125Ⅰ粒子敷贴式鼻饲营养管用于食管癌恶性梗阻

目的观察自制¹²⁵Ⅰ粒子敷贴式鼻饲营养管用于治疗食管癌恶性梗阻的可行性和安全性。方法对14例经病理证实的食管癌并伴Ⅲ~Ⅳ级吞咽困难高龄患者行DSA引导下¹²⁵Ⅰ粒子敷贴式鼻饲营养管置入术,使¹²⁵Ⅰ粒子完全覆盖肿瘤段上下各2 cm行近距离放射治疗;观察技术成功率、临床治疗成功率、手术时间、肿瘤吸收剂量[D90(90%肿瘤体积所接受的剂量)]、有无核素脱落、术后并发症及肿瘤控制情况,并比较术前与术后6~8周Karnofsky评分及Neuhaus吞咽困难分级差异。结果对所有患者均成功置入¹²⁵Ⅰ粒子敷贴式鼻饲营养管,技术成功率100%(14/14);手术时间(27.37±4.82)min。临床治疗成功率85.71%(12/14),D90为(52.19±6.64)Gy。9例(9/14,64.29%)患者诉治疗期间胸骨后间断性疼痛,可耐受。未发生核素脱落及其他并发症,肿瘤局部控制率为92.86%(13/14)。术后6~8周Karnofsky评分(t=-2.75,P=0.01)及Neuhaus分级(Z=9.72,P<0.01)均较术前明显改善。结论¹²⁵Ⅰ粒子敷贴式鼻饲营养管制作及置入简单、便捷,可同时实现近距离放射治疗和胃肠营养。     

一体化可携带125I粒子双链鼻饲管用于治疗食管癌合并Ⅳ级吞咽困难

目的观察一体化可携带~(125)I粒子双链鼻饲营养管用于治疗食管癌合并Ⅳ级吞咽困难的效果。方法对10例食管癌合并Ⅳ级吞咽困难患者采用介入导管技术开通食管闭塞段,沿导丝送入新型一体化携~(125)I粒子双链鼻饲营养管,使粒子段跨越食管闭塞段,行近距离放射治疗;统计技术成功率、临床成功率、术前与术后3天剂量学参数等指标;术后2个月根据Karnofsky评分、Neuhaus吞咽困难分级评价治疗效果,共随访半年观察疗效。结果 10例均顺利置入携~(125)I粒子双链鼻饲营养管,技术成功率100%,临床成功率70%,无严重并发症。术前与术后90%肿瘤靶区(GTV)剂量(D_(90%))、GTV最小边缘剂量(mPD)、GTV接受200%及100%处方剂量的体积百分比(V_(200%)、V_(100%))、适形指数(CI)及靶区外体积指数(EI)差异均无统计学意义(P均0.05)。术后2个月Karnofsky评分、Neuhaus分级均较术前明显改善(P均0.01),肿瘤局部控制率70%。随访半年,再发食管梗阻1例,死亡2例,7例未复发。结论一体化可携带~(125)I粒子双链鼻饲营养管可同时实现胃肠营养和近距离放疗,用于治疗食管癌合并Ⅳ级吞咽困难患者安全有效。     

125I粒子抑制裸鼠T24移形细胞癌效果

目的 观察不同活度¹²⁵I粒子抑制裸鼠T24移形细胞癌的效果。方法 将40只接种T24人移形细胞癌株荷瘤裸鼠均分为高、中、低活度组和对照组,每组10只,分别于肿瘤中心植入1枚活度0.9 mCi（33.3 MBq）、0.6 mCi（22.2 MBq）、0.3 mCi（11.1 MBq）和0 mCi（粒子不含核素）的¹²⁵I粒子。检测并对比各组植入10、20天后90%肿瘤组织吸收剂量（D₉₀）、抑瘤率（IR）、HE染色放射治疗反应分级（RRG）、凋亡指数及B淋巴细胞瘤-2（Bcl-2）蛋白表达。结果 ¹²⁵I粒子植入后10、20天,各组D₉₀及IR均逐渐降低（P均<0.05）,¹²⁵I粒子周围5 mm以内肿瘤组织均见明显坏死,粒子活度越高、时间越长,坏死范围越大;同期各组凋亡指数均逐渐降低,Bcl-2蛋白表达逐渐增加（P均<0.05）。结论 ¹²⁵I粒子能明显抑制裸鼠T24移形细胞癌生长,促进肿瘤细胞凋亡是其作用机制之一。     

