells in the peripheral blood of 3different TCM syndrome ITP groups were significantly lower than those of control group(P0.05),that of the bleeding due to blood-heat group was significantly lower than that of Yin deficiency with fire hyperactivity group and Qi deficiency-caused bleeding group(P0.05),and that of Qi deficiency-caused bleeding group was signficantly lower than that of Yin deficiency with fire hyperactivity group(P0.05).The percentages of Th17 cells in peripheral blood of 3different TCM syndrome ITP groups were significantly higher than that of control group(P0.05),and that of Yin deficiency with fire hyperactivity group was signficanlty higher than that of Qi deficiency-caused bleeding group(P0.05).The ratios of Treg/Th17 of the 3different TCM syndrome ITP groups were significantly lower than that of control group(P0.05),that of the bleeding due to blood-heat group was significantly lower than that of Qi deficiency-caused bleeding group and Yin deficiency with fire hyperactivity group(P0.05),and that of Qi deficiency-caused bleeding group was significantly lower than that of Yin deficiency with fire hyperactivity group(P0.05).The Foxp3 mRNA levels of 3different TCM syndrome ITP groups were significantly lower than that of control group(P0.05),and there were significant differences between each two groups by the pairwise comparison(P0.05).While ROR-γmRNA levels of the 3different TCM syndrome ITP groups were significantly higher than that of the control group(P0.01).Conclusion The decreased Treg cells in patients with ITP contributes to the development and progression of ITP.The imbalance of Treg/Th17 ratio may play a critical role in the pathogenesis of ITP.The distribution of the percentages of Treg cells,the ratio of Treg/Th17 and the mRNA level of Foxp3 in a increasing order is:bleeding due to blood-heat group Qi deficiency-caused bleeding group Yin deficiency with fire hyperactivity group.

Abstract 005: Involvement of Decreases in Regulatory T Cells and Splenic Sympathetic Nerve in the Development of Hypertension in Genetically Hypertensive Rats

Background: Autonomic nervous system can modulate immune system thereby influences the pathogenesis of hypertension. Among the immune cells, activated T cells have been implicated in the genesis of hypertension. In contrast, regulatory T cells (Treg cells), which maintain immune homeostasis, are reported to prevent AngII-induced hypertension. However, there are few studies of Treg cells in spontaneously hypertensive models. In particular, the spleen is an important organ to regulate immune system and splenic nerve can modulate immune responses in the spleen. Here, we investigated the role of Treg cells in hypertension and the involvement of splenic sympathetic nerve in genetically spontaneously hypertensive rats. Methods and Results: We evaluated Treg cells in stroke-prone spontaneously hypertensive rats (SHRSP) at 3 week (early pre-hypertensive stage), 5 week (late pre-hypertensive stage), or 15 week (established hypertensive stage) old, and in age-matched normotensive Wistar-Kyoto rats (WKY). CD4+CD25+Foxp3+ cells (Treg cells) in the spleen and peripheral blood did not differ between WKY and early pre-hypertensive SHRSP, whereas significantly decreased both in late pre-hypertensive (%CD25+Foxp3+ gated on CD4+ cells in the spleen; 7.7±0.5 vs. 5.5±0.3, n=5 for each, p=0.0080, blood; 6.7±0.7 vs. 3.4±0.8, n=4 for each, p=0.0060) and established hypertensive SHRSP (spleen; 9.9±0.7 vs. 5.4±0.4, n=4 for each, p=0.0011, blood; 8.8±0.7 vs. 4.5±0.1, n=4 for each, p=0.0009). We performed splenic denervation (or sham operation) in SHRSP at prehypertensive stage. After 4 weeks of splenic denervation, splenic Treg cells were increased compared with sham-operated SHRSP (4.2±0.1 vs. 6.1±0.3, n=7 for each, p&lt;0.0001). Furthermore, splenic denervation in SHRSP at prehypertensive stage delayed blood pressure elevation (n=7 for each, p&lt;0.001, vs. sham-operated SHRSP), whereas splenectomy did not affect blood pressure. Conclusion: Our results indicate that splenic denervation attenuates the decrease in splenic Treg cells and delays the development of hypertension, suggesting that splenic sympathetic nerve and decrease in Treg cells play a key role in the onset of hypertension in SHRSP.

Effect of Th17 and Treg axis disorder on outcomes of pulmonary arterial hypertension in connective tissue diseases.

