Autoimmunization against the neutrophil-specific NA1 antigen is associated with HLA-DR2.

A significant association of autoimmune neutropenia (AIN) in infants due to NA1-specific autoantibodies and HLA-DR2 is reported. Nineteen of 26 infants presenting with AIN and NA1 autoantibodies possessed the DR2 antigen, while only one out of six children with AIN, but non-NA1-specific autoantibodies, was DR2 positive. Furthermore, one adult patient with primary biliary cirrhosis and periods of neutropenia due to NA1 autoantibodies also carried the DR2 antigen. All DR2-negative patients were positive for DRw6. These findings indicate that a close relationship exists between autoimmunization against the NA1 antigen and HLA-DR2 and possibly also DRw6.