KIRGene

KIRGene is a term used to denote a member of the killer-cell immunoglobulin-like receptor (KIR) gene family, which encodes receptors expressed on natural killer (NK) cells and some T cells. In humans, KIR genes reside in the leukocyte receptor complex on chromosome 19 and show extensive genetic variation across individuals and populations. Standard references name individual genes such as KIR2DL1 or KIR2DS4; KIRGene, when used, refers to any such member rather than a single universal locus.

Structure and diversity: KIRGene products are membrane receptors with immunoglobulin-like domains. They are categorized as inhibitory or activating depending on their cytoplasmic tails, and differ in extracellular domain number among family members. The KIR gene cluster is highly polymorphic at both gene-content and allelic levels, contributing to a broad repertoire of receptors in individuals.

Function: KIRGene-encoded receptors recognize polymorphic HLA class I ligands on potential target cells, regulating NK cell cytotoxicity and cytokine production. Inhibitory receptors typically engage self-HLA to prevent autoimmunity, while activating receptors respond to stressed, infected, or transformed cells to promote immune responses.

Clinical relevance: Variation in KIR gene content and alleles influences immune responses with implications for transplantation, infectious disease susceptibility, pregnancy outcomes, and autoimmune conditions. Population studies show regional differences in KIR haplotype frequencies, notably between group A and group B haplotypes.

Research and methods: Genotyping KIR genes and their HLA ligands employs targeted sequencing, multiplex PCR, and SNP analysis. Ongoing research explores how KIR-HLA interactions shape immunity, disease risk, and responses to therapies. See also KIR gene family, NK cells, and HLA.