USEFULNESS OF GRANULOCYTE COUNT MEASUREMENT 4 HOURS AFTER INJECTION OF GRANULOCYTE-COLONY-STIMULATING FACTOR FOR DETECTING RECOVERY FROM ANTITHYROID DRUG-INDUCED GRANULOCYTOPENIA

This prospective study was designed to investigate the usefulness of g ranulocyte count measurements 4 hours after injection of granulocyte c olony-stimulating factor (G-CSF) for detecting recovery from antithyro id drug (ATD)-induced granulocytopenia or agranulocytosis. Granulocyte and white blood cell counts were measured 4 hours and 24 hours after patients with ATD-induced granulocytopenia had been given an injection of 75 mu g of G-CSF (1.1 to 1.9 mu g/kg; 1.5 +/- 0.2 mu g/kg [mean +/ - standard deviation]). Thirty-seven patients were studied and divided into three groups based on their initial granulocytopenic granulocyte count: 28 with mild (granulocyte count 0.501 to 1.0 x 10(9)/L), 6 wit h moderate (granulocyte count 0.101 to 0.5 x 10(9)/L), and 3 with seve re (granulocyte count less than 0.1 x 10(9)/L) ATD-induced granulocyto penia. Twenty-five of the 28 patients with mild granulocytopenia and 4 of the 6 patients with moderate granulocytopenia were found to have r ecovered from the granulocytopenia both 4 hours and 24 hours after inj ection, and their granulocyte counts remained normal thereafter. Howev er, the other 3 patients with mild granulocytopenia, 2 patients with m oderate granulocytopenia, and all 3 patients with severe granulocytope nia had not recovered by either 4 or 24 hours after the G-CSF injectio n. Despite daily C-CSF injections, the granulocyte continued to decrea se in most cases. It took 2 to 11 days for these counts to recover fro m granulocytopenia. These results indicate that granulocyte count meas urement 4 hours after injection of G-CSF is useful for detecting recov ery from ATD-induced granulocytopenia or agranulocytosis and for predi cting disease severity. Accordingly, its measurement enables physician s to make an appropriate decision about whether a patient with ATD-ind uced granulocytopenia should be treated in the hospital or in the outp atient clinic.