Presentation on theme: "HLA Typing for Blood Bankers"— Presentation transcript:
1HLA Typing for Blood Bankers Kaaron Benson, M.D.Professor and Senior MemberDepartments of Oncologic Science, and Pathology and Cell BiologyH. Lee Moffitt Cancer Center
2Introduction to the HLA System “HLA” – Human Leukocyte AntigensKey role in immunologic functionPart of the major histocompatibility complex (MHC)HLA antigens encoded for by genes from 6 primary loci on chromosome 6
3Structure of HLA Class I and Class II Molecules HLA typing targetsN Engl J Med 2000;343:702.
9New Nomenclature: April 2010 HLA-Cw becomes HLA-CCw*0202 now C*02:02, represents Cw2 AgColons (:) to delimit separate fieldsA*0301 becomes A*03:01A*2601 becomes A*26:01A*02 and A*92 to changeA*9201 becomes A*02:101A*9202 becomes A*02:102B*15 and B*95 to changeB*9501 becomes B*15:101B*9502 becomes B*15:102
10Nomenclature Confusion: One Example HLA-DRB1*03:01HLA-DRB1*03HLA-DR17HLA-DR3This one allele could be written these four different ways.All four do not refer to the same thing.
11GENES OF THE HUMAN MHC SYSTEM Chromosome 6Class II Class III Class IDP DQ DR B C AB1 A B1 A B1 B3/4/5 A C4 TNFDRB1*0401DRB1*0402DRB1*0403DRB1*0404DRB1*0405DRB1*0406B*0702B*0801B*1301B*1401B*1501A*0101A*0201A*0301
20All dead = Red Score =8All alive = GreenScore = 1
21HLA Typing by Molecular Methods ProsMore accurate and precise than serologye.g. DRB1 >300 alleles but only 17 serotypesBetter matching between pt and donorLess sample required, nonviable cellsWider variety of samples can be usedBecoming easier + automatedConsDoes not account for genes that are present but not expressed: Genotype ≠ PhenotypeRare alleles = growing list of ambiguities
38Confirmatory HLA Typing New sample must be collectedPatient: prior to final donor selectionDonor: prior to stem cell collectionBoth MRD and MUD transplantsNMDP donor typing counts as one typingOnly one typing must be at high resolutionLevel of typing (LR, IR, HR) decided by programMCC: IR/HR typing for original and repeat
39Clinical Applications of HLA Typing Population studiesDisease associationsPharmacogenomicsPlatelet transfusionTRALI risk reductionTransplantationhematopoietic stem cellsolid organ
42HLA-B27 and Ankylosing Spondylitis A.S.>90%B27+HLA-B*27~8% of population~2% of B*27+ dev AS
43Ingelman-Sundberg M. Pharmacogenomic Biomarkers for Prediction of Severe Adverse Drug Reactions NEJM 2008;358:
44Platelet Transfusion Platelet refractoriness: non-immune vs immune Non-immune refractorinessinfection, splenomeg, BMT, DIC, bleed, medsImmune platelet refractorinessHLA Abs (other Abs: plt-specific, drug-induced, ABO)HLA alloimmunization: due to allogeneic WBC exposure via prior transfusion or pregnancy (WBCs – cl. I and II, PLTs – cl. I only)Management: more PLTs vs. histocompat. PLTsPrevention: WBC-reduced blood
55Solid Organ Transplantation ABO compatibility essentialOrgan size requirementsCold ischemia time: organ to recipientMedical urgency / time on waiting listHLA matching for pt Ab / donor Ag essentialHLA flow cytometric XM = standard of careRecipient serum and donor lymphsHLA compatibility beneficialRequired for renal transplants matching: graft survival, meds
56Solid Organ Transplantation United Network for Organ Sharing (UNOS): federal contractHLA typing must be by molecular +/- serologic methodsHLA-A, B, C, DRB1, DRB3/4/5, DQB1 typingHLA-A, B, Bw4/6, Cw, DR51/52/53, DQ Ags reported+/-HLA-DPB1 typing for heart and/or lungsZero Ag MM (6/6) for HLA-A, B, DR Ags only“Zero Ag MM” for HLA-C, DQB1, DPB1
57Transplant HLA and ABO Matching HLA ABOKidney No* YesLiver No YesHeart No YesLung No YesPancreas No* YesCornea No NoStem cell Yes No*HLA matching preferred but not required
58Cadaver Kidney Transplants HLA-A+B+DR Mismatches (MM) HLA DNA Typing Review and Transplantation. Immunity, Vol. 14, 347–356, April, 2001
60HSCT: Donor Selection HLA compatibility essential ABO compatibility not requiredSiblings: best chance for identity25% chance of matching any one sib~30% of patients have a matched sibMonozygotic twin not preferred?Other family members may match ptNo MRD? Search for MUD ASAP!
