Soluble CD83 inhibits acute rejection by up regulating TGF-β and IDO secretion in rat liver transplantation

BackgroundAllogeneic transplantation immune tolerance is currently a hot research issue and soluble CD83(sCD83) is a novel immunomodulator with great potential in inducing transplantation tolerance.ObjectiveTo investigate the mechanism of the immune tolerance effect of sCD83 on rat liver transplantation.MethodA rat liver transplantation model was established to study the effects of sCD83 on the expression levels of IL-2, IL-10, and TGF-β in peripheral blood and the mRNA expressions of foxp3, TGF-β, and Indoleamine 2,3-dioxygenase (IDO) in liver. The expression changes of costimulatory molecules CD80, CD86, and MHC-II on the surface of DC cells and the expressions of IDO ⁺ DC cell, TGF-β ⁺ CD4 ⁺ T cell, and CD4 ⁺ CD25 ⁺ Foxp3 ⁺ T cell were analyzed and compared.ResultssCD83 alleviated the rejection activity index (RAI) of rat liver transplantation in the early stage, increased the expressions of TGF-β, IL-10 in peripheral blood and the mRNAs of IDO, TGF-β and foxp3 in the transplanted liver, and down-regulated the expressions of MHC-II, CD86, and CD80 in DC cells, resulting in significant increased numbers of tolerogenic TGF-β ⁺ CD4 ⁺ T cells, Treg cells, and IDO ⁺ DC cells with low expression.ConclusionsCD83 inhibited acute rejection after liver transplantation in an allogeneic rat, and the mechanism was associated with the effect that sCD83 increased the expression of TGF-β, activated IDO immunosuppressive pathway, and increased tolerogenic DC cells and Treg cells.     

miR-34b-5p promotes renal cell inflammation and apoptosis by inhibiting aquaporin-2 in sepsis-induced acute kidney injury

ObjectiveThis study was designed to uncover the mechanism of miR-34b-5p-mediated aquaporin-2 (AQP2) in sepsis-induced injury using human renal tubular epithelial cells (HK-2).MethodsSerum levels of miR-34b-5p, TNF-α, IL-1β, IL-6, serum creatinine (SCr), and blood urea nitrogen (BUN) in septic patients with acute kidney injury (AKI) and healthy controls were detected. Lipopolysaccharide (LPS) was used to induce sepsis in HK-2 cells. LPS-induced HK-2 cells were transfected with miR-34b-5p inhibitor, miR-34b-5p mimic, pcDNA3.1-AQP2, si-AQP2, miR-34b-5p inhibitor + si-NC, or miR-34b-5p inhibitor + si-AQP2. The expressions of miR-34b-5p, AQP2, Bax, Bcl-2, cleaved caspase-3, TNF-α, IL-1β, and IL-6 in HK-2 cells were detected. TUNEL staining revealed the apoptosis of HK-2 cells. Dual-luciferase reporter assay verified the binding between miR-34b-5p and AQP2.ResultsThe expression of miR-34b-5p and the inflammatory responses were augmented in septic AKI patients. miR-34b-5p was up-regulated and AQP2 was down-regulated in LPS-induced HK-2 cells. miR-34b-5p inhibition or AQP2 overexpression ameliorated apoptosis and inflammation in LPS-induced HK-2 cells. In contrast, overexpressing miR-34b-5p deteriorated LPS-induced injury in HK-2 cells. AQP2 was a downstream target of miR-34b-5p. AQP2 silencing abolished the suppressive effects of miR-34b-5p inhibition on LPS-induced apoptosis and inflammatory response in HK-2 cells.ConclusionmiR-34b-5p inhibits AQP2 to promote LPS-induced injury in HK-2 cells.     

