Monitoring of CMV-specific cell-mediated immunity in heart transplant recipients: clinical utility of the QuantiFERON®-CMV assay for the management of post-transplant CMV infection

Background: The clinical utility of QuantiFERON®-CMV (QFN®-CMV) assay in heart transplant recipients was assessed.Methods:Forty-four CMV-seropositive patients were enrolled: 17 received antiviral prophylaxis and 27 were managed pre-emptively. CMV-DNAemia monitoring was performed by a quantitative real-time PCR assay. QFN®-CMV assay was retrospectively performed on blood samples collected at five post-transplant time-points.Results:A higher proportion of patients with indeterminate QFN®-CMV result after the suspension of prophylaxis developed CMV infection compared to patients who showed a global T-cell responsiveness (P=0.036). Patients (42.9%) who reconstituted CMV-specific response following the first CMV-DNAemia showed median CMV-DNAemia peak 1 log of magnitude lower than patients with indeterminate results and all controlled viral replication spontaneously. The 25% of patients with an indeterminate result developed CMV disease.In the pre-emptive strategy group, no difference in the development of subsequent infection, magnitude of viral load and viral control were observed on the basis of QFN®-CMV measurements performed before and after the first CMV-DNAemia, respectively.Considering both CMV prevention strategies, the viral relapse was associated with the failure to reconstitute CMV-specific CMI after the resolution of the first episode of CMV infection (P=0.032).Conclusions:QFN®-CMV measurements can be a useful tool for identifying patients:i) at higher risk of developing infection after discontinuing antiviral prophylaxis;ii) with late CMV infection who would benefit from appropriate antiviral interventions andiii) at higher risk of viral relapses. QFN®-CMV measurements within 1 month post-transplant (early period) are not revealing.