高危角膜移植的围手术期治疗

目的　探讨高危角膜移植患者围手术期的处理措施 ,以降低术后免疫排斥反应率。方法　对 6 80例有完整随访记录的穿透性角膜移植中的 12 4例 (137眼 )高危角膜移植患者 ,分别在围手术期 (术前、术中、术后早期 )进行相应处理。结果　经围手术期处理后 ,本组 137眼高危患者穿透性角膜移植后的免疫排斥率为 37% ,植片透明率为 80 .1% .结论　重视高危角膜移植围手术期的处理 ,是减少术后免疫排斥反应和提高植片透明率的重要措施     

加强我国角膜移植免疫研究

通过角膜移植更换混浊或病变的角膜,是帮助角膜盲患者恢复视力的有效措施,但植片排斥反应的发生是导致角膜移植手术远期失败的主要原因,如何减少因植片排斥引起的再次致盲是角膜病研究的重点。本文分析了我国角膜移植免疫研究存在的问题：（1）没有建立标准的抗排斥治疗方案;（2）缺乏安全、有效的抗排斥反应治疗药物;（3）忽视围手术期的并发症处理;（4）角膜移植免疫基础研究薄弱。针对上述问题产生的原因,提出了相应的处理措施和建议,以增强角膜病专科医生对角膜移植免疫临床和基础研究的重视,促进我国角膜盲的防治工作取得更大的发展。     

穿透角膜移植术后免疫排斥反应高危因素分析

为确立角膜移植术后免疫排斥反应的有效防治策略。对穿透角膜移植术后发生免疫排斥反应的８６个病例（１００只眼）进行回顾性总结。统计分析结果表明：血管化角膜、大植片移植、植床术前的活动性炎症，偏中心移植、多次移植、联合手术均应视为穿透角膜移植术后免疫排斥反应的高危因素，而移植片上皮反复脱落、旧病复发、术眼再次手术、缝线松解与拆线等可能是诱导排斥反应发生的促发因素。结论：从分子水平减少供受体间的抗原差异，研制新一代高效安全的免疫抑制剂、创造免疫耐度的理想环境可能是控制高危角膜移植免疫排斥反应的有效防治措施。     

二次穿透性角膜移植术的临床研究

目的 对穿透性角膜移植术后植片混浊的原因及二次穿透性角膜移植术的临床技巧及疗效进行初步研究.方法 回顾性研究,对40例因植片混浊行二次穿透性角膜移植术的患者,对原发病、植片混浊原因和两次手术时间二次移植的植片的大小进行分析,随访观察植片透明度、视力及免疫排斥情况.结果 感染性角膜炎居原发病首位.免疫排斥反应为植片混浊的主要原因,其次为植片感染性角膜炎复发、再发或继发.10例因植片感染于6个月及以内更换植片,30例因植片混浊于6个月以上更换植片.5例原直径过大而采用小直径植片;29例原直径≤8.25mm而采用等直径植片;6例因复发感染累及植片周边而扩大植片直径.随访32例植片(≤8.25mm)透明,视力较术前明显提高.8例植片混浊,其中5例混浊由免疫排斥所致.结论 造成二次穿透性角膜移植术的主要原因为植片免疫排斥和感染性角膜炎复发、再发或继发,据植片混浊不同病因采取不同直径的二次植片可有效减低免疫排斥反应发生率及治疗原发病复发或再发,延长植片透明时间.     

重视儿童角膜移植术的特殊性

儿童角膜移植是减少角膜盲发生,促进视觉发育的重要手段.但是,由于儿童角膜巩膜刚性低,术中晶状体-虹膜隔易前移错位,术后易致屈光不正、植片发生免疫排斥反应,以及潜在的眼后节疾病对手术时机选择的影响等,儿童角膜移植的失败风险率较高.因此,对手术时机的慎重选择,以及术后角膜移植排斥反应、青光眼、植片感染和融解等的正确认识,有助于提高儿童角膜移植的成功率.     

儿童穿透性角膜移植术后并发症的临床分析

目的 探讨儿童穿透性角膜移植术后并发症的原因、治疗和预后,为临床围手术期处理提供参考.方法 对在1994年1月至2006年12月于山东省眼科研究所接受穿透性角膜移植具有完整随诊资料的儿童患者(年龄≤14岁)67例(80只眼)进行回顾性分析.随访时间6月至13年,平均2.7年.结果 44只眼(55.0%)发生术后并发症,发生率分别为免疫排斥反应41.3%,继发性青光眼10.0%,并发性白内障5.0%,缝线松脱3.8%,植片溃疡3.8%,虹膜前粘2.5%,植片哆开2.5%,植片上皮缺损2.5%,伤口漏水1.3%和视网膜脱离1.3%.及时针对不同病因治疗后18例植片恢复透明或部分透明,26例植片完全混浊.结论 儿童穿透性角膜移植术后并发症发生率高,是导致移植失败的主要原因,免疫排斥反应是最常见的并发症.积极采取有效措施防治术后并发症对于提高手术的成功率有着重要意义.     

