CD28 downregulation on CD4+ T cells is associated with age of kidney transplant recipient.

There is a growing body of evidence showing that the intensity of rejection is weaker in older kidney allograft recipients while chronic complications, but not rejection, are the main causes of graft loss. To investigate whether the age of the recipient is a factor affecting the expressions of the CD28, CTLA-4, and CD40L costimulatory molecules on CD4+ T cells. Their expression levels were determined in 78 kidney transplant recipients aged 17-68 years. The expression was assessed on unstimulated and anti-CD3 antibody + IL-2-stimulated CD4+ T cells. Median time after transplantation was 20 months and median serum creatinine was 1.5 mg/dl. Significant correlations between age and CD28 expression (r = -0.4, P = 0.0004) on CD4+ T cells and between age and CTLA-4 expression after stimulation (r = 0.34, P = 0.008) were found. CD40L expression on CD4+ T cells was not affected by recipient age. The decreased expression of CD28 and enhanced expression of CTLA-4 (after stimulation) associated with age may be helpful in transplant acceptance.     

Infusion of in vitro-generated DN T regulatory cells induces permanent cardiac allograft survival in mice

Previously, we have demonstrated that pretransplant donor lymphocyte infusion (DLI) can activate recipient-derived CD3+CD4-CD8- double negative T regulatory (DN Tr) cells which have a potent immune regulatory function in vitro and in vivo. Here we studied the regulatory ability of DN T cell clones generated from the spleens of nai;ve anti-L(d) transgenic TCR+ (2C x dm2)F1 mice. We were able to identify subsets of DN T cell clones that were able to kill anti-Ld CD8+ T cells, and therefore had regulatory properties, and DN T cells with no regulatory properties. Next, we investigated the ability of these in vitro generated DN T cell clones to enhance cardiac allograft survival. (2C x dm2)F1 transgenic mice were infused with either regulatory or non-regulatory DN T cell clones, or left untreated one day before receiving an Ld-mismatched cardiac grafts from (C57BL/6 x Balb/c)F1 mice. Injection of non-regulatory DN T clone cells did not prolong cardiac graft survival in (2C x dm2)F1 mice when compare to untreated controls. In contrast, all of the cardiac grafts survived more than 100 days in mice that received DN Tr clone cells prior to transplantation. These results demonstrate that DN Tr cells can be generated in vitro and protect cardiac allograft from rejection when infused into recipients prior to transplantation. They also suggest that DN Tr cells may provide a novel therapy for the treatment of allograft rejection.     

In Vivo Development of Transplant Arteriosclerosis in Humanized Mice Reflects Alloantigen Recognition and Peripheral Treg Phenotype of Lung Transplant Recipients

Experimentally, regulatory T cells inhibit rejection. In clinical transplantations, however, it is not known whether T cell regulation is the cause for, or an epiphenomenon of, long‐term allograft survival. Here, we study naïve and alloantigen‐primed T cell responses of clinical lung transplant recipients in humanized mice. The pericardiophrenic artery procured from human lung grafts was implanted into the aorta of NODrag^?/?/IL‐2rγc^?/? mice reconstituted with peripheral blood mononuclear cells (PBMCs) from the respective lung recipient. Naïve or primed allogeneic PBMCs procured 21 days post–lung transplantation with or without enriching for CD4⁺CD25^high T cells were used. Transplant arteriosclerosis was assessed 28 days later by histology. Mice reconstituted with alloantigen‐primed PBMCs showed significantly more severe transplant arteriosclerosis than did mice with naïve PBMCs (p = 0.005). Transplant arteriosclerosis was equally suppressed by enriching for autologous naïve (p = 0.012) or alloantigen‐primed regulatory T cells (Tregs) (p = 0.009). Alloantigen priming in clinical lung recipients can be adoptively transferred into a humanized mouse model. Transplant arteriosclerosis elicited by naïve or alloantigen‐primed PBMCs can be similarly controlled by potent autologous Tregs. Cellular therapy with expanded autologous Tregs in lung transplantation might be a promising future strategy.     

