CD34 and acute lymphoblastic leukemia: In particular, the work from Pflumio’s group reported that CD34+CD7-CD4- fraction from the blood of T-ALL patients does not produce leukemic blasts but undergoes normal hematopoiesis in vitro and after transplantation into immune-deficient mice [54], which is quite similar to what has been observed for the CD34+CD19-CD38- population from B-ALL patients [41,42], and that correspond to the residual and circulating normal hematopoietic stem and progenitor cells (HSPCs).