角膜移植术后免疫排斥反应的防治进展

由于角膜的免疫赦免地位 ,角膜移植是众多器官和组织移植中成功率最高的 ,也是角膜盲患者复明的唯一手段。然而移植后的免疫排斥反应仍然是造成角膜移植术后失败的主要原因。尤其二次移植、新生血管化植床等高危因素的患者 ,术后的免疫排斥发生率高达 6 0～ 90 %。而目前我国多数为高危因素的患者。因此 ,有效的控制角膜移植术后免疫排斥反应的发生就成为角膜植片能否长期存活的关键所在。目前用于减少或防治角膜移植术后免疫排斥反应的方法综合如下 :1 组织配型组织配型主要包括主要组织相容性抗原 (HLA)配型和ABO血型抗原配型。在心脏…     

共刺激分子Tim-1在角膜移植排斥反应中的作用

背景 角膜移植是目前临床上治疗角膜盲可靠且有效的复明手段,角膜移植术后的免疫排斥反应是角膜移植失败的主要原因. 目的 研究共刺激分子Tim-1在大鼠角膜组织中的表达及其在角膜移植排斥反应发生和发展过程中的作用.方法 40只清洁级成年雌性Wistar大鼠随机分为正常对照组、自体角膜移植组和同种异体角膜移植组.正常对照组大鼠未行任何手术,自体角膜移植组分别以Wistar大鼠作为供体和受体施行穿透角膜移植术,而同种异体角膜移植组以SD大鼠角膜作为供体,Wistar大鼠作为受体行穿透角膜移植术,各组供体角膜植片均为3.5mm,植床直径为3.0 mm.分别于术后7d、14d在裂隙灯显微镜下观察术眼角膜炎症反应情况,按照Larkin的标准进行排斥反应评分,计算排斥反应指数（RI）,观察各组角膜植片的平均存活时间和植片存活率.术后7d、14d,3个组各取3只大鼠眼球制备角膜组织切片,分别行组织病理学检查和免疫组织化学检测,观察角膜组织的炎症反应和共刺激分子Tim-1蛋白在角膜组织中的表达;此外分别于术后7d、14d各组取5只大鼠角膜制备组织匀浆,采用实时荧光定量PCR法检测共刺激分子Tim-1 mRNA在大鼠角膜植片中表达量（吸光度,A）的变化.结果 术后7d,自体角膜移植组和同种异体角膜移植组大鼠角膜植片均出现轻度水肿;术后14 d,自体角膜移植组角膜植片水肿消失,植片透明,而同种异体角膜移植组大鼠角膜植片水肿增厚,呈灰白色混浊,可见新生血管形成.自体角膜移植组植片的存活率为100％,同种异体角膜移植组植片存活率为0,平均生存时间为（9.8±1.2）d.组织病理学检查表明,术后7d自体角膜移植组植片基质层可见炎性细胞浸润,但术后14d炎性细胞明显减少;同种异体角膜移植组术后7d植片水肿,基质层可见炎性细胞浸润,术后14 d阳性细胞大量增加,可见新生血管.免疫?     

免疫赦免在小鼠角膜移植排斥中的作用研究

目的:阐明同种异体小鼠角膜移植术后免疫排斥反应及免疫赦免的相关性。方法:建立小鼠原位角膜移植及同种异体小鼠角膜移植实验模型。观察原位移植与同种异体移植术后角膜植片发生排斥的情况,对比两种移植术后植片的存活率,了解小鼠角膜移植术后发生排斥反应与免疫赦免反应之间的关系。结果:小鼠原位角膜移植术后植片100%存活;同种异体小鼠角膜移植术后存活率为25%。结论:小鼠角膜移植术后免疫排斥并非绝对,免疫赦免在角膜移植术中发挥重要作用。     

板层角膜移植术治疗真菌性角膜溃疡疗效分析

目的探讨板层角膜移植术治疗中、浅层真菌性角膜溃疡的手术适应证及临床疗效。方法67例（67眼）真菌性角膜溃疡经抗真菌药物治疗效果不满意者行板层角膜移植术,术后观察复发情况、角膜植片透明度及免疫排斥反应。结果术后随访6个月至2年,其中66例（66眼）术后有效控制了感染,植片透明,无排斥反应,术后视力提高至0.3-0.6。1眼真菌感染复发。结论板层角膜移植可有效治疗中、浅层真菌性角膜溃疡。     

