The basic science of lung allograft failure

Although great strides have been made in the field of lung transplantation with respect to surgical technique, treatment of acute rejection and post-operative management, the long term success of lung transplantation is limited by the development of chronic rejection as manifest by the bronchiolitis obliterans syndrome (BOS). In this chapter, we discuss the current basic scientific understanding of lung transplant rejection as it relates to the development of acute and chronic rejection. An overview of the basic immunological responses that lead to the development of BOS is presented, including the respective roles of HLA, non-HLA and lung specific antigens, humoral and cellular immune responses and regulatory T-cells. Taken together, these mechanisms represent our current knowledge for chronic lung transplant rejection and, hopefully, will result in novel therapeutics to combat this rate-limiting step in the long-term success of lung transplantation.