SCAR COLLAGEN DEPOSITION IN THE AIRWAYS OF ALLOGRAFTS OF LUNG-TRANSPLANT RECIPIENTS

Collagen subtype deposition has not been studied in the airways of tra nsplanted lungs. As part of rejection, a series of immunologic insults results in a remodeling of the allograft. In chronic rejection, chang es in the airway leading to obliterative bronchiolitis syndrome (OBS) are particularly important. To better understand the mechanism of OBS occurring in chronic lung rejection, we investigated deposition of thr ee fibrillar collagens (type I, III, V) in airway biopsies of lung all ograft; taken from 10 clinically well lung transplant recipients (wLTR ) and eight lung transplant recipients (LTR) with OBS (OBLTR) using an immunoperoxidase method. Collagen III deposition and the ratio of col lagen type III to type I were found to be significantly increased in O BLTR compared with wLTR (p < 0.05), and the latter correlated inversel y with both FEF25-75 (r = -0.69; p < 0.05) and FEV1 (r = 0.62; p = 0.0 5) in OBLTR. This suggests that an increased proportion of collagen II I in the airway walls of transplanted lungs might be an early signal o f the progression to terminal chronic lung allograft dysfunction. The changes in the ratio of type III to type I collagen in the airways of lung allografts may provide important insights into the process of air way remodeling in chronic lung rejection.