The HLA (human leukocyte antigens) complex is positioned on chromosome 6 (6p21.3). The HLA genes respect the principles of Mendelian genetics and are co-dominantly expressed. The classical HLA genes are considered important for transplantation. HLA-A, -B, and -C are the classical HLA class I genes and are expressed in most of the somatic cells. HLA-DR, -DQ , -DP are the classical HLA Class II genes and are mainly expressed in antigen presenting cells such as B- cells, Activated T cells, Macrophages, Dendritic cells, and Thymic epithelial cells. In the presence of interferon, class II expression can be seen in other types of cells. This chapter includes the review of the structure and the function of the HLA molecule, and the most current HLA nomenclature. Subsequently evolution of HLA testing methodologies and advanced terminologies and techniques of HLA antibody evaluation that enhanced the bone marrow and solid organ transplantation is also discussed.
Part of the book: Human Leukocyte Antigens