Granulocyte colony stimulating factor in neonatal alloimmune neutropenia: a possible association with induced thrombocytopenia.

Neonatal alloimmune neutropenia (NAIN) is a rare cause of congenital neutropenia seen in <1% of births. Significant morbidity, usually infections, may result from this disease. The pathophysiology of NAIN, mediated by maternal antibodies crossing the placenta to destroy fetal cells expressing paternal antigens, is similar to that of neonatal alloimmune thrombocytopenia, as well as Rh/ABO hemolytic disease of the newborn. The use of high-dose granulocyte colony stimulating factor in patients with NAIN may cause a reversible thrombocytopenia in some patients.