Influence of immune activation on the risk of allograft rejection in human immunodeficiency virus-infected kidney transplant recipients

BackgroundHIV infection is associated with high rates of acute rejection following kidney transplantation. The underlying mechanisms for such predisposition are incompletely understood. Pathological immune activation is a hallmark of chronic HIV infection that persists despite effective antiretroviral therapy. We hypothesized that the baseline levels of T cell activation in HIV⁺ candidates would correlate with their risk of acute rejection following kidney transplantation.MethodsSingle-center retrospective cohort analysis of HIV⁺ adult kidney transplants performed between October 2006 and September 2013. The frequency of CD3⁺ HLA-DR⁺ cells measured by flow cytometry served as a surrogate marker of immune activation. Patients were categorized into tertiles of activation, and the rates of biopsy-proven acute rejection were compared across groups.Results(1) Compared to matched HIV⁻ controls, the baseline number of CD3⁺ HLA-DR⁺ cells was higher in HIV⁺ kidney transplant candidates. (2) Abnormally high levels of activation did not decrease with transplant-associated immunosuppression. (3) Patients categorized within the lower and middle CD3⁺ HLA-DR⁺ tertiles had higher probability of rejection during the first 3 years post-transplant compared to those in the higher activation tertile (36.9% vs. 0%; log-rank P = 0.04).ConclusionsPathological immune activation in HIV⁺ transplant candidates does not explain their increased susceptibility to allograft rejection. Paradoxically, those with the highest levels of immune activation seem to be less prone to rejection.     

Rejection of Cardiac Xenografts Transplanted from α1,3‐Galactosyltransferase Gene‐Knockout (GalT‐KO) Pigs to Baboons

The use of α1,3‐galactosyltransferase gene‐knockout (GalT‐KO) swine donors in discordant xenotransplantation has extended the survival of cardiac xenografts in baboons following transplantation. Eight baboons received heterotopic cardiac xenografts from GalT‐KO swine and were treated with a chronic immunosuppressive regimen. The pathologic features of acute humoral xenograft rejection (AHXR), acute cellular xenograft rejection (ACXR) and chronic rejection were assessed in the grafts. No hyperacute rejection developed and one graft survived up to 6 months after transplantation. However, all GalT‐KO heart grafts underwent graft failure with AHXR, ACXR and/or chronic rejection. AHXR was characterized by interstitial hemorrhage and multiple thrombi in vessels of various sizes. ACXR was characterized by TUNEL⁺ graft cell injury with the infiltration of T cells (including CD3 and TIA‐1⁺ cytotoxic T cells), CD4⁺ cells, CD8⁺ cells, macrophages and a small number of B and NK cells. Chronic xenograft vasculopathy, a manifestation of chronic rejection, was characterized by arterial intimal thickening with TUNEL⁺ dead cells, antibody and complement deposition, and/or cytotoxic T‐cell infiltration. In conclusion, despite the absence of the Gal epitope, acute and chronic antibody and cell‐mediated rejection developed in grafts, maintained by chronic immunosupression, presumably due to de novo responses to non‐Gal antigens.     

Reduced CD4+ CD25++ CD45RA− Foxp3hi activated regulatory T cells and its association with acute rejection in patients with kidney transplantation

BackgroundIt was found that regulatory T cells (Tregs) importantly affect the maintenance of the kidney graft. However, Tregs are a heterogeneous population with less to more suppressive activity. The aim of this study was to determine the effects of different subsets of Tregs, as well as their ratio to effector T cells (Teff), on kidney transplantation outcomes.MethodsA total of 58 participants were enrolled in this study and divided into four groups: (i) first kidney transplant recipients (stable 1); (ii) second kidney transplant recipients (stable 2); (iii) transplant recipients with acute rejection (AR); and (iv) healthy control subjects. By using flow cytometer, the frequencies of CD4⁺ CD25⁺⁺ CD45RA⁻ Foxp3^hi activated Tregs (aTregs), CD4⁺ CD25⁺ CD45RA⁺ Foxp3^lo resting Tregs (rTregs), CD4⁺ CD25⁺ CD45RA⁻ Foxp3^lo non-suppressive T cells, CD4⁺ CD25⁺ Foxp3⁻ cells Teff, and total Tregs were analyzed in all subjects.ResultsThe frequency of aTregs (as well as the ratio of aTregs/Tregs) was significantly lower in the AR patients than the other three groups. In contrast to AR patients, stables 1 and 2 had a higher aTreg/Treg ratio than those in the control group. Although patients with AR had a significantly lower total Tregs than the other three groups, the balance of total Tregs and Teff was similar between patients with and without AR.ConclusionPatients with AR had poorer immunoregulatory properties than those with normal graft functioning, as well as those in the control group. These reduced immunoregulatory properties in patients with AR could lead to graft rejection.     

