肾移植后血清白细胞介素2、可溶性白细胞介素2受体和白细胞介素6的监测

动态监测６０例肾移植患者术后２个月内血清白细胞介素２（ＩＬ－２）、可溶性ＩＬ－２受体（ｓＩＬ－２Ｒ）和白细胞介素６（ＩＬ－６）的变化。结果发现发生急性排斥反应时，上述细胞因子的升高较临床诊断提早数天，并且显著高于环孢素Ａ肾中毒组；对甲泼尼龙敏感的排斥反应，抗排斥治疗数天后上述因子下降到排斥前水平。提示肾移植术后动态监测患者血清ＩＬ－２、ｓＩＬ－２Ｒ和ＩＬ－６有助于急性排斥反应的早期诊断、鉴别诊断、及时治疗和甲泼尼龙抗排斥的疗效评价。     

Angiotensin type 1 and type 2 receptor blockade in chronic allograft nephropathy

Angiotensin-II (Ang-II) type 1 (AT(1)) receptor blockers may delay the progression of chronic allograft nephropathy (CAN). However, neither the optimal time for initiating AT(1) receptor blockade in order to delay CAN potentially nor the role of Ang-II type 2 (AT(2)) receptors under AT(1) receptor blockade is known. Both AT receptors can regulate p53 expression and apoptosis. We investigated what time of initiation with AT(1) blockers most effectively delayed CAN as well as the role of the AT(2) receptor, and how angiotensin receptor blockade affected apoptosis and its regulating factors in this context in a rat model. Kidneys of Fisher (F344) rats were transplanted into Lewis rats. Animals were treated with AT(1) (candesartan) and/or AT(2) (PD123319) receptor antagonists, a calcium channel blocker, or vehicle (treatment periods: day -7 before to week 24 after transplantation (long term), week 12 to week 24 (late), day -7 to day +5 (early)) and observed the animals for 24 weeks. Reduction of proteinuria, grade of CAN, and number of apoptotic cells was most pronounced in animals receiving long-term AT(1) receptor blockade. A combined AT(1)/AT(2) blocker treatment reduced CAN similarly to AT(1) blocker treatment alone. The number of apoptotic cells and the level of p53 mRNA were significantly lower in long-term AT(1) blocker-treated animals. In summary, AT(1) receptor blockade delayed the progression of CAN, particularly in animals treated long term. Reduction of apoptosis could be related to these beneficial effects. The AT(2) receptor does not appear to play an important role in CAN.     

CD28 blockade induces division-dependent downregulation of interleukin-2 receptor alpha

BackgroundBlockade of T cell costimulatory molecules represents a promising new method of attenuating donor-reactive T cell responses to promote graft survival following transplantation. However, recent studies in murine models have shown the presence of an initial high frequency of naïve donor-reactive T cells may render this strategy ineffective.MethodsIn this report, we examined the phenotypic changes associated with CD28 blockade on T cells stimulated at increasing precursor frequencies in vitro.ResultsWe found that treatment with the CD28 blocker CTLA-4 Ig resulted in downregulation of the alpha chain of the IL-2 receptor (CD25) in a division-dependent manner. Significantly, blockade of the CD28 pathway was more effective in down-regulating CD25 when the donor-reactive T cell population was present at low as compared to high precursor frequency.ConclusionsThese results imply that treatment with CD28 blockers and anti-CD25 mAbs may cooperate in promoting graft survival under conditions of low MHC matching where the donor-reactive T cell precursor frequency is high.     

