An Inherited Blood Group A Variant in the Finnish Population

Abstract

Abstract. A variant of blood group A, provisionally designated Afinn, that occurs in an overall frequency of approximately 1 in 6,000 in Finnish blood donors is described. Agglutination involving a very small number of erythrocytes was observable only microscopically, even with the most powerful immune anti‐A sera. However, potent anti‐A antibody eluates were produced from cells sensitized with both natural and immune anti‐A or anti‐A+ B sera. Anti‐A1 agglutinins were demonstrated in the sera of all cases, and the saliva of secretors contained H but no A substances. Comparative examinations and previously published descriptions of other established variants clearly indicated that this was not identical with the Abantu, Am,Ax, or A°1 phenotypes. These properties are similar to those reported for group Aend, except for enzyme pretreatment effecting macroscopically visible agglutination of Afinn cells.