THE EFFECT OF HIGH-DOSE METHYLPREDNISOLONE COMBINED CHEMOTHERAPY ON CD34-POSITIVE CELLS IN ACUTE LYMPHOBLASTIC-LEUKEMIA

The expression of CD34 antigen on the surface of bone marrow cells dur ing remission induction was studied in 27 selected acute lymphoblastic leukemia (ALL) patients who were CD34 negative at presentation and we re stratified to receive high-dose methylprednisolone (30 mg/kg/day po ) or conventional-dose prednisolone (2 mg/kg/day po). Patients receive d either induction with L-Asparaginase, vincristine (VCR), and high-do se methylprednisolone [HDMP, 30 mg/kg/day po for 1 week, 20 mg/kg/day po for 1 week, and 20 mg/kg/day po every other day for 2 more weeks (2 0 patients)], or identical induction in which HDMP was replaced by pre dnisolone 2 mg/kg/day by mouth for 4 weeks (8 patients). Bone marrow c ells from all patients were studied 1,2, and 4 weeks after initiation of treatment for expression of the CD34 antigen using a three-step ind irect immunoperoxidase staining technique. In the 20-patients with ALL who received HDMP the percentage of normal bone marrow cells expressi ng CD34 was significantly higher (p < 0.05) than in the 8 patients who did not receive HDMP. The mean percentage of CD34-positive bone marro w cells during the fourth week was 17.2% in patients with ALL who rece ived HDMP, whereas patients who received 2 mg/kg prednisolone per day had only 6.1% CD34 cells in the marrow. Absolute polymorphonuclear leu kocyte (pmnl) count was also significantly higher in the patients who received HDMP in the second and third week of therapy [(absolute pmnl count was 2197.7/mm(3) in the second week and 4091.8/mm(3) in the four th week in the patients who received HDMP compared to 974.4/mm(3) and 1556.5/mm(3) in the patients who did not receive HDMP) (p < 0.05)]. Th is data indicates that treatment with HDMP results in a significantly higher percentage of CD34-positive bone marrow cells during the 4 week s of induction therapy, suggesting that high-dose methylprednisolone d irectly or indirectly stimulates CD34-positive hematopoietic cells.