AbstractThese abnormalities may include
(1) the presence of an increase in the frequencies of immature B cells (CD34+/CD19+ or CD20-/CD19+) or (2) the existence of an altered B-cell differentiation pathway due to a blockade or to the presence of B cells outside the normal pathway. A total of 180 BM samples from 45 consecutive precursor-B-ALL patients who achieved morphological complete remission (CR) were analysed by multiparametric flow cytometry. Our results show that a significant increase in immature B-cell subsets or an altered B-cell differentiation predicts a high relapse rate (P < 0.01) and a shorter disease-free survival (P < 0.01). Moreover, abnormalities in either of these two criteria detected at specific time points during follow-up (end of induction, maintenance, or after treatment) were associated with a significantly shorter disease-free survival (P < 0.01).