Tn-syndrome.
The idiopathic Tn-syndrome, formerly called 'permanent mixed-field polyagglutinability', is a rare hematological disorder characterized by the expression of the Tn-antigen on all blood cell lineages. The immunodominant epitope of the Tn-antigen is terminal alpha-N-acetylgalactosamine, O-glycosidically linked to protein. Normally this residue is 3'-substituted by 5-galactose thereby forming the core 1 structure known as the Thomsen-Friedenreich (TF) antigen (Galbeta1 ==> 3GalNAcalpha1 ==> Thr/Ser). The cause of the exposure of the Tn-antigen appears to be due to the silencing of the gene expression of beta1,3galactosyltransferase, since treatment of deficient Tn(+) lymphocyte T clones with 5'azacytidine or Na butyrate leads to reexpression of enzyme activity and the sialylated TF-antigen. The Tn-syndrome is acquired and permanent and affects both sexes at any age. Its origin is unknown. Pluripotent stem cells are affected since all lineages are involved but each one to a variable extent. Therefore, normal cells co-exist with Tn-transformed cells. Clinically, patients suffering from the Tn-syndrome appear healthy. Laboratory findings usually reveal moderate thrombocyto- and leukopenia and some signs of hemolytic anemia not warranting any treatment.
Berger
E G
EG
Institute of Physiology, University of Zurich, Switzerland. egberger@physiol.unizh.ch
D000743:Anemia, Hemolytic / Q000276:immunology; D000911:Antibodies, Monoclonal; D000951:Antigens, Neoplasm / Q000737:chemistry / Q000276:immunology; D015295:Antigens, Tumor-Associated, Carbohydrate / Q000737:chemistry / Q000276:immunology*; D001374:Azacitidine; D001773:Blood Cells / Q000276:immunology*; D004910:Erythrocyte Membrane / Q000276:immunology; D005700:Galactosyltransferases / Q000172:deficiency; D006402:Hematologic Diseases / Q000201:enzymology / Q000276:immunology* / Q000473:pathology; D006801:Humans; D037102:Lectins; D007970:Leukopenia / Q000276:immunology; D015394:Molecular Structure; D013577:Syndrome; D013921:Thrombocytopenia / Q000276:immunology
D000911:Antibodies, Monoclonal; D000951:Antigens, Neoplasm; D015295:Antigens, Tumor-Associated, Carbohydrate; D037102:Lectins; C040286:Tn antigen; C055491:sialosyl-Tn antigen; C016467:Thomsen-Friedenreich antigen; D005700:Galactosyltransferases; C076385:glycoprotein-N-acetylgalactosamine 3-beta-galactosyltransferase; D001374:Azacitidine