HLA: matching and donor selection Dr Bronwen Shaw Consultant in haematopoietic cell transplantation Royal Marsden Hospital Anthony Nolan Trust

Overview Why does HLA matter in transplantation? HLA Some examples Where is it found? What does it do? Tissue typing? What does the nomenclature mean and how do we classify ‘matching’ and ‘mismatching’? Polymorphism Some examples

Survival for CML Unrelated HCT: JMDP Tally Effect HCT Component Data Survival for CML Unrelated HCT: JMDP Tally Effect

What is HLA? What is it for? Human Leukocyte Antigen Discovered: in mice (1937), humans (1954) Function: to present peptides to T cells, thus allowing elimination of foreign particles and recognition of self (so in transplants this has to be modulated)

4 Mb 3 Mb 2 Mb 1 Mb 0 Mb HLA-A HLA-C HLA-B HLA-DR HLA-DQ HLA-DP

The HLA Family A1 A2 Cw7 Cw5 B8 B44

The HLA Family A1 A2 A3 A26 Cw7 Cw5 Cw7 Cw8 B8 B44 B7 B14

The HLA Family A1 A2 A3 A26 Cw7 Cw5 Cw7 Cw8 B8 B44 B7 B14 A1 A3 Cw7

The HLA Family A1 A2 A3 A26 Cw7 Cw5 Cw7 Cw8 B8 B44 B7 B14 A1 A3 A1 A26

The HLA Family A1 A2 A3 A26 Cw7 Cw5 Cw7 Cw8 B8 B44 B7 B14 A1 A3 A1 A26

The HLA Family B44 A1 A2 A3 A26 Cw7 Cw5 Cw7 Cw8 B8 B7 B14 A1 A3 A1 A26

The HLA Family A1 A2 A3 A26 Cw7 Cw5 Cw7 Cw8 B8 B44 B7 B14 A1 A3 A1 A26

The HLA Family A1 A2 A3 A26 Cw7 Cw5 Cw7 Cw8 B8 B44 B7 B14 A1 A3 A1 A26

The HLA Family A1 A2 A3 A26 Cw7 Cw5 Cw7 Cw8 B8 B44 B7 B14 A1 A3 A1 A26

The HLA Family A1 A2 A3 A26 Cw7 Cw5 Cw7 Cw8 B8 B44 B7 B14 A1 A3 A1 A26

The HLA Family A1 A2 A3 A26 Cw7 Cw5 Cw7 Cw8 B8 B44 B7 B14 A1 A3 Cw7

MHC Sequencing Consortium, 1999 One of the most gene-dense regions of the genome 224 genes identified within the 3.6 Mb 40% of the genes have functions within the immune response HLA is the most polymorphic region in the human genome

Map of the human MHC on chromosome 6

- found on all nucleated cells HLA Class I - found on all nucleated cells Polymorphism located in exons 2 & 3 1 L exon protein domain 5 TM 8 3'UT 6 7 CYT 2 3 4 a a a

Class I HLA-A

- restricted to cells of the immune system HLA Class II - restricted to cells of the immune system Polymorphism located in exon 2 1 L exon protein domain 5 3'UT -chain gene 2 3 4 TM/CYT 6 b-chain gene a1 a 1  TM CYT

Class II HLA-DR

HLA and Tissue Typing Cell

Serology-low resolution HLA and Tissue Typing Serology-low resolution e.g. A2 Cell

HLA and Tissue Typing Cell Medium resolution ‘string’ e.g. A*0201/0205/0209/0240 SSP, SSOP High resolution (definitive) e.g. A*02010101 SBT Cell

HLA Nomenclature Gene names Antigen names Allele names HLA-A or HLA-DRB1 Antigen names A2 or DR1 Allele names A*020101 or DRB1*01010101

HLA Allele Nomenclature Locus Asterisk Allele family (serological where possible) Amino acid difference Non-coding (silent) polymorphism Intron, 3’ or 5’ polymorphism N = null L = low S = Sec. A = Abr.

Level of resolution Low level of resolution A*02 Antigen matched Medium level (string) A*0201/0205/0209/0240 High level A*020101 Antigen matched Allele matched Type is ONE OF these four: Antigen matched BUT do not know if allele matched

Ambiguity Using medium level resolution typing it is possible to exclude some but not all alleles from a group, hence the National Marrow Donor Program (NMDP) codes. B*1501 or B*1502 = B*15AB B*1501/1502/1505/1515/1521/1545/1556/1570 = B*15FGR This is important for donor selection i.e. you may be able to tell if a donor is definitely MISMATCHED but not matched

Numbers of HLA antigens and alleles 1968 - 2004 120 New HLA Class I alleles per year 50 New HLA Class II alleles per year

Number of HLA Alleles June 2004/2006/2007 (http://www. ebi. ac HLA- A HLA- B HLA-C 325 (24) 592 (49) 175 (9) 489/617 830/960 210/335 DRB DQA1 DQB1 DPA1 DPB1 458 (20) 28 57 (7) 22 103 545 (DRB1 463/542) 34 78/87 23 125/127 MICA TAP 56 11 Figures in parenthesis indicate the number of serologically defined antigens at each locus.

