CD69 expression on peripheral CD8 T cells correlates with acute rejection in renal transplant recipients

BACKGROUND: The development of a noninvasive method to diagnose renal allograft rejection could prevent the complications associated with graft biopsy and allow more accurate surveillance of allograft function. The present study determines whether expression of CD69 on peripheral T lymphocytes of renal allograft recipients correlates with the presence of acute graft rejection. METHODS: Peripheral blood T lymphocytes from healthy volunteers, renal allograft recipients with elevated creatinine but no evidence of rejection on biopsy, and renal allograft recipients with biopsy-proven rejection were analyzed by flow cytometry for the expression of CD69 and various intracellular cytokines (interleukin-2, interferon-gamma). Results were then compared with the degree of rejection on biopsy. RESULTS: CD69 expression on CD3+, CD4+, and CD8+ T-cell subsets was low in controls and transplant recipients without allograft rejection. In contrast, patients with renal allograft rejection showed significantly elevated percentages of CD69+ cells in the CD3+ (P<0.01) and CD8+ subsets (P<0.01). The fraction of CD69+ and CD8+ T cells was found to be a more clinically useful test based on receiver-operator characteristics. CD69 expression on CD4+ T cells did not correlate with rejection. Significant intracellular cytokine levels were not detected in unstimulated T cells from any of the groups; stimulation with mitogens increased expression equally among the three groups. CONCLUSIONS: We demonstrate that expression of CD69 on CD3+ and CD8+ peripheral blood T cells correlates closely with the presence of acute graft rejection in renal allograft recipients. Measurement of this surface marker may provide a rapid, noninvasive, and accurate means by which graft rejection can be identified.     

Detection of B lymphocytes (CD20+) in renal allograft biopsy specimens

Acute allograft rejection represents an important complication after transplantation with significant impact on long-term graft survival. The involvement and relevance of B lymphocytes in this process is still not clear. The aim of this study was to quantify in renal allograft biopsy specimens the number of cells positive for CD20, a specific marker for B lymphocytes. Immunohistochemical techniques using monoclonal anti-CD20 antibody was used on paraffin sections from 38 renal allograft biopsy specimens. The biopsy specimens were classified into 3 groups, according to clinical and histological criteria: normal kidney, acute rejection, and chronic allograft nephropathy (CAN). In the normal kidney, no CD20(+) cells were detected. In contrast, in all cases of acute rejection and CAN, there were CD20(+) cells. The CD20(+) cells occurred in the infiltrate in 2 distinct patterns: scattered or nodular. In cases of acute rejection, the number of CD20(+) cells was significantly higher than in CAN cases (137.0 +/- 57.2 vs 45.4 +/- 9.8 cells/mm(2); P < 0.05). The nodular pattern was observed in 4 of 11 cases (36%) in the acute rejection group, and in 4 of 20 cases (20%) in the CAN cohort. In the acute rejection group, the presence of B-cell clusters tender to be associated with a higher level of serum creatinine (3.7 +/- 1.8 mg/dL vs 2.8 +/- 0.1 mg/dL in the scattered pattern group; not significant [ns]). In conclusion, these preliminary results demonstrated B lymphocytes in cases of renal allograft dysfunction, which were more pronounced in acute allograft rejection. Further analyses are required to determine whether the detection of CD20(+) cells in renal allograft biopsy specimens can be used as a prognostic marker.     

Frequency of T cell expressing Th1 and Th2 associated chemokine receptor in patients with renal allograft dysfunction

Acute rejection of human renal allografts is a frequent, serious posttransplantation complication, occurring in up to 50% of recipients. Leukocyte recruitment is a central feature of acute allograft rejection. Chemokine receptors are expressed on leukocytes in a cell type-specific manner. Recently CCR5+ and CXCR3+ cells have been observed in allograft biopsy specimens of patients undergoing acute cellular rejection (ACR). Herein we investigated the expression of Th1 (CCR5, CXCR3, and CCR2) and Th2 (CCR4, CCR3, and CCR8)-associated chemokine receptors on CD4 and CD8 T-cell populations. We sought to correlate chemokine receptor expression in peripheral blood T-cell subsets with the types of graft dysfunction (biopsy-proven rejections). In the peripheral blood CD4+ and CD8+ T-cell populations of patients with graft dysfunction, we observed a high frequency of Th1-associated chemokine receptors CCR5+ and CCR2+ but not CXCR3.     

