Sequencing of Cell-Free DNA to Monitor Cytomegalovirus Infection After Liver Transplant

Objectives: In the present study, we investigated donor-derived cell-free DNA dynamics and assessed the diagnostic efficacy of 2 tests: the sequencing of cytomegalovirus-derived cell-free DNA and the quantitative nucleic acid amplification test in cytomegalovirus infection following liver transplant. Materials and Methods: We first examined 6 patients who were identified with active cytomegalovirus DNAemia by both quantitative nucleic acid amplification test and next-generation sequencing of cytomegalovirus-derived cell-free DNA and then performed a receiver operating characteristic analysis to evaluate the efficacy of cell-free DNA sequencing and establish a cutoff for this assay. Further validation of the next-generation sequencing method was also performed in 84 liver transplant recipients. The study protocol conformed to the ethical guidelines of the Declaration of Helsinki and the Declaration of Istanbul. Results: In the first 6 patients, there was no significant correlation between the cytomegalovirus infection and donor-derived cell-free DNA. We determined that the levels of cytomegalovirus-derived cell-free DNA sequencing directly correlate with the results of the quantitative nucleic acid amplification test (area under the curve 0.982) and obtained a value of 0.015% as a cutoff for the cell-free DNA sequencing assay. In the validation cohort composed of 84 liver transplant recipients, next-generation sequencing of cell-free DNA revealed the occurrence of cytomegalovirus infection that remains otherwise undetected by the quantitative nucleic acid amplification test. Conclusions: Cytomegalovirus infections that do not cause direct graft injury (cytomegalovirus-related hepatitis) did not result in elevations of donor-derived cell-free DNA. Next-generation sequencing of cytomegalovirus-derived cell-free DNA provides a potential tool for detection of cytomegalovirus infection that remains undetected by the quantitative nucleic acid amplification test.