Differentiation of Leukemic Cells Induced by Short-Course High-Dose Methylprednisolone in Children with Different Subtypes of Acute Myeloblastic Leukemia

Abstract

Differentiation of myeloid leukemic cells to mature granulocytes by high-dose methylprednisolone (HDMP, 20–30 mg/kg/day) with a favorable antileukemic effect has previously been demonstrated in children with acute promyelocytic leukemia and acute myeloblastic leukemia (AML) M4. In the present study, three children with other morphological subtypes of AML (two AML M1, one AML M2) were given methylprednisolone (30 mg/kg/day) orally in a single dose. After a short-course (3 or 7 days) of HDMP treatment alone, a striking decrease in blast cells associated with an increase in maturing and abnormally nucleated poly-morphonuclear-like cells some containing Auer rods were detected in all patients in peripheral blood or bone marrow smears. During HDMP treatment, in parallel to morphological improvements, marked increases in the percentage of cells expressing granulocytic antigen (CD15) were observed. The increase of CD15 expression on myeloid cells, together with the steady expression of CD34 and CD117 antigens in Casel (AML M1), is suggestive of aberrant CD34 + CD117 + CD15 + cells, which may indicate the leukemic origin of the maturing myeloid cells. These results suggest that HDMP treatment may induce differentiation of myeloid leukemic cells in some children with different morphological subtypes of AML, and that the differentiation-inducing effect of HDMP should be explored in other malignant diseases.

Key Words:

• Acute myeloblastic leukemia
• High-dose methylprednisolone
• Differentiation
• Children