Interstitial Pneumonitis and the Risk of Chronic Allograft Rejection in Lung Transplant Recipients

Background: The presence of interstitial pneumonitis (IP) on surveillance lung biopsy specimens in lung transplant recipients is poorly described, and its impact on posttransplant outcomes is not established. The following study assessed the association of posttransplant IF with the development of bronchiolitis obliterans syndrome (BOS). Methods: We examined all recipients of primary cadaveric lung transplants at our institution between January 1, 2000, and December 31, 2007 (N = 145). Patients had bronchoscopies with BAL, and transbronchial biopsies performed for surveillance during posttransplant months 1, 3, 6, and 12 as well as when clinically indicated. Patients were given a diagnosis of IP if, in the absence of active infection and organizing pneumonia, they showed evidence of interstitial inflammation and fibrosis on two or more biopsy specimens. Results: IF was a significant predictor of BOS (OR, 7.84; 95% CI, 2.84-21.67; P < .0001) and was significantly associated with time to development of BOS (hazard ratio, 3.8; 95% CI, 1.93-7.39; P = .0001) within the first 6 years posttransplant. The presence of IF did not correlate with a significantly higher risk of mortality or time to death. There was no association between the presence of IF and the development of or time to acute rejection. Conclusions: The presence of IF on lung transplant biopsy specimens suggests an increased risk for BOS, which is independent of the presence of acute cellular rejection.