Corneal graft rejection

Penetrating keratoplasty is the most widely practiced type of transplantation in humans. Irreversible immune rejection of the transplanted cornea is the major cause of human allograft failure in the intermediate and late postoperative period. This immunological process causes reversible or irreversible damage to the grafted cornea in several cases despite the use of intensive immunosuppressive therapy. Corneal graft rejection comprises a sequence of complex immune responses that involves the recognition of the foreign histocompatibility antigens of the corneal graft by the host's immune system, leading to the initiation of the immune response cascade. An efferent immune response is mounted by the host immune system against these foreign antigens culminating in rejection and graft decompensation in irreversible cases. A variety of donor- and host-related risk factors contribute to the corneal rejection episode. Epithelial rejection, chronic stromal rejection, hyperacute rejection, and endothelial rejection constitute the several different types of corneal graft rejection that might occur in isolation or in conjunction. Corneal graft failure subsequent to graft rejection remains an important cause of blindness and hence the need for developing new strategies for suppressing graft rejection is colossal. New systemic pharmacological interventions recommended in corneal transplantation need further evaluation and detailed guidelines. Two factors, prevention and management, are of significant importance among all aspects of immunological graft rejection. Preventive aspects begin with the recipient selection, spread through donor antigenic activity, and end with meticulous surgery. Prevention of corneal graft rejection lies with reduction of the donor antigenic tissue load, minimizing host and donor incompatibility by tissue matching and suppressing the host immune response. Management of corneal graft rejection consists of early detection and aggressive therapy with corticosteroids. Corticosteroid therapy, both topical and systemic, is the mainstay of management. Addition of immunosuppressive to the treatment regimen helps in quick and long term recovery. Knowledge of the immunopathogenesis of graft rejection may allow a better understanding of the immunological process thus helping in its prevention, early detection and management.     

同种异体角膜移植后角膜内皮细胞的特征表现及生物学意义

同种异体角膜移植目前仍是治疗角膜疾病最为有效的方法,但术后发生的免疫排斥所引起的角膜炎症反应和血管化,最终导致植片水肿,甚至功能丧失仍是造成手术失败的最主要原因.角膜内皮细胞作为免疫赦免及角膜正常生理功能维系的首要屏障,在眼部系统中占据着至关重要的位置.本文就同种异体角膜移植术后免疫的识别,应答和最终反应的各阶段角膜内皮所呈现的特征改变及生物学意义进行阐述.

Abstract：

Allograft corneal transplantation is currently the most effective and optimum method to treat corneal disease, however it is the immune rejection that the main reason for graft edema caused by vascularization and inflammation of the cornea and surgical failure after transplantation. Corneal endothelial cells occupy a crucial position as immune privilege and the primary barriers for maintaining normal physiological function of eye. In this paper, the various stages (recognition, response and reaction of immune system) of corneal endothelial changes in the morphological and biological characteristics had been presented after allograft corneal transplantation.     

Graft failure IV. Immunologic mechanisms of corneal transplant rejection

Corneal transplantation is the oldest and the most common form of solid tissue transplantation in humans. Immunologic graft rejection is one of the main causes of short and long-term graft failure. Rejection involves donor tissue recognition and destruction by allo-specific immune cells of the recipient. This review outlines (1) the immunobiology of transplantation, with reference to ocular immune privilege, (2) factors that confer “high-risk” status to a graft and (3) the pathophysiologic mechanisms of corneal transplant rejection.     

Pharmacologic strategies in the prevention and treatment of corneal transplant rejection

Corneal transplantation remains one of the most successful organ transplantation procedures in humans. The unique structure of the cornea, with its absence of blood vessels and corneal lymphatic, allows the survival of corneal allograft. Recent advances in sutures, storage media, microsurgical instrumentation, and new pharmacological strategies have greatly improved the success of corneal transplantation and the prevention of corneal allograft rejection. Our strategies in the management and prevention of corneal graft rejection can modify and improve the survival of corneal allografts. Preoperative evaluation, understanding the risk factors, and management of ocular surface disorders may greatly improve the survival of the corneal transplant. Early recognition of corneal allograft rejection and aggressive treatment may improve the survival of the corneal graft. Furthermore, patients who undergo corneal transplantation should be maintained under close ophthalmic surveillance and patients should be informed to report immediately whenever symptoms of corneal graft rejection occur. The mainstay of therapy is topical corticosteroids. In severe cases, periocular, intravenous, and oral corticosteroids therapy can be rendered. New therapeutic modalities such as cyclosporine, tacrolimus, daclizumab, mycophenolate mofetil, leflunomide, rapamycin, and others may prove to be of help in the prevention and treatment of corneal graft rejection. Early recognition of corneal graft rejection and prompt treatment are mandatory for the successful survival of the corneal allograft.     

