CD19 and acute lymphoblastic leukemia: When the CD34+ CD38- BM population of ALL patients harboring this translocation (phenotype of normal HSCs) was divided into two subgroups: a CD34+ CD38- CD19+ (which was the major population and a minor CD34+ CD38- CD19- group it was shown that the CD19+ subset which is not present in healthy individuals was the target of the translocation and the subpopulation which could give rise to leukemic cells.