CD103分子介导CD8+T淋巴细胞对同种胰岛移植物的损伤

目的 检验CD103分子是否介导了CD8+T淋巴细胞对同种移植胰岛的免疫损伤.方法 用流式细胞仪检测野生型C57BL/6小鼠外周血CD8+T淋巴细胞表达CD103的情况.以Balb/c小鼠为供者,C57BL/6小鼠为受者,制作同种胰岛移植模型.受者分为3组:M290-SAP组小鼠注射CD103免疫毒素M290-SAP;M290组小鼠注射抗CD103单克隆抗体M290;另以仅接受胰岛移植、不注射任何药物的小鼠为未处理组.检测移植胰岛CD3、CD8、CD44和CD103阳性细胞的表达,检测肠系膜淋巴结中CD3、CD8和CD103阳性细胞的表达.移植物功能丧失或观察期结束时获取移植胰岛,行HE染色和免疫组织化学染色.结果 野生型C57BL/6小鼠外周血的CD8+T淋巴细胞中有44.06%表达CD103.未处理组移植胰岛浸润的细胞成分中有29%的CD8+T淋巴细胞表达CD103.M290-SAP组小鼠淋巴细胞不仅丧失了CD103的表达,而且CD8+T淋巴细胞的绝对数量也减少,该组小鼠血糖稳定时间超过100 d(未处理组为13 d,P＜0.05),移植胰岛组织学形态良好.结论 CD8+T淋巴细胞免疫损伤同种移植胰岛必须表达CD103,CD103有可能成为胰岛移植抗排斥反应治疗的新靶点.

Abstract：

Objective To test whether the CD103 molecule mediates CD8+ T lymphocytes on allogeneic islet graft immune injury. Methods By using flow cytometry, the expression of CD103 in peripheral CD8+ T lymphocytes in wild-type C57BL/6 mice was detected. Allogenic islet transplantation models were made using Balb/c donor mice and C57BL/6 recipient mice. Recipients were divided into 3 groups: M290-SAP-treated mice were injected with CD103 immunotoxin M290-SAP; M290-treated mice were injected with CD103 monoclonal antibody M290; untreated mice were only transplanted islet without any drug treatment. CD3, CD8, CD44 and CD103 positive cells were counted in islet allograft infiltrative lymphocytes. CD3, CD8, and CD103 positive cells were measured in the mesenteric lymph node. The islet allografts were removed and subjected to HE staining and immunohistochemical staining at the time of graft loss or the end of the observation period. Results 44. 06% peripheral CD8+ T cells expressed CD103 in wild-type C57BL/6 mice. 29 % CD8+ T cells expressed CD103 in the infiltrative lyrnphocytes of islet allografts in the untreated mice. In M290-SAP-treated mice, the lymphocytes had no CD103 expression and the absolute number of CD8+ lymphocytes was decreased as well The blood glucose was maintained stable for more than 100 days (13 days in untreated group, P＜0.05) in the M290-SAP-treated mice. Moreover, the transplanted islets retained intact. Conclusion CD103 expression is required for destruction of pancreatic islet allograft by CD8+ T cells. CD103 might provide a novel target for therapeutic intervention in islet allograft rejection.     

Heightened peripheral blood lymphocyte CD69 expression is neither sensitive nor specific as a noninvasive diagnostic test for renal allograft rejection