The presence of donor-reactive CD4 T cells in early-phase liver-induced tolerance in rats: analysis using donor passenger leukocytes from the recipient

In previous studies, we showed that the recipient spleen 12 h after liver transplantation included highly immunogenic donor passenger leukocytes (PLs) in the non-rejector rat strain combination (Lewis: LEW-->Wistar Furth: WF). Furthermore, we noted that giving anti-CD4 mAb to WF recipients at the time of liver grafting prolonged the liver damage due to primary rejection reaction, suggesting that CD4 T-cell regulation but not the deletional mechanism played a dominant role during the induction phase of tolerance in this combination. We proposed that in vitro CD4 T-cell response to the donor PLs from the recipient lymphoid organ may be observed in the early phase of tolerance induction. We initially observed donor-specific acceptance by 10 days after liver transplantation from the result of secondary heart transplantation, and showed that donor (LEW) PLs in recipient WF spleen 12 h after grafting were able to prime cytotoxic CD8 T cells in vivo. We then isolated functional donor PLs from the recipient WF spleen and established in vitro proliferation assay. When the enriched donor PLs were used as stimulator cells in the proliferation assay, a powerful alloimmunostimulatory ability was observed. Moreover, a potent response of recipient splenocytes to the PLs was observed on postoperative day 14. From these observations, we confirmed that clonal deletion of donor-reactive CD4 T cells did not participate in early phase of tolerance induction in this setting.     

近交系大鼠肝移植自发免疫耐受模型的建立及其CD8+CD28-T细胞的作用

目的建立近交系大鼠原位肝移植自发免疫耐受模型,并研究CD8+CD28- T细胞在自发免疫耐受形成中的作用.方法双袖套法建立原位肝移植模型;流式细胞技术检测CD8+CD28- T抑制细胞含量变化;利用补体细胞毒和免疫磁珠方法分离CD8+CD28- T细胞,通过体外混合淋巴细胞反应验证其抑制功能.结果我们成功建立了BN(供体)LEW(受体)原位肝移植自发免疫耐受模型,并发现自发免疫耐受模型大鼠脾脏CD8+CD28- T细胞含量(23.7%±7.2%)显著高于正常大鼠(5.4%±1.5%)和急性排斥组大鼠(6.0%±1.3%),而且,分离纯化后的自发免疫耐受组大鼠脾脏CD8+CD28- T细胞可以抑制混合淋巴细胞反应的增殖,但急性排斥组大鼠脾脏CD8+CD28- T细胞无抑制功能.结论 BN(供体)LEW(受体)原位肝移植模型为自发免疫耐受;脾脏CD8+CD28- T细胞作为一种T抑制细胞,在自发免疫耐受的形成过程中具有重要作用.     

Regulatory CD4+CD25+ T cells in the peripheral blood of lung transplant recipients: correlation with transplant outcome

BACKGROUND: The subset of CD4+CD25+ regulatory T cells, recently identified in humans, may play a central role in the regulation of immune tolerance to graft survival. METHODS: This study assesses the frequency and functional profile of CD4+CD25+CD69- cells in the peripheral blood of lung transplant recipients (>3 years from transplantation), 10 of whom were in a stable clinical condition and 11 of whom demonstrated chronic rejection (bronchiolitis obliterans syndrome). We also studied a group of seven healthy subjects. RESULTS: The frequency of CD4+ T cells expressing CD25 (CD4+CD25+) and the highest levels (CD25) were lower in patients with bronchiolitis obliterans syndrome compared with healthy subjects and subjects in a stable clinical condition (P < or = 0.01). Purified CD4+CD25+ cells exhibited a regulatory functional profile in vitro: they were hyporesponsive, suppressed the proliferation of CD4+CD25- cells, and produced interleukin-10. CONCLUSION: These results provide in vivo evidence that peripheral CD4+CD25+ T cells may represent an important regulatory subset in lung transplantation.     

CCR2 Regulates Monocyte Recruitment As Well As CD4+ Th1 Allorecognition After Lung Transplantation

Graft rejection remains a formidable problem contributing to poor outcomes after lung transplantation. Blocking chemokine pathways have yielded promising results in some organ transplant systems. Previous clinical studies have demonstrated upregulation of CCR2 ligands following lung transplantation. Moreover, lung injury is attenuated in CCR2‐deficient mice in several inflammatory models. In this study, we examined the role of CCR2 in monocyte recruitment and alloimmune responses in a mouse model of vascularized orthotopic lung transplantation. The CCR2 ligand MCP‐1 is upregulated in serum and allografts following lung transplantation. CCR2 is critical for the mobilization of monocytes from the bone marrow into the bloodstream and for the accumulation of CD11c⁺ cells within lung allografts. A portion of graft‐infiltrating recipient CD11c⁺ cells expresses both recipient and donor MHC molecules. Two‐photon imaging demonstrates that recipient CD11c⁺ cells are associated with recipient T cells within the graft. While recipient CCR2 deficiency does not prevent acute lung rejection and is associated with increased graft infiltration by T cells, it significantly reduces CD4⁺ T_h1 indirect and direct allorecognition. Thus, CCR2 may be a potential target to attenuate alloimmune responses after lung transplantation.     