69Unrelated Donor Searches HLA matched unrelated donors = MRDAvailable donors:NMDP: > 9.5 million volunteer donorsWorldwide: ~20 million totalCord blood: > 550,000Chance of finding A, B, DR match:~60-80% with one million donorsChance best:Cauc> Am. Indian> Hisp/Asian> Afr-AmerFebruary 2012
74Molecular vs Serologic HLA Typing: Benefits of Better Matching Improved rate of engraftmentDecreased incidence/severity aGVHDDecreased incidence/severity cGVHDImproved rate of overall survivalSerologic typing sufficient for MRD?
75Acceptable Mismatches? Locus important?A vs B vs C vs DRB1 > DQB1Marrow: A+DR MM worse than B+CPBSC: C MM worse than othersCord: C Ag MM increases TRMSpecific mismatches important?A*02:01 vs 02:02 vs 02:03No preformed anti-donor-specific HLA Ab (DSA)
76HLA Typing Guidelines for HSC Transplantation Type patient for A, B, C, DRB1 +/- DQB1Type siblings for A, B, C, DRB1 +/- DQB1 (may screen with HLA-LR class I or II)No sibling donor (MRD)? Consider MUDNo MUD? Consider cord or MMUDMolecular methods preferredHigh resolution (allele matching)
77HLA Typing Guidelines for HSC Transplantation Using URD Search all donor registries worldwideMatched URDmolecular HLA typing > serologychoose young, male / nonparous femaleconsider CMV status, donor/pt size, ABO/RhMismatched URDmismatch rare allelesethnic group matching preferredConsider cord blood donor
78HLA-DPB1: Need to Match? Studies have suggested that DPB1 matching does not impact overall survivalDPB1 match increases relapse riskDPB1 mismatch increases aGVHD and TRMLack of tight DPB1 linkage with other locidecreases the ease of finding a DPB1 matchOnly ~20% of 10 of 10 matched transplants will be matched for DPB1“Permissive” mismatches?
79HLA Alloantibodies in HSCT Presence of recipient HLA alloantibodies are not predictive of graft failureDonor-specific HLA Abs (DSA) are predictive of graft failure (e.g., recipient anti-A*02 and A*02 donor pair)HLA antibody evaluations should be a part of the routine workup for unrelated stem cell transplantationThe detection of donor-directed, HLA-specificalloantibodies in recipients of unrelated HCT ispredictive of graft failure. Blood 2010;115:
80Non-Inherited Maternal Antigens (NIMA) HLA-A*HLA-B*HLA-DRB1*Patient02, 2418, 3501:01, 11:04UCB donor unit02, 32UCB donor’s mother07, 3501:01, 13:01HLA-A*24 is not carried by UCB donor but is carried by UCB donor’s mother and the pt; this is a NIMA-matched UCBT.Van Rood JJ, et al. Proc Natl Acad Sci USA 2009;106:19952.Rocha V, et al. Biol Blood Marrow Transplant 2012; July 17 Epub.
81NIMA Mismatch HLA-A* HLA-B* HLA-DRB1* Patient 02, 11 18, 35 01:01, 11:04UCB donor unit02, 32UCB donor’s mother02, 2407, 3501:01, 13:01HLA-A*11 is not carried by UCB donor or the UCB donor’s mother; this is a NIMA-mismatched UCBT.
84HLA Typing Summary HLA typing nomenclature Low, intermediate, high resolution typingClinical application of HLA typingRole in TRALI risk mitigationImportant role in donor selection for solid organ transplant and HSCTOptimal matching between pt and donor