It has been reported that acute allograft rejection is associated with heightened expression of the peripheral blood lymphocyte (PBL) early activation marker CD69 and that this may serve as a potential biomarker of rejection. This study sought to determine whether PBL CD69 expression correlates with both acute clinical and subclinical renal allograft rejection as well as clinically inapparent cytomegalovirus (CMV) infection. Flow cytometric determination of PBL CD69 expression was performed at the time of clinical and protocol biopsies (n = 131) in 45 renal transplant recipients. Nineteen patients also underwent weekly monitoring of PBL CD69 expression for the initial 15 wk after transplantation. Simultaneous screening for CMV viremia was performed with a semiquantitative PCR assay. No differences were seen in either CD4+ or CD8+ lymphocyte CD69 expression between the biopsy diagnoses. CMV viremia however, independent of rejection, was associated with greater CD69 expression on CD8+ lymphocytes (17.8 +/- 10.4% versus 9.6 +/- 4.8%; P < 0.0001) but not CD4+ lymphocytes. No individuals experienced clinical CMV disease. Weekly monitoring of PBL CD69 expression did not change coincident with the diagnosis of rejection; however, CMV viremia coincided with a substantial rise in the proportion of CD8+69+ lymphocytes in a number of individuals. Thus, PBL CD69 expression is neither sensitive nor specific for the noninvasive diagnosis of renal allograft rejection. Furthermore, clinically inapparent CMV viremia is associated with heightened expression of this activation marker on CD8+ lymphocytes. This latter finding suggests that clinically inapparent CMV viremia may be a potential confounder for biomarkers of rejection that examine peripheral blood lymphocytes.     

Tim-3在小鼠心脏移植受者体内不同部位T淋巴细胞上表达的变化

目的 检测激活的T_H1类淋巴细胞标记分子"T淋巴细胞免疫球蛋白域及粘蛋白域蛋白-3(Tim-3)"在受者体内不同部位T淋巴细胞上表达的变化,探讨其与急性排斥反应的关系.方法 建立小鼠同基因和异基因心脏移植模型(简称:同基因组和异基因组);移植术后第3和第6天,分离和制备两组受者外周血、脾脏、引流淋巴结和移植心内淋巴细胞悬液,采用流式细胞仪检测Tim-3阳性细胞在CD4~+ 和CD8~+ T淋细胞中的比值.结果 两组受者术后外周血和脾脏内Tim-3~+/CD4~+以及Tim-3~+/CD8~+ 的比值比较,差异均无统计学意义(P>O.05).与同基因组比较,异基因组引流淋巴结内Tim-3~+/CD4~+ 比值轻度升高(P<0.05);但异基因组术后第6天与第3天比较,差异无统计学意义(P>0.05).与同基因组比较,移植心内Tim-3~+/CD4~+和TiM-3~+/CD8~+比值均显著升高(P<0.01);异基因组术后第6天与第3天比较.移植心TiM-3~+/CD4~+和Tim-3~+/CD8~+比值也显著升高(P<0.01).结论 小鼠异基因心脏移植受者引流淋巴结和移植心内T淋巴细胞上Tim-3的表达升高与急性排斥反应的进展动态相关.     

Low incidence of acute rejection after living-donor liver transplantation: immunologic analyses by mixed lymphocyte reaction using a carboxyfluorescein diacetate succinimidyl ester labeling technique

BACKGROUND: To monitor antidonor alloreactivity for accurate diagnosis of acute rejection after living-donor liver transplantation (LDLT), we used a mixed lymphocyte reaction (MLR) assay using an intracellular fluorescent dye carboxyfluorescein diacetate succimidyl ester (CFSE)-labeling technique (CFSE-MLR) in 29 consecutive patients who underwent adult-to-adult LDLT. METHODS: For patients who developed moderate or severe disorders in liver function, CFSE-MLR was performed together with needle biopsy of the liver allografts immediately after liver dysfunction had occurred. CFSE-labeled peripheral blood mononuclear cells (PBMC) from recipients and irradiated autologous, donor, or third-party PBMC were cultured, and then proliferation and CD25 expression in each of the CD4+ and CD8+ T cell subsets were analyzed by flow cytometry. RESULTS: Twelve (41.4%) of the 29 patients developed moderate or severe disorders in liver function within 6 months after LDLT. Eight of the 12 patients (overall incidence of 27.6%) suffering from liver function disorder were diagnosed on the basis of liver biopsy results as having mild or moderate acute rejection. However, only 4 of the 12 patients (overall incidence of 13.8%) showed remarkable proliferation of CD8+ T cells in association with CD25 expression on antidonor CFSE-MLR. The other eight patients were eventually diagnosed as having recurrence of original hepatitis, drug-induced hepatotoxicity, or congestion of the anterior segment of the liver allograft by further extensive examinations or in retrospect. CONCLUSIONS: The results of CFSE-MLR assays, which could be used for rigorously monitoring rejection, provided evidence of low incidence of acute rejection after LDLT.     

