The Role of Microbiology at the 1-Month Surveillance Bronchoalveolar Lavage in the Identification of Complications in the First Year After Lung-Transplantation-A Retrospective Single-Center Experience.

Acute rejection and infections are the most frequent complications in the first year after lung transplantation, often representing relevant causes of death. There is still no consensus on the ideal strategy for preventing these events, with a still open debate on active bronchoscopic surveillance protocols vs. clinically mandated ones. The aim of our single-center exploratory study was to evaluate retrospectively the role of microbiology at bronchoalveolar lavage (BAL) at the first month from transplantation in asymptomatic patients in relation to the development of complications up to 12 months from surgery. We collected data from 28 patients who underwent surveillance bronchoscopies according to our center protocol (transbronchial biopsies and BAL at months 1, 4, 8, 12, 18, and 24 post-transplantation) who had a 12-month follow-up. The inclusion criterion was the absence of infiltrates at 1-month post-transplantation chest CT. We excluded patients transplanted due to suppurative diseases of the lung to minimize the pre-transplantation risk factors for infection. We also assessed differences in complications according to the underlying disease. We enrolled 15 patients with interstitial lung diseases (ILDs) and 13 with chronic obstructive pulmonary disease (COPD). Of the 28 patients, 11 had a positive BAL for bacteria. Patients with a positive BAL developed a higher number of pulmonary infectious complications (odds ratio of 18.33, -value = 0.013 at regression model), with a near significance for moderate-severe pulmonary infections (odds ratio 4.8, -value = 0.061). We did not find a significant correlation with rejection, cytomegalovirus reactivation, or pseudomembranes. We did not find differences in the rates of complications when grouping subjects according to pre-transplantation disease. Our results suggest a possible role for BAL positivity for bacteria in asymptomatic patients at surveillance bronchoscopy in predicting the development of future infections, warranting a tailored follow-up of patients that considers this data. Larger, multicentric studies are needed to explore and confirm the utility of our findings.