Soluble interleukin-2 receptor level as an indicator of liver allograft rejection

We studied the serum levels of soluble interleukin-2 receptors (SIL-2R) in liver allograft recipients: a control group without rejection or CMV disease, a group with only rejection episodes, and a group with only cytomegalovirus disease. Rejection was diagnosed by the presence of compatible laboratory and histologic abnormalities and absence of other causes of graft dysfunction. CMV disease was diagnosed by isolation of CMV in blood or liver specimen cultures or identification of cytomegalic inclusions in the liver biopsy specimen. Of 82 consecutive recipients treated with cyclosporine and prednisone, 12 were in the control group, 20 in the rejection group, and 5 in the CMV disease group. The remaining 45 had other or multiple complications. In the control group the SIL-2R levels (determined by an ELISA) decreased by a mean of 4% per day after transplantation; in the rejection group the levels increased by a mean of 17% per day in the 10 days prior to the diagnosis of rejection; in the CMV disease group the levels tended to increase prior to the diagnosis of CMV disease. The rejection group had significantly higher SIL-2R levels than the control group at comparable times. Thus, SIL-2R levels were significantly increased at the time of allograft rejection compared with levels in a control group, and recipients with CMV disease had increased levels of SIL-2R but they were not as high as in recipients with rejection episodes.     

A critical analysis of soluble interleukin-2 receptor levels in kidney allograft recipients

Abstract  Soluble interleukin-2 receptor (sIL-2R) was measured by the Cellfree Kit (T Cell sciences) in 103 pretransplant and 1590 post-transplant samples from 103 patients with cadaveric kidney allo-grafts. The mean values (± SD) detected in pretransplant sera were significantly higher (1932 ± 1389 U/ml) than in 72 healthy adults (267 ± 139 U/ml), but after transplantation they continuously fell towards normal levels within the first 3 postoperative weeks. Recipients with acute rejection episodes showed higher sIL-2R levels (1762 ± 904 U/ml) than those with stable transplants at discharge (937 ± 398 U/ml). Highest values were detected during antirejection therapy with antithymocyte globulin (4996 ± 2166 Uiml) or OK (5905 ± 3910). Increases were also observed during bacterial and viral infections and even, in some cases, without any apparent cause. Because of this lack of specificity, elevated sIL-2R levels should be interpreted cautiously. Nevertheless, sIL-2R level can be useful for monitoring kidney allograft recipients. Increases point to a cellular immune activation process and can predict rejections or infections.     

A critical analysis of serum and urine interleukin-2 receptor assays in renal allograft recipients

A component of the interleukin 2 receptor (IL-2R) is released in soluble form during T cell activation and can be detected in the blood during acute renal allograft rejection. This study evaluates the diagnostic utility of a sandwich enzyme immunoassay test for serum and urine IL-2R in renal allograft recipients. A rise in serum IL-2R during the week prior to the clinical diagnosis of rejection correlated better with rejection than did isolated serum IL-2R levels or urine values. For the diagnosis of acute rejection, a rise in serum IL-2R (sensitivity 73%, specificity 87%) was comparable in overall test performance to a rise in serum creatinine (sensitivity 70%, specificity 84%). Overall, the two tests had equivalent receiver operating characteristic curves. Because the etiology of false positives in creatinine and IL-2R assays differed (primarily cyclosporine toxicity and infection, respectively), the predictive value of the combined tests was superior to either alone.     

Complement 5a receptor inhibition improves renal allograft survival

Complement activation plays a key role in mediating apoptosis, inflammation, and transplant rejection. In this study, the role of the complement 5a receptor (C5aR) was examined in human renal allografts and in an allogenic mouse model of renal transplant rejection. In human kidney transplants with acute rejection, C5aR expression was increased in renal tissue and in cells infiltrating the tubulointerstitium. Similar findings were observed in mice. When recipient mice were treated once daily with a C5aR antagonist before transplantation, long-term renal allograft survival was markedly improved compared with vehicle-treatment (75 versus 0%), and apoptosis was reduced. Furthermore, treatment with a C5aR antagonist significantly attenuated monocyte/macrophage infiltration, perhaps a result of reduced levels of monocyte chemoattractant protein 1 and the intercellular adhesion molecule 1. In vitro, C5aR antagonism inhibited intercellular adhesion molecule 1 upregulation in primary mouse aortic endothelial cells and reduced adhesion of peripheral blood mononuclear cells. Furthermore, C5aR blockade markedly reduced alloreactive T cell priming. These results demonstrate that C5aR plays an important role in mediating acute kidney allograft rejection, suggesting that pharmaceutical targeting of C5aR may have potential in transplantation medicine.     

