Dizygotic twins with neonatal alloimmune neutropenia associated with maternal anti-human neutrophil antigen-1b antibody

Abstract

Neonatal alloimmune neutropenia (NAIN), analogous to the erythrocyte disorder of hemolytic disease of the newborn, is estimated to occur in 3% of live births in the Caucasian population. Fetal neutrophil antigens sensitize the mother to develop IgG antibody during pregnancy. The IgG antibody crosses the placenta and destroys the infants neutrophils. Antibodies to human neutrophil antigen (HNA)-1a, HNA-1b, and HNA-2a are important in a number of clinical conditions, including autoimmune neutropenia of childhood and NAIN.2,3 Usually, the neutropenia resolves spontaneously because the antibody is catabolized over several weeks with no sign of infection. Some cases of severe NAIN require antibiotics appropriate for the infection, and granulocyte-colony stimulating factor (G-CSF). We report here a case of NAIN of dizygotic twins caused by maternal anti-HNA-1b antibody and discuss the frequency of this disease in the Japanese population compared with that in Caucasian people. © 2009 Japan Pediatric Society.