Leukemic blast cell infiltration and microvessel density of the bone marrow before and after 1 month of treatment with thalidomide.

Data are presented as individual values. A significant reduction of the blast cell infiltration in the 5 patients responding to thalidomide (panel A) with a concomitant decrease of the microvessel counts (panel B) was observed (P < .05, Wilcoxon matched-pair signed rank test). In contrast, in the 6 nonresponding patients, the percentage of blast cell infiltration (panel A) and microvessel density (panel B) increased (P < .05).