Prognostic significance of detecting CD19⁺ cells coexpressing CD10 and/or CD34 on day-19 bone marrow. Cumulative incidence of remission failure or ALL relapse according to the presence or absence (< 0.01%) of CD19⁺ cells coexpressing CD10 and/or CD34 in 84 children with B-lineage ALL enrolled in a single chemotherapy program.