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HLA-typing for Bone MarrowTransplantation:

From Serology to DNA

Evan F. Ray, CHS(ABHI), SI(ASCP)

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IntroductionStem cells in the bone marrow are affected

by cancers such as leukemia (AML, CML,ALL) and other potentially fatal diseasessuch as Aplastic Anemia.One therapy for treatment is bone marrowtransplantation.

Successful transplantation requires HLAmatching.

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HLA AntigensHLA antigens are proteins found on theouter surface of most cells in the body.Each individual expresses six differentgroups of HLA antigensClass I - HLA-A, -B, -CClass II - HLA-DR, -DQ, -DPPolymorphic system

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Map of the M HC

on chromosome 6

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T he frequencies of HLA-alleles differ among ethnic or racial populations.

Combinations of alleles and linkagedisequilibrium differ among populations.Extended haplotype:A1,Cw7,B8,DR3,DQ2Caucasian- DRB1*0901-DQB1*0303African Amer-DRB1*0901-DQB1*0201

D ifficulties in HLA-ma tching

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O ther D ifficulties with S erologic Ty ping

Strength and Specificity of the antiseraShort supplyRigorous testingCondition of the target cellsLow counts in leukemic or aplastic patients

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S O WHAT?Serology doesnt give us the best matchinginformation.DNA-typing defines antigens thatserological typing cannot.DNA-typing can give a higher resolutiontyping necessary for patients requiring

unrelated transplants.How much information is really necessary?