Corneal transplant allograft reactions in unilateral, double corneal transplants

In support of the idea that the HLA system plays a major role in corneal graft rejection, we report these two unique cases. Both had two penetrating grafts in the same eye. One was a regular graft and the second a patch graft to repair a perforation in the initial one. In the first case, the original graft had an allograft reaction and the patch graft remained unaffected. In the second case, an allograft reaction to the patch graft developed while the regular graft remained completely clear. Both grafts in the two cases cleared following medical therapy. The fact that in these two cases rejection reactions involved one transplant only, even though the other graft was subject to the same conditions, implies that the difference in the antigenicity of the two grafts is an important factor in the chain of events leading to rejection.     

Corneal scarring and irregular astigmatism following refractive surgery in a corneal transplant

Background: Scarring may follow refractive surgery, causing irregular astigmatism and loss of visual acuity. Methods: A case report of scarring and irregular astigmatism occurring in a corneal transplant following photorefractive keratectomy and arcuate incisions is presented. Results: Following surgical excision of the scan unaided visual acuity improved from 1/60 to 6/12. Histopathology of the excised scar was obtained. Conclusions: Refractive surgery following corneal transplantation may produce scarring. The origin of the scar in the present case has not been established.     

浅论基础免疫学研究新进展对眼科免疫学研究的启示

免疫稳态是维持机体生理健康的机制之一,免疫反应是引起或参与诸多疾病的病理过程.近年来国内外在免疫学的基础研究方面取得了较大进展,包括天然免疫机制的研究,树突状细胞（DCs）、T淋巴细胞及B淋巴细胞的亚群研究,微小RNA（miRNA）、长链非编码RNA（LncRNA）、表观遗传学对免疫功能的调控以及现代免疫学研究的新技术等,大大推动了临床免疫学研究的进步.眼是一个具有特定免疫学特征的重要器官,眼科多种疾病的病理机制涉及几大免疫学研究分支,如感染免疫、移植免疫、自身免疫、超敏反应等,因此基础免疫学的重大进展为研究眼科领域免疫学疾病的发病机制和防治策略提供了新的信息.此外,眼科免疫学是现代医学科学中研究十分活跃的领域,眼科免疫性疾病的研究成果可促进基础免疫学的重大科学问题研究.本文评述免疫学领域的最新进展趋势,并探讨其对中国眼科免疫学发展的启示.     

Corneal transplant utilizing a corneal graft that had undergone laser surgery--case report

Report on a successful clinical case of a corneal penetrating keratoplasty using inadvertently a corneal graft that had undergone laser assisted in situ keratomileusis (LASIK). Review of a clinical case of a patient of the Cornea Department of the "Hospital Oftalmológico de Sorocaba" who underwent a penetrating keratoplasty (PK) to correct keratoconus in his left eye. A corneal graft from a donor who had LASIK surgery was used. Surgery was completed without complications, although a separation of the corneal lamellae was noted during surgery. Patient evolution was good with a final corrected visual acuity of 20/40. PAM was also 20/40. Epithelial growth was noticed on the flap interface, although, without progression of this finding. Eye Banks should improve screening techniques to rule out refractive surgery in the donor corneas; there was no impairment of the final result of this transplant until the 6th month after surgery; long-term follow-up is necessary to reveal if surgical success was impaired by prior refractive surgery.     

细胞因子与角膜移植免疫

角膜移植免疫是多种免疫细胞和免疫分子参与的复杂的免疫反应过程。近来研究表明细胞因子在角膜移植免疫中起重要作用,本文对现阶段在角膜移植免疫反应中倍受关注的主要相关细胞因子的研究进行综述。     

细胞凋亡与角膜移植免疫

近年来研究表明细胞凋亡在器官移植中具有重要作用。本文从免疫郝免及免疫排斥2方面，对细胞凋亡在角膜移植中的作用进行了简要综述。     

角膜新生淋巴管与血管内皮生长因子C

角膜新生淋巴管（CL）存在于血管化角膜上，常引起并加重角膜混浊和角膜移植排斥反应，是重要的致盲原因之一。血管内皮生长因子C（VEGF—C）是血管内皮生长因子（VEGF）家族成员之一，是VEGFR-2和VEGFR-3受体的配体。VEGF-C通过与VEGFR-3结合促进淋巴管增生，是一个特异性的淋巴管生长因子，在CL形成中起着重要的作用。就近年来CL研究进展及与VEGF—C的关系进行综述。     

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.     