Improved renal allograft survival with vitamin D receptor polymorphism

BACKGROUND: Polymorphisms in genes, coding for proteins involved in immune response, or the pathogenesis of atherosclerosis may influence immunological and non-immunological mechanisms that lead to allograft loss. Vitamin D receptor (VDR) agonists reduce allograft rejection in animal models, and there are a number of functional polymorphisms in VDR. METHODS: In all, 379 renal transplant recipients were genotyped for VDR (FokI & ApaI) polymorphisms, and the association of each genotype with renal allograft survival and acute rejection was determined. RESULTS: There was significantly improved allograft survival for patients who were homozygous or heterozygous for the VDR FokI T allele (Hazard Ratio [HR] = 0.488, p < 0.001). CONCLUSION: The association of VDR FokI T allele with improved renal allograft survival is a unique observation. The finding is in keeping with data showing the prevention of chronic allograft rejection with the use of Vitamin D receptor agonists.     

Long-term pancreatic allograft survival after renal retransplantation in prior simultaneous pancreas-kidney recipients

Over a 23-year period, our center performed 82 renal retransplants in prior simultaneous pancreas-kidney recipients with functioning pancreatic allografts. All patients were insulin-independent at retransplantation. We aimed to quantify the risk of returning to insulin therapy and to identify factors that predispose patients to pancreatic allograft failure after renal retransplantation. Among these 82 patients, pancreatic allograft survival after renal retransplantation was 78%, 49% and 40% at 1, 5 and 10 years. When analyzing risk factors, we unexpectedly found no clear relationship between the cause of primary renal allograft failure, hemoglobin A1c (HbA1c) or fasting C-peptide level at retransplant and subsequent pancreatic allograft failure. An elevated HbA1c in the month after renal retransplant correlated with subsequent pancreatic graft loss and patients experiencing pancreatic graft loss were more likely to subsequently lose their renal retransplant. Although it is difficult to prospectively identify those patients who will return to insulin therapy after repeat renal transplantation, the relatively high frequency of this event mandates that this risk be conveyed to patients. Nonetheless, the survival benefit associated with renal retransplantation justifies pursuing retransplantation in this population.     

Prolongation of cardiac allograft survival in murine recipients treated with a diphtheria toxin-related interleukin-2 fusion protein

A diphtheria toxin-related IL-2 fusion gene has been constructed that encodes a 68KD recombinant toxin in which the diphtheria toxin receptor-binding domain has been replaced with amino acids 2-133 of IL-2. This chimeric IL-2 toxin is cytotoxic for cells expressing the high-affinity IL-2 receptor but not for cells lacking this receptor. The ability of this IL-2 toxin to prolong allograft survival was examined in a murine vascularized, heterotopic heart transplant model in the strain combination B10.BR into C57B1/10. When given at a dose of 1.0 micrograms/day for 10 days, the IL-2 toxin significantly prolonged allograft survival in all recipients. CRM-45, a fragment of diphtheria toxin missing the binding domain, was ineffective, confirming the specificity of the therapy. The results demonstrate that this IL-2 toxin, which targets activated T cells expressing the IL-2 receptor, will prolong allograft survival, offering a new option for immunosuppressive therapy.     

Differential effects of transferrin receptor blockade on the cellular mechanisms involved in graft rejection

