Treatment of alloimmune neonatal neutropenia with granulocyte colony-stimulating factor.

Despite numerous attempts to increase the neutrophil count of infants with alloimmune neonatal neutropenia, no therapy has been consistently effective. We describe two infants with alloimmune neutropenia who had a rapid and prolonged increase in neutrophil number after treatment with granulocyte colony-stimulating factor (G-CSF). Patient 1 had antibody directed against the neutrophil antigen NA2. He received three daily doses of G-CSF, and within 2 days his neutrophil count increased from 0.350 x 10(9) to 3.584 x 10(9)/L (350 to 3584/mm3). Despite cessation of treatment the neutrophil count remained in the normal range. Patient 2 had antibody to the neutrophil antigen NA1, and received six daily doses of G-CSF. Within 4 days his neutrophil count increased from 0.477 x 10(9) to 4.320 x 10(9)/L (477 to 4320/mm3) and remained in the normal range for 11 days after the last dose of G-CSF. We recommend that treatment with G-CSF be considered for selected infants with alloimmune neutropenia.