Human herpesvirus 6 (HHV-6) is a common virus that can reactivate in immunocompromised patients, including lung transplant (LT) recipients. This study aimed to evaluate the clinical and functional implications of HHV-6 infection in LT patients through a retrospective analysis of 175 individuals who
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Human herpesvirus 6 (HHV-6) is a common virus that can reactivate in immunocompromised patients, including lung transplant (LT) recipients. This study aimed to evaluate the clinical and functional implications of HHV-6 infection in LT patients through a retrospective analysis of 175 individuals who underwent lung transplantation at the City of Health and Sciences of Turin between 2014 and 2023. Surveillance bronchoscopies—including bronchoalveolar lavage (BAL) and transbronchial biopsies—were performed at scheduled intervals over a two-year period to detect HHV-6 and other pathogens, and to assess acute rejection. Spirometries were performed to evaluate graft function. Among the cohort, 33% of 822 BAL samples tested were positive for HHV-6, with a notable association between high viral load (≥500 copies/mL) and the development of post-transplant lymphoproliferative disorder (PTLD) (13% vs. 1%,
p = 0.02) at 1 month and (9% vs. 1%,
p = 0.026) at 12 months. Co-infection with CMV (78% in positives vs. 55% in negatives;
p = 0.006), Epstein–Barr virus (EBV) (35% vs. 16%;
p = 0.010), and bacterial and fungal infection (specifically, a higher rate of isolation of
Achromobacter xylosoxidans (13%),
p = 0.010) was frequently observed in conjunction with HHV-6 positivity. Notably, patients with at least one HHV-6 positive BAL exhibited a significant reduction in forced vital capacity (FVC) at multiple follow-up points, FVC 82% in positives vs. 92% in negatives (
p = 0.038) at 4 months and 87% vs. 98%
p = 0.033 at 8 months and 87% vs. 99%
p = 0.038 at 24 months. No direct associations with acute rejection or overall survival were found. By means of this study, we provide a wide overview of HHV-6 in lung transplant recipients, filling in a gap of evidence in the field. We report a remarkable incidence and a significant association with acknowledged clinically relevant viral infections, PTLD, and functional tests decline, with no association with mortality.
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