5. leukocyte antigens
TRANSCRIPT
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Human Leukocyte Antigen a specializedbranch or division of immunology for human
histocompatibility testing.
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HistoryPatients who have been previously transfused
have alloantibodies
Alloantibodies were directed againstalloantigens not present in recipient
MAC initials of the three volunteers
Implicated in FNHTR
Advent of HLA typingGenetics was elucidated HLA antigens were
coded by two closely linked loci, each codingfor multiple number of alleles
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Nomenclatur
e & Genetics
Chromosome 6
http://upload.wikimedia.org/wikipedia/en/4/4f/HLA_complex1.JPG -
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Nomenclatur
e & Genetics
Haplotype from each parent
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Nomenclature & GeneticsPolymorphic
HLA genetic region
Determines major histocompatibility factors Recognition and elimination of foreign tissues
Also known as the MHC region
35 to 40 genes physically grouped in three
regions located on the short arm ofchromosome 6
Related genes: Glyoxalase-1 (GLO) andphosphoglucomutase-3 (PGM-3) are also linked
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Nomenclature & GeneticsClass I region gene classic transplantation
molecules
HLA-A
HLA-B
HLA-C
HLA-E, HLA-F and HLA-G (non-classic)
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Nomenclature & GeneticsClass II region gene
HLA-DR
HLA-DPHLA-DQ
Class III regionC2 and C4, Bf (complement factors)
21-hydroxylaseTumor necrosis factor
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DetectionMolecular techniques
Serologic techniques
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SignificanceSELF vs NON-SELF
Pre-transfusion and transplantation
Platelet refractory therapy and randomplatelet donors
Disease correlation
Paternity testing
Anthropologic studies
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SignificanceUpon transfusion of
blood to someone who isnot genetically identical
(different HLA types):Transfused lymphocytes
mount an immuneresponse
Recipient with normal
immune systemcounterattacks
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SignificanceUpon transfusion of
lymphocytes withsimilar HLA:
Transfusedlymphocytes seessimilarity & doesntattack
Recipient seesdifference in HLA &clears away foreigncells
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SignificanceUpon transfusion of
lymphocytes withsimilar HLA:
Transfusedlymphocytes seesdifference & attacks
Recipient sees
similarity in HLA &does not respond
EVEN IF HOST IS IM-COMPETENT