This retrospective study was conducted to determine whether the total number of nucleated cells (TNC)/kg collected at marrow harvest was associated with outcome in 151 patients with acute myelogenous leukemia (AML) who received an autologous purged (n = 67) or non-purged (n = 84) marrow transplant. At the time of transplant 33 patients were in first complete remission (CR), 47 in second CR, 54 in first relapse and 17 beyond second CR. Ninety patients received busulfan (BU) 16 mg/kg and cyclophosphamide (CY) 120 or 200 mg/kg, 51 patients received CY 120 mg/kg and total body irradiation (TBI) 12-15.75 Gy and 10 patients received BU 8 mg/kg, CY 60 mg/kg and TBI 12 Gy as conditioning regimens. Patients whose marrow harvest yielded < 2 x 10(8) TNC/kg did not undergo purging with 4-hydroperoxycyclophosphamide (4HC). This group of patients (n = 28) had a 100 day mortality of 50% and only 54% achieved a granulocyte levels of > 0.5 x 10(9)/l and 29% achieved platelet transfusion independence. Patients whose marrow harvest yielded 2-4 x 10(8) TNC/kg and did not undergo marrow purging had a 20% mortality by day 100, 91% recovered granulocytes to > 0.5 x 10(9)/l and 61% became platelet independent. Patients whose marrow harvest yielded 2-4 x 10(8) TNC/kg and underwent marrow purging with 4HC had a 50% mortality by day 100 and 58% achieved a granulocyte levels of > 0.5 x 10(9)/l and 42% became platelet transfusion independent.(ABSTRACT TRUNCATED AT 250 WORDS)