Neonatal alloimmune neutropenia: still a diagnostic and therapeutical challenge.

OBJECTIVE: To describe a case of neonatal alloimmune neutropenia (NAN), a very rare disease of the newborn and the first ever reported in our neonatal intensive care unit, with emphasis in its management and outcome. DESCRIPTION: We report a case of NAN due to anti-human neutrophil antigen-1b alloimmunization in a 29-week preterm admitted to our neonatal intensive care unit. In this case, the neutropenia was severe and persisted for almost 2 months. There was a good response to the administration of intravenous immunoglobulin. COMMENTS: NAN is caused by maternal production of neutrophil-specific alloantibodies in response to antigens from paternal heritage present on the newborn neutrophiles. The course of the disease is usually mild and self-limiting. The optimal therapy is yet a debate, with some authors finding the use of intravenous immunoglobulin effective, prophylactic antibiotic therapy or recombinant human granulocyte colony-stimulating factor.