In vivo response of t(11;17)-AML-M3 to combined treatment with ATRA and hydroxyurea.

(A) Wright-Giemsa staining of bone marrow leukemic cells collected at the indicated days of treatment (day 0, 20, 43). A neutrophilic granulocyte displays several Auer rods in the cytosol, indicating its descent from differentiated leukemia blasts. Original magnifications, × 40. (B) Southern blot analysis of the RARα second intron in leukemia blasts pretreatment (day 0), maturing marrow cells collected at day 20, and neutrophils obtained from day 43 bone marrow buffy coat. The germline 19 kilobase (kb) band observed in normal placental DNA (lane C) and in all other lanes is indicated by the bar. An upper band is also visible in marrow DNAs obtained at day 0, 20, and 43, corresponding to the rearranged RARα allele. (C) Time course of peripheral blood leucocytes during treatment. (D) Sequential immunophenotypic study of bone marrow mononuclear cells as determined by FACS analysis. Increase of CD15 staining cells at day 20 was followed by augment of CD11b and CD14-positive elements (day 43) coupled to decrease of CD117 and CD56 staining cells (days 43 and 56).