全身照射预处理供体对异基因大鼠肝移植的作用及对受体内CD4~+CD25~+调节性T细胞的影响

目的 探讨全身照射(TBI)预处理诱导大鼠肝移植术后急性排斥反应的发生机制,及CD4~+ CD25~+调节性T细胞的变化在诱导免疫耐受中的作用.方法 以雄性Lewis、DA大鼠为供、受体,随机分为正常对照组、同种肝移植组、自发免疫耐受组、急性排斥反应组.观察各组受体的生存时间及生存率,检测受体术后外周血中ALT、TB含量、Foxp3~+ CD4~+ CD25~+ 调节性T细胞和T细胞亚群上GITR的表达,检测受体术后第14天移植肝的病理变化和受体脾脏CTL杀伤活性.结果 自发免疫耐受组,术后经历短暂排斥反应最终获得免疫耐受并长期存活.急性排斥反应组,在术后第17～21天死亡,与其他组相比,外周血血清中ALT、TB含量明显升高,而Foxp3~+ CD4~+ CD25~+调节性T细胞比例明显降低.TBI预处理大鼠供肝致受体外周血中CD3~+ CD4~+ T细胞上GITR表达降低,CD3~+CD8~+T细胞上GITR表达增加,提高CTL的杀伤活性.结论 通过TBI清除供体大鼠肝移植物中携带的旁路淋巴细胞,致受体外周血中Foxp3~+ CD4~+ CD25~+调节性T细胞表达降低,而使CD3~+ CD8~+T细胞上GITR表达增加,共同诱导大鼠肝移植术后急性排斥反应发生和耐受障碍.     

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.     

肝移植急性排斥反应者外周血CD4+CD25+Foxp3+调节性T淋巴细胞的变化

目的 探讨良性终末期肝病患者肝移植术后外周血CD4+CD25+叉状头螺旋转录因子(Foxp3)+调节性T淋巴细胞在急性排斥反应期的变化及意义.方法 2004年12月至2008年1月间,符合入选条件的良性终末期肝病患者共55例,按照术后是否发生急性排斥反应分为排斥组(14例)和无排斥组(41例).肝移植术前用流式细胞仪检测患者外周血CD4+CD25+Foxp3+T淋巴细胞占CD4+T淋巴细胞的百分率(简称CD4+CD25+Foxp3+T细胞百分率),出院后1年内每隔3～6个月复查;发生急性排斥反应时,于治疗前和治疗缓解后(3～6个月)复查.比较两组患者外周血CD4+CD25+Foxp3+T细胞百分率的变化,对排斥组发生急性排斥反应时外周血CD4+CD25+Foxr3+T细胞百分率与排斥反应活动指数(RAI的相关性进行统计学分析.结果 肝移植术前,排斥组与无排斥组外周血CD4+CD25+Foxp3+T细胞百分率的差异无统计学意义(P＞0.05).排斥组患者发生急性排斥反应时外周血CD4+CD25+Foxp3+T细胞百分率为(2.23±0.54)%,低于无排斥组的(2.99±0.86)%,差异有统计学意义(P＜0.01).排斥组中,患者发生急性排斥反应时外周血CD4+CD25+Foxp3+T细胞百分率低于未发生急性排斥反应时的(3.67±0.70)%,差异有统计学意义(P＜0.01).排斥组患者发生急性排斥反应时外周血CD4+CD25+Foxp3+T细胞百分率与RAI呈负相关(r=-0.80,P＜0.01).结论 监测肝移植受者外周血CD4+CD25+Foxp3+调节性T淋巴细胞的变化,可辅助诊断急性排斥反应及判断其严重程度.