iGuide虚拟导航辅助C臂CT引导下125I粒子植入术治疗溶骨性骨转移癌所致疼痛

目的 观察iGuide虚拟导航辅助C臂CT引导下经皮穿刺¹²⁵I粒子植入术治疗溶骨性骨转移癌所致疼痛的效果。方法 回顾性分析86例115处溶骨性骨转移癌引发疼痛患者,经常规治疗后疼痛无缓解或拒绝常规治疗,接受iGuide虚拟导航辅助C臂CT引导下经皮穿刺¹²⁵I粒子植入术。记录技术成功率、手术并发症、90%体积肿瘤吸收剂量（D90）,比较术前及术后1、4、8周患者每日吗啡摄入量（DMC）和视觉模拟量表（VAS）评分,以及术前与术后8周Karnofsky评分。结果 ¹²⁵I粒子植入术技术成功率100%;D90为93.56~142.46 Gy,平均（110.54±3.41） Gy。术前DMC及VAS评分分别为（86.28±22.18） mg及（6.40±0.96）分,术后1周降至（54.88±12.05） mg及（4.48±0.76）分,之后逐渐下降,至术后8周降为（23.14±7.07） mg及（1.86±0.65）分（P均<0.05）;Karnofsky评分由术前的（74.19±7.27）分升高至术后8周（88.37±6.66）分（P<0.05）。主要和次要并发症发生率分别为2.33%（2/86）和11.63%（10/86）。结论 iGuide虚拟导航辅助C臂CT引导下经皮穿刺¹²⁵I粒子植入术可有效缓解溶骨性骨转移癌所致疼痛,且安全性高。     

支架联合125I粒子条植入术治疗上腔静脉综合征

目的 观察支架联合¹²⁵I粒子条植入术治疗上腔静脉综合征(SVCS)的短期效果。方法 回顾性分析40例SVCS,其中23例接受上腔静脉支架植入术(支架组)、17例接受支架联合¹²⁵I粒子条植入术(联合组);比较组间技术成功率、临床成功率、并发症发生率、支架通畅率,以及患者肿瘤无进展生存期(PFS)和总生存期(OS)的差异。结果 2组技术成功率均为100%;联合组与支架组临床成功率(94.12% vs. 91.30%)、并发症发生率(17.65% vs. 8.70%),术后1个月支架通畅率(100% vs. 91.30%)、2个月支架通畅率(100% vs. 82.61%),以及患者中位PFS(4.12个月vs. 3.83个月)和中位OS(22.44个月vs. 20.36个月)差异均无统计学意义(P均>0.05)。术后4个月联合组支架通畅率高于支架组(100% vs. 78.26%,P<0.05)。结论 支架联合¹²⁵I粒子条植入术治疗SVCS短期效果确切。     

