Occurrence of periodic oscillations in the differential blood counts of congenital, idiopathic, and cyclical neutropenic patients before and during treatment with G-CSF

Using techniques developed in astrophysics to deal with unequally sampled d ata sets, we have analyzed serial differential cell counts from 45 congenit al, idiopathic, and cyclic neutropenic patients before and during treatment with recombinant human G-CSF (rhG-CSF), Our results show that the occurren ce of significant cycling in the absolute neutrophil count (ANC) of neutrop enics not classified as cyclical is much more prevalent than had been previ ously thought, and that not all the patients classified as cyclic show sign ificant ANC periodicity, In these patients, cycling in more than one cell l ine may be involved. The range of periods encountered in these patients is much broader (between 11 and 52 days) than is usually associated with class ical cyclical neutropenia, and there is no obvious connection between the r ange of periods and the patient's diagnostic category. Administration of rh G-CSF is able to induce significant cycling in neutropenic patients that we re not cycling prior to treatment. In patients who had significant cycling before treatment, rhG-CSF may either decrease the period to between 11 and 14 days, or may obliterate any statistical evidence of cycling. (C) 1999 In ternational Society for Experimental Hematology, Published by Elsevier Scie nce Inc.