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(H)J(H) and V(K)J(K) V(K)J(K)K((de)) and V(K)K((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(H)J(H)-rearranged, KL germline cycling pre-B I cells → CD34^- V(preB)⁺μH chain⁺ (pre-B receptor⁺) RAG- 1⁺ TdT, V(H)D(H)J(H)-rearranged, KL germline, cycling pre-B II cells → CD34^- V(preB)^-, intracytoplasmic μH chain⁺ (pre-B receptor) RAG-1⁺ TdT, V(H)D(H)J(H)-rearranged, mainly KL germline cycling pre-B II cells → CD34⁺ V(preB)^- intracytoplasmic μH chain⁺, RAG-1⁺ TdT, V(H)D(H)J(H)-rearranged, V(K)J(K)-rearranged, IgM^-, resting pre-B II cells → CD34⁺ V(preB)^-, sIgM⁺, RAG-1⁺ TdT^-, V(H)D(H)J(H)^- and V(K)J(K)-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.