Purpose: To determine the incidence and risk factors of late corneal graft rejection after penetrating keratoplasty (PKP).Methods: Records of all patients who had undergone PKP from 2002 to 2004 without immunosuppressive therapy other than systemic steroids and with at least one year of follow up were reviewed. The role of possible risk factors such as demographic factors, other host factors, donor factors, indications for PKP as well as type of rejection was evaluated.Results: During the study period, 295 PKPs were performed on 286 patients (176 male, 110 female). Mean age at the time of keratoplasty was 38±20 (range, 40 days to 90) years and mean follow up period was 20±10 (range 12-43) months. Graft rejection occurred in 94 eyes (31.8%) at an average of 7.3±6 months (range, 20 days to 39 months) after PKP.The most common type of rejection was endothelial (20.7%). Corneal vascularization, regrafting, anterior synechiae, irritating sutures, active inflammation, additional anterior segment procedures, history of trauma, uncontrolled glaucoma, prior graft rejection, recurrence of herpetic infection and eccentric grafting increased the rate of rejection. Patient age, donor size and bilateral transplantation had no significant influence on graft rejection.Conclusion: Significant risk factors for corneal graft rejection include corneal vascularization, anterior synechiae, irritating sutures, active inflammation, regrafting, additional surgery, trauma, uncontrolled intraocular pressure, history of graft rejection, recurrent herpetic infection, eccentric grafting and corneal scarring. Recipient age and donor cornea size do not seem to be risk factors for corneal graft rejection.

Purpose: To describe the clinical features, management, and visual outcome in a case of stromal rejection with a rare and unusual presentation after deep anterior lamellar keratoplasty (DALK).Case report: A 25-year-old healthy man with advanced keratoconus underwent DALK using the standard big bubble technique in his right eye. Five months after surgery, the patient involved in red eye, decreased vision, acute epithelial edema, acute and diffuse stromal edema, fine diffuse keratic precipitates (KPs) in the graft location and AC (anterior chamber) inflammation with cells and flair without any vascularization in the graft and recipient bed, and any infiltration or loosening of the sutures. Management with topical and systemic steroids, and topical antibiotic lead to complete resolution of stromal edema, KPs and AC inflammation. Nine months after the first episode, the patient was referred due to the same clinical presentation and similar findings on examination. Recurrence was treated successfully with the same prior medications and clear graft was achieved.Conclusion: Although there is no endothelial immune reaction after DALK for keratoconus, stromal graft rejection after DALK can be presented with the same features as endothelial graft rejection and should be differentiated from herpes simplex virus (HSV) keratouveitis.

Corneal transplantation is the most common and successful form of solid organ transplantation with a 2-year survival rate of over 90% in low risk cases. This high success rate may be due to the immune privileged status of the cornea, ACAID (anterior chamber associated immune deviation) induction phenomena and secretion of inhibitory molecules by corneal cells such as IL1-ra, IL-I a and Fas ligand. However, immunological rejection is the leading cause of corneal graft failure. This process is primarily mediated by CD4+ T cells of the Th1 phenotype. The mainstay of corneal graft rejection treatment is topical and systemic steroid. Recently topical and systemic cyclosporine A has also yielded promising results. This article reviews the molecular mechanisms of immunity in corneal graft rejection in addition to its prevention and treatment. Correct preoperative case selection is vital in preventing graft rejection.

Background: Monitoring of chemokines, CXCL9 and CXCL10, in serum may present a non-invasive detection method for rejection. Objective: To investigate the relationship between urinary levels of CXCL9 and CXCL10 and graft function following renal transplantation. Methods: 75 living-related donor renal transplant recipients were studied. Urinary levels of chemokines were collected pre-operatively, on post-operative 1st day, 7th day, 1st month, 3rd month, and at the time of rejection. Chemokines levels were assayed using and enzyme-linked immunosorbent assay. Results: Clinical variables were monitored. 10 (15%) patients had biopsy-proven rejection during the follow-up period. The urinary CXCL9 level in those with rejection was significantly higher than that in those with non-rejection group at the 1st day (p<0. 001), 7th day (p<0. 001), and at the time of rejection (p=0. 002). The urinary CXCL10 level was also significantly higher in those with rejection compared with non-rejection group at 1st day (p<0. 001), 7th day (p<0. 001), and at the time of rejection (p=0. 001). Serum creatinine level was strongly correlated with the urinary CXCL9 and CXCL10 levels at the time of rejection (r=0. 615, p=0. 002; and r=0. 519, p=0. 022, respectively). Among those with T cell-mediated rejections the mean urinary CXCL10 level increased to as high as 258. 12 ng/mL. Conclusion: Urinary CXCL9 and CXCL10 levels might have a predictive value for T cell-mediated rejection in early post-transplantation period. Measurement of urinary CXCL9 and CXCL10 levels could provide an additional tool for the diagnosis of rejection.