Abstract：

Objective To investigate the expression of peripheral blood (PB) CD4+ CD25+ Foxp3+ regulatory T cells (Tregs) in patients with benign end-stage liver disease after liver transplantation and the relationship between levels of PB Tregs and acute rejection. Methods A prospective analysis was performed on 55 consecutive patients who underwent liver transplantation.Fourteen out of 55 cases suffered from acute rejection after liver transplantation were defined as rejection group,while the rest patients were classified into no acute rejection group. PB was obtained from liver transplant patients at different time points longitudinally: pre-transplant, post-transplant within one year and acute rejection. The circulating CD4+ CD25+ Foxp3+ Tregs in PB were measured by flow cytometry. Blood samples were drawn during acute rejection, at the same time, liver biopsies were performed. The circulating CD4+ CD25+ Foxp3+ Tregs were compared between two groups.Results There was no difference between two groups in levels of circulating CD4+ CD25+ Foxp3 + Tregs cells pre-transplant. However, the levels of circulating CD4+ CD25+ Foxp3+ Tregs in rejection group were decreased significantly as compared with no-rejection group (2. 23 % ± 0. 54 % vs. 2. 99 % ±0. 86 %,P＜0.01). The frequency of CD4+ CD25+ Foxp3+ T cells was negatively correlated with rejection activity index (RAI) (r = - 0. 80, P＜0. 01 ). Conclusion Monitoring PB CD4+ CD25+ Foxp3+ Tregs levels may be helpful in evaluating the immune state and act as a more sensitive marker for acute rejection diagnosis in the patients following liver transplantation.     

Human mesenchymal stem cells are susceptible to lysis by CD8(+) T cells and NK cells

There is growing interest in the use of mesenchymal stem cells (MSCs) to improve the outcome of organ transplantation. The immunogenicity of MSCs is, however, unclear and is important for the efficacy of MSC therapy and for potential sensitization against donor antigens. We investigated the susceptibility of autologous and allogeneic MSCs for lysis by CD8(+) T-lymphocytes and NK cells in a kidney transplant setting. MSCs were derived from adipose tissue of human kidney donors and were CD90(+), CD105(+), CD166(+), and HLA class I(+). They showed differentiation ability and immunosuppressive capacity. Lysis of MSCs by peripheral blood mononuclear cells (PBMCs), FACS-sorted CD8(+) T cells, and NK cells was measured by europium release assay. Allogeneic MSCs were susceptible for lysis by cytotoxic CD8(+) T cells and NK cells, while autologous MSCs were lysed by NK cells only. NK cell-mediated lysis was inversely correlated with the expression of HLA class I on MSCs. Lysis of autologous MSCs was not dependent on culturing of MSCs in FBS, and MSCs in suspension as well as adherent to plastic were lysed by NK cells. Pretransplant recipient PBMCs did not lyse donor MSCs, but PBMCs isolated 3, 6, and 12 months after transplantation showed increasing lysing ability. After 12 months, CD8(+) T-cell-mediated lysis of donor MSCs persisted, indicating there was no evidence for desensitization against donor MSCs. Lysis of MSCs is important to take into account when MSCs are considered for clinical application. Our results suggest that the HLA background of MSCs and timing of MSC administration are important for the efficacy of MSC therapy.     

Reactivation of rat cytomegalovirus in lung allografts: an experimental and immunohistochemical study in rats.

Reactivation of latent rat cytomegalovirus (RCMV) from a lung allograft or from a recipient was studied in RCMV-mismatched combinations (donor [D]-/recipient [R]+, D+/R-, and D+/R+) with latently infected lung grafts and chronically infected rats in an inbred rat model. Nineteen transplants in a major histocompatibility complex different strain combination (Brown-Norway/Lewis) were immunosuppressed daily (cyclosporine, azathioprine, and prednisolone) from day 3 after orthotopic left lung transplantation and killed on days 3, 6, and 21. Control groups consisted of nine chronically RCMV-infected rats with immunosuppression without transplantation and six allografts with immunosuppression without RCMV infection. Reactivation of latent RCMV was tested by immunohistochemical staining with monoclonal antibodies against RCMV-induced antigens and by plaque assays of the virus in the salivary glands. The following results were obtained: (1) All allotransplants developed acute ongoing rejection on days 3 and 6, and the rejection was resolved on day 21 by immunosuppression. (2) Reactivation was observed in allotransplanted groups, but not in the control rats. (3) In the D+/R+ and D-/R+ groups on days 3 and 6, the number of RCMV-related antigen-positive cells increased in the recipient spleen and lymph nodes and in the bronchus-associated lymphoid tissue of the donor lung in the D-/R+ group, but not in the chronically RCMV-infected controls. (4) In the D+/R- group on day 6, RCMV-induced antigen-positive cells were observed in the spleen and lymph nodes of the recipient and also around the vessels in the recipient lung. (5) In the D-/R+ group, vascular endothelial cells or mildly infiltrated mononuclear cell subpopulations around the vessels in the lung allograft showed weakly positive staining against RCMV-related antigens on day 6. (6) After the initial acute rejection on days 3 and 6 was treated by immunosuppressive drugs, reactivated acute RCMV infection became chronic or latent again on day 21. We conclude that RCMV infection could be transferred with latently infected lung allografts by reactivation of latent RCMV. In rats, as in man, alloimmune responses seemed to have a definite influence on the reactivation of latent RCMV after lung transplantation.     

