Chronic neutropenia: Response to plasma with high colony-stimulating activity.

A child with repeated infections was immunologically normal but was found to have neutropenia with periodic elevations of the absolute mature polymorphonuclear count at 21-day intervals. Immediately following the PMN rise, bone marrow morphology and in vitro cultures demonstrated a maturation arrest at the myelocyte stage with an increase in proliferative capacity. His cycle was not altered by infusions of normal plasma or by injections of epinephrine or typhoid vaccine. Infusion of 10 ml/kg of "stimulated" plasma from donors reactive to TV, obtained 60 minutes following immunization, resulted in an out-of-phase rise in PMN cells and clinical improvement. In vitro assays, using normal or patient marrow, detected high levels of colony-stimulating activity only in those plasma samples that were effective in the patient. These observations support a role of CSA as a physiologic regulator of granulopoiesis in man.