title: Dispermic chimerism identified during blood group determination and HLA typing.
abstract: BACKGROUND
  Chimerism is the presence of two or more genetically distinct cell populations in one organism.
  
  
  METHODS
  We report the identification of dispermic chimerism in a 19-year-old female volunteer blood donor. During routine ABO blood grouping strong reactions of the blood donors red blood cells (RBCs) with anti-A reagents and mixed-field reactions with anti-B reagents were observed, while serum-testing showed the absence of anti-A and anti-B antibodies. AB0 blood group genotyping, HLA-typing and microsatellite analysis were performed using blood-samples, buccal mucosa and fibroblasts of the blood-donor and blood-samples of her parents.
  
  
  RESULTS
  AB0 blood group genotyping showed three ABO blood group alleles (0(1), A(2) and B) in the DNA-samples of the blood-donor. The evidence of chimerism was supported by the detection of three alleles for the HLA-A and HLA-DRB1 loci. Microsatellite analysis with ten markers revealed three alleles for loci D7S821 and D19S412. All studies carried out, the third allele was always of paternal origin. CONCLISION: The results suggested a case of a human dispermic chimerism. Our proposed explanation for the development of chimerism in the reported case is the fertilization of an oocyte and the corresponding second polar body by two different sperms.
authors.affiliation: Institute of Transfusion Medicine and Immunohematology and the Institute of Human Genetics, Otto-von-Guericke University Magdeburg, Magdeburg, Germany. mira.mosebach@medizin.uni-magdeburg.de
authors.forename: Mira
authors.initials: M
authors.lastname: Mosebach
authors.forename: Andreas
authors.initials: A
authors.lastname: Parkner
authors.forename: Sybille
authors.initials: S
authors.lastname: Jakubiczka
authors.forename: Peter
authors.initials: P
authors.lastname: Wieacker
authors.forename: Marcell U
authors.initials: MU
authors.lastname: Heim
mesh_terms: D000017:ABO Blood-Group System / Q000235:genetics*; D000328:Adult; D000483:Alleles; D001788:Blood Grouping and Crossmatching / Q000379:methods; D046528:Chimerism; D005260:Female; D005306:Fertilization; D015234:HLA-A Antigens / Q000235:genetics*; D006684:HLA-DR Antigens / Q000235:genetics*; D059811:HLA-DRB1 Chains; D006650:Histocompatibility Testing / Q000379:methods; D006801:Humans; D008297:Male; D018895:Microsatellite Repeats / Q000235:genetics*; D040641:Quantitative Trait Loci / Q000235:genetics; D017422:Sequence Analysis, DNA / Q000379:methods; D013094:Spermatozoa
chemical_list: D000017:ABO Blood-Group System; D015234:HLA-A Antigens; D006684:HLA-DR Antigens; D059811:HLA-DRB1 Chains