Novel alleles of Lan− in Japanese populations

Abstract

T he Lan antigen and antibody (anti-Lan) were first reported by van der Hart and colleagues in a severe hemolytic transfusion reaction case. The Lan− phenotype is very rare worldwide and is usually identified through the presence of anti-Lan. The Lan− phenotype has been reported in the black, Caucasian, and Japanese populations. The Japanese Red Cross Blood Centers have been screening red blood cells (RBCs) for Lan− donors since the establishment of human monoclonal anti-Lan (OSK43) in 2003. Recently, Helias and coworkers reported that purified Lan antigen from RBCs using OSK43 was identified as ABCB6 by mass spectrometry. ABCB6 is located on Chromosome 2q36 and comprises 19 coding exons that span approximately 9.2 kb of genomic DNA. It encodes ABCB6, an 842-amino-acid protein, which is a multipass N-glycosylated “halftransport protein” present on RBCs. Lan− individuals were genotyped and 10 alleles of the ABCB6 with silencing changes defining Lan− phenotypes were reported. Additionally, Saison and coworkers reported that a missense nucleotide change (c.574C>T [Arg192Trp]) in ABCB6 encodes the Lan− phenotype. To date, 19 ABCB6 alleles that encode Lan− or Lan+/−, or Lan+ phenotypes have been described. We previously reported Lan− individuals in a Japanese donor with anti-Lan. Furthermore, in this study, we report the identification of 10 new alleles and 12 new nucleotide changes in Japanese Lan− donors who do not have anti-Lan. MATERIALS AND METHODS