Characterization of Null Alleles of the Human Leukocyte Antigens
1 , 2Bendukidze N., 3Záhlavová L., 4Kolesár L., 4Pokorná K., 1Slavčev A.
1Oddělení imunogenetiky IKEM, Praha 2H&I DNA Reference Laboratory, National Blood Service, Bristol, UK 3Ústav hematologie a krevní transfuze, Praha 4Přírodovědecká fakulta Univerzity Karlovy, Praha
The widespread application of DNA techniques in medicine and biology has allowed the typing of human leukocyte
antigens (HLA) at the molecular level. Comparative studies between serological and molecular biology methods
have shown the existence of null alleles, which code HLA antigens with low or no cell surface expression. Null
alleles are not detectable by standard serological typing methods and may be overlooked /or incorrectly assigned by
available DNA methods. Although null alleles are infrequent in human populations, they should not be ignored.
Errors in typing of null alleles may cause complications in the evaluation of HLA matching of donor / recipient pairs
that were originally considered HLA-compatible. The detection of null alleles and their frequency in various
populations requires typing of a large number of individuals by both serological andDNA-basedmethods. Knowledge
of the haplotype(s) associated with null alleles may be helpful for their identification. For this purpose, it is necessary
to perform family studies.
histocompatibility antigens, null alleles, polymorphism, transplantation.