西罗莫司替代钙调磷酸酶抑制剂治疗肾毒性和慢性移植肾肾病

背景：西罗莫司替代钙调磷酸酶抑制剂治疗肾移植后钙调磷酸酶抑制剂肾毒性和慢性移植肾肾病,转换对象的选择和时机至关重要。 目的：观察不同血肌酐水平下应用西罗莫司替代钙调磷酸酶抑制剂治疗肾移植患者钙调磷酸酶抑制剂肾毒性和慢性移植肾肾病的临床效果。 方法：选择肾移植后确诊钙调磷酸酶抑制剂慢性肾毒性和慢性移植肾肾病患者,根据转换前血肌酐≤220 μmol/L和血肌酐> 220 μmol/L,各分为钙调磷酸酶抑制剂肾毒性组、慢性移植肾肾病组和钙调磷酸酶抑制剂维持组;前两组将原有免疫抑制方案中钙调磷酸酶抑制剂转换为西罗莫司,转换组共53例,钙调磷酸酶抑制剂维持患者为对照组共28例,随访3年。动态观察各组在不同随访时间点的血肌酐水平及不良事件发生率,并在随访终点共行移植肾穿刺活检9例。 结果与结论：转换前血肌酐≤ 220 μmol/L钙调磷酸酶抑制剂肾毒性组、慢性移植肾肾病组血肌酐值,在随访第24、36个月血肌酐较转换前明显降低(P < 0.05),钙调磷酸酶抑制剂维持组血肌酐呈缓慢爬行上升高于前两组(P < 0.05)。血肌酐> 220 μmol/L钙调磷酸酶抑制剂肾毒性组血肌酐转换后显著下降(P < 0.05);后两组转换后血肌酐呈爬行上升(P < 0.05)。转换后主要不良事件有轻度贫血(30.2%)、高脂血症(35.8%)、白细胞低下(22.6%)等。肾移植后血肌酐爬行升高转换西罗莫司方案疗效显著,转换前穿刺活检确诊钙调磷酸酶抑制剂肾中毒还是慢性移植肾肾病,并结合血肌酐水平综合判断是否行西罗莫司转换治疗,注意监测血脂水平;转换应在移植肾功能发生严重损害前进行,早期转换,患者将获益更大。 中国组织工程研究杂志出版内容重点：肾移植;肝移植;移植;心脏移植;组织移植;皮肤移植;皮瓣移植;血管移植;器官移植;组织工程全文链接：     

西罗莫司在肾移植受者中的转换治疗

背景：传统的钙调磷酸酶抑制剂能导致慢性移植肾肾病的发生,新型免疫抑制剂西罗莫司的出现就为替换这一治疗方案提供了可能。 目的：验证西罗莫司在肾移植后受者中转换治疗的临床效果及其安全性。 方法：对同种异体肾移植后以口服钙调磷酸酶抑制剂为主的60例受者,进行以西罗莫司为主的转换治疗,观察转换后6个月内临床效果、安全性和不良反应。 结果与结论：西罗莫司转换治疗后6个月内急性排斥反应发生率为13.3%。因慢性移植肾肾病进行药物转换的受者,转换后肾功能改善;其他转换后移植后肝损害及高血糖有所改善。结果提示西罗莫司在转换治疗时疗效优于钙调磷酸酶抑制剂。     

小剂量环孢素A减轻西罗莫司导致的移植肾蛋白尿

背景：西罗莫司作为一种低肾毒性的免疫抑制剂越来越多地取代钙调神经抑制剂用于肾脏移植后,但蛋白尿是其最常见的不良反应之一,迄今为止尚无有效的治疗措施,这很大程度上制约了它的广泛使用。 目的：观察小剂量环孢素A减轻西罗莫司导致的移植肾蛋白尿的效果和安全性。 方法：24例采用以西罗莫司为基础的三联免疫抑制方案(西罗莫司+吗替麦考酚酯+皮质激素)出现蛋白尿的肾移植患者,10例加用小剂量环孢素A(25 mg/d)的四联免疫方案患者(四联组)与14例维持原三联方案的患者(三联组),随访6个月。 结果与结论：①四联组6个月后蛋白尿有显著下降(P < 0.01),同时与三联组比较,差异也有显著性意义(P < 0.05)。②两组肾小球滤过率比较,差异无显著性意义(P=0.10)。③三联组3例次泌尿生殖系感染,四联组发生3人6例次感染,其中1例次肺部感染,5例次泌尿生殖系感染。表明小剂量环孢素在不明显增加肾毒性和感染风险的情况下可以显著减少西罗莫司导致的肾移植后蛋白尿。     

