MEDICAL BIOLOGY, HUMAN ANATOMY, PHYSIOLOGY AND PATHOLOGY - Ya.I. Fedoniuk 2010

BIOLOGY

SECTION 1. BIOLOGICAL BASES OF HUMAN VITAL ACTIVITY

1.4. ONTOGENETIC LEVEL OF LIFE ORGANIZATION

1.4.2. Fundamentals of Human Genetics

Immunogenetics

Immunogenetics is a science that investigates the inheritance patterns of antigenic Specificity and the genetic determination of immune responses. The Human Body features the Major Histocompatibility Complex (MHC), an antigen system unique to each individual that determines tissue incompatibility between a donor and a recipient. MHC Antigens are prominently expressed On the surface of peripheral Blood Leukocytes; therefore, the human major histocompatibility complex is known as the HLA system (Human Leucocyte Antigen). The synthesis of these antigens is controlled by a group of tightly linked genes located on the 6th pair of Chromosomes, which include loci A, B, C, D, D₂, and R. Each Gene has multiple alleles: there are over 20 known alleles for the A gene, about 50 for the B gene, and 8 for the C gene. The combination of these alleles accounts for the vast diversity of human genotypes regarding antigens within populations. To determine human HLA antigens, serum panels in microlymphocytotoxicity tests are utilized. Determining Histocompatibility Antigens is of paramount importance for Organ and tissue transplantation, as well as for establishing Databases on the antigens of recipients and donor Organs. Furthermore, evidence links certain diseases with specific HLA antigens. For instance, HLA-B27 antigens are found in 70–100% of patients with Ankylosing spondylitis and in 3–12% of healthy individuals. The GENES OF THE major histocompatibility complex control the functioning of The Immune System and drive The Development of transplantation Immunity.