title: DAK, a new low-incidence antigen in the Rh blood group system.
abstract: BACKGROUND
  Some low-incidence antigens in the Rh blood group system (e.g., VS, Rh32, FPTT) are expressed by more than one Rh complex. We describe a new low-incidence antigen that is present on RBCs with the partial D phenotypes, DIIIa or DOL, on RN RBCs and on one example of STEM+S RBCs.
  
  
  METHODS
  Standard hemagglutination testing was performed with two sera that agglutinated DIIIa RBCs on our in-house antibody identification panel. DNA-based assays were performed on selected samples.
  
  
  RESULTS
  RBCs with the DIIIa (n = 31), DOL (n = 5), or RN (n = 10) phenotype were agglutinated by both sera, as were RBCs from one STEM+S person. Reactivity with RBCs of either DIIIa or DOL phenotypes was stronger than with RN RBCs and could not be separated by adsorption and elution.
  
  
  CONCLUSIONS
  An antibody, anti-DAK, which recognizes a novel low-incidence antigen that is more strongly expressed on DIIIa and DOL RBCs than on RN RBCs is described. The antibody agglutinated RBCs from 4 percent of D+ African American blood donors in New York. The antigen, DAK, has been assigned the ISBT number RH54 (004.054).
mesh_terms: D000293:Adolescent; D000328:Adult; D005260:Female; D006386:Hemagglutination Tests; D006801:Humans; D007519:Isoantigens / Q000032:analysis* / Q000276:immunology; D010641:Phenotype; D012204:Rh-Hr Blood-Group System / Q000276:immunology*
chemical_list: D007519:Isoantigens; D012204:Rh-Hr Blood-Group System