In vitro clonogenic assays in selective neutropenia.

Granulocyte-monocyte colony forming cell (GM-CFC) concentration and the proportion of GM-CFC in DNA synthesis (S) were determined in 43 patients with varying degrees of selective neutropenia, including 5 patients who were normal extremes (2.0-2.5 x 10(9) neutrophils/1), to study the diagnostic and prognostic significance of clonogenic assays and to determine the response of the committed myeloid stem cell to neutropenia. The proportion of GM-CFC in S proved to be a more useful parameter than the GM-CFC concentration. 75% of the patients with greater than 60% GM-CFC in S returned to normal within 1 month. Patients with less than 20% GM-CFC in S had at least a 10 times greater incidence of developing a malignant or autoimmune disease than the other 28 patients. The 11 patients with 41-51% in GM-CFC in S had greater than 1 x 10(9) neutrophils/1 and no significant clinical problems but all have remained mildly neutropenic for a long period. An indirect relationship existed between the degree of neutropenia and the proportion of GM-CFC in S (r = -0.70).