TACE联合放射性125I粒子植入治疗不宜消融肝癌的安全性及有效性分析

目的 评价TACE联合¹²⁵I粒子植入治疗不宜消融肝癌的疗效。方法 将82例不宜消融的肝癌患者分为2组：联合组40例,予TACE联合¹²⁵I粒子植入治疗;对照组42例,予单纯TACE治疗。比较2组治疗后肝功能、血常规、血清甲胎蛋白（AFP）、并发症、客观有效率及远期生存率。结果 联合组¹²⁵I粒子植入术前、术后剂量学差异均无统计学意义（P均>0.05）。联合组术后3、6个月客观有效率[85.00%（34/40）、67.50%（27/40）]明显高于对照组[61.90%（26/42）、45.24%（19/42）;P均<0.05]。联合组患者中位生存时间为25.7个月,对照组为10.7个月;联合组1、2、3年累积生存率分别为77.50%、54.30%、23.30%,对照组为45.20%、32.60%、13.60%。联合组术后3个月及6个月血清AFP水平明显低于对照组（P均<0.05）。联合组治疗后1个月肝功能及血常规与术前差异均无统计学意义（P均>0.05）。结论 TACE联合¹²⁵I治疗不宜消融肝癌安全、有效。     

对比经远端桡动脉与肱动脉入路支架成形术治疗髂动脉慢性闭塞症的有效性及安全性

目的 对比经远端桡动脉入路与肱动脉入路支架成形术治疗髂动脉慢性闭塞症的有效性及安全性。方法 回顾性分析70例接受经左侧桡动脉远端入路（A组）与72例经左侧肱动脉入路（B组）支架成形术治疗髂动脉慢性闭塞症患者,其中B组18例因穿刺左侧桡动脉远端失败而改为穿刺左侧肱动脉;观察2种方法穿刺成功率、2组髂动脉开通成功率和穿刺并发症发生率。结果 穿刺桡动脉远端成功率为79.55%（70/88）,穿刺肱动脉成功率为100%（72/72）。髂动脉顺行开通成功率[78.57%（55/70）vs.80.56%（58/72）,<χ²=3.67,P=0.09]及总体开通成功率[94.29%（66/70）vs.95.83%（69/72）,χ²=2.34,P=0.10]组间差异均无统计学意义。A组穿刺并发症发生率低于B组[5.71%（4/70）vs.13.89%（10/72）,<χ²=3.24,P=0.02]。结论 相比经肱动脉入路,经远端桡动脉穿刺入路腔内支架成形术治疗髂动脉慢性闭塞症更为安全,而开通成功率相当。     

125I粒子植入术联合支气管动脉化疗栓塞治疗纵隔型肺癌和/或肿瘤纵隔淋巴结转移

目的 观察¹²⁵I粒子植入术联合经支气管动脉化疗栓塞(BACE)治疗纵隔型肺癌和/或肿瘤纵隔淋巴结转移的价值。方法 回顾性分析20例接受¹²⁵I粒子植入术联合BACE治疗的纵隔型肺癌和/或肿瘤纵隔淋巴结转移患者,观察术后肿瘤疗效反应、患者生存情况及生活质量等,评价联合治疗疗效。 结果 粒子植入术后患者均出现轻度不良反应,1例发生中度不良反应,未见重度不良反应。术后随访8~49个月,术后1个月卡诺夫斯基绩效状态量表(KPS)评分显著提高(P=0.019);术后6个月5例肿瘤完全缓解、9例部分缓解,4例疾病稳定,2例疾病进展,客观反应率为70.00%,局部控制率为90.00%;患者中位无进展生存期10.5个月,中位总生存期为20.5个月,总生存率45.00%。结论 ¹²⁵I粒子植入术联合BACE用于纵隔型肺癌和/或肿瘤纵隔淋巴结转移疗效和安全性均较好。     

