BCR and B-cell chronic lymphocytic leukemia: To formally address the possibility that a single normal B cell could express a CLL-SLS BCR IG carrying a single IGHV-D-J and IGKLV-J as found in patients with CLL, we performed single cell V(D)J sequencing analysis of B-cell populations sorted for surface membrane expression of IGHV4-34 using the 9G4 mAb.