Editing Duffy antigen system (section)

== History ==

It was noted in the 1920s that black Africans had some intrinsic resistance to malaria, but the basis for this remained unknown. The Duffy antigen gene was the fourth gene associated with the resistance after the genes responsible for [[sickle cell anaemia]], [[thalassemia]] and [[glucose-6-phosphate dehydrogenase]].{{citation needed|date=January 2021}}

In 1950, the Duffy [[antigen]] was discovered in a multiply-transfused [[hemophiliac]] named Richard Duffy, whose serum contained the first example of anti-Fya [[antibody]].<ref>
{{cite journal | title = A New Human Blood Group | journal = Nature | date = 4 February 1950 | vauthors = Cutbush M, Mollison PL, Parkin DM | volume = 165 | issue = 188–189 | pages = 188–189 | doi = 10.1038/165188b0 | bibcode = 1950Natur.165..188C | s2cid = 4265241 }}
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In 1951, the antibody to a second antigen, Fyb, was discovered in [[blood plasma|serum]]. Using these two antibodies, three common [[phenotypes]] were defined: Fy(a+b+), Fy(a+b-), and Fy(a-b+).{{citation needed|date=April 2021}}

Several other types were later discovered bringing the current total up to 6: Fya, Fyb, Fy3, Fy4, Fy5 and Fy6. Only Fya, Fyb and Fy3 are considered clinically important. Reactions to Fy5 have also rarely been reported.  The Fy4 antigen, originally described on Fy (a–b–) RBCs, is now thought to be a distinct, unrelated antigen and is no longer included in the FY system.{{citation needed|date=April 2021}}