title: Mosaic differentiation of human villus enterocytes: patchy expression of blood group A antigen in A nonsecretors.
abstract: BACKGROUND
  The authors have shown that a mosaicism of brush border antigens may occur spontaneously on enterocytes of small intestine in human adult-type hypolactasia. The present paper gives another example of spontaneously occurring mosaicism as indicated by the patchy expression of blood group antigens on villus enterocytes.
  
  
  METHODS
  Thirty-five individuals were examined by immunomorphological techniques with antibodies against blood group antigens.
  
  
  RESULTS
  In 4 of 16 A blood group individuals, the blood group antigens were expressed only in some villus enterocytes. The individuals with this mosaic pattern were all shown to be nonsecretors. The A antigen in the positive enterocytes of these individuals was only present as the ALe(b) structure, whereas ALe(y) and ALe(d) were also present in the secretors. The patches of positive enterocytes were randomly distributed along the villus wall.
  
  
  CONCLUSIONS
  A nonsecretor individuals express the blood group antigens only in some villus enterocytes; this mosaicism does not arise from a heterogeneous population of stem cells within the crypts but rather reflects subtle differences in the pattern of differentiation between monoclonally derived epithelial cells on the villus.
authors.affiliation: Department of Pediatrics, II Medical School, University of Naples, Italy.
authors.forename: L
authors.initials: L
authors.lastname: Maiuri
authors.forename: V
authors.initials: V
authors.lastname: Raia
authors.forename: R
authors.initials: R
authors.lastname: Fiocca
authors.forename: E
authors.initials: E
authors.lastname: Solcia
authors.forename: M
authors.initials: M
authors.lastname: Cornaggia
authors.forename: O
authors.initials: O
authors.lastname: Norèn
authors.forename: H
authors.initials: H
authors.lastname: Sjostrom
authors.forename: D
authors.initials: D
authors.lastname: Swallow
authors.forename: S
authors.initials: S
authors.lastname: Auricchio
authors.forename: E
authors.initials: E
authors.lastname: Dabelsteen
mesh_terms: D000017:ABO Blood-Group System / Q000276:immunology*; D000911:Antibodies, Monoclonal; D000918:Antibody Specificity; D015153:Blotting, Western; D002454:Cell Differentiation; D006801:Humans; D007150:Immunohistochemistry; D007413:Intestinal Mucosa / Q000378:metabolism; D007422:Intestines / Q000166:cytology / Q000502:physiology* / Q000648:ultrastructure; D007518:Isoantibodies / Q000276:immunology; D007519:Isoantigens / Q000032:analysis*; D008854:Microscopy, Electron; D008871:Microvilli / Q000502:physiology / Q000648:ultrastructure; D009030:Mosaicism; D017350:N-Acetylgalactosaminyltransferases / Q000276:immunology
chemical_list: D000017:ABO Blood-Group System; D000911:Antibodies, Monoclonal; D007518:Isoantibodies; D007519:Isoantigens; D017350:N-Acetylgalactosaminyltransferases