Significance of Lewis phenotyping using saliva and gastric tissue: comparison with the Lewis phenotype inferred from Lewis and secretor genotypes.

Lewis phenotypes using various types of specimen were compared with the Lewis phenotype predicted from Lewis and Secretor genotypes. This is the first logical step in explaining the association between the Lewis expression and Helicobacter pylori. We performed a study of the followings on 209 patients who underwent routine gastroscopy: erythrocyte and saliva Lewis phenotyping, gastric Lewis phenotyping by the tissue array, and the Lewis and Secretor genes genotyping. The results of phenotyping were as follows [Le(a-b-), Le(a+b-), Le(a-b+), and Le(a+b+), respectively, in order]: erythrocyte (12.4%, 25.8%, 61.2%, and 0.5%); saliva (2.4%, 27.3%, 70.3%, and 0.0%); gastric mucosa (8.1%, 6.7%, 45.5%, and 39.7%). The frequency of Le, le (59/508) , le (59/1067) , and le (59) alleles was 74.6%, 21.3%, 3.1%, and 1.0%, respectively, among 418 alleles. The saliva Lewis phenotype was completely consistent with the Lewis phenotype inferred from Lewis and Secretor genotypes, but that of gastric mucosa could not be predicted from genotypes. Lewis phenotyping using erythrocytes is only adequate for transfusion needs. Saliva testing for the Lewis phenotype is a more reliable method for determining the peripheral Lewis phenotype of an individual and the gastric Lewis phenotype must be used for the study on the association between Helicobacter pylori and the Lewis phenotype.