Myeloid-Antigen Expression in Childhood Acute Lymphoblastic Leukemia

To the Editor: Wiersma and coworkers (March 21 issue)¹ found that expression of myeloid antigens (CD14 [My4], CD13 [My7], and CD33 [My9]) was an independent predictor of a poor outcome among 236 children with acute lymphoblastic leukemia (ALL) treated according to at least five different clinical protocols. This result contrasts sharply with our recent observation that myeloid-associated antigens lacked prognostic value in 267 children treated intensively with similar regimens of combination chemotherapy.² As Wiersma et al. suggest, differences in definitions of myeloid-antigen expression, immunophenotyping methods, study populations, treatment regimens, or a combination of these factors may explain the discordant results. . . .