THE EFFECT OF HIGH-DOSE METHYLPREDNISOLINE ON CD34 - POSITIVE BONE-MARROW CELLS IN CHILDREN WITH ACUTE MYELOBLASTIC-LEUKEMIA

The expression of CD34 antigen on the surface of bone marrow (BM) cell s during remission induction was studied in 20 patients with CD34-nega tive acute myeloblastic leukemia (AML). The patients were given high-d ose methylprednisolone (HDMP) alone for one week, after which time mit oxantrone and low-dose Ara-C were added. BM cells from all patients we re studied one, two and four weeks after initiation of treatment to ev aluate CD34 antigen expression using a three-step peroxidase antiperox idase staining technique. The mean percentage of CD34-positive BM cell s was 5.3% at presentation, increasing to 15.6% in the first week, 12. 9% in the second week end 21.7% in the fourth week of therapy. During the same period the mean percentages of the initial BM blasts decrease d from 64% to 22%, 7% and 2% in the first, second and fourth weeks of therapy, respectively. The increase in the CD34-positive BM cells one week after HDMP treatment alone suggests that HDMP directly or indirec tly stimulates CD34-positive hematopoietic progenitor cells while decr easing BM blasts in patients with AML.