肾移植后西罗莫司致不良反应的文献分析

背景:西罗莫司是一新型免疫抑制剂,肾毒性小,已在中国用于防治肾移植后排斥反应。目的:分析肾移植后应用免疫抑制剂西罗莫司所致不良反应的临床特征和相关因素。方法:计算机检索2002/2009中国知网数据库、万方数据资源的中国期刊全文数据库国内文献收载的西罗莫司不良反应报道资料,检索词"西罗莫司、肾移植",采用文献计量学方法进行统计、分析。纳入近年中国国内报道的西罗莫司临床应用及安全性方面的研究论文,要求其中不良反应报告的病例在性别、年龄、不良反应表现等方面详细具体。排除综述类文献及不良反应报告过于简单的病例资料。结果与结论:共选入文献15篇,患者500例,其中发生不良反应病例合计468例次。468例不良反应中高脂血症发生最多(182例,占38.9%),其次为感染和发热(62例,占13.2%),肝功能异常(54例,占11.5%)等。提示西罗莫司主要不良反应为高脂血症、感染和肝功能异常等,不良反应发生与血药浓度等因素相关,定期监测血药浓度,合理调整用量,可增加西罗莫司应用的有效性及安全性。     

亲属活体供肾移植后低剂量钙调蛋白酶抑制剂的应用

背景：亲属活体肾移植供、受者移植前准备充分,供肾热、冷缺血时间较短,HLA配型的组织相容性好,移植后排斥反应发生率低,为亲属活体供肾肾移植后采用低剂量免疫抑制剂方案提供了可能性。 目的：探讨亲属活体供肾移植后低剂量钙调蛋白酶抑制剂的安全性和有效性。 方法：选取2006-01/2008-06在南京医科大学第一附属医院肾移植中心行亲属活体供肾移植的受者38例,移植后常规使用环孢素A/他克莫司+吗替麦考酚酯+泼尼松的三联免疫抑制方案。将38例患者随机分为两组：CNI常规剂量组(n=18),移植后初始药物剂量为环孢素A 6 mg/(kg•d)或他克莫司0.12 mg/(kg•d);CNI低剂量组(n=20),术后初始药物剂量为环孢素A 4 mg/(kg•d)或他克莫司0.08 mg/(kg•d);两组吗替麦考酚酯和泼尼松使用剂量相同。移植后密切随访,比较两组患者移植后不同时期的肾功能以及急性排斥反应、肺部感染、肝功能损害、肾毒性等并发症的发生情况。 结果与结论：随访12个月,CNI常规剂量组重度肺部感染死亡1例,CNI低剂量组无死亡病例。两组移植肾功能及急性排斥反应发生率比较差异均无显著性意义(P > 0.05);CNI低剂量组肝功能损害、钙调蛋白酶抑制剂肾毒性发生率显著低于CNI常规剂量组 (P < 0.05)。此外,采用低剂量钙调蛋白酶抑制剂免疫抑制方案明显减轻了亲属肾移植患者的经济负担。说明亲属活体供肾移植后采用低剂量钙调蛋白酶抑制剂的免疫抑制剂方案安全、有效。     

钙调神经蛋白抑制剂引起的肾毒性:肾移植术后的早期预防和治疗

目的:就近年来国内外预防和治疗钙调神经蛋白抑制剂肾毒性的方法进行综述。方法:应用PubMed检索及CNKI中国期刊全文数据库检索系统,以"环孢素A,他克莫司,钙调神经蛋白抑制剂肾毒性"和"Ciclosporine A,Tacrolimus,CNIS drug-induced chronic nephrotoxicity"为关键词检索相关文献。时间范围为1980-01/2010-01。选择文章主要内容与钙调神经蛋白抑制剂肾毒性直接相关、针对性强、代表性好、相关领域权威杂志的文章共44篇进行综述。结果:环孢素A与他克莫司做为常用的免疫抑制剂,明显改善了器官移植者的生活质量和生存率,如果要取得移植肾的长期存活,必须考虑到导致移植物丧失功能的病因学问题。目前,已经证明慢性移植物肾病和钙调神经蛋白抑制剂的肾毒性是导致移植肾丧失功能的主要原因,而同时钙调神经蛋白抑制剂肾毒性在慢性移植物肾病的自然病程中又起到了重要的作用。结论:目前没有有效预防和治疗钙调神经蛋白抑制剂肾毒性的手段。移植术后早期减少钙调神经蛋白抑制剂用量或撤除,或许是预防钙调神经蛋白抑制剂肾毒性更好的选择。     

