International Society of Blood Transfusion Working Party on Red Cell Immunogenetics and Blood Group Terminology: Report of the Dubai, Copenhagen and Toronto meetings

Abstract

Background and objectives: The International Society of Blood Transfusion (ISBT) Working Party for Red Cell Immunogenetics and Blood Group Terminology meets in association with the ISBT congress and has met three times since the last report: at the international meetings held in Dubai, United Arab Emirates, September 2016 and Toronto, Canada, June 2018; and at a regional congress in Copenhagen, Denmark, June 2017 for an interim session. Methods: As in previous meetings, matters pertaining to blood group antigen nomenclature and classification were discussed. New blood group antigens were approved and named according to the serologic and molecular evidence presented. Results and conclusions: Fifteen new blood group antigens were added to eight blood group systems. One antigen was made obsolete based on additional data. Consequently, the current total of blood group antigens recognised by the ISBT is 360, of which 322 are clustered within 36 blood groups systems. The remaining 38 antigens are currently unassigned to a known system. Clinically significant blood group antigens continue to be discovered, through serology/sequencing and/or recombinant or genomic technologies.

It's time to phase out “serologic weak D phenotype” and resolve D types with RHD genotyping including weak D type 4

“… *For the more than 150 other known weak D alleles, typically associated with a serologic weak D phenotype, not listed in this tabulation, the risk for anti‐D is often unknown, but no clinically significant hemolytic disease of the fetus and newborn or transfusion reaction have been reported.…”

“…Recipients carrying weak D type 4.1 are also more likely to be routinely transfused with D+ RBC units than recipients carrying weak D type 4.0 . We recommend changing the classification of these two alleles from partial D to weak D in RHD allele tables . We also recommend continuing the collection and publication of clinical outcomes data in patients with weak D type 4.0 or type 4.1 and anti‐D .…”

“…From ACOGʼs 2017 recommendation, 36 it is evident that optimal, up-to-date management of serologic weak D phenotypes and interpretation of RHD genotype results should be guided by subject matter experts in blood group genetics. There is observational indirect serologic evidence, with [41][42][43] and without genotyping results, 6 to support the premise that patients who * For the more than 150 other known weak D alleles, typically associated with a serologic weak D phenotype, 32,33 not listed in this tabulation, the risk for anti-D is often unknown, but no clinically significant hemolytic disease of the fetus and newborn or transfusion reaction have been reported. † Strength of reactivity 34 is variable and depends on technical details, such as test method, reagent, and RBC condition.…”

“…15,16,50 We recommend changing the classification of these two alleles from partial D to weak D in RHD allele tables. 33 We also recommend continuing the collection and publication of clinical outcomes data in patients with weak D type 4.0 or type 4.1 and anti-D. 2,17 In the African American population, weak D type 4.0 is not uncommon, with an allele frequency of 0.02. In the United States, 38 cases with anti-D have been reported 17 : While adsorption studies to differentiate allo-from auto-anti-D formation remain to be published, most importantly, no hemolytic transfusion reaction or hemolytic disease of the fetus and newborn have been associated.…”

Hybrid glycophorin and red blood cell antigen genotyping in Asian American type O blood donors with Mia phenotype

“…004) in terms of complexity. Forty‐nine MNS antigens are carried on glycophorin A, glycophorin B, and hybrids of the glycophorins . The M and N antigens are on glycophorin A, and the S and s antigens are on glycophorin B, which are encoded by Exon 2 of GYPA and Exon 4 of GYPB genes, respectively.…”