Effect of DNPS inhibition on antileukemic effects.

(A) Full DNPS inhibition (n = 71) was associated with a greater percentage decrease in circulating leukocytes compared with partial inhibition (n = 38) or no inhibition (n = 26) (P < .01). There was no difference in the percentage decrease in circulating leukocytes between patients exhibiting partial or no inhibition (P = .11). (B) Full DNPS inhibition was associated with a greater percentage decrease in circulating leukocyte counts at day 3 compared with pretherapy counts in patients with nonhyperdiploid B-lineage and T-lineage ALL but not in those with hyperdiploid B-lineage ALL. Within patients having full DNPS inhibition (n = 71), those with nonhyperdiploid B-lineage (n = 39) and T-lineage ALL (n = 15) had a greater percentage decrease in circulating leukocyte counts compared with those with hyperdiploid B-lineage ALL (n = 17) (P < .01). In contrast, among patients with partial or no inhibition of DNPS (nonhyperdiploid B lineage, n = 36; hyperdiploid B lineage, n = 20; T lineage, n = 8), no difference in antileukemic effect was observed among ALL lineages (P = .39).