Modern Blood Banking & Transfusion Practices
6th Edition
Chapter 8
Blood Group Terminology and the Other Blood
... [Show More] Groups
Copyright © 2012 F.A. Davis Company
Modern Blood Banking & Transfusion Practices
6th Edition
Blood Groups and Terminology
▪ A blood group system is one or more antigens produced by alleles at a single gene locus or at loci so closely linked that crossing over does not occur or is very rare.
▪ Codominant alleles
▪ Silent or amorphic alleles
▪ Null phenotype
▪ Regulator or modifying genes
Copyright © 2012 F.A. Davis Company
Modern Blood Banking & Transfusion Practices
6th Edition
Blood Groups and Terminology (cont’d)
▪ Although gene and antigen names seem confusing at first, certain conventions are followed when writing alleles, antigens, and phenotypes.
▪ Genes
▪ Antigen names
▪ Phenotype
▪ Subscripts, superscripts, and italics
Copyright © 2012 F.A. Davis Company
Modern Blood Banking & Transfusion Practices
6th Edition
Blood Groups and Terminology (cont’d)
▪ For letter antigens, a plus sign or minus sign written on the same line as the antigen is used to designate that the antigen is present or absent.
▪ Antibodies are described by their antigen notation with the prefix “anti-”, including a hyphen before the antigen symbol.
Copyright © 2012 F.A. Davis Company
Modern Blood Banking & Transfusion Practices
6th Edition
Blood Groups and Terminology (cont’d)
▪ 1980: International Society of Blood Transfusion (ISBT) formed a Working Party on Terminology for Red Cell Surface Antigens.
▪ Enables communication on computer systems
▪ Each antigen given a six-digit number
▪ First three digits: identify system, collection, or series
▪ Second three digits: identify the antigen
▪ 30 blood group systems to date
Copyright © 2012 F.A. Davis Company
Modern Blood Banking & Transfusion Practices
6th Edition
Blood Groups and Terminology (cont’d)
▪ Collections are antigens that have a biochemical, serologic, or genetic relationship but do not meet the criteria for a system.
▪ Antigens classified as a collection are assigned a 200 number.
▪ All remaining RBC antigens that are not associated with a system or a collection are catalogued into the 700 series of low-prevalence antigens or the 901 series of high-prevalence antigens.
Copyright © 2012 F.A. Davis Company
Modern Blood Banking & Transfusion Practices
The Lewis (007) System
6th Edition
▪ The Lewis blood group system is unique because the Lewis antigens are not intrinsic to RBCs but are on type 1 glycosphingolipids that are passively adsorbed onto the RBC membrane from the plasma.
▪ There are several Lewis antigens, but the two of primary concern are Lea and Leb.
▪ Two alleles at the Lewis locus, Le and the amorph le, and two alleles at the Secretor locus, Se and the amorph se.
Copyright © 2012 F.A. Davis Company
Modern Blood Banking & Transfusion Practices
6th Edition
The Lewis (007) System (cont’d)
▪ Four phenotypes
▪ Secretors or nonsecretors
▪ Antigens of the Lewis blood group system recognized by ISBT
▪ Distribution of Lewis antigens
▪ Enzyme treatment results
Copyright © 2012 F.A. Davis Company
Modern Blood Banking & Transfusion Practices
Lewis Antibodies
6th Edition
▪ Frequently naturally occurring antibodies made by Le(a−b−) persons; that is, they occur without any known RBC stimulus.
▪ Generally IgM and do not cross the placenta.
▪ Not well developed on fetal RBCs.
▪ Anti-Lea is the most commonly encountered.
▪ Anti-Leb is not as common or generally as strong as anti-Lea.
Copyright © 2012 F.A. Davis Company
Modern Blood Banking & Transfusion Practices
6th Edition
Synthesis of Lewis Antigens
▪ Secretors and nonsecretors
▪ Lewis antigens produced in saliva and other secretions are glycoproteins, but Lewis cell- bound antigens absorbed from plasma onto the RBC membranes are glycolipids
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