The Lewis Blood Group System among Chinese in Taiwan

127

This review summarises present knowledge of the chemistry, immunology, genetics and clinical significance of antibodies in the Lewis and secretor histo- blood group systems. Although red cell serology has laid the foundations for these systems, more recent advances have been made by studying Lewis and related glycoconjugates with monoclonal antibodies, determining structures by mass spectrometry and NMR spectroscopy, identifying enzymes and their specificities, and identifying the genes by molecular biology. The expression of Lewis system antigens is dependent on Lewis and secretor loci. Fucosyltrans- ferases coded by genes at these loci compete and interact with each other and with other transferases to determine an individual’s Lewis and secretor phenotype. Exocrine epithelial cells, mostly of endodermal origin, synthesise the Lewis antigens which, as plasma glycolipids, are secondarily acquired by cells of the peripheral circulation. Phenotyping red cells is often regarded as a simple way of determining the Lewis and sometimes the secretor status of an individual; however, the red cell phenotype is influenced by many factors and may not necessarily reflect someone’s Lewis and secretor genotypes. Two main red cell Lewis groups are usually found, Lewis negative and Lewis positive. In Lewis-negative individuals, the secretor genotype does not affect the Lewis phenotype, but in Lewis-positive individuals, the non-secretor genotype generates the Le(a+b-) phenotype, the secretor genotype causes the Le(a-b+ ) phenotype, and the partial secretor genotype gives rise to the Le(a+b+) phenotype.

Section: Lewis and Secretor Phenotypesmentioning

confidence: 99%

Lewis Histo-Blood Group System and Associated Secretory Phenotypes

Henry¹,

Oriol²,

Samuelson³

1995

127

“…The Se w allele, resulting in the Le (a+b+) phenotype, only distributes in certain populations [2, 11, 12, 17]and has a relatively high gene frequency in all ethnic groups of Taiwan [12], but is virtually absent in Caucasians. In Caucasians, about 20% of individuals are nonsecretors, resulting from a common se allele with a nonsense mutation at nucleotide 428 (G to A) [4].…”

Section: Resultsmentioning

confidence: 99%

“…In Caucasians, the nonsecretor phenotype has an approximate frequency of 20%, but it is virtually absent in Taiwanese (Minnan and Hakka Chinese) and mainland Chinese [11, 12]. A null se allele bearing a nonsense mutation of G 428 to A was demonstrated to be the common nonsecretor allele responsible for the nonsecretor phenotype in Caucasians [4].…”

Section: Introductionmentioning

confidence: 99%

A Newly Identified Nonsecretor Allele of the Human Histo–Blood Group α(1,2)Fucosyltransferase Gene (FUT2)

Yu¹,

Lee²,

Chu³

et al. 1999

Background and Objectives: The human Secretor α(1,2)fucosyltransferase gene determines the ABH secretor status and influences the Lewis phenotype of an individual. Studies were carried out on the Lewis (a+b–) nonsecretors of different groups indigenous to Taiwan to demonstrate their se genotypes. Methods: The Lewis phenotype of the blood samples was determined by a microplate method. The se genotypes of the individuals with the Lewis (a+b–) phenotype were analyzed by a polymerase chain reaction restriction fragment length polymorphism (PCR–RFLP) method designed for the se alleles reported previously. PCR and cloning techniques were used to determine the coding sequence of the novel se gene. Results: A new se allele, se⁶⁸⁵, with a three–nucleotide deletion of GTGGT to GT in the coding region of nucleotides 685 through 689 was identified in a Le (a+b–) nonsecretor from the Ami tribe indigenous to Taiwan. The deletion predicts the loss of the amino acid Val²³⁰ in the corresponding secretor enzyme's C–terminal segment. The distribution of the se⁶⁸⁵ allele in the Ami tribe was further verified by PCR–RFLP analysis. Conclusion: The Se gene exhibits heterogeneity with some Se alleles being common but others displaying a unique distribution in different ethnic populations. The newly identified se⁶⁸⁵ allele seems to exist only in the Ami tribe indigenous to Taiwan.

“…It has been sug gested that the Le(a+b+) phenotype is a result of the weak secretor gene, Sew [12], However, it would appear that the Se" gene is not involved in causing neonatal hyperbilimbi nemia in Taiwanese infants because the jaundiced infants that were followed up at 2-3 years of age showed similar Lewis phenotype frequencies to that of the general popula tion, without any predominance of the Le(a+b+) phenotype. In addition, the presence of the Le(a+b+) phenotype in vari ous Polynesian groups (10^40) [13] and also the occurrence of severe neonatal hyperbilimbinemia of uncertain etiology among Polynesians [14] again suggests the possibility of a relationship between either the Se and/or Le genes and neo natal hyperbilirubinemia.…”

Section: Discussionmentioning

confidence: 99%

“…IgG antibodies were eluted from red cells by the Lui/Eicher meth od [12] in cases of suspected ABO system hemolytic disease of the newborn (HDN), Rh system IgG antibodies in cases of HDN and IgG autoantibodies in lymphoma patients were eluted with an acid elution test kit (from BAG/Lich, Germany), or using a modified chloroform elution method [13].…”

Section: Methodsmentioning

confidence: 99%

Flow Cytometric Analyses of the Subclasses of Red Cell IgG Antibodies

Lynen¹,

Neuhaus²,

Schwarz³

et al. 1995

We report on flow cytometric IgG subclass determinations of red cell antibodies using polyclonal FITC-labeled antibodies. The limit of detection of this method was 1 ng anti-D per 1x10^7 red cells. The inter- and intra-assay coefficients of variance were 8.2 and 2.3%, respectively. In 8 newborns with a positive direct antiglobulin test (DAT) in the gel centrifugation test (GCT), due to ABO antibodies, IgGl was detected in all and IgG2 additionally in 4 of these cases. In 5 severe cases of hemolytic disease of the newborn (HDN) due to anti-D, large amounts of IgGl were found, and in 3 of these 5, IgG3 in combination with IgGl. In 8 mild or moderate HDN cases (4 anti-D, 2 anti-E, 1 anti-Fy^a, 1 anti-Jk^a), phototherapy sufficed, and IgGl was the only antibody. In 7 adult patients with malignant lymphoma and a positive DAT (GCT), only small amounts of IgG1 red cell autoantibodies could be demonstrated by flow cytometry. In 5 further patients with malignant lymphoma, a positive DAT, and severe hemolytic anemia, large amounts of IgGl autoantibodies were found and IgG3 was also present in 3 of these cases. Flow-cytometric determination of IgG subclasses may be a useful tool in immunohematology, since subclass determinations were possible in all of these cases. This method is suited for clinical routine and offers the possibility of sufficient standardization.