CYP3A5基因多态性与肾移植后钙调神经蛋白抑制剂慢性肾毒性的相关性

背景：钙调神经蛋白抑制剂是实体器官移植后抗排斥治疗中最重要的一线药物之一,主要通过包括CYP3A5在内的CYP3A亚家族进行代谢。但关于CYP3A5基因多态性与钙调神经蛋白抑制剂慢性肾毒性的相关研究国内外鲜有报道。 目的：观察CYP3A5基因多态性与中国人群中钙调磷酸酶抑制剂慢性肾毒性发生的关系。 方法：分别收集200例肾移植后出现慢性肾毒性的中国人种患者设为肾毒组;200例肾移植至少12个月后没有出现慢性肾毒性的中国人种患者设为对照组,取两组血样和临床数据。采用聚合酶链反应-限制性内切酶片段长度多态性技术分别检测两组的CYP3A5突变位点基因型。通过统计学分析CYP3A5的基因多态性与钙调神经蛋白抑制剂慢性肾毒性之间的关系。 结果与结论：慢性肾毒组中CYP3A5基因型*1/*1+*1/*3(显示CYP3A5活性)和*3/*3(不显示CYP3A5活性)分别占39.5%(79/200)和60.5%(121/200);对照组中CYP3A5基因型*1/*1+*1/*3(显示CYP3A5活性)和*3/*3(不显示CYP3A5活性)分别占28.5%(57/200)和71.5%(143/200)。两组间差异有显著性意义(χ²=9.000,P < 0.05,OR=1.638,95%CI=1.078-2.488)。通过Logistic回归分析CYP3A5*1/*1和CYP3A5*1/*3是显著的引起CNI慢性肾毒性的危险因素(P < 0.05,OR=1.638,95%CI=1.078~2.488)。提示,CYP3A5的基因多态性可能增加肾移植患者慢性肾毒性的遗传易感性;参与钙调神经蛋白抑制剂慢性肾毒性疾病的发生。     

药物基因组学影响肾移植术后他克莫司疗效的研究进展

他克莫司(tacrolimus,FK506)是从链霉菌属中分离出来的钙调磷酸酶抑制剂,是用于预防器官移植排斥反应的一线免疫抑制剂.他克莫司作为免疫抑制剂,具有良好的治疗效果.然而,其治疗窗狭窄和药动学个体差异巨大,容易导致免疫抑制不足或过度抑制而诱导肾毒性、糖尿病等不良反应,目前是困扰临床实践的关键问题.     

夫妻间活体供肾移植

背景：近几年随着各项移植法规相继出台,中国做为器官移植大国,发展迅速,除了尸体肾移植外,活体肾移植亦得到健康快速发展,夫妻供肾做为没有直接血缘关系的活体移植,在器官移植界占据着重要地位。 目的：观察夫妻间供肾亲属活体肾移植的疗效。 方法：郑州人民医院器官移植科2008-10/2010-09进行夫妻间供肾移植11例,同期尸体供肾肾移植83例为对照组。两组受者均采用供肾静脉与髂外静脉端侧吻合,供肾动脉与髂内动脉端端吻合,输尿管-膀胱乳头式吻合,隧道包埋。免疫抑制诱导方案采用甲基泼尼松龙,基础免疫抑制采用钙调磷酸酶抑制剂(他克莫司或环孢素)、吗替麦考酚酯、肾上腺皮质激素(激素)三联免疫治疗,根据血药谷浓度调整他克莫司或环孢素的用量。移植后6个月内进行随访,评价两组受者移植后的肾功能恢复及早期并发症发生情况。 结果与结论：肾移植后两组急性排斥反应、移植物功能延迟恢复等早期并发症发生率比较,夫妻肾移植组优于尸体肾移植组,差异有显著性意义(P < 0.05)。结果提示夫妻间肾移植由于移植前准备充分,肾脏缺血时间短及夫妻间长期共同生活产生相应的免疫耐受,其疗效优于同样无血缘关系的尸体供肾移植。     

