Objective To review the role of polymorphism of major histocompatibility complex class I-related chain A (MICA) gene and antibodies against MICA antigens in transplant immunology.
Data sources The data used in this review were mainly from our own results and from the relevant English language literatures published from 1999 to 2010. Some data presented in this review are in press.
Study selection Articles regarding MICA gene discovery and pioneering finding of antibodies against MICA antigen and allograft rejection were selected. This review chronicles the development of our understanding of the role that MICA antigens and antibodies may play in organ transplantation.
Results Polymorphic glycoprotein MICA antigens were detected on freshly isolated human umbilical cord endothelial cells, but not on peripheral lymphocytes. Antibodies were found and typing of recipients and donors by sequencing the MICA alleles has established that de novo antibodies produced in kidney transplant recipients are directed at mismatched MICA epitopes and are associated with acute rejection and chronic transplant failure. The specificity of antibodies against the epitopes of MICA antigens were well characterized by donor MICA typing, single antigen array testing with antibody absorption and elution. Acute graft-versus-host disease was observed in stem-cell recipients who were mismatched for MICA.
Conclusions Immunization against mismatched MICA epitopes encountered in donor organs after transplantation may result in antibodies against MICA alleles. Testing for MICA donor-specific antibodies (DSA) which are associated with early failure of kidney transplants may be helpful for identifying some of the targets of antibodies against antigens other than the human leukocyte antigen (HLA) and for improving transplantation outcome.
相似文献Background Immunosuppression for immunologically high-risk kidney transplant patients usually involves antithymocyte globulin induction with triple drug maintenance therapy. Alemtuzumab, a humanized anti-CD52 antibody, was expected to be a promising induction therapy agent for kidney transplantation. However, currently no consensus is available about its efficacy and safety. This study aimed to evaluate the efficacy and safety of alemtuzumab as immune induction therapy in highly sensitized kidney transplant recipients.
Methods In this prospective, open-label, randomized, controlled trial, we enrolled 23 highly immunological risk patients (panel reactive antibody >20%). They were divided into two groups: alemtuzumab group (trial group) and anti-thymocyte globulin (ATG) group (control group). Patients in the alemtuzumab group received intravenous alemtuzumab (15 mg) as a single dose before reperfusion. At the 24th hour post-operation, another dosage of alemtuzumab (15 mg) was given. The control group received a bolus of rabbit ATG (9 mg/kg), which was given 2 hours before kidney transplantation and lasted until the removal of vascular clamps when the anastomoses were completed. Maintenance immunosuppression in both groups comprised standard triple therapy consisting of tacrolimus, prednisone, and mycophenolate mofetil (MMF). Acute rejection (AR) and infection episodes were recorded, and kidney function was monitored during a 2-year follow-up. χ2 test, t test and Kaplan-Meier analysis were performed with SPSS17.0 software.
Results Median follow-up was 338 days. In both the alemtuzumab group and ATG group, creatinine and blood urea nitrogen values in surviving recipients were similar (P >0.05). White blood cell counts were significantly reduced in the alemtuzumab group for the most time points up to 6 months (P <0.05). One patient receiving alemtuzumab died for acute myocardial infarction at the 65th day post-operation. Two ATG patients died for severe pulmonary infection or cardiac and pulmonary failure. Cumulative 2-year graft survival rate was 90.9% in the alemtuzumab group and 81.8% in ATG group (P >0.05) respectively. There was one graft failure in the alemtuzumab group and two graft failures in ATG group, with all graft failures at tributed to rejection episodes. The alemtuzumab group had a 2-year cumulative freedom from rejection rate of 81.8%, compared with 72.7% for the ATG group (P >0.05).
Conclusion Alemtuzumab induction therapy for highly sensitized kidney transplant recipients is an effective and safe protocol yielding an acceptable acute rejection rate.
相似文献Conclusions Our study provides new information on efficacious renal transplantation, which might be useful for understanding the function of immature CD4+ DCs in modulating renal transplant rejection and improving clinical outcome in future studies.
