Decreased expression of FcγRIII mRNA in leukemic granulocytes

Abstract

Morphologically mature granulocytes from patients with chronic myeloid leukemia show significant impairment in their ability to internalize aggregated IgG, a ligand that is rapidly phagocytosed by normal human granulocytes. With a view to understand the molecular basis of this defect, normal and leukemic granulocytes were examined for the steady-state levels ofmRNA for Fc?'RIIL a memb=are-associat~xl receptur that initially binds and traps the !gG-opsonized antigens. Northern blot analyses revealed that the level ofthe specific mRNA in CP,[L granulocytes was between 0.08 and 0.69 times that seen in the normal granulocytes. This could be one of the contributory factors for the observed endocytic defect in the leukemic granulocytes.

Motility of rhG‐CSF‐induced neutrophils in patients undergoing chemotherapy: evidence for inhibition detected by image analysis

“…We would like to emphasize that the results reported here were found in patients receiving low dosage of rhG-CSF (5 g/ kg/d), whereas the only previous study performed on this topic (Spiekerman et al, 1994) did not show any inhibition with dosages ranging from 2 to 5 g/kg/d but only with dosages 4-20 times higher (in the agarose method). Similarly, a statistically significant reduction in the surface expression of CD16 -which may be an expression of abnormal neutrophil maturation Monteiro et al, 1992) -was found, by Spiekermann et al (1994), with high rhG-CSF dosages, whereas this molecule was found unchanged in our seven patients after low-dosage rhG-CSF treatment . So it may be that, apart from the unimportant number of band cells, rhG-CSF-induced PMN are 'morphologically' mature, but 'structurally' altered, because of the short maturation time.…”

“…Similarly, a statistically significant reduction in the surface expression of CD16 -which may be an expression of abnormal neutrophil maturation Monteiro et al, 1992) -was found, by Spiekermann et al (1994), with high rhG-CSF dosages, whereas this molecule was found unchanged in our seven patients after low-dosage rhG-CSF treatment . So it may be that, apart from the unimportant number of band cells, rhG-CSF-induced PMN are 'morphologically' mature, but 'structurally' altered, because of the short maturation time.…”