Progressive increase of CD4(+)/CD45RC(-) lymphocytes after allograft rat lung transplantation: a marker of acute rejection

BACKGROUND: Acute rejection remains one the most serious problems in lung transplantation. Although biopsy has been used for assessing the dysfunction of grafts, it is difficult to determine rejection at an early stage. Lymphocyte infiltration and activation play an important role in acute rejection of transplanted organs, and the dynamic change of lymphocyte subpopulations might be a marker to determine graft rejection after lung transplantation. METHODS: A rat lung transplant model was used. Graft-infiltrating lymphocytes in lung tissues were examined by means of histology, and isolated cells were analyzed by means of flow cytometry. Phenotypes of lymphocytes in the regional and remote lymph nodes, spleen, peripheral blood, and bronchoalveolar lavage fluid were also measured by means of flow cytometry. RESULTS: After allograft transplantation, increased lymphocytes were seen in allografts but not in isografts. In allografts the percentage of T cells increased from day 1 to day 5, whereas that of B cells was decreased. The CD4(+)/CD8(+) ratio decreased in allografts. The proportion of CD4(+)/CD45RC(-) cells increased in the allografts, which was mainly due to the increase of CD45RC(-) cells in the total CD4(+) cells. Similar changes were found in regional mediastinal lymph nodes but not in the mesenteric lymph nodes, spleen, or peripheral blood. Thus this is a specific response to lung allografts. Importantly, CD45RC(-) cells were significantly increased in the bronchoalveolar lavage fluid. CONCLUSION: Significant change of lymphocyte subpopulations is a sign of lymphocyte activation. Increased CD4(+)/CD45RC(-) cells in lung allografts could be an early marker of acute rejection, which can be examined by means of lung lavage and flow cytometry.     

The effects of OKT3 therapy on infiltrating lymphocytes in rejecting renal allografts

OKT3 antibody therapy is effective in the treatment of renal allograft rejection. However its exact mode of action is unknown. Following OKT3 administration, peripheral blood lymphocytes fail to express the CD3 antigen, although other membrane antigens are relatively preserved. In this way the lymphocytes are unable to respond to foreign antigens. It is not known whether this modulation of CD3 on lymphocytes occurs within the rejecting allograft. Ten patients who received OKT3 therapy for steroid-resistant renal allograft rejection were studied. The aim of the study was to examine whether OKT3 antibody therapy altered the degree or the relative composition of the inflammatory infiltrate and to assess whether OKT3 treatment resulted in modulation of CD3 on intragraft lymphocytes. The study involved immunoperoxidase examination of biopsy material and flow cytometric analysis of peripheral blood lymphocytes obtained before and during treatment with OKT3 antibody. The results show that the total number of infiltrating leukocytes decreased after 5 days of treatment (3215 +/- 700 cells/l. 0 mm2 of tissue before vs. 1730 +/- 635 at day 5; P less than 0.001). The relative proportions of macrophages, total lymphocytes, CD4 +ve and CD8 +ve cells did not alter during therapy. Despite marked modulation of peripheral blood lymphocytes (CD3/CD2 ratio 0.89 +/- 0.13 before vs. 0.10 +/- 0.11 during treatment, P less than 0.001), there was no evidence of modulation of intragraft lymphocytes (CD3/CD2 ratio 0.98 +/- 0.14 before vs. 0.90 +/- 0.21 during treatment, P = NS). Although OKT3 antibody therapy is effective clinically at improving renal allograft rejection, this study demonstrates that it does not appear to cause modulation of the CD3 antigen on intragraft lymphocytes.     

