Clinical significance of an alloantibody against the Kell blood group glycoprotein

MATTALONI, STELLA MARIS; ARNONI, CARINE; CÉSPEDES, ROSARIO; NONAKA, CLAUDIA; TRUCCO BOGGIONE, CAROLINA; LUJÁN BRAJOVICH, MELINA ELIANA; TREJO, ANDREA; ZANI, NÉSTOR; BIONDI, CLAUDIA; CASTILHO, LILIAN; COTORRUELO, CARLOS

TRANSFUSION MEDICINE AND HEMOTHERAPY

KARGER

Lugar: Basel; Año: 2016

1660-3796

Background: Kell null (K0) individuals can produce anti-Ku, an antibody againstmany epitopes in the Kell glycoprotein, after transfusion and/or pregnancy. Since sensitized K0 patients are rare, little is known about anti-Ku clinical relevance and in particular about its association to Hemolytic Disease of the Fetus and Newborn. Case report: 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.06 allele) was found to be responsible for the lack of Kell antigens 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.