Influence of HLA-A, HLA-B, and HLA-DR matching on rejection of random corneal grafts using corneal tissue for retrospective DNA HLA typing.

AIM: To establish if coincidental HLA-A, HLA-B, and HLA-DR tissue matching is associated with a reduced likelihood of corneal graft rejection. METHODS: Organ culture preserved random donor corneas were used for penetrating keratoplasty (PKP). Corneal tissue from all graft recipients and donors or blood samples from recipients after repeated transplantation were obtained in order to perform retrospective molecular HLA typing. A group of 21 recipients with a rejection episode (cases) after corneal transplantation was compared with a control group of non-rejectors (n = 43). 31 graft recipients were considered as high risk patients. The influence of HLA-A, HLA-B, and HLA-DR matching on rejection free graft survival time was analysed with Kaplan-Meyer statistics and Cox regression. RESULTS: A prolonged rejection free survival time was observed in graft recipients with one or two HLA-A matches (log rank test, p = 0.034). This effect was also observed in high risk graft recipients with one or two HLA-DR matches (log rank test, p = 0.030). CONCLUSIONS: Coincidental HLA-A and HLA-DR matches were observed and associated with a prolonged rejection free survival time in the total group and in the high risk group, respectively. These results support the beneficial effect of prospective HLA-A and HLA-DR typing upon corneal graft survival.

Detection of herpes simplex virus type 1, 2 and varicella zoster virus DNA in recipient corneal buttons.

AIM: To study the value of polymerase chain reaction (PCR) analysis, to detect viral DNA in recipient corneal buttons taken at the time of penetrating keratoplasty (PKP) in patients with an initial diagnosis of herpetic stromal keratitis (HSK). Since HSK has a tendency to recur, an accurate diagnosis of previous HSK could be the reason to start antiviral treatment immediately, thereby possibly decreasing the number of graft failures due to recurrent herpetic keratitis. METHODS: Recipient corneal buttons and aqueous humour (AH) samples were obtained at the time of PKP from HSK patients (n=31) and from other patients (n=78). Eye bank corneas were also used (n=23). Herpes simplex virus type 1 (HSV-1), type 2 (HSV-2), and varicella zoster virus (VZV) infection were assessed by PCR and antibody detection. RESULTS: The clinical diagnosis HSK could be confirmed by PCR for HSV-1 in 10/31 (32%). In these corneal buttons HSV-2 DNA was detected in 1/31 (3%) and VZV DNA in 6/31 (19%). Intraocular anti-HSV antibody production was detected in 9/28 AH samples tested (32%). In the other patient derived corneas HSV-1 DNA was detected in 13/78 (17%), including eight failed corneal grafts without clinically obvious herpetic keratitis in the medical history. In clear eye bank corneas HSV-1 was detected in 1/23 (4%). CONCLUSIONS: PCR of HSV-1 on corneal buttons can be a useful diagnostic tool in addition to detection of intraocular anti-HSV antibody production. Furthermore, the results were suggestive for the involvement of corneal HSV infection during allograft failure of corneas without previous clinical characteristic signs of herpetic keratitis.

Cytokines in aqueous humour and serum before and after corneal transplantation and during rejection.

Cytokine profiles in aqueous humour were studied in relation to corneal disease and subsequent corneal graft survival or rejection. Cytokine levels in samples obtained from eyes with clear grafts (n = 59) were all within the normal range. At the time of penetrating keratoplasty (n = 146), intraocular levels of IL-6 were increased in 38% (50/131), most markedly in eyes with previous allograft failure or herpetic stromal keratitis. The level of IL-10 was increased in 1 eye (n = 144) and of IL-4 and IFN-gamma in none. During rejection (n = 10), the levels of IL-6 in aqueous humour were increased in 75% (3/4), of IL-10 in 50% (3/6), of IL-4 in none (0/4) and of IFN-gamma in 40% (2/5). In conclusion, the levels of total protein and IL-6 were increased prior to penetrating keratoplasty in eyes with previous inflammation. These results could however not predict the final outcome of the graft. Increased intraocular levels of IL-6, IL-10 and IFN-gamma were observed during rejection.

Molecular cloning of a new angiopoietinlike factor from the human cornea.

PURPOSE: To isolate tissue-specific gene products that contribute to corneal integrity. METHODS: A cDNA library was constructed and differentially hybridized. Cornea-specific clones were purified and further characterized. RESULTS: In this study cornea-specific gene products were isolated by differential cDNA hybridization. In addition to known cornea-specific gene products, a transcript was isolated coding for a protein homologous to the angiopoietins, a recently described family of (anti)angiogenic factors. Subsequently, the full cDNA was sequenced, and the identified open reading frame was named cornea-derived transcript 6 (CDT6). Similar to the angiopoietins, CDT6 contains a hydrophobic NH2-terminal sequence, a coiled-coil domain, and a COOH-terminal fibrinogenlike domain. Expression of CDT6 could be detected only in the cornea and not in several other adult human tissues. Within the cornea, expression of CDT6 is confined to the stromal layer. CONCLUSIONS: The human cornea shows high-level expression of a gene product homologous to the (anti)angiogenic factors, the angiopoietins. This homology, together with stromal-specific expression, suggests that this factor may contribute to the avascularity of the human cornea.