Significance of aberrant immunophenotypes in childhood acute lymphoid leukemia

Leukemic cells from 51 pediatric patients (younger than 18 years) diagnosed with acute lymphoid leukemia by standard morphologic and cytochemical methods were subjected to flow cytometric studies using a panel of monoclonal antibodies against T‐cell (CD1, 2, 3, 4, 5, 7, 8), B‐cell (CD10, 19, 20, 21), myeloid (CD13, 14, 15, 33), and HLA‐DR antigens. Cases of “conventional” acute lymphoid leukemia (leukemic cells with a normal configuration of B‐cell or T‐cell differentiation antigens) were observed in 26 of 51 (51%) cases, whereas cases of “aberrant” acute lymphoid leukemia (cells with abnormal patterns of B‐cell or T‐cell antigens or with concomitant myeloid antigens) were noticed in 25 (49%) cases. Myeloid antigen‐positive acute lymphoid leukemia was observed in the leukemic cells of eight (16%) individuals. No significant differences were observed between conventional and aberrant ALL in the distribution of sex, age, leukocyte count, hemoglobin concentration, platelet count, blast count, French‐American‐British (FAB) type, lymphadenopathy, organomegaly, rate or duration of remission, or survival. When only myeloid antigen‐positive cases were compared with myeloid antigen negative‐cases, no significant correlations were observed except for duration of first remission (myeloid antigen positive, 26+ ± 22 months; myeloid antigen negative, 40+ ± 18 months; P < 0.001), and duration of survival (myeloid antigen positive, 27+ ± 24 months; myeloid antigen negative, 62+ ± 17 months; P = 0.001). These data suggest that pediatric patients with ALL blasts possessing myeloid antigens may represent a high‐risk group for length of remission and survival.