Memory T cell–mediated rejection is mitigated by FcγRIIB expression on CD8+ T cells

Donor‐reactive memory T cells generated via heterologous immunity represent a potent barrier to long‐term graft survival following transplantation because of their increased precursor frequency, rapid effector function, altered trafficking patterns, and reduced reliance on costimulation signals for activation. Thus, the identification of pathways that control memory T cell survival and secondary recall potential may provide new opportunities for therapeutic intervention. Here, we discovered that donor‐specific effector/memory CD8⁺ T cell populations generated via exposure to acute vs latent vs chronic infections contain differential frequencies of CD8⁺ T cells expressing the inhibitory Fc receptor FcγRIIB. Results indicated that frequencies of FcγRIIB‐expressing CD8⁺ donor‐reactive memory T cells inversely correlated with allograft rejection. Furthermore, adoptive T cell transfer of Fcgr2b^?/? CD8⁺ T cells resulted in an accumulation of donor‐specific CD8⁺ memory T cells and enhanced recall responses, indicating that FcγRIIB functions intrinsically to limit T cell CD8⁺ survival in vivo. Lastly, we show that deletion of FcγRIIB on donor‐specific CD8⁺ memory T cells precipitated costimulation blockade‐resistant rejection. These data therefore identify a novel cell‐intrinsic inhibitory pathway that functions to limit the risk of memory T cell–mediated rejection following transplantation and suggest that therapeutic manipulation of this pathway could improve outcomes in sensitized patients.     

Renal Contrast‐Enhanced Sonography Findings in a Model of Acute Cellular Allograft Rejection

Noninvasive methods to diagnose and differentiate acute cellular rejection from acute tubular necrosis or acute calcineurin inhibitor toxicity are still missing. Because T lymphocytes play a decisive role in early states of rejection, we investigated the suitability and feasibility of antibody‐mediated contrast‐enhanced ultrasound by using microbubbles targeted to CD3⁺, CD4⁺, or CD8⁺ T cells in different models of renal disease. In an established rat renal transplantation model, CD3‐mediated ultrasound allows the detection of acute rejection as early as on postoperative day 2. Ultrasound signal intensities increased with the severity of inflammation. Further, an early response to therapy could be monitored by using contrast‐enhanced sonography. Notably, acute tubular necrosis occurring after ischemia–reperfusion injury as well as acute calcineurin inhibitor toxicity could easily be differentiated. Finally, the quantified ultrasound signal correlated significantly with the number of infiltrating T cells obtained by histology and with CD3 mRNA levels, as well as with chemokine CXCL9, CXCL11, and CCL19 mRNA but not with KIM‐1 mRNA expression, thereby representing the severity of graft inflammation but not the degree of kidney injury. In summary, we demonstrate that antibody‐mediated contrast‐enhanced ultrasound targeting T lymphocytes could be a promising tool for an easy and reproducible assessment of acute rejection after renal transplantation.     

The relationship between adenosine triphosphate within CD4(+) T lymphocytes and acute rejection after liver transplantation