移植肾活检：病理及组织学的早期诊断价值

背景：移植肾活检病理学组织学早期诊断意义重大,单中心回顾性研究临床诊断与治疗较少。 目的：通过对肾功能不全移植肾进行常规穿刺病理活检,根据病理诊断采取相应临床治疗方式,观察治疗效果,同时明确移植肾穿刺病理活检的安全性以及在临床诊治中的意义及其重要性。 方法：选取解放军第309医院器官移植中心202例肾移植患者为研究对象,其中80例为肾移植后移植肾功能延迟恢复,122例肌酐不明原因升高。在B超引导下应用活检穿刺针行移植肾穿刺活检,对活检组织标本予以相应染色和病理组织学观察,并进行相应的临床治疗。 结果与结论：穿刺组织中,除3例(1.5%)由于组织少难以诊断,其余病理诊断移植肾正常12例(5.9%),缺血再灌注损伤合并(或)急性肾小管坏死28例(13.9%),轻度钙调磷酸酶抑制剂类免疫抑制剂急性毒性损伤22例(10.9%),轻度钙调磷酸酶抑制剂类免疫抑制剂慢性毒性损伤12例(5.9%),超急性排斥反应1例(0.5%),疑为急性排斥反应29例(14.4%),急性T细胞性排斥反应34例(16.8%),急性抗体介导性排斥反应19例(9.4%),慢性T细胞介导排斥反应16例(7.9%),慢性T细胞介导排斥反应伴急性T细胞介导性排斥反应12例(5.9%),慢性抗体介导性排斥反应3例(1.5%),高血压因素4例(2.0%),间质纤维化和肾小管萎缩,未发现特定致病因素所致病变2例(1.0%),缺血性坏死2例(1.0%),移植后肾病复发３例(1.5%),C4d免疫组化染色阳性23例(11.4%),未发现患者及移植肾的不良反应。     

The pros and the cons of mTOR inhibitors in kidney transplantation

Sirolimus and its derivate everolimus are two immunosuppressive drugs with similar chemical structure that inhibit the proliferation of T cells by interfering with a serine-threonine kinase, called mTOR. Apart from their immunosuppressive effects, these agents may also inhibit endothelial intimal proliferation, the replication of cytomegalovirus, and the development of certain cancers. The main dose-dependent adverse events of mTOR inhibitors are hyperlipidemia, thrombocytopenia, mucositis, edema, and proteinuria. The use of mTOR inhibitors in renal transplantation may allow to reduce the doses of calcineurin inhibitors. Withdrawal of calcineurin inhibitors is also possible and may improve renal function, but some patients do not tolerate this regimen because of side effects. Further studies are needed to assess the role of mTOR inhibitors in the long-term.     

Use of mTOR inhibitors in human organ transplantation

The mammalian target of rapamycin (mTOR) inhibitor drugs rapamycin (sirolimus) and everolimus have undergone extensive clinical trials for a variety of organ grafts and have been licensed for use in human transplantation. Uniquely, they block the function of a master chemical switch, the protein kinase mTOR, which integrates the multiple biochemical pathways that are necessary for growth factors to induce cell proliferation. Many of these pathways are abnormal in tumorigenesis, and the role of mTOR and its inhibitors in cancer treatment is undergoing intense investigation. There are pharmacokinetic differences between the rapamycins, however, in all major respects, their actions are the same. They show synergy with the calcineurin inhibitors in antirejection effects but also augment the nephrotoxicity of both cyclosporine and tacrolimus. They allow marked reduction in calcineurin inhibitor drug doses, which also reduces the nephrotoxicity of the combinations. In clinical trials in kidney, heart, lung, small bowel, pancreas, islet and liver transplantation in combination with cyclosporine and tacrolimus, rejection rates are equivalent or superior to those achieved with mycophenolate mofetil combinations. Despite this, its clinical usage remains limited. The side-effect profile, especially elevations in serum lipids and nephrotoxicity when administered in combination with calcineurin inhibitors, are the major factors. However, these drugs are finding an increasing place in other areas of medicine, including incorporation into endovascular coronary artery and peripheral arterial stents and in cancer therapy. Their ability to reduce fibrosis and neovascularization suggests other areas of potential use.     