相似文献Background Long-term use of steroid with large dosage might cause many adverse effects in kidney transplant patients; reducing steroid dosage to a low level for maintenance is helpful in avoiding the side-effects, but meanwhile, acute rejection may rise to be a main concern. The present research monitored the immune function changes and the incidence of acute rejection and infection after rapid steroid reduction to investigate the safety of this strategy.
Methods A prospective trial was conducted, using tacrolimus and mycophenolate mofetil as the basic immunosuppressive regimen, in addition to antibody induction with basiliximab. Corticosteroid dosage was rapidly reduced to 10 mg/d seven days post-transplantation in the experimental group, and the standard corticosteroid therapy was employed in the control group. Patient immunity was monitored by the Immune Cell Function Assay pre- and two weeks post-transplantation. The incidence of acute rejection and infection were compared between the experimental and control group.
Results Comparison of intracellular adenosine triphosphate (iATP) values detected two weeks post-transplantation for the control group ((324±45) ng/ml) and the experimental group ((345±91) ng/ml) did not reveal a significant difference (P >0.05). The incidence of acute rejection was analogous between groups (P >0.05), while an increased incidence of infection was observed in the control group (53% (n=16)) versus the experimental group (22% (n=6), P <0.05). Overall, recipients in the control group had longer and more recurrent infections than those in the experimental group (P <0.05). Patients in the control group had a lower immune response ((235±35) ng/ml) than those in the experimental group ((286±16) ng/ml) when infection occurred (P <0.05).
Conclusion Rapid reduction of steroid early after kidney transplantation does not lead to a significant rise in patient immunity. It is a safe and effective therapy for kidney transplant patients.
相似文献Background Endothelial progenitor cells (EPCs) transplantation is a promising therapeutic strategy for ischemic retinopathy. The current study aimed to establish a simple, reliable and fluorescent labeling method for tracking EPCs with 5-(and-6)-carboxyfluorescein diacetate succinimidyl ester (CFSE) in laser-injured mouse retina.
Methods EPCs were isolated from human umbilical cord blood mononuclear cells, cultivated, and labeled with various concentrations of CFSE. Based on fluorescence intensity and cell morphology, a 15 minutes incubation with 5 μmol/L CFSE at 37°C was selected as the optimal labeling condition. The survival capability and the apoptosis rate of CFSE-labeled EPCs were measured by Trypan blue staining and Annexin V/PI staining assay respectively. Fluorescence microscopy was used to observe the label stability during the extended culture period. Labeled EPCs were transplanted into the vitreous cavity of pigmented mice injured by retinal laser photocoagulation. Evans Blue angiography and flat mounted retinas were examined to track the labeled cells.
Results EPCs labeled with 5 μmol/L CFSE presented an intense green fluorescence and maintained normal morphology, with no significant changes in the survival capability or apoptosis rate after being labeled for 2 days, 1 and 4 weeks. The fluorescence intensity gradually decreased in the cells at the end of 4 weeks. Evans Blue angiography of the retina displayed the retinal capillarity network clearly and fluorescence leakage was observed around photocoagulated spots in the laser-injured mouse model. One week after transplantation of labeled EPCs, the fluorescent cells were identified around the photocoagulated lesions. Four weeks after transplantation, fluorescent tube-like structures were observed in the retinal vascular networks.
Conclusion EPCs could be labeled by CFSE in vitro and monitored in vivo for at least 4 weeks, and participate in the repair of injured retinal vessels.
相似文献Background Mesenchymal stem cells (MSCs) transplantation may partially restore heart function in the treatment of acute myocardial infarction (AMI). The aim of this study was to explore the beneficial effects of MSCs modified with heme xygenase-1 (HO-1) on post-infarct swine hearts to determine whether the induction of therapeutic angiogenesis is modified by the angiogenic cytokines released from the implanted cells.
