Autoimmune neutropenia in early infancy: a review

Fourteen infants with autoimmune neutropenia reported in the literature have been reviewed. Autoantibodies directed against their own neutrophils were demonstrated in the sera of these infants by agglutination, complement-dependent cytotoxicity, and immunofluorescence techniques. These antibodies were highly specific and were directed against antigens present on neutrophils. Among the currently known neutrophil antigens (NA1, NA2, NB1, NC1, NE1, ND1, 9A), antibodies reacting with either NA1 or NA2 have been identified frequently in the sera of infants with autoimmune neutropenia. Good correlation was demonstrated between the presence or absence of autoantibodies and the episodes of neutropenia in many cases. Antibodies from the patients also reacted with neutrophils from their parents and from normal unrelated volunteers when they shared the neutrophil-specific antigen against which the antibody was directed. Antibodies demonstrable by complement-dependent cytotoxicity appeared to detect different antigens which may also cause autoimmune neutropenia. Infants with this disorder were healthy at birth and for a few months afterwards, then became chronically ill with such symptoms as intermittent fever, diarrhea, and infections. Their hemoglobin levels, lymphocyte and platelet counts, and other immunological studies were normal except for severe to moderate neutropenia.