Calcineurin-mediated BAD Ser155 dephosphorylation in ammonia-induced apoptosis of cultured rat hippocampal neurons

We previously reported that ammonia induced apoptosis in cultured rat hippocampal neurons with moderate increases in the intracellular calcium concentration and decreases in phospho-BAD levels. Since this suggested the involvement of calcineurin in the apoptosis, the effects of calcineurin inhibitors, 1 microM cyclosporin A and 1 microM FK506, on the ammonia-induced neuronal apoptosis were tested. Both of the inhibitors abolished the neuronal apoptosis assessed by double staining with Hoechst 33258 and anti-neurofilament antibody, and the ammonia-induced decrease in phospho-BAD Ser(155) level. Thus, calcineurin appeared to be involved in the dephosphorylation of BAD at the sites including Ser(155) in ammonia-induced apoptosis.     

Role of anti-interleukin-2 receptor antibodies in kidney transplantation

From the early 1960s, the mainstay of immunosuppression for kidney transplantation has been corticosteroids. Since then, many new drugs have been developed to maintain the renal allograft. Current maintenance immunosuppression commonly consists of corticosteroids, antiproliferative agents and calcineurin inhibitors (e.g. cyclosporin). More recently, antihuman antibodies, either monoclonal or polyclonal, have been developed to use for induction at the time of transplantation or to treat rejection. With the advances in molecular technology, a new class of antihuman antibodies [the anti—interleukin-2 receptor (IL-2R) antibodies] has emerged that incorporate a murine antigen-binding site on to a human immunoglobulin backbone. Such methodology creates antihuman antibodies with high affinity for the epitope and with prolonged serum antibody half-lives. Interleukin-2 and its receptor are central to lymphocyte activation and are the main targets of calcineurin inhibitors. In addition, the anti—IL-2R antibodies inhibit a key target in immune activation. Daclizumab and basiliximab have been shown to significantly reduce the incidence of acute rejection in kidney transplantation. Since these anti—IL-2R antibodies are well tolerated and since calcineurin inhibitors are intrinsically nephrotoxic, anti—IL-2R antibodies have been used in an attempt to avoid cyclosporin after transplantation. Data from clinical trials seem to indicate that the addition of an anti-IL-2R antibody is not sufficient to warrant complete withdrawal of calcineurin inhibitors for more than a very short period after transplantation. A more promising role for anti—IL-2R antibodies may be in renal transplant recipients with delayed graft function (DGF). Recent data on the use of either low-dose calcineurin inhibitors or sirolimus (rapamycin) in conjunction with the anti-IL-2R antibodies for patients with DGF showed no increased risk of acute rejection. Long-term graft survival with use of these low-dose calcineurin inhibitor protocols has yet to be established.     

The effect of mammalian target of rapamycin inhibition on T helper type 17 and regulatory T cell differentiation in vitro and in vivo in kidney transplant recipients

Sirolimus (SRL) is a promising alternative to calcineurin inhibitors, such as tacrolimus (TAC), in kidney transplant recipients (KTRs), but the immunological benefits of conversion from calcineurin inhibitors to SRL are not fully investigated. In the present study, we evaluated the effect of conversion from TAC to SRL on the T helper type 17/regulatory T (Th17/Treg) axis in three separate studies. First, the effect of SRL on the Th17/Treg axis was evaluated in vitro using peripheral blood mononuclear cells (PBMCs). Second, the effect of conversion from TAC to SRL on the Th17/Treg axis was studied in KTRs. Finally, the effect of SRL on CD8⁺ Treg cells was evaluated. In vitro analysis of PBMCs isolated from KTRs showed that SRL suppressed Th17 cell differentiation but TAC did not. Conversion from TAC to SRL markedly decreased the number of effector memory CD8⁺ T cells and significantly increased the proportion of CD4⁺ and CD8⁺ Treg cells compared with TAC in KTRs. SRL treatment induced the CD8⁺ Treg cells, and these cells inhibited the proliferation of allogeneic CD4⁺ T cells and Th17 cells. In conclusion, conversion from TAC to SRL favourably regulates Th17 and Treg cell differentiation in KTRs. These findings provide a rationale for conversion from TAC to SRL in KTRs.     

