GUTI: a new antigen in the Cromer blood group system

BACKGROUND : The Cromer blood group system consists of seven high‐incidence and three low‐incidence antigens carried on decay‐accelerating factor (DAF). This report describes the identification and characterization of a new Cromer high‐incidence antigen, named GUTI. STUDY DESIGN AND METHODS : RT‐PCR and sequence analysis were performed on cDNA prepared from a Chilean donor whose serum contained the alloantibody (anti‐GUTI). Based on the observed point mutation, a PCR‐RFLP assay using Mae II was developed. To map the epitope, DAF‐deletion mutants were tested by immunoblotting with anti‐GUTI. RESULTS : Sequence analysis revealed a substitution of 719G>A in DAF in the proband. The proband's parents and two daughters were heterozygotes for 719G>A, one sister whose RBCs typed GUTI– was homozygous for 719A, and one sister had the wild‐type DAF (719G). Seven additional heterozygote samples were identified among 214 Chileans. No heterozygotes were found in 197 New York donors. Analysis using DAF‐deletion mutants showed the antigenic determinant to be within short consensus repeat (SCR) 4. CONCLUSION : This study describes a novel high‐ incidence antigen (GUTI) in the Cromer blood group system characterized by the amino acid arginine at position 206 in SCR4 of DAF. The GUTI‐negative proband has a substitution mutation that predicts for histidine at this position.