Relationship between microorganism presence in bronchial aspirate and acute rejection in transbronchial lung biopsy

Acute cellular rejection in lung transplantation is diagnosed in 30-60% in the 1 year and requires lung biopsy. An increase in local cellular immunity produced by local infection is considered to increase the incidence of acute cellular rejection. We present a retrospective analysis of lung transplant patients from 01/01/2009 to 10/21/2013. The total number of patients studied was 139. 64.02% men, 35.97% women. 64.02% bipulmonar transplants, 35.97% unipulmonar transplants. The underlying disease was 43.88% ILD; 39.56% COPD, bronchiectasis 8.63%, 1.42% lung hypertensions, and others. All patients had a transbronchial biopsy 3 weeks after the transplant to diagnose acute cellular rejection, and some had other transbronchial biopsies made during bronchoscopies over time. In every bronchoscopy performed there was bronchial aspirate collected for microbiological culture. There is a total of 287 bronchoscopies in which we made bronchial aspirate as well as transbronchial biopsy. Throughout this study we pretend to relate the presence of microorganisms at culture with acute cellular rejection in the same bronchoscopy. In total 33,4% of the bronchoscopies had microrganims in the culture also 39,4% had acute rejection. In the 139 bronchoscopies executed at the third week there was not a statistically significant relationship between the presence of microorganisms and acute cellular rejection (p=0,495). The same result was obtained for the 287 procedures (p=0.838). In conclusion we did not find a relationship between the presence of microorganisms and acute rejection. Acute rejection can be related to other factors aside from pulmonary infection.