Real-world experience of Quantiferon-CMV directed prophylaxis in lung transplant recipients

Background: The Quantiferon-Cytomegalovirus (QF-CMV) assay was introduced to predict CMV infection and inform prophylaxis duration in our lung transplant recipients (LTR) from 2012. The aims of this retrospective cohort study were to review our QF-CMV experience, understand factors associated with positive results and further explore its predictive utility. Methods: LTR with QF-CMV testing performed at 5 months post-transplant were included. Patients receiving QF-directed prophylaxis (5 or 11 months) were compared to those receiving our prior standard of care (5 months). Outcomes were CMV infection >1,000 IU/mL in blood and/or bronchoalveolar lavage fluid. Factors associated with positive QF-CMV results were identified. Patients were compared based on serostatus, QF-CMV results and prophylaxis duration. Results: Our cohort included 263 LTR (59 D+/R-, 204 R+). QF-directed prophylaxis was used in 195 of 263 (74%) and was associated with reduced CMV infection (84/195, 43% vs 41/68, 60%, p < .001). Patients receiving extended prophylaxis experienced less CMV if negative and/or indeterminate (43% vs 70%, p < .01) or positive (10% vs 51%, p < .01). Only 5 of 59 (8%) D+/R- patients were QF-CMV positive compared to 155 of 204 (76%) R+ patients (adjusted OR 0.03, 0.01-0.07, p < .001). After controlling for prophylaxis duration, only D+/R- serostatus remained independently associated with CMV infection (adjusted HR 4.90, 95% CI 2.68-9.00, p < .0001). Conclusions: QF-CMV results were strongly correlated with serostatus, with D+/R- patients unlikely to test positive while receiving prophylaxis. Extended prophylaxis was associated with delayed onset, reduced frequency and severity of CMV infection across all subgroups. After accounting for serostatus, the incremental predictive value of QF-CMV in this cohort was limited.