Molecular basis of NB1 (HNA-2a, CD177) deficiency.

Alloimmunization to the neutrophil antigen NB1 (HNA-2a, CD177) can result in immune neutropenia and transfusion-related acute lung injury. Recently, we were able to elucidate the primary structure of NB1. To shed light also on the molecular basis of the NB1-negative phenotype, we studied the neutrophils of 2 women with NB1-specific alloantibodies for intracellular and extracellular NB1 expression, NB1-specific mRNA production, and the presence of the NB1 gene.