Corneal thickness: measurement and implications

The thickness of the cornea was reported in more than 100-year-old textbooks on physiological optics (Helmholtz, Gullstrand). Physiological interest was revived in the 1950s by David Maurice, and over the next 50 years, this 'simple' biological parameter has been studied extensively. Several techniques for its measurement have been described and physiological and clinical significance have been studied. In this review, the different methods and techniques of measurement are briefly presented (optical, ultrasound). While the corneal thickness of many animals are the same over a considerable part of the surface, in the human cornea anterior and posterior curvature are not concentric giving rise to a problem of definition. Based on this the precision and accuracy of determining the central corneal thickness are discussed. Changes in corneal thickness reflects changes in function of the boundary layers, in particular the endothelial barrier. The absolute value of thickness is of importance for the estimation of IOP but also in diagnosis of corneal and systemic disorders. Finally it is discussed to what extent the thickness is a biometric parameter of significance, e.g. in the progression of myopia or in the development of retinal detachment.     

Limbal lymphangiogenesis after corneal injury: an autoradiographic study

Blood and lymphatic vessel proliferation into the cornea occurs after severe trauma. Whilst the events early in blood vessel growth are reasonably understood, little is known of the early events in lymphangiogenesis. In this study, a model for proliferating lymphatic vessels using tritiated-thymidine autoradiography and light microscopy is described. A two-hour labeling index of 0.59% occurred in the lymphatic endothelium of the normal unstimulated limbus. After thermal cautery of the peripheral cornea, labeling of the limbal lymphatic vessels increased significantly at 36 hours, rose to a maximum of 6.8% four days after injury and thereafter returned to normal levels. Blood capillaries with a background level of 0.83% showed an increase in labeling at 17 hours, with high levels occurring at 36 hours (13.6%) and again from 61 to 84 hours (12.6%). Venular cells increased labeling at 25 hours from a control level of 0.58%, with a sharp peak of activity around 36 hours (13.2%). Synthesis of DNA similarly returned to normal levels in the blood vessels after four days. The staggered onset and differing durations of significantly increased labeling suggest either that various stimuli or arrays of stimuli are involved, or each cell type responds differently to the same stimulus for proliferation.     

碱烧伤后角膜新生淋巴管与炎症反应指数间的关联

目的 探讨角膜碱烧伤后的角膜新生淋巴管与炎症反应指数间的关联.方法 实验研究.制备大鼠角膜碱烧伤模型.采用5'核苷酸酶-碱性磷酸酶(5'-NA-ALP)双重酶组织化学染色及全角膜免疫荧光法分别检测碱烧伤后1、3 d,1、2、3、4、5、6、7及8周的角膜新生淋巴管和血管的动态变化,并进行淋巴管计数(LVC)和血管计数(BVC).同时,于裂隙灯显微镜下观察角膜炎症反应的变化,记录炎症反应指数(IF),并比较LVC和IF之间的关联.11例人角膜取自碱烧伤后行角膜移植的11例患者.淋巴管内皮细胞受体(LYVE-1)免疫组织化学染色法标记人角膜中的新生淋巴管,LVC和IF之间的关联运用Pearson's相关分析,采用配对t检验比较角膜中存在淋巴管和不存在淋巴管的患者之间IF、炎性细胞计数、碱烧伤病史、年龄的差异.结果 碱烧伤后,角膜基质层存在着新生淋巴管.碱烧伤后3 d时出现角膜新生淋巴管,2周末达到高峰,5周末消退.新生淋巴管的出现滞后于炎症反应,但先于炎症反应和新生血管而消退.LVC与IF之间呈正相关(r=0.572,P＜0.01).11例患者中3例存在着角膜新生淋巴管.与另8例角膜中无新生淋巴管的患者相比,前者IF显著性升高(t=3.28,P＜0.05)、炎性细胞计数显著性增加(t=2.42,P＜0.05),年龄显著性下降(t=2.62,P＜0.05),而碱烧伤病史无显著性差异(t=1.28,P＞0.05).结论 角膜碱烧伤后有淋巴管生成,角膜新生淋巴管和炎症反应指数之间存在着密切的关联.     

Corneal tattooing: an alternative treatment for disfiguring corneal scars

BACKGROUND: The performance and results of corneal tattooing are described in a case series of 11 patients suffering from a disfiguring corneal scar using a technique similar to conventional dermatography. METHODS: Drawing ink in different shades was applied into the anterior corneal stroma by punctures performed with a conventional spatula needle. RESULTS: Up to 4 years after surgery all patients still had satisfactory staining of the formerly cosmetically disfiguring corneal scar. CONCLUSION: Tattooing of unsightly corneal scars proved to be an efficient and easy to perform technique, yielding acceptable results during follow up.