Dong J‐Y, Yin H, Li R‐D, Ding G‐S, Fu Z‐R, Wu Y‐M, Wang Z‐X. The relationship between adenosine triphosphate within CD4⁺ T lymphocytes and acute rejection after liver transplantation.
Clin Transplant 2011: 25: E292–E296. © 2011 John Wiley & Sons A/S. Abstract: Background: There have been increasing interests in the relationship between CD4⁺ T lymphocytes and acute rejection (AR) in transplantation. In this study, we explore the role of CD4⁺ T lymphocytes after liver transplantation. Methods: From February to October 2009, 87 patients underwent liver transplantation. They were divided into the AR group and non‐acute rejection (NAR) group, with 56 healthy individuals in the control group. Blood specimens were collected preoperatively and at one, two, and four wk postoperatively for all groups and also on the day when AR occurred and one wk after intravenous glucocorticoid therapy for the AR group. Adenosine triphosphate (ATP) levels were measured using the ImmuKnow? test kits for immune cell functions. Results: After transplantation, the ATP levels within CD4⁺ T lymphocytes were significantly elevated in the two groups when compared with the preoperative levels. It peaked in the AR group and was significantly higher than that of the NAR group (p < 0.05). By ROC curve analysis, the obvious elevation of the ATP value one wk after transplantation had better sensitivity and specificity in diagnosing the AR. The ATP sensitivity rate for early AR was 85.7% and specificity rate 80.9% when the cutoff value was 407 μg/L. The ATP value collected on the day of AR occurrence has apparently positive correlation with the rejection acting index (RAI) (p < 0.01). After the intravenous glucocorticoid therapy, all the ARs were reversed and the ATP value declined significantly compared with the control group and that on the day when AR occurred (p < 0.01). Conclusions: During the early postoperative period (especially at first week after liver transplantation), the elevation of ATP levels within CD4⁺ T lymphocytes has good sensitivity and specificity in diagnosing the AR at early stage. And the degree of AR has positive relationship with ATP value. After the intravenous glucocorticoid therapy, the obvious declination of AR might be used in evaluating the effectiveness of anti‐rejection treatment.     

KCNQ1OT1 mediates keratinocyte migration to promote skin wound healing through the miR-200b-3p/SERP1 axis

BackgroundThe basic functions of keratinocyte are crucial steps during skin wound healing. KCNQ1OT1 long noncoding RNA was found to accelerate the migration and proliferation of keratinocyte in psoriasis. Here, we elucidated the action and mechanism of KCNQ1OT1 in skin wound healing.MethodsExpression levels of genes and proteins were evaluated by quantitative real-time PCR (qRT-PCR) and western blotting. Cell migration was assessed by using scratch and transwell assays. The interaction between miR-200b-3p and KCNQ1OT1 or SERP1 (Stress Associated Endoplasmic Reticulum Protein 1) was confirmed by bioinformatics analysis, dual-luciferase reporter assay, RNA immunoprecipitation (RIP) assay and pull-down assay.ResultsKCNQ1OT1 had increased significantly in wound edge 1 day and 7 day after injury. Functionally, overexpression of KCNQ1OT1 promoted keratinocyte migration. Mechanistically, KCNQ1OT1/miR-200b-3p/SERP1 constituted a competing endogenous RNA (ceRNA) network in keratinocytes. A series of rescue experiments showed that miR-200b-3p up-regulation in keratinocytes attenuated the pro-migration action of KCNQ1OT1 in cells. Moreover, knockdown of miR-200b-3p could promote keratinocyte migration, which was abolished by SERP1 silencing. KCNQ1OT1 competitively sponged for miR-200b-3p to elevate the expression of its target SERP1.ConclusionKCNQ1OT1 could promote keratinocyte migration by miR-200b-3p/SERP1 axis, suggesting that KCNQ1OT1 might play a crucial role in skin wound healing.     

Role for exosomes with self-antigens and immune regulatory molecules in allo- and auto-immunity leading to chronic immune injury following murine kidney transplantation