胆道支架联合引流管置入125I粒子条治疗恶性梗阻性黄疸

目的 观察胆道支架联合引流管置入¹²⁵I粒子条治疗恶性梗阻性黄疸(MOJ)的价值。方法 回顾性分析35例接受胆道支架植入联合引流管置入¹²⁵I粒子条的MOJ患者,观察手术效果、术后支架通畅时长及患者生存期。结果 35例均成功完成治疗。术前总胆红素(TBIL)、直接胆红素(DBIL)、谷丙转氨酶(GPT)及谷草转氨酶(GOT)与术后1周及1个月差异均有统计学意义(P均<0.05)。术后16例显著有效、19例有效;高、低位梗阻总显著有效率分别为38.10%(8/21)和57.14%(8/14),差异无统计学意义(χ²=1.228,P=0.268)。截至随访日共对26例更换粒子条,其中19例更换1次、7例更换2次,均未发生放射剂量累积过高而致胆管破溃及穿孔等情况。35例术后支架通畅时长(7.83±2.02)个月,患者生存期(14.06±4.78)个月。结论 胆道支架植入联合引流管置入¹²⁵I粒子条用于胆道受压及狭窄均不严重MOJ患者疗效较佳。     

对比TACE联合125I粒子与联合仑伐替尼治疗肝细胞癌伴门静脉癌栓的有效性及安全性

目的 对比TACE联合¹²⁵I粒子植入或仑伐替尼治疗肝细胞癌(HCC)伴门静脉癌栓(PVTT)的有效性及安全性。方法 回顾性分析52例HCC伴Ⅱ/Ⅲ型PVTT患者,分为TACE联合¹²⁵I粒子组(A组,n=27)及TACE联合仑伐替尼组(B组,n=25);比较2组客观缓解率(ORR)、总生存期(OS)及不良反应率。结果A组ORR、中位OS、Ⅱ型PVTT中位OS及Ⅲ型PVTT中位OS分别为70.37%(19/27)、13.6个月、14.1个月及13.2个月;B组分别为32.00%(8/25)、11.3个月、12.3个月及10.4个月;A组上述指标均优于B组(P均<0.05)。A组不良反应发生率为48.15%(13/27),均未见严重并发症;B组不良反应发生率为88.00%(22/25),5例(5/25,20.00%)出现严重药物毒性反应。结论 TACE联合¹²⁵I粒子治疗HCC伴PVTT的有效性及安全性均优于TACE联合仑伐替尼。     

Scintiscanning demonstration of thymoma: Comparative study on scintiscans using201Tl,67Ga and75Se

Thymus scintigraphy was performed using²⁰¹Tl-chloride,⁶⁷-Ga-citrate and⁷⁵Se-selenomethionine on 30 thymoma patients with or without myasthenia gravis. Mass negativity was observed in 6 out of 17 (35.3 per cent) and 3 out of 13 cases (23.1 per cent), respectively. A rate of 70 per cent (21 cases out of 30) of mass positivity was observed by thymus scan using²⁰¹Tl. With regard to the relation between thymus scan and cell type,²⁰¹Tl-scan exhibited a high rate of mass positivity, regardless of the cell type while the⁷⁵Sescan showed a trend toward mass positivity in epithelial cell predominant cases. With²⁰¹Tl, mass positivity was observed when the CPM/g ratio for tumors and blood exceeded 3.0. This trend can serve as an index for the suitability of supplementary chemo- and radiotherapies, as well as for prognosis in cases of relapse, and in those for whom excision was not complete.     

Inhibition of bone cell metabolism increases strontium-85 uptake

Summary Experiments have been performed on the canine tibia to investigate whether perturbation of the energy metabolism of bone cells can influence the short-term exchange of bone mineral. Simultaneous injection of three radioactive tracers,¹²⁵I-albumin,⁸⁵Sr, and⁸⁶Rb, into the tibial nutrient artery was followed immediately by measurement of the concentration of these tracers in the venous outflow from the bone for a period of 5 minutes. This procedure was performed before and after the injection of potassium cyanide into the bone. From the measured concentrations, extraction ratios for⁸⁵Sr and⁸⁶Rb with respect to¹²⁵I-albumin were calculated. It was found that net extraction after 5 minutes of⁸⁵Sr was significantly increased. This result indicates that efflux of ions from exchangeable mineral is dependent to a significant extent on the metabolic activity of bone cells.     