Racial Disparities in Corneal Transplantation Rates,Complications, and Outcomes

ABSTRACT

Corneal transplantation is a common type of tissue transplantation that aims to improve vision or relieve pain. Given the immune privilege of the cornea, the primary graft often has a high success rate, approaching 90%. Despite the good overall outcome of corneal transplantation in various studies, the individual graft survival rate varies, depending on the preoperative diagnosis and donor and recipient factors. Race and ethnicity have been shown to be important in other types of organ transplantation. The aim of this study was to review the available ophthalmic literature regarding any differences in rates and outcomes of corneal transplantation based on ethnicity and race. A small body of evidence suggests that race might be an important risk factor for graft rejection and graft failure. More robust studies are needed to clarify these associations.     

角膜移植排斥反应中调节性T细胞的发展及应用

角膜移植术是角膜盲的有效治疗方式,是角膜盲患者复明的唯一希望。角膜无血管、无淋巴管,被称为免疫赦免器官,因此角膜移植术的成功率明显高于其他器官移植术,但角膜移植术后的排斥反应仍然是角膜移植术失败的主要原因。器官移植术后的免疫反应主要是免疫细胞向淋巴组织、炎症部位的定向移动,而调节性T细胞(regulatory T cells,Treg)在免疫调节中起着关键性作用,其可以通过调节和抑制效应T细胞的活化来诱导免疫耐受,从而减轻角膜移植术后的排斥反应。据此,文章对在角膜移植术后发生免疫排斥反应中Treg的来源、作用机制以及治疗等多方面做简单综述,同时也探讨了应用冬虫夏草提取物FTY720增强Treg的有效性,以期为后续针对性开展临床应用转化及基础研究提供一定的参考。     

Current concepts and techniques in keratoprosthesis

PURPOSE OF REVIEW: Diseases affecting the cornea are a major cause of blindness worldwide, second only to cataract in overall importance, with an estimated 10 to 15 million affected people. Although keratoplasty is by far the most successful transplantation surgery, the outcomes in high-risk adult patients, including those with ocular surface diseases and multiple graft rejections, and in pediatric patients with congenital corneal opacities are disappointing. RECENT DEVELOPMENTS: Regrettably, no significant clinical developments have been achieved in the field of corneal transplantation since the introduction of steroids for graft rejection. Furthermore, obtaining donor corneal tissues and eye banking, particularly in the developing countries where corneal blindness is most prevalent, are problematic. Although the postoperative complications may be severe and limit the use of currently available devices, keratoprosthesis--artificial corneal implantation--has a role in the management of corneal blindness in carefully selected patients with complex ocular diseases who are at high risk for graft failure. SUMMARY: This article reviews the recent ophthalmic literature published on the current concepts and techniques of keratoprosthesis surgery.     

角膜内皮移植术

角膜内皮移植是一种新的治疗角膜内皮病变的手术方法,主要是采用健康的角膜内皮片替代病变内皮层.该方法因为几乎不改变患者的角膜曲率和屈光状态,损伤小,视力恢复快,近年来在临床上逐渐被推广应用,取得较好愈后效果.该方法是角膜移植手术不断精细化和向屈光性手术转化的具体体现.角膜内皮移植术后良好的屈光效果和可能的低排斥率,使其有望成为角膜内皮病变治疗的重要方式.但是,目前内皮移植手术仍然需要完善,改进植入方法以减少脱片率和内皮细胞损失率,利用飞秒激光等进一步提高屈光效果,以及观察术后免疫排斥率是今后眼科学者的研究重点.     

The taming of the shrew? The immunology of corneal transplantation

Corneal transplantation, first reported a century ago, is the oldest and most frequent form of solid tissue transplantation. Although keratoplasty is also considered as the most successful transplant procedure, several studies indicate that the long term survival of corneal grafts is even lower than that of transplanted parenchymatous organs. Despite the immune privilege enjoyed by the cornea and anterior segment of the eye, immunologic graft rejection is a major limitation to corneal transplantation. This review gives an update on corneal immunobiology and the mechanisms of corneal graft rejection, focusing on antigen presentation, as well as on the molecular and cellular mediators of this particular immune response.