Purpose: To evaluate the risk factors of corneal graft rejection and failure in cases of penetrating keratoplasty (PK) performed during the years 1998-1999.Materials and Method: As a cross sectional study, demographic and individual characteristics, causes of PK, rejection types, and risk factors were evaluated. Risk factors of graft rejection, survival, duration of clarity, and finally failure rates for each factor were studied. Data was analyzed with SPSS 10.0; Chi- square and multivariate regression tests were used for statistical analysis.Result: During two years of study, 295 PKs were performed on 286 patients including 67% men. Average age was 37 ± 20 years. Patients were followed for 20 ± 10 months. Graft rejection occurred in 31.8% of cases within 7.3 ± 6 month. Endothelial rejection was the most common type of rejection (20.7%). Risk factors for rejection were: extensive corneal vascularization, regraft, iridocorneal adhesions, irritating suture, active intraocular inflammation at the time of operation, secondary anterior segment surgery, history of trauma, poorly controlled intraocular pressure (IOP) and glaucoma, previous graft rejection, reactivation of herpes on the graft, and eccentric PK (P<0.05). On the other hand, patients' age at the time of PK, donor cornea size, and bilateral PK were not found to be a significant risk factor for graft rejection (P>0.05).Conclusion: Severity and extent of recipient corneal vascualrization, iridocorneal adhesions, irritating sutures, active inflammation, regraft, trauma, poorly controlled IOP, recurrence of herpetic keratitis, eccentric graft, and graft ulcer were related to graft rejection. Recognition of these risk factors and early diagnosis and proper treatment of graft rejection can extend graft survival and clarity.

Purpose: To investigate the efficacy of topical cyclosporine A 2% in treating and preventing recurrent graft rejection episodes after penetrating keratoplasty (PKP) in patients with history of previous rejection episodes.Methods: In this clinical trial, eligible PKP patients were randomly given topical cyclosporine A 2% or placebo in addition to a standard corticosteroid regimen for an episode of recurrent subepithelial or endothelial graft rejection. Primary indications for transplantation were keratoconus, Fuchs' endothelial dystrophy, corneal stromal dystrophy, and nonvascularized scars. Topical cyclosporine and placebo were continued for 6 months. The duration of corticosteroid therapy and resolution of graft rejection episode, the number of concurrent and subsequent rejection episodes and the rate of rejection-free survival were compared between the study groups.Results: Twenty-two eyes of 22 patients (12 men) received a combination of topical cyclosporine A 2% and betamethasone 0.1% (group 1) and 21 eyes of 21 patients (10 men) received topical betamethasone 0.1% and placebo (group 2) for an episode of recurrent graft rejection. Mean patient age was 32.48±11.9 and 35.48±11.7 years in group 1 and 2, respectively (P=0.42). Mean follow-up period was 16.6±6.1 months in group 1 and 16.0±6.3 months in group 2 (P=0.75). The episode for which topical cyclosporine 2% or placebo was started completely resolved after 25.6±21.0 and 33.2±16.7 days in group 1 and 2, respectively (P=0.22).The rejection free graft survival rate was 34.8% in group 1 and 31.7% in group 2 (P=0.89).Conclusion: Adding topical cyclosporine A 2% had no further advantage over corticosteroid therapy alone to treat and prevent graft rejection in repeated rejection.

Corneal transplantation is among the most successful organ transplantations in humans due to its immune privilege. This owes to lack of blood and lymph vessels and the absence of major histocompatibility complex antigen presenting cells (MHC-II APCs) in the cornea. However, vaccination may trigger MHC-II response as well as antigenic cross reactivity, resulting in allograft rejection. This has been reported earlier in sporadic cases after influenza and yellow fever vaccines. With the rampant vaccination and booster doses against COVID-19, similar episodes of post-vaccination graft rejection in penetrating and lamellar keratoplasties have been reported. We had reported a case of corneal graft rejection post covid vector vaccine which recovered with steroid medications. Allograft rejection with various subtypes of vaccination opens the door to comprehend immune privilege mechanisms and prophylaxis against organ rejection. Clinicians and patients are advised to be alert to this possibility, for prompt recognition as well as treatment of postvaccination corneal graft rejection.

Background and Objectives: Immunologic rejection of the transplanted cornea is the major cause of human allograft failure with several risk factors contributing to it. Since in the corneal graft, most individuals do not reject the graft, we used the survival analysis with cure rate for the assessment of the factors influencing the cure rate at the time of data analysis. The main aim of this study was to evaluate the cure rate and assess the risk factors for corneal graft rejection in the keratoconus disease in Labafinejad Hospital, Tehran, Iran.Methods: This was a routine data base study in which the data were gathered from keratoconus patients’ files that had undergone penetrating keratoplasty operation. In the survival analysis, individuals who didn’t reject corneal were considered cured. To study the factors influencing the cure rate, we used the Weibull distribution for survival function and the logistic link function for the cure rate because of their tractability and accuracy.Results: Out of 119 patients 31 patients (26%) rejected grafts. Among the factors influencing cure rate, only in vascularization and in persons older than 25 years of age was ameaningful effect on decreasing cure rate. With this cure model, the expected cure rate in the non-vascularization and less than 25 year- old patients was 81, in non-vascularization and more than 25 year- olds it is 64, in the vascularization and less than 25 year- olds, the cure rate is 19 and in the vascularization and more than 25 years of age, the cure rate is 9 percent and the observed cure rate for Kaplan-Meier product limit estimator was 79, 61, 27 and 0 percent, respectively. The results showed that the estimate of cure rate in the survival analysis was near the Kaplan-Meier product-limits estimator.Conclusion: One of the benefits of modeling is its ability to generalize the results, using them in the prediction. According to the results obtained from the fitting cure model the vascularization is a major risk factor for decreasing cure rate in the keratoconus disease. We could use the cure rate model in the analysis of survival data with cure fraction.