CD8 T cell-mediated rejection of intestinal allografts is resistant to inhibition of the CD40/CD154 costimulatory pathway

BACKGROUND: Disruption of the CD40/CD154 pathway inhibits rejection in numerous models. The importance of this pathway on intestinal allograft rejection was examined in this study. METHODS: Intestinal grafts from B6C3F1 mice transplanted into C57BL/6 recipients were assessed histologically for rejection. RESULTS: The monoclonal antibody to CD154, MR1, failed to inhibit rejection in wild-type mice. Similarly, CD154-/- recipient mice rejected intestinal allografts. MR1 did inhibit early rejection in CD8-/- mice, but had no effect in CD4-/- recipients. All MR1-treated CD8-/- recipients eventually developed rejection. No benefit was observed when blockade of the CD40/CD154 pathway by MR1 was combined with blockade of the CD28/B7 pathway by mCTLA4Ig. CONCLUSIONS: These data suggest that CD4+ T cells mediating intestinal allograft rejection may be more dependent upon the CD40/CD154 pathway than CD8+ T cells. This finding highlights the importance of identifying agents that suppress CD8+ T cell-mediated rejection.     

Targeting acute allograft rejection by immunotherapy with ex vivo-expanded natural CD4+ CD25+ regulatory T cells

BACKGROUND: Natural CD4CD25 regulatory T (Treg) cells have been implicated in suppressing alloreactivity in vitro and in vivo. We hypothesized that immunotherapy using ex vivo-expanded natural Treg could prevent acute allograft rejection in mice. METHODS: Natural CD4+ CD25+ Treg were freshly purified from naive mice via automated magnetic cell sorter and expanded ex vivo by anti-CD3/CD28 monoclonal antibody (mAb)-coated Dynabeads. Suppression was assayed in vitro by mixed lymphocyte reaction and in vivo by targeting cardiac allograft rejection. Survival of Treg or effector T (Teff) cells after adoptive transfer in vivo was tracked by flow cytometry and all allografts were examined by histology and immunohistochemistry. RESULTS: By day nine in culture, 26.6+/-5.3-fold of expansion was achieved by co-culture of fresh natural Treg with anti-CD3/CD28 mAb-coated Dynabeads and interleukin-2. Ex vivo-expanded Treg exerted stronger suppression than fresh ones towards alloantigens in vitro and prevented CD4 Teff-mediated but only delayed CD4+/CD8+ Teff-mediated heart allograft rejection in Rag-/- mice. Long-term surviving allografts showed no signs of acute or chronic rejection with graft-infiltrating Treg expressing CD25 and FoxP3. Infused Treg persisted and expanded long-term in vivo and trafficked through the peripheral lymphoid tissues. CD25 expression was dynamic in vivo: maintained CD25 expression on Treg was indicative for the preservation of allosuppression, while significantly enhanced CD25 expression on CD4+ effector T cells was most likely associated with T-cell expansion and graft rejection. CONCLUSIONS: Therapeutic use of ex vivo-expanded natural CD4+ CD25+ Treg may be a feasible and nontoxic modality for controlling allograft rejection or perhaps inducing allograft tolerance.     

体外刺激肾移植受者外周血淋巴细胞进行免疫监测的临床研究

目的探讨应用体外刺激外周血淋巴细胞的方法进行免疫监测来预测肾移植术后急性排斥反应的价值。方法选取40例肾移植受者,将其分为急性排斥反应组(20例)和肾功能正常组(20例);选取10名健康供者作为正常对照组。抽取所有研究对象的外周静脉血,分离出外周血淋巴细胞,并经佛波酯(phorbol myfismte acetate,PMA)和离子霉素(ionomycin,Ion)体外刺激8h。应用流式细胞术检测细胞培养上清液白介素(IL)-2、IL-6的表达强度及CD3+CD69+、CD3+CD71+淋巴细胞比例;应用受试者工作特征(ROC)曲线评价IL-2联合IL-6、CD3+CD69+联合CD3+CD71+预测肾移植术后急性排斥反应的敏感度和特异度。结果急性排斥反应组的IL-2、IL-6的荧光强度和CD3+CD69+、CD3+CD71+淋巴细胞比例均显著高于肾功能正常组(P≤0.01);IL-2联合IL-6预测肾移植受者急性排斥反应的敏感度为0.90,特异度为0.95。CD3+CD69+联合CD3+CD71+预测急性排斥反应的敏感度为0.95,特异度为0.90。结论监测肾移植受者外周血淋巴细胞体外刺激上清液中的IL-2、IL-6及CD3+CD69+、CD3+CD71+的表达强度,可以预测急性排斥反应。此法简便,敏感度和特异度高。     

