Active Replication of Porcine Cytomegalovirus (PCMV) Following Transplantation of a Pig Heart into a Baboon despite Undetected Virus in the Donor Pig

Abstract

Viral zoonoses may represent a serious problem when xenotransplantation using pig cells, tissues, and organs will be performed. Recently we reported multiorgan failure, mainly liver failure, in a baboon (Papio anubis) after orthotopic transplantation of a heart from a genetically modified pig and showed that the baboon was not infected with hepatitis E virus (HEV). Since pigs are frequently infected with porcine cytomegalovirus (PCMV), and the infection is latent and therefore difficult to detect, screening for PCMV was performed, using a highly sensitive real-time PCR and a nested PCR. In addition, to confirm the absence of HEV, more specific immunological methods and a real-time PCR were used. Only two out of six available pigs, including the selected donor animal, were found negative for both viruses. Nevertheless, PCMV was detected in the blood of the baboon. The titre of PCMV in the blood was above 3x104/ ml and analysis of its sequence confirmed that it was PCMV, but not baboon CMV. The data highlight a considerable risk of PCMV infection and call for regular screening of donor pigs applying the most sensitive detection methods.