Methods In vitro, MSCs were divided into four groups: (1) non-transfected MSCs (MSCs group), (2) MSCs transfected with the pcDNA3.1-Lacz plasmid (Lacz-MSCs group), (3) MSCs transfected with pcDNA3.1-hHO-1 (HO-1-MSCs group), and (4) MSCs transfected with pcDNA3.1-hHO-1 and pretreatment with an HO inhibitor, tin protoporphyrin (SnPP) (HO-1-MSCs+SnPP group). Cells were cultured in an airtight incubation bottle for 24 hours, in which the oxygen concentration was maintained at <1%, followed by 12 hours of reoxygenation. After hypoxia/reoxygen treatment, ELISA was used to measure transforming growth factor (TGF-β) and fibroblast growth factor (FGF-2) in the supernatant. In vivo, 28 Chinese mini-pigs were randomly allocated to the following treatment groups: (1) control group (saline), (2) Lacz-MSCs group, (3) HO-1-MSCs group, and (4) HO-1-MSCs + SnPP group. About 1×107 of autologous stem cells or an identical volume of saline was injected intracoronary into porcine hearts 1 hour after MI. Magnetic resonance imaging (MRI) assay and postmortem analysis were assessed four weeks after stem cell transplantation.
Results Post hypoxia/reoxygenation in vitro, TGF-β in the supernatant was significantly increased in the HO-1-MSCs ((874.88±68.23) pg/ml) compared with Lacz-MSCs ((687.81±57.64) pg/ml, P <0.001). FGF-2 was also significantly increased in the HO-1-MSCs ((1106.48±107.06) pg/ml) compared with the Lacz-MSCs ((853.85±74.44) pg/ml, P <0.001). In vivo, at four weeks after transplantation, HO-1 gene transfer increased the capillary density in the peri-infarct area compared with the Lacz-MSCs group (14.24±1.66/HPFs vs. 11.51±1.34/HPFs, P <0.001). Arteriolar density was also significantly higher in HO-1-MSCs group than in the Lacz-MSCs group (7.86±2.00/HPFs vs. 6.45±1.74/HPFs, P=0.001). At the same time, the cardiac function was significantly improved in the HO-1-MSCs group compared with the Lacz-MSCs group ((53.17±3.55)% vs. (48.82±2.98)%, P <0.05). However, all these effects were significantly abrogated by SnPP.
Conclusion MSCs provided a beneficial effect on cardiac function after ischemia/reperfusion by the induction of therapeutic angiogenesis, and this effect was amplified by HO-1 overexpression.
相似文献Background Sensitization in transplant candidates increases risk of irreversible immunologic injury of graft in the early period postoperatively. Elimination of anti-human leukocyte antigen (HLA) antibodies using protein A immunoadsorption (IA) might benefit these patients.
Methods Protein A IA was used in 21 patients with high panel reactive antibody (PRA). The patients had IA 1–6 times (median 5 times) with the interval period was 2–5 days (median 2.5 days).
Results Total 67 IA procedures were carried out smoothly in all patients. IA treatment reduced PRA I (pre (31.4±3.8)% vs. post (24.4±3.4)%, P <0.01) and II (pre (37.1±4.3)% vs. post (34.1±3.9)%, P <0.01). However, PRA did not change in some patients after the treatment. The serum immunoglobulin (IgG, IgM and IgA) and complement C3, C4 level were decreased significantly. Hemoglobin and albumin levels were slightly decreased associated with IA procedures. Flu-like symptoms were observed in a few of cases during the procedure but generally mild and transient.
Conclusion Protein A IA is capable to efficiently remove serum immunoglobulin and complement, reduce HLA class I and class II PRA in high sensitized transplant candidates, which is likely to benefit the kidney transplantation in these patients.
相似文献Marfan syndrome is a systemic disorder of connective tissue, caused by mutations in the FBN1, TGFBR1 or TGFBR2 genes. This syndrome is characterized by involvement of three major systems, skeletal, ocular, and cardiovascular. The continuing improvements in molecular biology and increasing availability of molecular diagnosis in clinical practice allow recognition of Marfan syndrome in patients with incomplete phenotypes. Additionally, molecular analyses could also be used for preimplantation genetic diagnosis. The identification of a mutation allows for early diagnosis, prognosis, genetic counseling, preventive management of carriers and reassurance for unaffected relatives. The importance of knowing in advance the location of the putative family mutation is highlighted by its straightforward application to prenatal and postnatal screening.