In vitro hypoxia and excitotoxicity in human brain induce calcineurin-Bcl-2 interactions

Although pathogenesis of neuronal ischemia is incompletely understood, evidence indicates apoptotic neuronal death after ischemia. Bcl-2, an anti-apoptotic and neuroprotective protein, interacts with calcineurin in non-neuronal tissues. Activation of calcineurin, which is abundant in the brain, may play a role in apoptosis. Using co-immunoprecipitation experiments in biopsy-derived, fresh human cortical and hippocampal slices, we examined possible interactions between calcineurin and Bcl-2. Calcineuin-Bcl-2 interactions increased after exposure in vitro to excitotoxic agents and conditions of hypoxia/aglycia. This interaction may shuttle calcineurin to substrates such as the inositol-1,4,5-tris-phosphate receptor because under these experimental conditions interactions between calcineurin and inositol-1,4,5-tris-phosphate receptor also increased. A specific calcineurin inhibitor, FK-520, attenuated insult-induced increases in calcineurin-Bcl-2 interactions and augmented caspase-3 like activity. These data suggest that Bcl-2 modulates neuroprotective effects of calcineurin and that calcineurin inhibitors increase ischemic neuronal damage.     

Calcineurin B1 is essential for positive but not negative selection during thymocyte development

During development, discrete cell fates often result from variation in the intensity of a particular signal. The mechanisms underlying these seemingly analog-to-digital switches are not understood. In developing T lymphocytes, low-intensity signals through the antigen receptor result in positive selection while more intense signals give rise to negative selection. By deleting the genetic locus encoding the regulatory B1 subunit of calcineurin specifically in thymocytes, we found an absolute requirement for calcineurin in positive selection. In contrast, calcineurin activity was dispensable in several models of negative selection. Unexpectedly, we found that removal of calcineurin activity from thymocytes results in inefficient ERK activation at the double-positive stage of thymocyte development, when selection occurs. These studies clarify the mechanism by which graded signals are converted to discrete outcomes in T cell development and further indicate that the developmental roles of calcineurin likely contribute to immunosuppression by calcineurin inhibitors.     

Macrophage colony-stimulating factor-dependent macrophage proliferation is mediated through a calcineurin-independent but immunophilin-dependent mechanism that mediates the activation of external regulated kinases

Calcineurin is constitutively expressed in bone marrow-derived macrophages. However, macrophage response to macrophage colony-stimulating factor (M-CSF) was not impaired by the use of either calcineurin inhibitors (W-13, chlorpromazine and trifluoperazine), calcium chelators (BAPTA-AM) or Ca2+ channel antagonists (verapamil, nifedipine and diltiazem). Inhibition of calcineurin expression by inhibitory antisense RNA treatment did not result in an inhibition of M-CSF-dependent proliferation. Only very high doses of cyclosporin A and FK506 inhibited macrophage proliferation induced by growth factors, such as M-CSF, granulocyte-macrophage (GM)-CSF or IL-3. This inhibitory action is mediated by the peptidylprolyl isomerase activity of the immunophilins, as demonstrated bythe use of specific inhibitors (rapamycin and sanglifehrin A). These isomerase inhibitors exerted a negative effect on a key element involved in macrophage proliferation, namely the M-CSF-dependent activation of the extracellular signal-regulated kinases (ERK). In summary, the data presented here provide new insights in the mechanism of macrophage proliferation, which may have relevant consequences. First, we showed that in M-CSF-dependent proliferation calcineurin is not involved, and second, that immunophilins play a key role and their activation blocks ERK activation.     

Immunomodulating options for liver transplant patients

Much has changed since the early years of liver transplantation. Improvements in post-transplant survival are largely due to more selective and less toxic immunosuppression regimens and advances in operative and perioperative care. This has allowed liver transplantation to become an extremely successful treatment option for patients with endstage liver disease. Beginning with cyclosporine, a cyclic endecapeptide of fungal origin and the first of the calcineurin inhibitors to find widespread use, immunosuppressive regimens have evolved to include additional calcineurin inhibitors, steroids, mTOR inhibitors, antimetabolites and antibodies, mostly targeting T-cell activation. This review will present currently available immunosuppressive agents used in the perioperative period of liver transplantation, as well as maintenance treatments, tailoring therapeutic strategies for specific populations, and advances in immune monitoring and tolerance.