Comparison of methods for the detection of porcine cytomegalovirus/roseolovirus in relation to biosafety monitoring of xenotransplantation products.

BACKGROUND: The porcine cytomegalovirus, a porcine roseolovirus (PCMV/PRV), is widely distributed in pig populations. It has been shown that PCMV/PRV was transmitted by pig xenotransplants to non-human primates, and significantly reduced the survival time of the recipient. PCMV/PRV was also transmitted during the first transplantation of a pig heart into a human patient. PCMV/PRV establishes a lifelong persistent infection (latency) in the host, is difficult to detect in this stage, and consequential poses a threat to future clinical xenotransplantations. Therefore, sensitive and specific methods and goal-oriented strategies how, when, and where to test should be used for screening donor pigs.

METHODS: In this study we compared experimentally the PCMV/PRV detection methods including PCR-based (real-time PCR, nested PCR) and immunological methods (Western blot assay, ELISA) recently published by Halecker et al. (Sci. Rep. 2022;12(1):21545) and Fischer et al. (Xenotransplantation 2023:e12803). We also compared the antigens used for antibody detection (a recombinant protein and synthetic peptides corresponding to a conserved region of the glycoprotein B, gB).

RESULTS: The published methods can be used for screening donor pigs, with the results being similar. The antigens used for the detection of PCMV/PRV-specific antibodies are almost identical and give comparable results. Overall, the optimal diagnostic tests, the samples used for testing and the time of sampling play a crucial role in preventing the transmission of PCMV/PRV during xenotransplantation.

CONCLUSION: Sensitive methods are available to screen donor pigs for PCMV/PRV, but a rational application of a combination of PCR-based and immunological methods as well as rational detection strategies are important for the detection of the virus during latency.