ABO-Blutgruppensystem

Transcription

1 ABO-Blutgruppensystem Swisstransfusion 2012 Bern 7. September 2012 E. A. Scharberg Institut für Transfusionsmedizin und Immunhämatologie Baden-Baden DRK-Blutspendedienst Baden-Württemberg-Hessen

2 Grundlage der ABO-Blutgruppen Fuc O Gal GlcNAc Fuc A GalNAc Gal GlcNAc Fuc B Gal Gal GlcNAc Glykosyltransferase (ABO-Gen) Erythrozyt

3 Genetik der ABO-Blutgruppen Chromosom 9 ABO-Gen ~15 kb genom. DNA Exon Exon 6 Exon 7 Allele A 1 (wt) G C C G C G G G C A 2 - T del B - - T A A - C A - O 1 del O A Phänotyp A 1 A 2 B O O 4 Positionen in der DNA-Sequenz sind für die Spezifität und Aktivität der kodierten Glykosyltransferase entscheidend und ermöglichen die Unterscheidung der Blutgruppen A 1, A 2, B und O

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5 Serumeigenschaften: Anti-A1: ++ Anti-A2: negativ Anti-B: negativ Anti-O (H): negativ Genotyp: O0301/B101

6 Serumeigenschaften : Anti-A1: ++ Anti-A2: negativ Anti-B: negativ Anti-O (H): negativ Genotyp: A3(neu)/B101 (107T>C exon 7 A201)

7 Serumeigenschaften: Anti-A1: ++ Anti-A2: negativ Anti-B: negativ Anti-O (H): negativ Genotyp: A3(neu)/B T>C exon 7 A201

8 Anti-A1: + Anti-A2: neg Anti-B: ++++ Anti-O/H: neg Genotyp: Ax01/O01

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10 Bx03/O02

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12 Ax03/O03 Ax01/O01

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14 Routine ABO, (RhD, RhCcEe, K) phenotyping of first and second time donors on Olympus PK 7200 with monoclonal anti-a, anti-b reagents and reverse typing (A1, A2, B, O red cells) Unclear results in ABO proved in tube test (incubation 30 minutes at room temperature) with monoclonal anti-a, anti-b reagents and reverse typing (A1, A2, B, O red cells) Since May 2004 Samples with weak or negative A and B antigens and missing or weak (+) corresponding isoagglutinins Low resolution ABO genotyping for A, A2, B, O01, O03 alleles (PCR-SSP) If no correlation between phenotype and genotype ABO subtyping for 36 rare alleles (Ael, Ax, Aw, Bx, Bw, etc.) (PCR-SSP) If still no correlation between phenotype and genotype Exon amplification and sequencing of entire ABO gene from genomic DNA

15 Results Donors with aberrant ABO phenotypes May 2004 thru December 2007: 206,262 first and second time donors 412 samples with aberrant ABO phenotypes (0.20%) 45 samples with weak antigens Ax01 (646T>A): n=15 Aw06 (502C>G): n=5 Aw13 (2T>C): n=3 Ael01 (804insG): n=2 Ax03, Aw04, Aw09, B(A)03: n=4 (one each) novel variant (Bw21): n=1 347 samples with negative antigens and weak or absent isoagglutinins non-deletional O alleles (O03, Aw08, O51): n=255 other alleles (Ax03, Ax01): n=6 novel variants (Bw20, Aw15): n=3 molecular basis unknown: 123 molecular basis unknown: n=15

16 Geno-/Phänotypen im ABO-System serologische Nachweisgrenze Phänotyp 0 A el A x /A weak A 3 A 2 A 1 Allele O01 O03 Ael01 Aw01 A301 A201 A101 O02 Aw08 Ael02 Ax01 A302 A202 A Ax Die Genotyp-Phänotyp-Korrelation bei den seltenen Varianten ist ein quantitativer Effekt. D.h. es ändert sich nicht das Antigen sondern die Antigendichte. Dieser quantitative Effekt ist genetisch nicht verlässich bestimmbar.

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18 Clinical significance of non-deletional O alleles in blood donors? Transfusion practice: No deferral of donors with missing or weak isoagglutinins Red cell units with clear serological ABO antigen typing used for transfusions No transfusion reaction reported Do some of the non-deletional O alleles have low antigen expression that might boost the isoagglutinins of recipients?

