CD19 and acute lymphoblastic leukemia: The fusion protein was observed in each analyzed stem/progenitor compartment from ALL samples: CD34+CD38+, CD34+CD38−CD19+, CD34+CD38−CD19− as well as CD34+CD33−CD19+ pro-B cells or CD34+CD33+CD19− and CD34−CD33+CD19− myeloid populations (202).