CD19 and lymphoproliferative syndrome: Further, we have found that CD123, along with CD19, CD34, CD38 and HLA-Dr, identifies B-cells in the M2 tube, which is especially valuable to discern and document discordant expression in normal and abnormal precursor B-cells.35,36 Concurrent assessment of most T-cell markers in the T-cell tube was valuable for discerning both immature and mature T-cell lymphoproliferative disorders.