CD152 and PD-1 Down-Regulation on CD8 T Cells Is Associated With Human Acute Liver Allograft Rejection

PurposeTo investigate CD152 and PD-1 expression on T lymphocytes and the function of CD152- and PD-1–positive CD8 T cells in human acute liver allograft rejection.Materials and methodsSixty-three patients undergoing liver transplantation were enrolled in this study, including 26 cases with acute allograft rejection (Gr-AR) and 37 cases with stable allograft liver function (Gr-SF). The expression of CD152 and PD-1 on T lymphocytes and the expression of granzyme and perforin on CD152- and PD-1–positive CD8 T cells in peripheral blood were analyzed using flow cytometry.ResultsThe peripheral CD4/CD8 ratio in Gr-AR was significantly lower than that in Gr-SF (P < .01). The expression of CD152 and PD-1 on CD8 and CD4 T cells was significantly lower in Gr-AR than in Gr-SF (all P < .01). The expression of granzyme B and perforin was significantly higher in Gr-AR than in Gr-SF (P < .01).ConclusionsDown-regulation of the expression of negative costimulatory molecules such as CD152 and PD-1 on CD8 T cells may be associated with human acute liver allograft rejection.     

Fc-receptor for mouse IgG1 (Fc gamma RII) and antibody-mediated cell clearance in patients treated with Leu2a antibody

A pilot study was performed to explore the clinical potential of Leu2a antibody in reversing acute renal allograft rejection. Anti-Leu2a, a murine IgG1 monoclonal antibody (mIgG1 mAb), is specific for the CD8 molecule that is expressed in high density on class I reactive T cells. Of the 6 recipients treated with anti-Leu2a, two responded with a complete reversal of rejection with long-term allograft function maintained for over a year. In two other recipients, acute rejection was initially reversed, but later rejection episodes resulted in allograft failure at 2-3 months posttreatment. Rejection in the two other recipients showed no response to Leu2a mAb treatment. Specific depletion of peripheral blood CD8+ cells occurred in four of the six recipients. Even in this small series, it was evident that cell clearance was neither necessary nor sufficient for reversal of rejection. However, a complete correspondence between cell clearance and the ability of the recipients' mononuclear cells to undergo mitogenic response to the mIgG1 anti-CD3 (Leu4) mAb in vitro was noted. Binding of IgG1 mAb to the Fc-receptor (Fc gamma RII/CD32) expressed on blood monocytes is known to be essential for the T cell mitogenic response to soluble mIgG1 CD3 mAb in vitro. Our data suggest that binding to Fc gamma RII may be an essential step in the process of mIgG1 Leu2a mAb-mediated cell clearance in vivo.     

Mononuclear cells in renal allografts. Correlation with peripheral blood T lymphocyte subpopulations and graft prognosis

Cellular infiltrates in 20 renal allograft biopsies taken at the time of acute rejection episodes were analyzed with antibodies reactive with monocytes (BRL antihuman monocyte monoclonal antibody), T lymphocyte subpopulations (OKT- and Leu-series of monoclonal antibodies), and B lymphocytes (heterologous antihuman IgM antibodies). For demonstration of the various mononuclear cells, an indirect immunoperoxidase technique was used. The number of monocytes in the infiltrates varied from 10-20%; the number of B lymphocytes was always below 10%. The T lymphocytes accounted for 50-90% of the total number of mononuclear cells. The OKT4/OKT8 ratios for the T lymphocytes in the graft infiltrates were correlated with the peripheral blood OKT4/OKT8 ratios measured by indirect fluorescence and flow cytometry. The OKT4/OKT8 ratios for perivascular infiltrates correlated far better with peripheral blood OKT4/OKT8 ratios (r = 0.72) than did the OKT4/OKT8 ratios for interstitial infiltrates (r = 0.58). Low or inverted OKT4/OKT8 ratios and low or inverted Leu 3a/Leu 2a ratios were associated with a high risk of irreversible graft rejection (P less than 0.001 for perivascular infiltrates).     