This prospective cohort study is to verify the hypothesis that the balance of Th17 and Treg cells frequencies in the peripheral circulation is disturbed in patients with varying degrees of connective tissue diseases-associated pulmonary arterial hypertension (CTD-aPAH) and to prove the influence of Th17/Treg imbalance on prognosis. We detected the frequencies and absolute counts of Th17 and Treg cells and related serum cytokines secretion and expressions of key transcription factors in 117 patients with connective tissue diseases (CTD), 53 patients with CTD-aPAH, and 48 healthy volunteers. Moreover, the median value according to levels of Th17/Treg ratios in patients with CTD-aPAH was chosen as basis of group division for survival analysis. CTD-aPAH patients revealed significant increase in peripheral Th17 cells, Th17-related cytokines, and ROR γt mRNA levels. They also presented a significant decrease in Treg cells, Treg-related cytokines, and Foxp3 mRNA levels as compared with CTD patients and healthy controls. More importantly, the Th17/Treg ratio was significantly related to the severity and prognosis of CTD-aPAH. This study indicated that the Th17/Treg axis disorder plays a critical role in CTD-aPAH. Furthermore, the dynamic balance between Th17 and Treg cells was likely to influence prognosis of patients with CTD-aPAH.

Imbalance between IL-17A-producing cells and regulatory T cells during ischemic stroke.

Immune responses and inflammation are key elements in the pathogenesis of ischemic stroke (IS). Although the involvement of IL-17A in IS has been demonstrated using animal models, the involvement of IL-17A and IL-17-secreting T cell subsets in IS patients has not been verified, and whether the balance of Treg/IL-17-secreting T cells is altered in IS patients remains unknown. In the present study, we demonstrated that the proportion of peripheral Tregs and the levels of IL-10 and TGF-β were reduced in patients with IS compared with controls using flow cytometry (FCM), real-time PCR, and ELISA assays. However, the proportions of Th17 and γ δ T cells, the primary IL-17A-secreting cells, increased dramatically, and these effects were accompanied by increases in the levels of IL-17A, IL-23, IL-6, and IL-1β in IS patients. These studies suggest that the increase in IL-17A-producing cells and decrease in Treg cells might contribute to the pathogenesis of IS. Manipulating the balance between Tregs and IL-17A-producing cells might be helpful for the treatment of IS.

Imbalance between Th17 and Regulatory T-Cells in Sarcoidosis

Sarcoidosis is a systemic granulomatous disease, which is thought to result from an aberrant immune response. CD4+ T lymphocytes play an important role in the development of granulomas. Previously, the immunopathogenesis of sarcoidosis was focused on Th1/Th2 disturbances. The aim of this study was to evaluate the balance between newer CD4+ T lymphocytes, i.e., Treg and Th17 cells. In our studies, a decrease in Treg cells and an increase in Th17 cells were observed in the peripheral blood and BALF of sarcoidosis patients. A significant increase in the Th17/Treg cell ratio was observed in sarcoidosis patients. After treatment with prednisone, the expression of Foxp3 mRNA was elevated in the peripheral blood, and expression of (ROR)γt mRNA showed a downward trend. These findings suggest that sarcoidosis is associated with an imbalance between Th17 and Treg cells in peripheral blood and BALF. Therefore, targeting the cytokines that affect the Th17/Treg ratio could provide a new promising therapy for pulmonary sarcoidosis.

Effect of NADPH oxidase 2 deficiency on allergic lung inflammation and differentiation of helper T cells (P6045)

Abstract Nox2 has been originally identified in phagocytes, which kills engulfed pathogens by producing reactive oxygen species (ROS). It has been also revealed that activated T cells produce ROS that is an important second messenger for the functions of effector T cells. Recent studies have shown that Nox2 dificient CD4 T cells contain increased IL-17 producing capability and Nox2 knock-out mice have a tendency an enhanced susceptibility to spontaneous arthritis with age. To investigate whether Nox2 or ROS deficiency in T cells affect differentiation and function of CD4 T cells in T cell intrinsic manner. Specifically we adopted allergic asthma model to clarify the function of Th2 cells without Nox2 or ROS. Asthma phenotypes were analyzed in fungal protease mixed with chicken egg ovalbumin (OVA) allergen (APO) induced experimental asthma. To understand mechanisms of exaggerated effector T cell functions, we investigated the degree of T cell activation and differentiation of Treg cells with Nox2 deficient and wild type CD4 T cells. All experimental asthma phenotypes including airway hyper-responsiveness, lung inflammation along with eosinophilia and mucus production were increased in Nox2 deficient mice. Nox2 deficient T cells also showed enhanced hyper-activation, reduced AICD and decreased Treg cell differentiation. Our results indicate that Nox2/ROS deficiency showed exaggerated experimental asthma, which was caused by enhanced function of Th2 cells.