Page 1947 - Hematology_ Basic Principles and Practice ( PDFDrive )

Chapter 113 Human Leukocyte Antigen and Human Neutrophil Antigen Systems 1727

107
association was recently noted between a low IL-10 producer geno- conventionally called HLA antigens. The second system is based on
type and a tendency to develop melanoma and prostate cancer. 104,105 the molecular identification of nucleotide sequences in genomic
deoxyribonucleic acid (DNA), and results are conventionally referred
to as HLA alleles. Because molecular typing has higher resolution, it
HUMAN LEUKOCYTE ANTIGEN NOMENCLATURE has gained increasing popularity.

The history of the HLA system nomenclature was summarized by Sir
Walter Bodmer who, together with Ruggero Ceppellini, was primar- IMMUNOLOGICALLY DEFINED HUMAN
106
ily involved in its development. It began as HL-A, for human LEUKOCYTE ANTIGEN NOMENCLATURE
leukocyte locus A. With the recognition that HLA molecules are
encoded by more than one locus, the A came to stand for antigen and Immunologically defined nomenclature follows this rule: HLA sepa-
a locus designation was added after HLA (i.e., HLA-A, HLA-B, rated by a hyphen from a capital letter identifying the locus encoding
2
HLA-C, HLA-D, etc.). From then on, the WHO has updated distinct HLA class I (-A, -B, -C) or class II (-DR, -DQ, -DP) antigens.
nomenclature on a quarterly basis. The most recent update was The letter is followed by a number that identifies a serologic family
4
assigned in January 2015, as seen in Table 113.2. At present, two of alleles sharing epitopes recognized by alloantibodies or alloreactive
systems are used. An immunologically defined nomenclature is based cytotoxic T cells. With improved understanding of the molecular
on the identification of HLA antigens on the surface of leukocytes. genetics of the HLA region, various appendages have been removed
Therefore HLA phenotypes described by immunologic methods are from the HLA nomenclature. For instance, the letter w was used to

TABLE Name of Genes in the HLA Region Considered by the WHO Nomenclature Committee
113.2
Name Previous Equivalents Molecular Characteristics No. of Alleles January (2015)
HLA-A – Class I α-chain 3107
HLA-B – Class I α-chain 3887
HLA-C – Class I α-chain 2623
HLA-E E, “6.2” Associated with class I 6.2-kBa Hind III fragment 17
HLA-F F, “5.4” Associated with class I 5.4-kBa Hind III fragment 22
HLA-G G, “6.0” Associated with class I 6.0-kBa Hind III fragment 50
HLA-H H, AR, “12.4”, HLA-54 Pseudogene association with class I 5.4-kBa Hind III fragment 12
HLA-J cda 12, HLA-59 Pseudogene association with class I 5.9-kBa Hind III fragment 9
HLA-K HLA-70 Pseudogene association with class I 7.0-kBa Hind III fragment 6
HLA-L HLA-92 Pseudogene association with class I 9.2-kBa Hind III fragment 5
HLA-X – Class I gene fragment 0
HLA-DRA DRα DR α-chain 7
HLA-DRB1 DRβI, DR1B DR β 1 determining specificity for DR1, DR2, DR3, etc. 1726
HLA-DRB2 DRβII2 Pseudogene with DRβ-like sequence 1
HLA-DRB3 DRβIII, DR3B DR β3 determining DR52, Dw24, w25, -26 specificity 59
HLA-DRB4 DRβIV, DR4B DR β4 determining DR53 specificity 15
HLA-DRB5 DRβV, DR5B DR β5 determining DR52, Dw24, w25, -26 specificity 21
HLA-DRB6 DRBX, DRBσ Pseudogene found in DR1, DR2, and DR10 haplotypes 3
HLA-DRB7 DRBψ1 Pseudogene found in DR4, DR7, and DR9 haplotypes 2
HLA-DRB8 DRBψ2 Pseudogene found in DR4, DR7, and DR9 haplotypes 1
HLA-DRB9 M 4.2 β exon Pseudogene isolated fragment 1
HLA-DQA1 DQα1, DQ1A DQ α-chain as expressed 54
HLA-DQB1 DQβ1, DQ1B DQ β-chain as expressed 780
HLA-DOA DNA, DZα, DOα DO α-chain 12
HLA-DOB DOβ DO β-chain 13
HLA-DMA RING 6 DM α-chain 7
HLA-DMB RING 7 DM β-chain 13
HLA-DPA1 DPα1, DP1A DP α-chain as expressed 33
HLA-DPB1 DPβ1, DP1B DP β-chain as expressed 520
TAP1 ABCB2, RING4 ABC (ATP-binding cassette) transporter 12
TAP2 ABCB3, RING 11 ABC (ATP-binding cassette) transporter 12
MICA PERB 11.1 Class I chain-related gene 101
MICB PERB 11.2 Class I chain-related gene 18 41
ATP, Adenosine triphosphate; HLA, human leukocyte antigen; WHO, World Health Organization.
Data from Marsh SGE, Albert AD, Bodmer WF, et al: Nomenclature for factors of the HLA system, 2010. Tissue Antigens 75:291, 2010.