CD8+ T cells contribute to the development of transplant arteriosclerosis despite CD154 blockade

BACKGROUND: The CD40-CD154 receptor-ligand pair plays a critical role in allograft rejection by mediating the activation of endothelial cells, antigen-presenting cells, and T cells. Blockade of this interaction prevents acute allograft rejection and leads to prolonged allograft survival in numerous experimental models, but in most cases indefinite graft survival is not achieved due to evolving transplant arteriosclerosis. In this study, we have used a model of transplant arteriosclerosis to investigate whether CD4+ and CD8+ T cells are differentially affected by CD154 blockade. METHODS: BALB/c (H2d) aortic grafts were transplanted into C57BL/6 (H2b) recipients treated with anti-CD154 monoclonal antibody in the presence or absence of CD8+ T-cell depletion. Histology and morphometric measurements were performed on day 30 after transplantation. RESULTS: Only combined treatment with anti-CD154 and anti-CD8 monoclonal antibodies resulted in a significant reduction of intimal proliferation (33 +/-10% vs. 67+/-14%; untreated control). Administration of either antibody alone did not produce this effect. Thymectomy did not alter the degree of intimal proliferation observed in any of the treatment groups. CONCLUSIONS: Our data provide direct evidence that CD8+ T cells are not targeted effectively by CD154 blockade and that the transplant arteriosclerosis seen after CD154 blockade is not due to recent thymic emigrant T cells.     

A novel CD154 monoclonal antibody in acute and chronic rat vascularized cardiac allograft rejection

BACKGROUND: The CD40-CD154 interaction is critically important in the cell-mediated immune responses. Blockade of this costimulatory pathway has been shown to prevent acute allograft rejection in murine, as well as nonhuman primate models. However, the role of the CD40-CD154 pathway in the development of chronic rejection and the effects of CD154 targeting on progression of chronic rejection have not been evaluated. METHODS: We examined the effect of AH.F5, a new hamster anti-rat CD154 monoclonal antibody, in a fully allogeneic acute(u) into Lewis [LEW] (RT11) and chronic [WF.1L (RT1l) into LEW (RT1l)] vascularized cardiac allograft rejection model. In the chronic model, the antibody was evaluated for prevention (starting day of transplant) and interruption of progression (starting day 30 or 60 after transplant) of chronic vasculopathy. Graft survival, morphology, and immunohistology were evaluated. RESULTS: In the acute rejection model, anti-CD154 therapy alone prevented acute allograft rejection and resulted in 50% long-term allograft survival (>200 days) and donor-specific tolerance. In recipients treated with anti-CD154 monoclonal antibody in combination with a short course of cyclosporine, 100% of allografts survived long-term and all recipients achieved donor-specific tolerance. In the chronic rejection model, allografts from animals treated with the anti-CD154 antibody had a statistically significant lower score of graft arteriosclerosis and fibrosis in both the prevention and 30-day interruption groups when compared with control allografts. In addition, immunohistochemistry showed a decrease in intragraft mononuclear cell infiltration and activation. CONCLUSION: A new anti-CD154 antibody not only prevents acute allograft rejection, but also inhibits and interrupts the development of chronic rejection. In the acute rejection model cyclosporine acts synergistically with anti-CD154 therapy to prolong allograft survival and induce tolerance. In the chronic rejection model relatively early initiation of therapy is essential to prevent progression of chronic allograft vasculopathy and fibrosis.     