Since transferrin receptor (TfR) appears on activated T cells following the interaction of the antigen-major histocompatibility complex (MHC) with the T cell receptor (TCR) and the appearance of interleukin (IL)-2R, we therefore hypothesize that in vivo blockade of TfR prolongs allograft survival by altering the cellular mechanisms involved in graft rejection. Previous results in our laboratory have demonstrated that anti-TfR monoclonal antibody (mAb) at 100 microg on days 0 and 1 of transplantation significantly prolonged allograft survival to 25.7 +/- 0.9 days in a murine heterotopic, nonvascularized cardiac allograft model. In the current studies, administration of anti-TfR mAb at the time of maximal TfR expression, on days 2 and 3 post-transplantation, failed to prolong allograft survival (13.0 +/- 0.0 days) compared to the isotype controls (10.5 +/- 0.5 and 10.7 +/- 0.4 days) (p < 0.01, Wilcoxon rank sum). A 4-day course of anti-TfR mAb significantly prolonged allograft survival compared to the isotype controls, but was no more effective than a 2-day course of the mAb. Anti-TfR mAb suppressed the mixed lymphocyte response to donor-specific and third-party alloantigen by 78.7% (p < 0.05) and 80.8% (p < 0.05), respectively, while stimulating the CTL response to donor-specific (16.3%, p < 0.05) and third party (49.3%, p < 0.01) alloantigen. Anti-TfR mAb suppressed IL-15 and increased IL-4 intragraft mRNA expression when compared to the isotype controls. Examination of cell surface receptors important during T cell activation revealed alterations in expression following anti-TfR mAb treatment. Anti-TfR mAb is an effective immunosuppressant prolonging allograft survival by altering cell-mediated immune responses and the intragraft cytokine micro-environment.     

输注外源性白细胞介素13延长同种肝移植大鼠的存活时间

目的 探讨外源性重组白细胞介素13(rIL-13)抑制同种肝移植大鼠的排斥反应和延长大鼠存活时间的作用及其机制.方法 以Lewis大鼠为供鼠,BN大鼠为受鼠,采用重建肝动脉的大鼠肝移植方法建立同种大鼠原位肝移植模型.采用随机数字表法将受鼠分为两组,实验组于术后第1、2、3、4和5天经尾静脉注射rIL-13 10μg/d,同期对照组注射等体积生理盐水.术后第7天,检测两组移植肝功能,测定移植肝组织病理改变、细胞因子表达及CD8+T淋巴细胞浸润等情况,并根据Banff标准计算排斥活动指数(RAI),观察术后2周的存活率.结果 与对照组相比,实验组肝功能明显改善,肝组织肿瘤坏死因子α(TNF-α)与E选择素的表达明显降低(P＜0.05),CD8+T淋巴细胞浸润明显减少(P＜0.05),术后2周存活率明显提高(P＜0.05).实验组的RAI为4.8±1.2,明显低于对照组的7.5±1.2(P＜0.05).结论 外源性重组rIL-13可减少促炎症因子TNF-α的释放和抑制E选择素的表达,减少移植物CD8+T淋巴细胞的浸润,从而减轻肝移植后急性排斥反应,延长大鼠的存活时间.     

No synergy between ATG induction and costimulation blockade induced kidney allograft survival in rhesus monkeys

BACKGROUND: Costimulation blockade with antibodies directed against human CD40 and CD86 leads to prolonged kidney allograft survival in rhesus monkeys, but fails to induce permanent graft acceptance. We have tested whether costimulation blockade is more effective after peripheral T-cell ablation with antithymocyte globulin (ATG), with the aim to remove already primed autoreactive cells present in the normal repertoire. METHODS: Rhesus monkeys were transplanted with a mismatched kidney allograft. ATG was given around the time of transplantation (day -1 and 0). Costimulation blockade with anti-CD40+anti-CD86 was given at tapering dosages from day -1 to 56. Cyclosporin A (CsA) was given from day 42 onwards and first rejections occurring after day 42 were treated with prednisone. RESULTS: We observed accelerated rejection in ATG-treated monkeys, compared to animals receiving only costimulation blockade. The accelerated rejection of the kidney allograft occurred despite the application of rejection therapy with steroids and CsA. Three of the five ATG-treated animals were found seropositive for donor-specific alloantibodies. Early biopsies (day 21) from animals treated with ATG and anti-CD40+anti-CD86 show substantially reduced expression of cytotoxic T lymphocyte-associated antigen-4 (CTLA-4) and forkhead box P3 (FOXP3) in focal infiltrates as compared to animals treated with only costimulation blockade. Furthermore, we observed the rapid reappearance of CD8 T-cells with a memory phenotype (disappearance of naive CD95/CD11a T-cells) in peripheral blood. CONCLUSION: We conclude that (subtotal) T-cell depletion using ATG does not add to costimulation blockade induced kidney allograft survival.