Adoptive transfusion of ex vivo donor alloantigen-stimulated CD4(+)CD25(+) regulatory T cells ameliorates rejection of DA-to-Lewis rat liver transplantation

BACKGROUND: Adoptive transfusion of splenocytes from long-term survivors of a tolerance model of rat orthotopic liver transplantation can induce acceptance of liver allografts in a rejection model preconditioned with donor gamma-irradiation before liver transplantation. Recent studies suggest that the regulatory T cells (Treg cells) in splenocytes from long-term survivors play an important role in the induction of liver graft tolerance, but this observation was made from a rejection model preconditioned with donor gamma-irradiation; little is known about the role of Treg cells in liver graft rejection using a naive rejection model. In this study, we examined the therapeutic potential of CD4(+)CD25(+) Treg cells in a naive rejection model of rat liver transplantation. METHODS: Freshly isolated or ex vivo alloantigen-stimulated CD4(+)CD25(+) Treg cells (1 x 10(6) cells) from naive Lewis RT(1) (LEW) rats were adoptively transferred into another LEW rat on days 1 and 7 after liver transplantation from a Dark Agouti RT1(a) (DA) rat. Recipients were treated with or without oral tacrolimus (FK506) (0.1 mg/kg/day) from days 1 to 7 after transplantation. For ex vivo alloantigen-stimulation, CD4(+)CD25(+) Treg cells from LEW rats were cocultured with mitomycin C-treated DA (donor alloantigen specific) or Brown Norway (BN)(RT1(n), third party) splenocytes for 72 hours. Ex vivo alloantigen-specific CD4(+)CD25(-) T-cell proliferation responses were assessed with fresh and stimulated CD4(+)CD25(+) Treg cells. RESULTS: Freshly isolated, donor alloantigen-stimulated and third-party alloantigen- stimulated CD4(+)CD25(+) Treg cells suppressed antigen-specific CD4(+)CD25(-) T-cell proliferation ex vivo, and adoptive transfusion of these 3 kinds of CD4(+)CD25(+) Treg cells prolonged survival of the liver allografts. The group transfused with the donor alloantigen-stimulated CD4(+)CD25(+) Treg cells had the greatest mean survival among the 3 groups (fresh Treg cells, 21 +/- 2 days, n = 6; third-party alloantigen-stimulated Treg cells, 20 +/- 2 days, n = 6; donor alloantigen-stimulated Treg cells, 30 +/- 2 days, n = 6). When combined with short-term tacrolimus administration, adoptive transfusion of donor antigen-stimulated Treg cells induced the greatest survival time in recipients (greater than 60 days; n = 6). CONCLUSION: Adoptive transfusion of ex vivo donor alloantigen-stimulated CD4(+)CD25(+) Treg cells combined with short-term tacrolimus treatment may represent a new strategy for preventing rejection after liver transplantation.     

Increased expression of the lymphocyte early activation marker CD69 in peripheral blood correlates with histologic evidence of cardiac allograft rejection

BACKGROUND: The human leukocyte membrane protein CD69 is an early activation marker induced in T lymphocytes, B cells, and natural killer cells in response to inflammatory stimuli. Cardiac catheterization and endomyocardial biopsy remain the "gold standard" for diagnosis of rejection after transplantation, and noninvasive methods of rejection surveillance have long been sought. We studied CD69 membrane protein expression in peripheral blood T lymphocytes obtained from pediatric cardiac transplant recipients at the time of biopsy and correlated the results with histologic rejection scores. METHODS: Heparinized whole blood samples were obtained from pediatric cardiac transplant recipients at the time of cardiac biopsy, as well as from control subjects. Lymphocytes were labeled with antibodies for CD3, CD4, CD8, and CD69 and analysis performed using flow cytometric methods. RESULTS: Resting CD69 expression (measured as a percentage of gated events) was significantly increased in patients with concurrent histologic evidence of rejection (International Society for Heart and Lung Transplantation grade > or =3A) when compared to those with minimal or no rejection and controls. Although statistically significant for both lymphocyte subsets, this relationship was more pronounced for CD8+ T cells (P<0.001) than for CD4+ T cells (P=0.001). When data were analyzed by rejection score, a percentage activation of the CD8+ subset (CD69+/CD8+ cells as a percentage of total gated events) exceeding 15% correlated with significant rejection. CONCLUSIONS: Measurement of the expression of the early activation marker CD69 in peripheral blood lymphocytes by flow cytometry may provide a noninvasive means of assessing immune activation and possible rejection in cardiac transplant recipients.     