Urinary Cell mRNA Profiles and Differential Diagnosis of Acute Kidney Graft Dysfunction

Noninvasive tests to differentiate the basis for acute dysfunction of the kidney allograft are preferable to invasive allograft biopsies. We measured absolute levels of 26 prespecified mRNAs in urine samples collected from kidney graft recipients at the time of for-cause biopsy for acute allograft dysfunction and investigated whether differential diagnosis of acute graft dysfunction is feasible using urinary cell mRNA profiles. We profiled 52 urine samples from 52 patients with biopsy specimens indicating acute rejection (26 acute T cell–mediated rejection and 26 acute antibody-mediated rejection) and 32 urine samples from 32 patients with acute tubular injury without acute rejection. A stepwise quadratic discriminant analysis of mRNA measures identified a linear combination of mRNAs for CD3ε, CD105, TLR4, CD14, complement factor B, and vimentin that distinguishes acute rejection from acute tubular injury; 10-fold cross-validation of the six-gene signature yielded an estimate of the area under the curve of 0.92 (95% confidence interval, 0.86 to 0.98). In a decision analysis, the six-gene signature yielded the highest net benefit across a range of reasonable threshold probabilities for biopsy. Next, among patients diagnosed with acute rejection, a similar statistical approach identified a linear combination of mRNAs for CD3ε, CD105, CD14, CD46, and 18S rRNA that distinguishes T cell–mediated rejection from antibody-mediated rejection, with a cross-validated estimate of the area under the curve of 0.81 (95% confidence interval, 0.68 to 0.93). Incorporation of these urinary cell mRNA signatures in clinical decisions may reduce the number of biopsies in patients with acute dysfunction of the kidney allograft.     

Mechanism of portal venous tolerant long-term MHC Class I L(d)-specific skin graft survival in transgenic 2CF1 mice

BACKGROUND: Administration of alloantigen via the portal vein (PV) in non-transgenic animals has been shown to promote immunologic tolerance and enhance transplant allograft survival. The underlying mechanisms remain unclear. In 2C x dm2 F1 (2CF1) transgenic mice, the monoclonal antibody, 1B2, identifies specific 2C TCR transgenic CD8+ T cells that are cytotoxic against Class I MHC L(d). In these mice, the specific response by these cells to L(d+) skin grafts after PV administration of L(d+) antigen was determined. MATERIALS AND METHODS: Saline (control) or allogeneic C57BL/6 x BALB/c F1 (CB6F1) spleen cells (25 x 10(6)), which differ from 2CF1 only at L(d), were injected PV into 2CF1 mice. One week later, CB6F1 tail skin was transplanted onto the dorsum of these 2CF1 mice. Skin graft rejection was defined as >50% loss of the graft. Parallel experiments were performed in non-transgenic littermates [B6F1 (C57BL/6 x dm2)]. FACS analysis of 2CF1 peripheral blood for 1B2+, CD4+, and CD8+ T cells was performed 2 days before PV injection (9 days prior to skin grafting), 5 days after PV injection (2 days prior to skin grafting), and 7, 14, 21, 28, and 60 days after skin grafting. FACS analysis of nai;ve, saline control, and CB6F1 PV-treated 2CF1 thymocytes was also performed. Responsiveness of saline (control)-treated and PV-treated 2CF1 splenocytes was measured by in vitro cytotoxic T lymphocyte (CTL). RESULTS: All CB6F1 skin grafts were rejected in <14 days by PV saline controls. However, a single PV injection of donor L(d+) CB6F1 cells was sufficient to induce indefinite CB6F1 (L(d+)) skin allograft survival in 100% of non-transgenic B6F1 and transgenic 2CF1 (anti-L(d)) TCR transgenic recipients. FACS analysis of 1B2+ T cells demonstrated that PV injection of donor antigen followed by a CB6F1 skin graft led to a 70% decrease in peripheral donor-reactive 1B2+ CD8+ T cells by day 7, while central thymocytes were unchanged. CTL of 2CF1 splenocytes following PV CB6F1 demonstrated that they were hyporesponsive to L(d) compared to saline-treated 2CF1 splenocytes. Despite recovery of peripheral CD8+ T cells to near normal levels by 60 days post-transplantation, skin graft survival persisted indefinitely. CONCLUSIONS: Administration of specific PV antigen results in exquisite long-term L(d+) skin allograft acceptance. This tolerance induction is related to a significant peripheral deletion of donor-reactive 1B2+ CD8+ transgenic T cells and anergy of the residual T cells.