To the Editor.
—In regard to the interesting report by Knospe and Gregory on "Smoldering Acute Leukemia" (Arch Intern Med127:910-918,1971). I would like to suggest the alternative interpretation that at least in some instances, seemingly indolent leukemia may represent "wheel spinning" rather than "smoldering." It should be apparent that the population kinetics of this disorder must be rather unusual. Either the cells proliferate very slowly or they proliferate at usual or even supranormal rates, but have a high spontaneous death rate, resulting in little net growth of the disease.Clarkson et al1 have studied the cell kinetics of a similar patient, and found that the leukemic cells were in fact rapidly proliferating. This patient, in his 70s, subsequently had a one year remission after treatment.Thus, the smoldering leukemics should be carefully studied, not only as Knospe and Gregory have done, but also in regard to their