Abstract
Purpose :
A case-control study to determine the influence of HLA class I matching on 5-year graft survival and risk of rejection in high-risk penetrating keratoplasty (PK).
Methods :
Transplants in the CTFS II, an observational, prospective, longitudinal clinical trial (ISRCTN25094892) to determine the influence of HLA class II matching in high-risk PK, were all matched for HLA class I antigens. Matching was defined as ≤2 mismatches in total at the A and B class I loci combined. Tissue typing used DNA methodology to avoid serological typing errors. Non-HLA matched control PKs were selected from the NHS Blood and Transplant (NHSBT) UK Transplant Registry using the same high risk criteria that were applied when recruiting patients for CTFS II; namely, the presence of pre-operative risk factors such as vascularization, glaucoma and infection/inflammation, and indications, such as pseudophakic bullous keratopathy, that were considered per se to be at higher risk of rejection or failure. Transplants were followed for 5 years and the primary outcome measures were time to first rejection episode and time to graft failure. All donor corneas were stored by organ culture for up to 4 weeks and had an endothelial cell density of at least 2200 cells/mm2.
Results :
Kaplan-Meier 5-year graft survival estimates were 68% (95% CI 66-69%, n=5732) for unmatched controls and 76% (95% CI 71-80%, n=450) for HLA class I matched cases (p=0.002). When risk factors that had an influence on PK survival in CTFS II were taken into account, the HLA matched cases still showed higher 5-year graft survival (p=0.02). However, this benefit of class I matching in terms of 5-year graft survival was not reflected in reduced risk of allograft rejection in the matched group.
Conclusions :
Matching for HLA class I improved 5-year graft survival in high risk PK but did not apparently reduce the risk of rejection.
This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.