General aspects and advances in RH and other blood groups Florianopolis 17h15-17h45 W. A. Flegel, MD Professor Transfusion Medicine Chief, Laboratory Services Section, Dept. Transfusion Medicine, Center National Institutes of Health, Bethesda, Maryland Disclaimer. The views expressed do not necessarily represent the view of the National Institutes of Health, the Department of Health and Human Services, or the U.S. Federal Government. Disclosure. Former employee of DRK Blutspendedienst Baden-Wurttemberg Hessen with patents on molecular genetics for RHD. Relevance of Rh blood group > 300 blood group antigens Biological RhCE and RhD RHCE: ancestral position RHD is the duplicated gene P N RHD upstream downstream Rhesus box P N SMP1 RH SMP1 ancestral in mouse RHCE 1 2 RHD positive human P N hybrid SMP1 50.000 bp Blood 99(2002)2772 RHCE RHD negative Relevance of Rh blood group RhD and RhCE differences > 260 blood group antigens Biological relevance RhCE and RhD Transfusion Vol 49 June 2009 1
Springe 43 samples with serological abnormalities 34 samples with RHCE variants 22 RHCE alleles 10 new alleles Frequency phenotype 1 in 8,449 for each allele < 1 in 488 (95% CI) 122 blood donors 13 patients with problems in automated RH testing 34 RHCE alleles 23 new alleles 70 of 122 E variant I = RHcE(M167K) Transfusion 2009;49:1803-1811 Transfusion 2009;49:1793-1802 Summary of Northern and Southern Germany studies Common picture Highly diverse allele composition 34 alleles (Northern) 22 alleles (Southern) 9 alleles common in both Mostly caused by single missense mutations No molecular cause found 9 alleles in both studies relevant fraction Striking differences high prevalence of E cat I explained by different typing approaches Systematic characterization important for improvement of molecular and serological typing methods Family studies to link RHCE and RHD alleles Family studies are often required to determine the association of variant RHCE and RHD alleles Here: DOL-2 is associated with a regular RHce allele Current mass scale genotyping for blood groups in donors 10,555 genotyped blood donors Perreault et al. Vox Sang 2009 in press 46,133 RHD genotyped D neg. donors Flegel et al. Transfusion 2009;46:465 23,330 RHD genotyped D neg. donors Polin et al. Transfusion 2009;49:676 Hema-Quebec Montreal/Quebec City 10,555 genotyped blood donors * * 2
Bioarray Blood groups covered CO DI DO FY JK LU MNS SC LW HbS BloodGen EU-project: Bloodchip 1,000 samples Rh announced Bloodchip Do we still need serology? 3,000 samples CE marking in EU DJ Anstee Transfusion 45(2005)653 There will be plenty of work for blood group serologist for many years to come. Before agglutination is replaced in the near future by the emergence of molecular methods,... PJ Schmidt & TJ Greenwalt Transfusion 46(2006)448 Innovative serologists apply molecular testing for the benefit of their patients. Routine RHD genotyping of donors Objectives Enhance safety of D neg. RBC Expand current knowledge from Caucasians to African American and Asian populations systematic analysis of uncommon RHD alleles in non-caucasian populations Application in mixed donor populations develop techniques document feasibility Routine RHD genotyping in donors Examples for current mass scale genotyping for blood groups in donors restricted to Europe 46,133 RHD genotyped D neg. donors Southwestern Germany Transfusion 2009;46:465 23,330 RHD genotyped D neg. donors Austria Transfusion 2009;49:676 no data yet outside of Europe 3
DRK Blutspendedienst Ulm 46,133 RHD typed D neg. donors Molecular tests in prenatal care Fetal genotyping from maternal plasma eliminate prenatal RhIg if fetus is RHD gene negative Weak D genotyping of mother eliminate all RhIg if mother carries weak D types 1, 2, 3, 4.0 Current fetal genotyping from maternal plasma 851 samples 99.5 % accuracy Rouillac-Le Sciellour C et al. Mol Diagn 2004 Multiple studies Generally good accuracy No guideline in any health care system Not mandatory anywhere RhIg may be dropped,...... if mother carries certain weak D types may save 3% 5% of all anti-d shots one test per mother s lifetime Health and cost benefits... if fetus types D neg. from maternal plasma may save 40% of prenatal anti-d shots one or more tests per pregnancy Rhesus protein structure and function DOL > 260 blood group antigens Biological relevance RhCE und RhD Channel extracellular Rh protein vestibule Transfusion Vol 48 Jan 2008 4
D variants with amino acid substitutions at loops 3 and 4 Soluble recombinant blood group proteins Easy single-step method for detection and identification identification of antibodies to high-prevalence antigens detection of admixed antibodies Reagents would be useful for serology lab recombinant blood group proteins mixtures of recombinant proteins Soluble recombinant proteins as serology reagents Knops Neutralization of Knops system antibodies using soluble complement receptor 1 introduced in 1996 by JM Moulds/KE Rowe Lutheran Ridgwell et al. Transf Med 2003 Seltsam et al. Transfusion 2007 Kell/Duffy/Lutheran ELISA Ridgwell et al. Transf Med 2007 JMH Seltsam et al. Transfusion 2008 Identification of admixed antibodies in the presence of anti-scianna Mixtures of soluble proteins as serological reagents Conclusion and Outlook AABB RAP session Molecular Immunohematology Remove potentially harmful constituents of the therapeutically required cells blood group antigens foreign to the recipient as non-essential blood constituents have been largely removed from today s blood products Old paradigm: the least incompatible blood product New Goal the best compatible blood product Seltsam/Grueger/Blasczyk/Flegel, Transfusion in press 5