Transient effect of granulocyte colony-stimulating factor in allo-immune neonatal neutropenia

The effect of recombinant human granulocyte colony-stimulating factor (rhG- CSF) administration at 10 mug/kg/day for 15-30 min over 3 consecutive days in 3 preterm neonates with allo-immune neonatal neutropenia (ANN) is report ed. Patients 1 and 2 had antibodies against antigen NA2, while patient 3 ha d antibodies against NA1. All neonates developed a rapid increase in absolu te neutrophil count which reached the normal range within 48 h (from 75-640 /mm(3) to 2,520-4,700/mm(3)). However, 23-25 days later, a 113 neonates rel apsed into a second phase of severe neutropenia (408-870/mm(3)). Antibodies against neutrophil antigens were still positive during this period. This s econd-phase neutropenia persisted for 20-30 days and resolved spontaneously . It may be possible that when rhG-CSF is administered within a short time after birth in neonates with ANN, its effect is exhausted before the concen tration of circulating antibodies decreases, with the result that a second phase of neutropenia can be expected. Copyright (C) 2000 S. Karger AG, Base l.