Resolving Erythrocytosis and Hypertension after Open Surgical Extirpation of Giant Renal Cyst Measuring 30 cm: Case Report

We previously described a method to measure GFR in conscious spontaneously voiding rats. This method circumvents the need for anesthesia and for bladder instrumentation. It's main principle is the correction of renal ¹²⁵I-iothalamate clearance for incomplete urine collection by the ratio of plasma and renal clearance of co-infused ¹³¹I Hippuran. A disadvantage of this technique is the requirement of an intra-arterial catheter for infusion of the renal function tracers. We therefore tested whether intraperitoneal infusion of ¹²⁵I-Iothalamate and ¹³¹I-Hippuran can be used for such a GFR measurement in conscious spontaneously voiding rats.

We found that during intraperitoneal administration, stable plasma levels of ¹³¹I-Hippuran could be obtained. However, urinary recovery of ¹³¹I-Hippuran was incomplete (66 ± 32%), leading to a significant overestimation of GFR by 140 ± 113% in comparison with the GFR measured by the intra-arterial technique. Thus intraperitoneal infusion of renal function tracers cannot replace intra-arterial infusion.     

Induction of transplantation tolerance by allogeneic donor-derived CD4(+)CD25(+)Foxp3(+) regulatory T cells

Several studies have shown that recipient-derived CD4(+)CD25(+)Foxp3(+) regulatory T cells (Tregs) are involved in transplantation tolerance. However, it is not clear whether allogeneic donor-derived Tregs are able to regulate T cell alloreactivity after solid organ allograft transplantation. Related studies in experimental bone marrow transplantation have shown that allogeneic donor-derived Tregs are capable of promoting early and long-term allogeneic hematopoietic engraftment, accompanied by tolerance to donor and recipient antigens. However, in these models, donor-derived Tregs are syngeneic with respect to the T responder cells. The role of Tregs in solid organ transplantation models where recipient-derived T responder and donor-derived Tregs are allogeneic has been scarcely studied. In order to determine whether allogeneic Tregs were able to regulate T cell alloreactivity, CD4(+)CD25(-) and CD8(+) T responder cells were cultured with stimulator dendritic cells in several responder-stimulator strain combinations (C57BL/6-->BALB/c, BALB/c-->C57BL/6 and C3H-->BALB/c) in the presence of responder-derived, stimulator-derived or 3rd-party-derived Tregs. Then, the frequency of IFN-gamma+ alloreactive T cells was determined by means of ELISPOT assay. The results of this study demonstrate that, regardless of the responder-stimulator strain combination, both responder-derived and stimulator-derived Tregs, but not 3rd-party-derived Tregs, significantly inhibited CD4(+) and CD8(+) T cell alloreactivity. The effect of allogeneic stimulator-derived Tregs was dependent on IL-10 and TGF-beta and reversed by exogenous IL-2. In vivo experiments in nu/nu recipients reconstituted with CD4(+)CD25(-) T responder and Tregs showed that recipient and donor-derived, but not 3rd-party-derived Tregs, significantly enhanced skin allograft survival. Importantly, T cells from both recipient-derived and donor-derived Treg-reconstituted nu/nu recipients exhibited donor-specific unresponsiveness in vitro. These results show that allogeneic donor-derived Tregs significantly inhibit T cell alloreactivity and suggest their potential use in the induction of transplantation tolerance.     

Radionuclide Therapy of Bone Metastases

The skeleton is a potential metastatic target of many malignant tumors. Up to 85% of prostate and breast cancer patients may develop bone metastases causing severe pain syndromes in many of them. In patients suffering from multilocular, mainly osteoblastic lesions and pain syndrome, radionuclide therapy is recommended for pain palliation. Low-energy beta-emitting radionuclides ((153)samarium-ethylenediaminetetrameth-ylenephosphonate (EDTMP) and (89)strontium) deliver high radiation doses to bone metastases and micrometastases in the bone marrow, but only negligible doses to the hematopoietic marrow. The response rate regarding pain syndrome is about 75%; about 25% of the patients may even become pain free. The therapy is repeatable, depending on cell counts. Concomitant treatment with modern bisphosphonates does not interfere with the treatment effects. Clinical trials using a new, not yet approved nuclide ((223)Radium) and/or combinations of chemotherapy and radionuclides are aiming at a more curative approach.     

