Minor histocompatibility antigens (mHAs) are a group of proteins or peptides found on the surfaces of cells in an individual's body, specifically on the cells of the major histocompatibility complex (MHC). These antigens serve as markers that distinguish one individual's cells from another's, playing a crucial role in the immune system's recognition of self and non-self.
mHAs are produced from normal cellular proteins through various processes, such as DNA mutations, gene polymorphisms, or post-translational modifications. The subtle differences in these antigens allow the immune system to distinguish between healthy cells and foreign or cancerous cells. As a result, mHAs are involved in the initiation and regulation of immune responses, particularly in the context of organ transplantation and disease development.
The recognition of mHAs by the immune system triggers both immune tolerance and immune responses. In the case of organ transplantation, mHAs can lead to graft rejection if the recipient's immune system recognizes these antigens as foreign. Therefore, matching the donor and recipient mHAs is crucial to increase the success of organ transplants.
Furthermore, mHAs play a role in the development of graft-versus-host disease (GVHD), a serious complication that can occur after hematopoietic stem cell transplantation. In GVHD, the transplant recipient's immune system attacks the donated stem cells due to the recognition of mHAs as foreign, resulting in inflammation and tissue damage.
Understanding and studying minor histocompatibility antigens are essential for improving the success rates of organ and stem cell transplantations and developing targeted immunotherapies for diseases involving aberrant immune reactions.