ObjectiveAntibodies against donor human leukocyte antigen are a risk factor for chronic immune injury (CII) following renal transplantation; however, it is often not detectable. The main goal of this study is to gain new insights into the kinetics of exosome release and content in sensitized vs non-sensitized recipients. Towards this, we investigated the role for circulating exosomes with allo and self-antigens as well as immunoregulatory molecules in the development of CII and acute rejection.MethodsUsing murine kidney allograft rejection models, we investigated the role of exosomes on immune responses leading to allo- and auto-immunity to self-antigens resulting in rejection. Exosomes were analyzed for kidney self-antigens (Collagen-IV, fibronectin, angiotensin II receptor type 1), and immune-regulatory molecules (PD-L1, CD73) using western blot. Antibodies to donor MHC in serum samples were detected by immunofluorescence, self-antigens by enzyme-linked immunosorbent assay and kidney tissue infiltrating cells were determined by immunohistochemistry.ResultsBALB/c; H2^d to C57BL/6; H2^b renal transplantation (BALB/c), resulted in tubulitis and cellular infiltration by day 14, suggestive of acute inflammation, that was self-limiting with functioning graft. This contributed to CII on post-transplant day >100, which was preceded by induction of exosomes with donor and self-antigens leading to antibodies and immune-regulatory molecules. The absence of acute rejection in this allogenic transplant model is likely due to the induction of splenic and, graft-infiltrating CD4 + FoxP3+ T regulatory cells. In contrast, prior sensitization by skin graft followed by kidney transplantation induced antibodies to MHC and self-antigens leading to acute rejection.ConclusionWe demonstrate a pivotal role for induction of exosomes with immune-regulatory molecules, allo- and auto-immunity to self-antigens leading to chronic immune injury following murine kidney transplantation.     

Vitamin D3 combined with antibody agents suppresses alloreactive memory T-cell responses to induce heart allograft long-term survival

BackgroundThe pre-stored memory T cells in organ transplant patient carry a high risk of allograft rejection. The current study aimed to determine whether the allogenic response of adoptively transferred memory T cells in mice was suppressed by vitamin D3 monotherapy alone or in combination with monoclonal antibody treatment.MethodsPrior to vascularized heterotopic heart transplantation, naïve C57BL/6 mice were primed with memory T cells. Recipient mice were administered vitamin D3 alone or in combination with monoclonal antibodies (anti-CD40L/ anti-LFA-1). Memory T cells and CD4⁺ forkhead box P3⁺ T cells in recipient spleens were measured using flow cytometry. Additionally, the expression of cytokines was measured by ELISA and quantitative PCR. Inflammatory factors in the grafts were identified by hematoxylin and eosin staining.ResultsVitamin D3 in conjunction with anti-CD40L/ anti-LFA-1 antibodies were administered according to the median survival time from 6.5 to 80 days. The results revealed that grafts were protected through the prevention of inflammatory cell infiltration. Combined treatment decreased the mRNA levels of IL-2, IFN-γ and IL-10 and increased the mRNA levels of IL-4, Foxp3 and TGF-β in the allograft. Rejection was suppressed by a reduction of CD4⁺CD44^high CD62L⁺ and CD8⁺ CD44^high CD62L⁺ memory T cells, the induction of regulatory T cells in the recipient spleen and a reduction of serum IL-2, IFN-γ and IL-10 levels.ConclusionVitamin D3 efficiently protected allografts from memory T-cell allo-responses when combined with anti-CD40L/anti-LFA-1 antibodies therapy.     

The changes in the expression levels of β-catenin gene in pre- and post- Kidney Transplants

PurposeWnt signaling is an important pathway in kidney development and disease. We aimed to establish the levels of β-catenin expression in CD4⁺ T cells before and after renal transplantation and to associate it with the form of transplant type, rejection, and graft dysfunction.MethodsCD4⁺ T cells were isolated from patients before and after kidney transplantation and their purity was confirmed by flow cytometer. RNA isolation and cDNA synthesis were carried out from these cells. The expression changes of the β-catenin were investigated by real-time polymerase chain reaction (RT-PCR). Changes in the β-catenin protein levels were determined by the western blot analysis.ResultsThe increasing expression levels of β-catenin were detected in 60.8% of the patients 6 months after transplantation when compared to patients before transplantation result. 12 of these 14 patients had no graft rejection. It was observed that 11 of 14 patients with increased β-catenin expression had not graft dysfunction after the transplantation.ConclusionAccording to our results, the increased levels of β-catenin expression after transplantation may have a protective function for kidney survival. To understand this protective mechanism, further analysis of this signaling pathway is necessary.     

