RT Book, Section A1 Park, Jeong M. A1 Jasiak, Natalia M. A2 Sutton, S. Scott SR Print(0) ID 1158314108 T1 Solid Organ Transplantation T2 McGraw-Hill's NAPLEX® Review Guide, 3e YR 2019 FD 2019 PB McGraw-Hill Education PP New York, NY SN 9781260135923 LK accesspharmacy.mhmedical.com/content.aspx?aid=1158314108 RD 2024/03/28 AB Rejection is a primary barrier to success of solid organ transplantation. There are three types of graft rejection that can occur after solid organ transplantation: antibody-mediated, acute cellular, and chronic rejection. Antibody-mediated rejection is mediated by donor-specific antibodies against human leukocyte antigens or other antigens and typically occurs intraoperatively or within days after receiving ABO blood type mismatched or positive crossmatch organ transplant. Avoiding mismatched transplant or desensitizing recipients with known detectable donor-specific antibodies may prevent this mode of rejection, but treating antibody-mediated rejection remains challenging. Acute cellular rejection (ACR) is the most common type of rejection and is generally reversible with appropriate diagnosis and timely treatment. It results from an orchestrated immune response that involves alloantigen presentation by antigen presenting cells (APCs) that leads to alloreactive T cells. The cytotoxic T cells infiltrate the graft and cause direct tissue damage, whereas the helper T cells produce cytokines to cause subsequent immunological and inflammatory events. Although ACR can occur anytime following transplant, the risk is highest in the first several months after transplant. Prevention and treatment of ACR is of utmost importance, as it is a significant predictor of chronic rejection. The exact etiology of chronic rejection is unknown. It is a slow process of graft fibrosis and arteriopathy, which results in graft dysfunction, usually manifested years after transplantation. While ACR can be treated pharmacologically, the only therapy for chronic rejection is retransplantation.