HLA Typing
In 1975, Peter Doherty and Rolf Zinkernagel identified human leukocyte antigens (HLA). HLA are proteins found everywhere in the body except
red blood cells. They are especially prevalent in white blood cells. Many types of HLA exist, often varying greatly from person to person. Doherty
and Zinkernagel were awarded the 1996 Nobel Prize in Physiology or Medicine for this discovery.
Since many types of HLA exist, scientists can use HLA typing for genetic identification. They are able to compare the types of HLA
in different people and determine if the people are related based on similarities between these proteins. HLA have become increasingly important for
identifying positive matches between donors and recipients of bone marrow transplants.
The degree of variation among HLA in different people provides for fairly accurate paternity testing, with a power of exclusion from 80
to 90% when combined with
blood typing
and
serological testing
.
The accuracy of HLA typing increases with the rarity of a tested person's HLA. However, this procedure is normally performed serologically, requiring
a relatively large amount of fresh (no more than a few days old) blood. Additionally, the collection process can be considered uncomfortable, especially
for children, and cannot be performed on infants under the age of 6 months.
(1900s) Blood Typing
(1930s) Serological Testing
(1970s) HLA Typing
(1980s and 1990s) RFLP Technique
(1990s) PCR Technique
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