Editing Histocompatibility (section)

{{Short description|Tissue compatibility between individuals}}
'''Histocompatibility''', or '''tissue compatibility''', is the property of having the same, or sufficiently similar, [[allele]]s of a set of [[gene]]s called [[human leukocyte antigen]]s (HLA), or [[major histocompatibility complex]] (MHC).<ref>{{cite book |title=Dorlands Illustrated Medical Dictionary |publisher=Elsevier |year=2012 |location=Philadelphia, PA |chapter=Histocompatibility}}</ref> Each individual expresses many unique HLA proteins on the surface of their cells, which signal to the immune system whether a cell is part of the self or an invading organism.<ref name="GHR_HLA">{{cite web | url = https://ghr.nlm.nih.gov/primer/genefamily/hla | title = Human leukocyte antigens | work = Genetics Home Reference | access-date = 2018-01-25 }}</ref> [[T cell]]s recognize foreign HLA molecules and trigger an immune response to destroy the foreign cells.<ref name="Ingulli_2010">{{cite journal | vauthors = Ingulli E | title = Mechanism of cellular rejection in transplantation | journal = Pediatric Nephrology | volume = 25 | issue = 1 | pages = 61–74 | date = January 2010 | pmid = 21476231 | pmc = 2778785 | doi = 10.1007/s00467-008-1020-x }}</ref> Histocompatibility testing is most relevant for topics related to whole organ, tissue, or stem cell transplants, where the similarity or difference between the donor's HLA alleles and the recipient's triggers the immune system to [[Transplant rejection|reject]] the transplant.<ref>{{cite book| title = Kurby Immunology | last1=Kindt|first1=Thomas J.|last2=Goldsby|first2=Richard A.|last3=Osborne|first3=Barbara Anne|last4=Kuby|first4=Janis | name-list-style = vanc |publisher=W. H. Freeman & Company|year=2006|isbn= 978-1-4292-0211-4 }}</ref> The wide variety of potential HLA alleles lead to unique combinations in individuals and make matching difficult.