Linkage Disequilibrium/ Haplotypes LD: Alleles occur together with a greater frequency than would be expected by chance B/C strong, DR/DQ strong, A less strong, DP weak e.g. B*0801 - 99% will be Cw*0701 But B*1801 either Cw*0501, *0701 e.g DRB1*1501 - will be DQB1*0602 But DRB1*0401 either Cw*0301, *0302 Haplotype: A group of genes inherited together e.g. A*0101,B*0801,Cw*0701,DRB1*0301,DQB1*0201

Examples for search coordinators and data managers

Example 1: VUD search Patient: Finding a donor: A*0101, B*0801, DRB1*0301 Finding a donor: Common haplotype - therefore likely Usually in strong LD - therefore ‘predictable’ Even at low resolution (A1, B8, DR3) good chance of being matched

Example 1: Data entry Patient: Donor: A*0101, B*0801, DRB1*0301 A1, B8, DRB1 03: Antigenic match for A, B, DRB1 No data can be entered for C, DQB1, DPB1 No data can be entered for allele level matching A*0101, B*0801, DRB1*0301: Allelic and antigenic match for A, B, DRB1

Example 2: VUD search Patient: Finding a donor: A*0201, B*1801, DRB1*0401 Finding a donor: Less strong LD - therefore ‘ NOT predictable’ i.e. equal chance of C being *0701, *0501, *1203; DQB1 50/50 chance of *0301, *0302 At low resolution (A2, B18, DRB4) unable to predict this will match

Example 2: VUD search (cont) Donor A*02

Example 2: VUD search (cont)

Example 2: VUD search (cont)

Example 2: VUD search (cont)

Example 2: VUD search (cont)

Example 2: VUD search (cont)

Example 2: VUD search (cont)

Example 2: Data entry Patient: Donor: A*0201, B*1801, DRB1*0401 A2, B18, DRB1 04: Antigenic match for A, B, DRB1 No data can be entered for C, DQB1, DPB1 No data can be entered for allele level matching A*0201, B*1801, DRB1*0401: Allelic and antigenic match for A, B, DRB1 A*0201/05, B*1801, DRB1*0401: Allelic and antigenic match for B, DRB1 Antigenic match for A BUT cannot say that this is an allelic match

Example 2: Data entry Patient: Donor: A*0201, B*1801, DRB1*0401 A2, B18, DRB1 04: Antigenic match for A, B, DRB1 No data can be entered for C, DQB1, DPB1 No data can be entered for allele level matching A*0201, B*1801, DRB1*0401: Allelic and antigenic match for A, B, DRB1 A*0201/05, B*1801, DRB1*0401: Allelic and antigenic match for B, DRB1 Antigenic match for HLA-A BUT cannot say that this is an allelic match

Example 3: search and data patient donor search data A*0201/9207/9209 Probable match (rare) Select donor Antigen match (probable allelic) B*3503 B*4403 Match Antigenic and allelic match Cw*0401/24 Cw*1601 Cw*0401/20/24 DRB1*0701, DRB1*1501/18 DQB1*0202 DQB1*0602 Rare alleles: A*9207, *9209, Cw*0420, Cw*0424, DRB1*1518

Example 3: search and data patient donor search data A*0201/9207/9209 Probable match (rare) Select donor Antigen match (probable allelic) B*3503 B*4403 Match Antigenic and allelic match Cw*0401/24 Cw*1601 Cw*0401/20/24 DRB1*0701, DRB1*1501/18 DQB1*0202 DQB1*0602 Rare alleles: A*9207, *9209, Cw*0420, Cw*0424, DRB1*1518

Example 3: search and data patient donor search data A*0201/9207/9209 Probable match (rare) Select donor Antigen match (probable allelic) B*3503 B*4403 Match Antigenic and allelic match Cw*0401/24 Cw*1601 Cw*0401/20/24 DRB1*0701, DRB1*1501/18 DQB1*0202 DQB1*0602 Rare alleles: A*9207, *9209, Cw*0420, Cw*0424, DRB1*1518

Example 4: search and data patient donor search data A*0101-03/06 A*0201-14/16-22/24-31/33/36-41 A*0101-03/06/07 A*0201-14/16-22/24-31/33/36-42/44/45 Probable match - but not certain Antigen match Cannot report allelic status B*0801/05/07/10 B*4402/05/11/14 B*0801/05/07/10/12 Cw*0701/05/06/08/14 Cw*0401/03/04/05/06/07 Cw*0501-04 Probable match (one antigen)- but not certain Definite mismatch Antigen match x1 Cannot report allelic status Antigen and allelic mm x1 DRB1*1301/40 DRB1*1401 DRB1*1301 DQB1*0603/14 DQB1*050301 Rare alleles: ???????????

Useful websites Anthony Nolan Trust: www.anthonynolan.org.uk NMDP allele codes: http://bioinformatics.nmdp.org/HLA/Allele_Codes/Allele_Code_Lists/index.html World Marrow Donor association: www.worldmarrow.org Bone marrow donor worldwide: www.bmdw.org HLA database: http://www.ebi.ac.uk/imgt/hla/