Human leukocyte antigen molecule (HLA molecule)

Human leukocyte antigen molecules are cell-surface transmembrane glycoproteins encoded by genes within the major histocompatibility complex (MHC) region on chromosome 6. These molecules play a central role in regulating the immune response by presenting antigenic peptides (derived from self or foreign proteins) to T cells, thereby enabling the distinction between self and non-self. There are two main classes: class I (HLA-A, HLA-B, HLA-C) present on all nucleated cells and primarily recognized by cytotoxic CD8 T cells, and class II (HLA-DP, HLA-DQ, HLA-DR) primarily on antigen-presenting cells recognized by helper CD4 T cells. HLA molecules are highly polymorphic, which provides diverse immune responses and affects susceptibility to autoimmune diseases, infectious diseases, cancer, and compatibility in organ transplantation. HLA typing is essential in clinical practice for matching transplant donors/recipients and predicting disease risk. Therapeutic interventions frequently target HLA-mediated pathways to manage rejection, autoimmunity, and infectious diseases.

Other names

Human leukocyte antigenHLAMajor histocompatibility complex (MHC) in humansMHC class I moleculesMHC class II molecules

Modulation of immune recognition (drugs may block T cell reactivity or HLA-antigen presentation) Blocking costimulatory pathways (monoclonal antibodies) Suppressing T-cell activation Reducing antibody-mediated rejection (anti-HLA antibody therapies) Binding to and altering cytokine or complement pathways (class III products)