title: Clinical Significance of an Alloantibody against the Kell Blood Group Glycoprotein.
abstract: BACKGROUND
  Kell null (K0) individuals can produce anti-Ku, an antibody against many epitopes in the Kell glycoprotein, after transfusion and/or pregnancy. Since sensitized K0patients are rare, little is known about anti-Ku clinical relevance and in particular about its association to hemolytic disease of the fetus and newborn.
  
  
  METHODS
  This work describes a case of neonatal hyperbilirubinemia due to immune-mediated erythrocyte destruction by an alloantibody directed against the Kell glycoprotein. Serologic and molecular approaches identified an anti-Ku alloantibody in maternal serum. A homozygous IVS3 + 1g>a point mutation (KEL*02N.06allele) was found to be responsible for the lack of Kell antigen expression in the mother's red blood cell and subsequent alloimmunization after a previous pregnancy. Even though in most cases Kell antibodies are clinically severe and may cause suppression of erythropoiesis, in our case the newborn had a moderate anemia and hyperbilirubinemia that was successfully treated with phototherapy without requiring exchange transfusion. Serological and molecular studies performed in the proband's family members allowed us to provide them with proper counseling regarding alloimmunization after transfusion and/or pregnancy.
  
  
  CONCLUSIONS
  This case enlarges the understanding of the clinical significance of alloantibodies against Kell blood group antigens.
authors.affiliation: IDICER-CONICET, Rosario, Argentina; Laboratorio de Inmunohematología - Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, Rosario, Argentina.
authors.forename: Stella Maris
authors.initials: SM
authors.lastname: Mattaloni
authors.affiliation: Colsan-Associaçao Beneficente de Coleta de Sangue, Sao Paulo, Brazil.
authors.forename: Carine
authors.initials: C
authors.lastname: Arnoni
authors.affiliation: Hospital Zonal General de Agudos Dr. Carlos Bocalandro, Buenos Aires, Argentina.
authors.forename: Rosario
authors.initials: R
authors.lastname: Céspedes
authors.affiliation: Hospital Nacional Profesor Alejandro Posadas, Buenos Aires, Argentina.
authors.forename: Claudia
authors.initials: C
authors.lastname: Nonaka
authors.affiliation: IDICER-CONICET, Rosario, Argentina; Laboratorio de Inmunohematología - Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, Rosario, Argentina.
authors.forename: Carolina
authors.initials: C
authors.lastname: Trucco Boggione
authors.affiliation: IDICER-CONICET, Rosario, Argentina; Laboratorio de Inmunohematología - Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, Rosario, Argentina.
authors.forename: Melina Eliana
authors.initials: ME
authors.lastname: Luján Brajovich
authors.affiliation: Hospital Zonal General de Agudos Dr. Carlos Bocalandro, Buenos Aires, Argentina.
authors.forename: Andrea
authors.initials: A
authors.lastname: Trejo
authors.affiliation: Hospital Nacional Profesor Alejandro Posadas, Buenos Aires, Argentina.
authors.forename: Néstor
authors.initials: N
authors.lastname: Zani
authors.affiliation: Laboratorio de Inmunohematología - Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, Rosario, Argentina.
authors.forename: Claudia Silvia
authors.initials: CS
authors.lastname: Biondi
authors.affiliation: Hemocentro - Unicamp, Campinas, Brazil.
authors.forename: Lilian
authors.initials: L
authors.lastname: Castilho
authors.affiliation: IDICER-CONICET, Rosario, Argentina; Laboratorio de Inmunohematología - Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, Rosario, Argentina.
authors.forename: Carlos Miquel
authors.initials: CM
authors.lastname: Cotorruelo
keywords: Alloimmunization; Anti-Ku alloantibody; Hemolytic disease of the fetus and newborn; K0 phenotype; Kell blood group system; Kell null phenotype