Clinical Utility of Molecular Surveillance for Cytomegalovirus After Antiviral Prophylaxis in High-Risk Solid Organ Transplant Recipients

BACKGROUND: Cytomegalovirus (CMV) disease after discontinuation of prophylaxis is a significant problem for CMV-seronegative recipients of CMV-seropositive organs (donor seropositive and recipient seronegative [D+/R-]). Virologic monitoring after prophylaxis has been proposed as a way to prevent late-onset disease. METHODS: We reviewed the efficacy of this strategy. CMV D+/R- organ transplant recipients received 3 to 6 months of antiviral prophylaxis, and then viral loads were performed weekly for 8 weeks. Preemptive antiviral therapy was initiated at a predefined threshold. RESULTS: Seventy-one CMV D+/R- patients were assessed. Symptomatic CMV disease occurred in 29 of 71 (40.8%) patients during the first-year posttransplant. A significant portion of disease occurred only after the 8-week surveillance period (n=16). Viremia occurred in 19 of 71 (26.8%) patients during the 8-week surveillance. Preemptive therapy was successfully used in only 3 of 19 (15.8%) viremic patients with no further disease development. The remaining patients cleared low-level viremia spontaneously (n=3) or had CMV disease (n=13) either at the first detection of viremia or before preemptive therapy initiation because of rapid viral load doubling (median doubling time 1.1 days). CONCLUSION: CMV D+/R- patients had significant incidence of late-onset disease after prophylaxis. However, the use of a preemptive after prophylaxis strategy was of limited benefit in this group because of rapid viral doubling times and disease occurring after the surveillance period.