Neutrophil kinetics in hereditary and congenital neutropenias

Neutrophil production and distribution were studied in two families with autosomal dominantly inherited neutropenia to distinguish their illness from other neutropenic disorders. In addition to a reduced post-mitotic pool of bone-marrow neutrophils and neutrophil precursors, mitotic pool size was also reduced, ranging from 1.1 to 2.9 X 10(9) cells per kilogram (normal, 3.8 +/- 0.4 X 10(9) per kilogram). In vitro committed stem cells were reduced as well, ranging from 2 to 12/10(5) marrow cells (normal, 30 to 120/10(5)). In three patients neutrophil counts were observed to return to normal when they were adults. In one such subject studied, however, both the mitotic pool of neutrophil precursors and marrow committed stem cells were reduced. These abnormalities were in contrast to studies of a patient with chronic benign neutropenia of childhood and an infant with Kostmann-type congenital neutropenia, both of whom had increased marrow committed stem cells. These studies demonstrate several different mechanisms for production of neutropenia in these syndromes.