Neutropenia, recurrent bacterial infections, and congenital deafness in patients with monocytopenia. Absence of peripheral blood colony-stimulating activity.

The factors that regulate granulopoiesis in vivo are unclear, but recent evidence suggests a role for monocytes; these cells produce a leukopoietin termed colony-stimulating activity (CSA), which stimulates growth of colonies of myeloid cells in vitro. We describe a family in which three of four siblings had neutropenia with myeloid marrow hypoplasia, deafness, and monocytopenia. Two of the three affected siblings died of bacterial septicemia; the third sibling, who resided in a long-term care facility, remained relatively free of infections. Studies of this patient's peripheral blood disclosed deficient CSA production consistent with the virtual absence of monocytes. These findings support the purported role of monocytes as a source of peripheral blood leukopoietic factors.