Prevalence and Clinical Impact of Polyomaviruses KI and WU in Lung Transplant Recipients

Abstract The newly discovered polyomaviruses KI and WU (KIV and WUV) were isolated from secretions of patients with respiratory symptoms as well as in blood, spleen, lymphoid tissues, and stools, especially in immunocompromised conditions. The aim of this work was to evaluate the prevalence of KIV and WUV in bronchoalveolar lavage (BAL) from lung transplant recipients. We also examined potential correlations between these viruses and occurrences of pneumonia, acute respiratory insufficiency, or other acute respiratory conditions and acute rejection episodes. Discharge diagnosis was based on the International Classification of Diseases–Italian version 2002, based on the 9th-revision clinical modification. A rejection episode was diagnosed by transbronchial lung biopsy in accordance with the 2007 International Society for Heart and Lung Transplantation Working Formulation. Overall, we analyzed 53 BALs obtained from 24 transplant recipients. Positive polymerase chain reaction results were observed in 6 samples (11.3%) from 6 patients (25%), versus 7 samples (13.2%) from 7 patients (29.2%) for KIV and WUV, respectively. Regarding the diagnosis of pneumonia, the prevalence was 22.2% and 33.3% for KIV and WUV, respectively. In cases of acute respiratory insufficiency or other acute respiratory conditions, 2 out of 9 samples were positive for KIV (22.2%) and 4 out of 9 for WUV (44.4%). An Acute rejection episode (ARE) was diagnosed in 7 instances among 6 lung transplant patients: The corresponding BAL specimens showed positive results for KIV in 3 out of 7 (42.8%) cases with ARE vs 3 out of 46 (6.5%) without an ARE ( P < .05), and for WUV in 3 out of 7 (42.8%) vs 4 out of 46 (8.7%) ( P < .05), respectively. Although the small number of specimens limits the statistical analysis, our results showed a higher prevalence of WUV compared with KIV. The compromised pulmonary environment in the lung allograft may cause reactivation of these viruses. Their roles in this context need to be further evaluated.