Monitoring neutrophil engraftment in allogeneic stem cell transplantation by flow cytometric analysis of neutrophil‐specific antigens NA1 and NA2

Summary Neutrophil-specific antigen (NA) expression on neutrophils was analysed in 18 Japanese children before and after allogeneic stem cell transplantation (allo-SCT) with myeloablative regimen. Donor–recipient NA-incompatibility was present in one of eight NA1/NA2 heterozygous patients and eight of 10 NA1/NA1 or NA2/NA2 homozygous patients. After allo-SCTs from NA-incompatible donors, a neutrophil recipient-to-donor conversion was confirmed in all cases. Conversion to donor NA type was complete before the absolute neutrophil count reached 0·1 × 109/l. These observations indicate that flow cytometric analysis of NA antigens is a simple and useful method for monitoring neutrophil engraftment in NA-incompatible allo-SCT.