Does HCV Core Antigen or Nucleic Acid Testing in Graft Donors Improve Organ Transplantation Viral Safety?

Organ transplantation recipients are exposed to the transmission of various viruses. Viral safety is based on careful selection of the grafts, based on both clinical criteria and systematic screening for the following markers: anti-human immunodeficiency virus antibodies and p24 antigen, anti human T-cell leukemia virus antibodies, anti-cytomegalovirus antibodies, anti-Epstein- Barr virus antibodies, HBs antigen, anti-HBs antibodies and anti-HBc antibodies, and anti-hepatitis C virus (HCV) antibodies. A residual risk of HCV transmission is theoretically associated with the "serological window" that can occur in an acutely infected patient before seroconversion, and that can last for up to 70 days. The objective of this study was to determine the value of HCV core antigen detection and of nucleic acid testing (NAT) to improve viral safety of organ grafts. We tested blood samples prospectively collected between may 1992 and may 2000 in 2000 consecutive organ donors from the Paris area for the presence of: i) HCV core antigen with a new enzyme immunoassay (Core Antigen ELISA Test System, Ortho-Clinical Diagnostics, Raritan, New Jersey), ii) HCV RNA using the Transcription-Mediated Amplification assay (Chiron Procleix[sup TM] TMA HIV-1/HCV Assay, Chiron). HCV core antigen positive results were confirmed by neutralization. Of 2000 samples tested, 5 were found to be positive for the HCV core on first determination, among which 4 were confirmed to be specific (prevalence 0.20%; 95% confidence interval: 0.10%-0.30%). These four donors were also anti-HCV antibody-positive. The donor with a nonspecific reaction was antibody-negative and HCV RNA negative in PCR. NAT preliminary results show that 1.2% of sample tested were reactive. In conclusion, the residual risk of HCV transmission by organ transplantation appears to be very small. HCV-infected patients are well identified by the detection of anti-HCV antibodies and implementation of HCV core antigen detection would increase the cost without clear benefit for viral safety. [ABSTRACT FROM AUTHOR]