Ordering of Human Bone Marrow B Lymphocyte Precursors by Single-Cell Polymerase Chain Reaction Analyses of the Rearrangement Status of the Immunoglobulin H and L Chain Gene Loci

CD19⁺CD10⁺ human B lineage bone marrow cells were separated into cycling or resting cells, which differ in their expression of CD34, V_preB, recombination activating gene (RAG-1), and terminal deoxynucleotidyl transferase (TdT). Polymerase chain reaction analyses developed for D_HJ_H and V_κJ_κ, V_κJ_κK^(de) and V_κK^(de) rearrangements with DNA of single cells and a comparison with B lineage cell development in mouse bone marrow, allow to delineate the human B lymphocyte pathway of development as follows: CD34⁺V_preB⁺RAG-1⁺TdT⁺, D_HJ_H-rearranged, κL germline cycling pre-B I cells → CD34⁻V_preB⁺μH chain⁺ (pre-B receptor⁺) RAG-1⁻TdT⁻, V_HD_HJ_H-rearranged, κL germline, cycling pre-B II cells → CD34⁻V_preB⁻, intracytoplasmic μH chain⁺ (pre-B receptor⁻) RAG-1^+/− TdT⁻, V_HD_HJ_H-rearranged, mainly κL germline cycling pre-B II cells → CD34⁻V_preB⁻ intracytoplasmic μH chain⁺, RAG-1⁺TdT⁻, V_HD_HJ_H-rearranged, V_κJ_κ-rearranged, IgM⁻, resting pre-B II cells CD34⁺V_preB⁻, sIgM⁺, RAG-1⁺TdT⁻, V_HD_HJ_H- and V_κJ_κ-rearranged IgM⁺ immature B cells → CD34⁻, CD10⁻, sIgM⁺/sIgD⁺ mature B cells. This order, for the first time established for human B lineage cells, shows striking similarities with that established for mouse B lineage cells in bone marrow.