Interleukin‐17 positive cells accumulate in renal allografts during acute rejection and are independent predictors of worse graft outcome

Interleukin‐17 (IL‐17) plays an important role in the regulation of cellular and humoral immune responses. Recent studies suggest a role for IL‐17 in transplantation. Our study investigated whether quantifying IL‐17⁺ cells in renal transplant biopsies during acute rejection could have additional prognostic value for better stratifying patients at risk for nonresponsiveness to anti‐rejection therapy and future graft dysfunction. Forty‐nine renal biopsies with acute rejection were double immunostained and quantitatively analyzed for IL‐17 and CD3 (IL‐17⁺ T‐lymphocytes), tryptase (IL‐17⁺ mast cells) or CD15 (IL‐17⁺ neutrophils). Total IL‐17⁺ cell count correlated with total percentage of inflamed biopsy and estimated GFR during rejection. Most IL‐17⁺ cells were mast cells and neutrophils. We could hardly find any IL‐17⁺ T‐lymphocytes. IL‐17⁺ mast cells correlated with interstitial fibrosis/tubular atrophy (IF/TA). None of the IL‐17⁺ cell counts had an additional prognostic value for response to anti‐rejection treatment. Multivariate analysis correcting for C4d positivity and time from transplantation to biopsy showed that total IL‐17⁺ cell count independently predicts graft dysfunction at the last follow‐up, which was validated in an independent cohort of 48 renal biopsies with acute rejection. We conclude that intragraft IL‐17⁺ cell count during acute allograft rejection could have an additional value for predicting late graft dysfunction.     

Prolongation of corneal xenotransplant survival by T-cell vaccination-induced T-regulatory cells

Abstract: Background: Corneal xenotransplantation is an alternative approach for overcoming shortage of allograft in clinics. However, the mechanism of acute corneal xenograft rejection and the method of prolonging xenograft survival have not been well defined. Methods: In this study, we used an orthotopic corneal guinea pig‐to‐rat xenotransplantation model to study the effects of CD4 and CD8 T cells, T‐cell vaccination (TCV) and TCV‐induced T‐regulatory (Treg) cells on xenograft survival. Results: The acute rejection of xenografts occurred in untreated rats as early as 6 days post‐transplantation, while TCV significantly prolonged xenograft survival from 6–12 to 21–27 days. The lymph node cells of the TCV‐treated rats exhibited significant response to the anti‐guinea pig T cells and the responding cell populations contained two Treg cell subsets, CD4⁺ CD25^? and CD8⁺ CD28^? T cells, both of which lack expression of Foxp3. Adoptive transfer of CD8⁺ CD28^? T cells resulted in profound inhibition of corneal xenograft rejection, while transfer of CD4⁺ CD25^? T cells alone exhibited no significant inhibition. However, transfer of the CD4⁺ CD25^? and CD8⁺ CD28^? T‐cell mixture remarkably enhanced the in vivo protective activity against xenograft rejection. Conclusions: These data suggest that TCV induces the activation of specific Treg cell subsets, CD4⁺ CD25^? and CD8⁺ CD28^? T cells, which may act cooperatively to mediate prolongation of corneal xenograft survival. Therefore, TCV can be used as immunotherapy for suppression of acute xenograft rejection.     

Bacterial products in donor airways prevent the induction of lung transplant tolerance

Although postoperative bacterial infections can trigger rejection of pulmonary allografts, the impact of bacterial colonization of donor grafts on alloimmune responses to transplanted lungs remains unknown. Here, we tested the hypothesis that bacterial products present within donor grafts at the time of implantation promote lung allograft rejection. Administration of the toll-like receptor 2 (TLR2) agonist Pam₃Cys₄ to Balb/c wild-type grafts triggered acute cellular rejection after transplantation into B6 wild-type recipients that received perioperative costimulatory blockade. Pam₃Cys₄-triggered rejection was associated with an expansion of CD8⁺ T lymphocytes and CD11c⁺CD11b^hiMHC (major histocompatibility complex) class II⁺ antigen-presenting cells within the transplanted lungs. Rejection was prevented when lungs were transplanted into TLR2-deficient recipients but not when MyD88-deficient donors were used. Adoptive transfer of B6 wild-type monocytes, but not T cells, following transplantation into B6 TLR2-deficient recipients restored the ability of Pam₃Cys₄ to trigger acute cellular rejection. Thus, we have demonstrated that activation of TLR2 by a bacterial lipopeptide within the donor airways prevents the induction of lung allograft tolerance through a process mediated by recipient-derived monocytes. Our work suggests that donor lungs harboring bacteria may precipitate an inflammatory response that can facilitate allograft rejection.     

