Cardiac allograft rejection: diagnosis and treatment.

GIORDANINO EF; PADROS K; VIGLIANO C

Heart Transplantation: Indications, Postoperative Management and Long-Term Outcomes.

Nova Science Publishers, Inc

Lugar: Hauppauge, Nueva York; Año: 2022; p. 183 - 206

The main obstacle to organ transplantation from one individual to another of the same species (allograft) is the immunological rejection of the transplanted tissue.Rejection is a complex phenomenon involving cell-mediated hypersensitivity reactions and antibodies that destroy the graft. The major antigenic differences between a donor and recipient that result in rejection of transplants are differences in HLA alleles.Following transplantation, the recipient?s T cells recognize donor antigens from the graft by direct and indirect pathways of allorecognition. In the direct pathway, host T cells directly recognize allogeneic (donor) MHC molecules that are expressed on graft cells. In the indirect pathway, host CD4+ Tcells recognize donor MHC molecules after they are taken up, processed, and presented by the host´s own antigen presenting cells (APC).B lymphocytes also recognize antigens in the graft, including HLA and other antigens that differ between donor and recipient. The activation of these B cells typically requires T cell help.The pathogenesis of acute cardiac allograft rejection involves cell-mediated and antibody-mediated immunologic mechanisms of action.