Transfer of allograft specific tolerance requires CD4+CD25+T cells but not interleukin-4 or transforming growth factor-beta and cannot induce tolerance to linked antigens

BACKGROUND: The mechanisms by which CD4+T cells, especially CD4+ CD25+T cells, transfer allograft specific tolerance are poorly defined. The role of cytokines and the effect on antigen-presenting cells is not resolved. METHODS: Anti-CD3 monoclonal antibody (mAb) therapy induced tolerance to PVG heterotopic cardiac transplantation in DA rats. Peripheral CD4+T cells or CD4+ CD25+ and CD4+ CD25-T cell subsets were adoptively transferred to irradiated DA hosts grafted with PVG heart grafts. For specificity studies, tolerant CD4+T cells were transferred to hosts with Lewis or (PVGxLewis)F1 heart grafts. Cytokine mRNA induction and the requirement for interleukin (IL)-4 and transforming growth factor (TGF)-beta in the transfer of tolerance was assessed. RESULTS: CD4+T cells transferred specific tolerance and suppressed na?ve CD4+T cells capacity to effect rejection of PVG but not Lewis grafts. (PVGxLewis)F1 grafts had a major rejection episode but recovered. Later these hosts accepted PVG but not Lewis skin grafts. Adoptive hosts restored with tolerant or na?ve cells had similar levels of mRNA expression for all Th1 and Th2 cytokines and effector molecules assayed. Transfer of tolerance by CD4+T cells was not blocked by mAb to IL-4 or TGF-beta. CD4+ CD25-T cells from either na?ve or tolerant hosts effected rejection. In contrast neither tolerant nor na?ve CD4+ CD25+T cells restored rejection. CONCLUSIONS: Specific tolerance transfer required CD4+ containing CD4+ CD25+T cells. An inflammatory response with induction of mRNA for Th1 and Th2 cytokines plus cytotoxic effector molecules occurred, but IL-4 and TGF-beta were not essential. Inhibition of antigen presenting cells was not the sole mechanism as there was no linked tolerance.     

Cumulative exposure to CD8+ granzyme Bhi T cells is associated with reduced lung function early after lung transplantation

Outcomes following lung transplant remain suboptimal. This is attributable to variable posttransplant recovery of lung function, and inconsistent degrees of lung function loss after peak function is reached. Granzyme B is elevated in the blood and bronchoalveolar lavage (BAL) in acute rejection. We hypothesized that persistent exposure to T cells high in granzyme B would negatively correlate with lung function. We investigated cumulative exposure measured as the area-under-the-curve (AUC) of CD8⁺ T cell granzyme B^hi cells in the first year posttransplant in both BAL and blood in 24 transplant recipients. We assessed the correlation between cumulative 1-year exposure and FEV₁ slope. There was a negative correlation between 1-year exposure and FEV₁ slope within the first year (r = −0.63; P = .001). This relationship persisted even when adjusted for transplant type, gender, age, rejection, and indication for transplantation. In contrast, no relationship was seen with the 1-year AUC and lung function after 1 year posttransplant. In contrast to the BAL granzyme B^hi levels, granzyme B^hi levels from the blood showed no relationship with lung function. These findings suggest that CD8⁺ T-cell–driven factors are responsible for early improvements in lung function after transplantation.     

骨髓输注减轻大鼠肺移植急性排斥反应的研究

目的 研究供体骨髓细胞输注减轻大鼠肺移植急性排斥反应。方法 应用Cuff技术改进大鼠原位单肺移植模型，同时输注供体骨髓细胞，采集受体鼠外周血动态监测嵌合；存活4周大鼠杀死后切取移植肺进行排斥反应分级，切取脾应用免疫组织化学方法检测组织嵌合。结果 流式细胞术在骨髓输注组外周血中检测到明显的嵌合，在脾脏中得到组织嵌合。骨髓输注组移植肺急性排斥反应明显减轻。结论 肺移植同时输注供体骨髓细胞，可以产生显著的供体细胞与受体细胞嵌合，有效地抑制大鼠肺移植急性排斥反应。