Testing of corneoscleral discs and their culture media of seropositive donors for hepatitis B and C virus genomes

The prevalence of donors seropositive for hepatitis B virus (HBV) surface antigen (HBsAg) or hepatitis C virus (HCV) antibody (anti-HCV) in western countries is estimated to be 0.5%-1%. There have been only two cases, however, published so far, where hepatitis B was suspected to have been transmitted by penetrating keratoplasty [4]. Concerning HCV, no suspected transmission by keratoplasty has been reported so far. This is also true for the time before serological screening for infectious diseases became mandatory for corneal donors. In the Lions Cornea Bank North Rhine Westfalia, 4.7% (HBV) and 3.2% (HCV) respectively of the corneas of the years 1995 to 1999 were discarded due to a "non-negative serology". In about 50% of these cases the screening test (ELISA) generated no valid signal and, therefore, a "questionable positivity" was assumed. Since in Germany corneal graft shortage still is a limiting factor for penetrating keratoplasty, this study was to evaluate the detectability of HBV-DNA and HCV-RNA in the serum samples, organ culture media and corneas of donors tested seropositive for HBsAg or anti-HCV in an attempt to obtain information as to the potential infectivity of this donor material. In this study, 29 corneas of 17 donors seropositive by ELISA for HBsAg and 27 corneas of 14 donors seropositive by ELISA for anti-HCV were evaluated. The organ culture media and the sera were screened for the presence of HBV-DNA or HCV-RNA by PCR. The corneoscleral discs were divided into a central trephinate (7 mm) and the corneoscleral rim. Concerning HBV-DNA both tissues were examined separately by polymerase chain reaction (PCR). In the case of HCV-RNA, a further, more sensitive nucleotide amplification method (NAT), the transcription mediated amplification (TMA), was used to test media, central corneas and cornealscleral rims. The media were additionally tested by PCR. Viral nucleic acid was detected in the sera from 6 of 17 HBsAg positive donors and from 6 of 14 anti-HCV positive donors. Viral genomes could not be detected in the organ culture media nor in the central corneas or corneoscleral rims by PCR at a detection limit of 1000 and 100 copies/ml. Concerning HCV-RNA, two media were positive in the TMA with 50-100 copies/ml. CONCLUSION: according to our results, the risk of transmitting hepatitis B or C virus by penetrating keratoplasty appears to be low: although hepatitis C virus RNA could be detected in 2 media (from two donors) out of 27 with a low concentration of virus copies between 50-100/ml. It remains open whether such a low virus particle number may cause infection in the recipient.