Matriderm versus Integra: a comparative experimental study

Aim

To compare engraftment rates and vascularisation in a rat model using either Integra Artificial Skin^® or Matriderm^®.

Methods

Matriderm^® and the dermal part of Integra^® were compared in a two-step procedure including matrix implantation and subsequent epidermal grafting. Neonatal rat epidermis was used as coverage to test for rapid and complete take.

Results

Efficiency and quality of vascularisation expressed by take rate of epidermis, and thickness of resulting neodermis, were identical for both matrices.

Conclusion

This first comparison of Matriderm^® with Integra^® in a rat model revealed no major differences in engraftment rates or vascularisation.     

Bone resorption measurement with unusual bone markers: Critical evaluation of the method in phosphorus-deficient and calcium-deficient growing rats

An in vivo method to evaluate bone resorption in rats, by using unusual bone seekers not dependent on renal tubular transfer, is described and a critical evaluation of the method is made. In our experimental conditions,⁸⁵Sr and¹⁷⁷Lu are virtually exclusively localized in bone whereas²³⁷Np remains unchanged in different soft organs, so that the concomitant use of these markers can be used for measuring bone resorption. If osteolysis occurs 21 days after the injection of these markers, under our experimental conditions, any increase in the urinary excretion of¹⁷⁷Lu and²³⁷Np represents a rise in bone resorption, whereas an increase in Sr excretion reflects both bone and renal tubular events. According to our bone localization studies, the enhancement of Lu and Np excretion reflects primarily an increase in cortical bone resorption localized at the endosteal (Lu) and at the periosteal (Np) surfaces respectively. In addition, strontium is considered to be the marker of mineral resorption whereas Lu and Np, under our experimental conditions, would reflect the organic bone resorption. This method is tested in phosphorus-deficient rats and in calcium-deficient rats which exhibit disturbances of calcium metabolism at both the bone and kidney levels. In agreement with previous investigations, the use of these bone markers to evaluate osteolysis shows: (a) after a 1-week phosphorus deficiency, a slight increase in cortical bone resorption with a simultaneous fall in calcium and strontium renal tubular reabsorption, and (b) after a 1-week calcium deficiency, a high rise in cortical bone resorption with a simultaneous increase in the renal tubular reabsorption of calcium and strontium.     

Prognostic value of peripheral blood T lymphocyte subsets in clear cell renal cell carcinoma

BackgroundTo date, few studies have evaluated the role of peripheral blood T lymphocyte subsets in patients with clear cell renal cell carcinoma (ccRCC). Here we measured the levels of peripheral blood T lymphocyte subsets and evaluated its prognostic value in ccRCC.MethodsData from 122 patients with RCC from January 2018 to January 2020 were collected. Preoperative peripheral blood T lymphocyte subsets and medical records were analyzed. Kaplan-Meier cures and log rank test were used for analyzing overall survival (OS). Univariate and multivariate survival analyses were underwent by performing the Cox proportional hazards models. Correlations were tested by Pearson’s correlation analysis.ResultsOf 122 patients, a total of 80 ccRCC patients was enrolled. Patients with low CD3⁺ T cells and low CD4⁺/CD8⁺ ratio displayed a worse OS than patients with high CD3⁺ T cells and high CD4⁺/CD8⁺ ratio (P=0.029 and 0.002, respectively). Multivariate analyses showed CD3⁺ T cells and CD4⁺/CD8⁺ ratio were independent predictive factors for the OS (HR: 0.295, 95% CI, 0.091–0.956; P=0.042 and HR: 0.244, 95% CI, 0.065–0.920; P=0.037, respectively). Moreover, NLR negatively correlated with both levels of CD3⁺ T cells and CD4⁺/CD8⁺ ratio (P<0.001, r=−0.398 and P=0.012, r=−0.280, respectively).ConclusionsThe findings of our study suggest that preoperative CD3⁺ T cells and CD4⁺/CD8⁺ ratio in peripheral blood are independent predictors for patients with ccRCC.     