相似文献Background The status of sensitization in kidney transplant recipients in the last 10 years and the trend of induction and maintenance therapy in patients of different panel-reactive antibody (PRA) levels have not been analyzed. The aim of this study was to investigate the current status of pre-transplant sensitization and its association with graft outcome.
Methods A total of 155 570 kidney transplants reported to United Network for Organ Sharing (UNOS) during 2000–2009 were included in this study. We investigated the current status of pre-transplant sensitization and its association with graft outcome, and also compared the usage trend of 16 induction agents and 7 maintenance immunosuppressants in patients at different PRA levels. The difference of distributions of categorical variables between groups was investigated using the chi-square test. Unpaired t test or one-way analysis of variance (ANOVA) were used for numerical variables. The survival rates of transplant recipients were estimated using Kaplan-Meier methods and significance was determined by Log-rank test. Two-side P value <0.05 was considered statistically significant. All statistical analyses were performed using STATA 10 with all available updates as of March 2010 (StataCorp LP, College Station, Texas 77845, USA).
Results Despite the fact of the decreased percentages of kidney transplant recipients with presensitization history, the mean PRA levels of all kidney recipients has been increasing in the last 7 years, which was possibly due to the introduction of more sensitive antibody testing techniques. The percentage of patients with treated rejection episodes within one year post-transplant were significantly higher in sensitized patients (PRA=50%–100%:14.3% and PRA= 1%–49%:13.9%) than in non-sensitized patients (12.4%). Both 1- and 5-year graft survival rates improved in the last 10 years; this was more significant in high PRA patients. Thymoglobulin was the most commonly used induction agent in last 10 years. Its users increased from 10% to 46% in non-sensitized patients, from 12% to 57% in PRA 1%–49% patients, and from 19% to 63% in PRA 50%–100% patients. The users of Campath, intravenous immunoglobulin (IVIG), and Rituximab have been increasing and reached 16%, 20%, and 11% in highly sensitized patients. In the last 5 years, steroid-free patients were 33%–36%, 30%–37%, and 10%–25% for PRA 0, 1%–49%, and 50%–100% respectively. Almost 90% of patients were on Prograf at discharge. It seems that Myfortic users have been increasing since 2005 and it may soon replace mycophenolate mofetil (MMF) if long-term follow-up study conforms its safety and efficacy.
Conclusions Application of sensitive antibody testing techniques increased the mean PRA levels of transplant recipients in spite of a decreased percentage of sensitized recipients. Induction and maintenance therapy differed in patients at different PRA levels.
相似文献Background Neural tube defects are the most common human birth defects. The causes are multifactorial with complex genetic and environmental factors, although the exact genetic causes are unknown. This research was conducted to study the frequency of Msx2 gene polymorphisms in 59 women with a history of pregnancy with a neural tube defect and in 73 healthy controls. We aimed to determine the effect of this genetic polymorphism on the incidence of neural tube defects in the Han Chinese population.
Methods We studied 59 mothers with at least one previous child with a neural tube defect (the case group) and 73 case-control subjects during the same period, from Shanxi Province, China. We analyzed the genotypic distributions and allele frequencies of Msx2 C386T polymorphisms in DNA samples from the case and control groups. A three-dimensional protein model was predicted using Swiss-Pdb Viewer software version 4.0. Disease association was analyzed using chi-square tests.
Results Significant differences were observed in the genotypes and allele frequencies of the Msx2 C386T allele between the case and control groups (CT: 32% vs. 15%, P=0.0073 and TT 15% vs. 4%, P=0.013, respectively). Logistic regression analysis showed that the C386T mutation is a potential risk factor for neural tube defects (P <0.05; OR: 3.466; 95%CI: 1.831–6.560). Three-dimensional structure prediction revealed that the Msx2 C386T mutation results in a threonine substitution for methionine at position 129 of exon 2, which might lead to structural mutations or dysfunctions in the protein encoded by Msx2.
