This gene encodes the integrin alpha M chain. Integrins are heterodimeric integral membrane proteins composed of an alpha chain and a beta chain. This I-domain containing alpha integrin combines with the beta 2 chain (ITGB2) to form a leukocyte-specific integrin referred to as macrophage receptor 1 ('Mac-1'), or inactivated-C3b (iC3b) receptor 3 ('CR3'). The alpha M beta 2 integrin is important in the adherence of neutrophils and monocytes to stimulated endothelium, and also in the phagocytosis of complement coated particles. Multiple transcript variants encoding different isoforms have been found for this gene. [provided by RefSeq, Mar 2009]
Forensic Context
A study in humans demonstrated that the ITGAM was highly expressed in the plasma of sepsis patients compared to those with systemic inflammatory response syndrome and was predominantly localized within macrophage lineages, as confirmed by meta-analysis of public datasets and single-cell RNA sequencing [Chen et al. DOI:10.1038/s41598-024-59400-0]. Another human study found the ITGAM was significantly upregulated in salivary extracellular vesicles from emergency department patients with acute traumatic brain injury compared to healthy participants, indicating its role in inflammation-related gene profiles for injury diagnosis and severity evaluation [Cheng et al. DOI:10.4103/1673-5374.266924]. A study in mice demonstrated that wound-infiltrating cells from both burn and non-burn cutaneous wounds were primarily CD11b+, with a significant number expressing this myeloid cell marker, though the mean fluorescent intensity was slightly but significantly reduced in cells from burn wounds [Schwacha et al. DOI:10.1016/j.jss.2008.07.034]. In a rat model of severe burn injury, the protein and mRNA levels of CD11b/c in enriched adipose-derived stem cells were not significantly different between burned and non-burned animals, indicating stability of this marker in that specific cell population post-injury [Prasai et al. DOI:10.007/s12015-017-9721-9].