19 Plasma or serum samples of all 6,387 patients tested in our laboratory from January 1 thru December 31, 2007 stored at -30 C. Look back procedure (January 2008) identifying patients who randomly received ABO variants with non-deletional O alleles In patients with follow up samples Titration of anti-a and anti-b in samples at the time of the cross-match of the ABO variant and in follow up samples in gel technique using A1 and B red cells: Neutral gel cards: incubation 15 minutes at room temperature Antiglobulin gel cards: incubation 15 minutes at 37 C

20 20,566 red cell units cross-matched for 6,387 patients tested in our laboratory from January 1 thru December 31, 2007 stored at -30 C. 35 patients received red cell units with non-deletional O alleles 21 of them had follow up samples (6 to 286 days after transfusion) 17 patients (all group O) received units with O03 allele 2 patients (both group A) received units with Bw20 allele 1 patient (group O) received a unit with Aw08 allele 1 patient (group O) received a unit with Ax03 allele

21 Variant ABO alleles in this study *O01 261delG *O03 *Aw08 53G>T 220C>T 297A>G 526C>G 802G>A *Ax03 220C>T 297A>G 526C>G 802G>A 488C>T *Bw20 646T>A 771C>T 681G>A 829G>A 817insG 297A>G 526C>G 703G>A 803G>C 657C>T 796C>A

22 Anti-A Titer before and after Transfusion of Red Cell Units with O03 Allels Titer Sample IgG after Transfusion IgG before Transfusion IgM after Transfusion IgM before Transfusion

23 Anti-B Titer before and after Transfusion of Red Cell Units with O03 Allels Titer Sample IgG after Transfusion IgG before Transfusion IgM after Transfusion IgM before Transfusion

24 Anti-A Titer before and after Transfusion of Red Cell Units with Aw08 and Ax03 Alleles Titer 1 IgG after Transfusion Aw08 Ax03 IgM after Transfusion IgG before Transfusion IgM before Transfusion

25 Anti-B Titer before and after Transfusion of Red Cell Units with Aw08, Ax03 and Bw20 Alleles Titer Aw08 1 Ax03 Bw20-1 Bw20-2 IgM before Transfusion IgM after Transfusion IgG before Transfusion IgG after Transfusion

26 Conclusions: The increasing number of known ABO variants with non-deletional alleles raises the question of their clinical significance especially in blood donors. Transfusion of red cell units with the variant ABO alleles O03, Aw08, and Ax03 typed and transfused as group O, and Bw20 typed and transfused as group A did not boost anti-a and anti-b titers in blood group O/A recipients. For these variants no donor referral because of missing or weak isoagglutinins seems to be necessary.

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28 Exon 2 wild type: mutant: 98G>T T T G T T T G G g t a a g a c T T G T T T G K g t a a g a c intron 2 Provisional Allele Name: Aw32, GenBank JX398332

29 Intron 1 (reverse) IVS1+2insT wild type: mutant: t g c a c t c - a c C G G C C t g c a c t c a m c S G S C M intron 1 exon 1 Provisional Allele Name: O76, GenBank JX519571

30 Exon 3 wild type: mutant: 107T>C T A C G G G G T C C T A A G C T A C G G G G Y C C T A A G C Provisional Allele Name: A309, GenBank JX398333

31 Exon 7 wild type: mutant: 815G>A T T C G G G G G G T C G G T G T T C G G G G R G T C G G T G Provisional Allele Name: O75, GenBank JX519569

32 Exon 7 wild type: mutant: 926A>G A A C A A G T A C C T G C T G A A C A A G T R C C T G C T G Provisional Allele Name: Aw30, GenBank JX398330

33 Genetische Vielfalt im ABO System 238 Genvarianten (Stand Juni 2012) A-Allele (96): Phänotyp *A1 9 Allele A 1 *A2 21 Allele A 2 *A3 8 Allele A 3 *Ael 9 Allele A el *Aw 29 Allele A weak *Ax 20 Allele A weak B-Allele (68): Phänotyp *B1 18 Allele B *B3 8 Allele B 3 *Bel 6 Allele B el *Bw 27 Allele B weak *Bx 9 Allele B weak O-Allele (74): Phänotyp *O1 (261delG) 57 Allele 0 *O2 (non-261delg) 17 Allele 0; schwache oder fehlende Isoagglutinine The Blood Group Antigen Gene Mutation Database

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37 6 days before!!!

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43 Acknowledgments Peter Bugert Gaby Rink Institut für Transfusionsmedizin und Immunologie DRK-BSD Baden-Württemberg-Hessen Mannheim Nureyla Kanbur Raphaela Baudendistel Sabine Roth Susanne Seyboth Ekkehard Richter Institut für Transfusionsmedizin und Immunhämatologie Baden-Württemberg-Hessen Baden-Baden

44 Thank you!

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46 Schwaches A-Antigen

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48 Mischfeldagglutination nach ABO-ungleicher Transfusion

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50 A-Antigen-Verlust (MDS-Patient)

51 Thank you!