Transplant long-surviving induced by CD40-CD40 ligand costimulation blockade is dependent on IFN-γ through its effect on CD4(+)CD25(+) regulatory T cells

BackgroundIFN-γ was documented to be commonly associated with acute rejection. In the present study, we investigated the role of IFN-γ in the transplant long-surviving induced by blocking CD40–CD40 ligand (CD40–CD40L) costimulation and its mechanisms.MethodsIFN-γ expression in cardiac allografts and spleens from syngeneic and allogeneic recipients with or without anti-CD40L monoclonal antibody (MR-1) treatment was examined by real-time RT-PCR. The grafts survival time in Wild type (IFN-γ^+/+) and IFN-γ deficient (IFN-γ^?/?) recipients was investigated. Mixed lymphocyte reaction (MLR) of CD4⁺ T cells and cytotoxic T lymphocyte (CTL) assay of CD8⁺ T cells were also studied. FoxP3 expression in allografts and spleens from IFN-γ^+/+ or IFN-γ^?/? recipients with MR-1 treatment was examined. Furthermore, FoxP3, IL-10 and CTLA-4 expressions and the suppressive capability of CD4⁺CD25⁺ regulatory T cells were examined.ResultsRejected allografts showed significantly higher IFN-γ expression than long-surviving allografts. Allograft survival was not prolonged in nonimmunosuppressed IFN-γ^?/? mice. Administration of MR-1 induced long-term survival in 90.1% of IFN-γ^+/+ recipients (98 ± 6.6 days) but failed to do so in IFN-γ^?/? group (16.2 ± 4.0 days). IFN-γ^?/? recipients facilitated the proliferation and CTL generation of T cells. The allografts and spleens from IFN-γ^+/+ recipients contained higher FoxP3 expression than IFN-γ^?/? recipients. Moreover, CD4⁺CD25⁺ T cells from IFN-γ^+/+ recipients displayed a higher FoxP3 and IL-10 expression and suppressive capability.ConclusionIFN-γ plays an important role in the long-surviving induced by blocking CD40–CD40L through inhibiting the function of activated T cells and increasing suppressive capability of CD4⁺CD25⁺ regulatory T cells.     

T helper 1, 2 and 17 cell subsets in renal transplant patients with delayed graft function

Ischemia‐reperfusion injury (IRI) in kidney transplantation is the major cause of delayed graft function (DGF), an event associated with an increased risk of acute rejection. The aim of this study was to evaluate T helper (Th) cell phenotype in renal transplants with DGF. T‐bet (Th1), GATA‐3 (Th2) and IL‐17 (Th17) protein expression was investigated in pretransplant biopsies, DGF and acute tubular damage (ATD) caused by calcineurin‐inhibitor toxicity. Intracytofluorimetric analysis of IFN‐γ, IL‐4 and IL‐17 was performed to analyze Th1, Th2 and Th17 responses in peripheral blood mononuclear cells of recipients with early graft function (EGF) and DGF, before (T0) and 24 h after transplantation (T24). In pretransplant biopsies, T‐bet⁺, GATA‐3⁺ and IL‐17⁺ cells were barely detectable. In DGF, T‐bet⁺ and IL‐17⁺ cells were significantly increased compared with pretransplant and ATD. More than 90% of T‐bet⁺ and less then 5% of IL‐17⁺ cells were CD4⁺. GATA‐3⁺ cells were increased to a lower extent. T‐bet⁺/GATA‐3⁺ cell ratio was significantly higher in DGF. Peripheral CD4⁺ IFN‐γ/IL‐4 ratio was significantly decreased in DGF, while CD4⁺/IL‐17⁺ cells did not differ between T0 and T24 in DGF. Our data suggest that DGF is characterized by a prevalent Th1 phenotype within the graft. This event might represent a link between DGF and acute rejection.