Amoeboid neutrophils with few granules in childhood acute precursor B cell leukemia.

BACKGROUND We sometimes treat children with acute lymphoblastic leukemia in whom neutrophil function is impaired at diagnosis. Transmission electron microscopy enables more accurate assessment by providing greater morphological detail. Using transmission electron microscopy, we have found 2 types of neutrophils in the peripheral blood of children: 1) amoeboid neutrophils, which are characterized as amoeboid cells with pseudopodia and few granules, and 2) round neutrophils with many granules at different stages and glycogen particles. AIM To assess the pathological role of amoeboid neutrophils, we investigated amoeboid neutrophils in the peripheral blood of children with leukemia. METHODS Amoeboid neutrophils were examined in peripheral blood from 12 children with acute B-cell precursor lymphoblastic leukemia (BCP-ALL). Eight children with short stature served as healthy control subjects. RESULTS The percentage of amoeboid neutrophils (per total neutrophil count) at onset or relapse of BCP-ALL was significantly higher than at remission. Children with short stature showed a lower percentage of amoeboid neutrophils than did children with acute leukemia. CONCLUSION The presence of fewer intracellular granules in amoeboid neutrophils suggests lower neutrophil activity. These results indicate that amoeboid neutrophils in patients with BCP-ALL have lower function at onset and relapse.