HLA-Cw4

HLA-Cw4 is a human leukocyte antigen (HLA) serotype, specifically an allele of the HLA-C locus. The HLA-C locus is a gene located on human chromosome 6 that encodes a major histocompatibility complex (MHC) class I cell-surface receptor.

HLA-Cw4, like other HLA class I molecules, plays a critical role in the adaptive immune system. Its primary function is to present peptide fragments derived from intracellular proteins (including viral or tumor-associated antigens) to cytotoxic T lymphocytes (CTLs), also known as CD8+ T cells. When a CTL recognizes a peptide-HLA-Cw4 complex as foreign, it triggers an immune response, leading to the destruction of the infected or cancerous cell.

The HLA-C locus is highly polymorphic, meaning there are many different alleles within the human population. HLA-Cw4 is one such variant. Individuals inherit two HLA-C alleles, one from each parent, and can therefore be homozygous or heterozygous for HLA-Cw4.

The presence or absence of HLA-Cw4, along with other HLA alleles, is genetically determined and can be identified through HLA typing. HLA typing is used in various medical contexts, including:

• Transplantation: To match organ donors and recipients, as HLA compatibility significantly influences transplant success. Mismatches can lead to graft rejection.
• Disease association studies: Certain HLA alleles, including HLA-Cw4, are associated with an increased or decreased risk of developing particular autoimmune diseases, infectious diseases, and cancers. These associations reflect the role of HLA molecules in presenting specific antigens and influencing the immune response. For example, HLA-Cw4 has been studied in relation to psoriasis and HIV control.
• Pharmacogenomics: Predicting an individual's response to certain medications, as HLA alleles can influence drug metabolism and efficacy.

The specific peptide-binding properties of HLA-Cw4, determined by its amino acid sequence, dictate which peptides it can present to T cells and thus shape the immune response. Research continues to investigate the precise role of HLA-Cw4 in various disease processes and in the context of personalized medicine. The allele frequencies of HLA-Cw4 vary among different ethnic groups.