Conclusion Maternal Msx2 C386T gene polymorphisms were associated with fetal neural tube defects in Han Chinese women in Shanxi Province.
相似文献Background Interferon (IFN) can inhibit human immunodeficiency virus type 1 (HIV-1) replication in vitro and in clinic. However, IFN therapy for HIV infection was limited by its moderate antiviral efficacy and its frequent adverse effects. In the present study we evaluated the anti-HIV efficacy of a novel synthesized superior interferon α (sIFNα).
Methods We performed in vitro experiments with HIV-1 IIIB infected MT4 cells, and evaluated in vivo anti-HIV efficacy of sIFNα in severe combined immunodeficient (SCID) mice reconstituted with human peripheral blood leukocytes (hu-PBL-SCID mice).
Results We found that the 50% effective concentrations (EC50) of sIFNα against the replication of HIV-1 in MT4 cells was 0.06 ng/ml, representing stronger antiviral activity than interferon-α in vitro. In the hu-PBL-SCID mice, a dose-dependent protection pattern was observed: with 0.45 μg and 1.35 μg sIFNα daily treatments, parts of SCID mice were protected from HIV infection, whereas 2.25 μg sIFNα daily treatments resulted in a terminally complete protection.
Conclusions sIFNα shows good anti-HIV activity both in vitro and in SCID mice, may be a promising anti-HIV agent deserving clinical investigation, especially considering the potential of IFN-α to inhibit HIV replication in patients infected with drug-resistant variants or co-infected with hepatitis C virus (HCV).
相似文献Background The Syntax score was recently developed as a comprehensive, angiographic tool grading the complexity of coronary artery disease (CAD). It aims to assist in patient selection and risk stratification of patients with extensive CAD undergoing revascularization. However, the prognostic value of the Syntax score in patients undergoing percutaneous coronary intervention (PCI) has not been validated. The aim of this study was to evaluate its role in predicting long-term incidences of major adverse cardiac and cerebrovascular events (MACCE) in patients undergoing PCI for 3-vessel disease.
Methods Two hundred and three consecutive patients with de novo 3-vessel CAD undergoing PCI with sirolimus-eluting stents were studied. Their angiograms were scored according to the Syntax score. The patients were divided into tertiles according to the Syntax score: lowest Syntax score tertile (Syntax score ≤22), intermediate Syntax score tertile (Syntax score of 23 to 32), and the highest Syntax score tertile (Syntax score ≥33). During the 1-year follow-up, the MACCE-free survival curves were estimated by the Kaplan-Meier method. Univariate and multivariate Cox proportional hazard regression analyses were performed to evaluate the relation between the Syntax score and the incidence of MACCE. Performance of the Syntax score was studied with respect to predicting the rate of MACCE by receiver operator characteristic (ROC) curves with an area under the curve.
Results The overall Syntax score ranged from 6 to 66 with mean ± standard deviation of 27.9±12.6 and a median of 26. At 1 year, the Syntax score significantly predicted the risk of MACCE (HR 1.07/U increase, 95% CI 1.04 to 1.11, P <0.001). The rate of MACCE was significantly increased among patients in the highest Syntax score tertile (17.9%) as compared with those with the lowest Syntax score tertile (1.4%, P <0.001) or intermediate Syntax score tertile (6.2%, P=0.041). After the adjustment for all potential confounders, the Syntax score remained a significant predictor of the rate of MACCE (adjusted HR 1.12/U increase, 95% CI 1.05 to 1.20, P <0.001). The Syntax score accurately predicted MACCE with an area under the receiver operator curve of 0.77 (95% CI 0.65 to 0.90, P <0.001). A Syntax score of 29.5 was identified as the optimal cutoff to predict MACCE with a sensitivity of 82.4% and specificity of 65.6%.
Conclusion The Syntax score predicts the risk of MACCE in patients with 3-vessel disease undergoing PCI.
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