A quantitative assessment of neutrophil marrow in seven patients with chronic granulocytic leukaemia.

Neutrophil marrow cellularity was determined in seven patients with chronic granulocytic leukaemia (CGL). The size of the mitotic pool (promyelocytes and myelocytes) and the number of metamyelocytes and bands and of segmented neutrophils in the postmitotic pool were determined from measurements of neutrophil--erythroid ratios in marrow biopsy sections and ferrokinetic estimates of marrow normoblasts. A section mitotic index was calculated in each patient from the numbers of mitotic figures and mitotic pool cells counted on marrow sections. Basal values previously established in normal subjects for the mitotic pool, for metamyelocytes and bands, and for segmented neutrophils, were 2.11 +/- 0.36 x 10(9) cells/kg, 3.33 +/- 0.61 x 10(9) cells/kg, and 2.26 +/- 0.42 x 10(9) cells/kg, respectively (+/- 1 SD, n = 13). The basal section mitotic index was 0.07 +/- 0.01 (+/- 1 SD, n = 13). In the seven patients with CGL the mitotic pool comprised 3.71--25.70 x 10(9) cells/kg, metamyelocytes and bands 7.70--51.02 x 10(9) cells/kg, and segmented neutrophils 3.45--28.81 x 10(9) cells/kg. Mitotic indices ranged from 0.04 to 0.10. No relationship was found between marrow cellularity and blood neutrophil count. A negative correlation existed between mitotic pool cellularity and mitotic index (r = -0.76, n = 7 pairs). The results provide quantitative affirmation of neutrophil marrow hyperplasia and of increased neutrophil production by the marrow in CGL.