Uptake of45calcium and85strontium by bone in tissue culture

Embryonic chick calvaria were cultured alive and after killing by various procedures. The uptakes of⁴⁵Ca and⁸⁵Sr were measured and it was found that both live and dead calvaria discriminated against strontium in favour of calcium. The discrimination in live bone at 37° was usually higher than that in dead bone or that in live bone cultured at 4°. However, discrimination did not approach the physicochemically predicted level, which suggests that discrimination against strontium is modified by the nature of the bone crystals and their environment.

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Zusammenfassung Calvarien von Kückenembryonen wurden lebend oder nach Abtöten mittels verschiedener Techniken gezüchtet. Die Aufnahme von⁴⁵Ca und⁸⁵Sr wurde gemessen, und es zeigte sich, daß sowohl die lebenden wie die toten Calvarien Calcium gegenüber Strontium vorzogen. Die Bevorzugung war im allgemeinen im lebenden Knochen bei 37° höher als im toten Knochen oder im lebenden, bei 4° gezüchteten Knochen. Jedoch erreichte diese Bevorzugung nicht den anhand physikochemischer Überlegungen vorausgesagten Grad. Dies läßt vermuten, daß die Calciumbevorzugung gegenüber Strontium durch die Natur der Knochenkristalle und deren Umgebung modifiziert wird.

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Résumé Des calottes craniennes d'embryons de poulet sont cultivées à l'état vivant et après mortification selon divers procédés. L'absorption de⁴⁵Ca et⁸⁵Sr est mesurée et il apparait que les calottes vivantes et mortifiées prennent du calcium au détriment du strontium. Cette action au niveau de l'os vivant à 37°, est généralement plus intense que celle observée au niveau de l'os mortifié ou celle de l'os vivant cultivé à 4°. Cependant cette absorption préférenttielle n'avoisine pas les concentrations prévues par la physico-chimie, ce qui laisse penser que l'action anti-strontium est modifiée par la nature des cristaux osseux et leur environnement.

     

Induction of transplantation tolerance—the potential of regulatory T cells

Solid organ transplantation is widely accepted as an effective treatment for end organ failure. Although the treatment with immunosuppressive drugs has undoubtedly greatly improved graft survival, chronic rejection still has considerable impact on long term outcome. This, together with the undesirable side effects associated with life long treatment with immunosuppressive drugs, have significant implications for long term outcomes.In a small number of patients, drug non-compliance as well as controlled reduction or removal of maintenance immune suppressive drug therapy has led to the uncovering of a tolerant state. The challenge of achieving improved monitoring of all transplant patients may allow tailoring of immunosupression in a proportion of recipients thereby increasing the opportunities for the induction of specific unresponsiveness to donor alloantigens in the future. The immune system using several mechanisms to both induce and maintain tolerance to alloantigens, including the deletion of allo-reactive T cells, the induction of anergy, clonal exhaustion, ignorance and active suppression (immunoregulation) of allo-responses. A minor subpopulation of CD4⁺ T cells, regulatory or suppressor CD4⁺ T cells that co-express the cell-surface molecule CD25 (IL2 α subunit) at a high level may play a major role in the maintenance of specific unresponsiveness and operational tolerance to donor antigens in vivo. Intensive investigation of these cells in recent years has started to uncover the mechanisms of active suppression by regulatory T cells in this setting.