HLA-A34

HLA-A34 is a human leukocyte antigen (HLA) serotype within the HLA-A locus. HLA-A is a major histocompatibility complex (MHC) class I gene located on human chromosome 6. The HLA system is critical for the immune system's ability to distinguish between self and non-self, playing a key role in organ transplantation, autoimmune diseases, and infectious disease susceptibility.

HLA-A34, specifically, refers to a group of HLA-A alleles that elicit a similar antibody response. HLA-A molecules are expressed on the surface of nearly all nucleated cells and present peptide fragments derived from intracellular proteins to T cells, specifically cytotoxic T lymphocytes (CTLs, also known as CD8+ T cells). If a presented peptide is recognized as foreign, the CTL will initiate an immune response to eliminate the cell expressing the foreign antigen.

Variations in HLA-A alleles, including HLA-A34, result in differences in the peptides that can be presented and the T cell receptors that can recognize them. This genetic polymorphism contributes to individual differences in immune responses and susceptibility to various diseases. The specific amino acid sequence of the HLA-A34 allele influences its peptide-binding repertoire.

The presence or absence of HLA-A34, along with other HLA alleles, is often determined through HLA typing, which is performed using serological assays, DNA-based techniques, or a combination of both. HLA typing is crucial for matching organ donors and recipients in transplantation to minimize the risk of rejection. Furthermore, HLA-A34 has been associated with susceptibility to certain autoimmune diseases and infectious diseases, although these associations can vary depending on the population studied. The precise mechanisms underlying these associations are complex and often involve interactions with other genes and environmental factors.

While HLA-A34 is a defined serotype, molecular techniques have identified numerous alleles that belong to the HLA-A34 serogroup. Therefore, specifying the exact allele is often important for precise characterization in research and clinical settings. Further research continues to investigate the role of HLA-A34 and other HLA alleles in various aspects of human health and disease.