title: Fates of human B-cell precursors.
abstract: Development of mammalian B-lineage cells is characterized by progression through a series of checkpoints defined primarily by rearrangement and expression of immunoglobulin genes. Progression through these checkpoints is also influenced by stromal cells in the microenvironment of the primary tissues wherein B-cell development occurs, ie, fetal liver and bone marrow and adult bone marrow. This review focuses on the developmental biology of human bone marrow B-lineage cells, including perturbations that contribute to the origin and evolution of B-lineage acute lymphoblastic leukemia and primary immunodeficiency diseases characterized by agammaglobulinemia. Recently described in vitro and in vivo models that support development and expansion of human B-lineage cells through multiple checkpoints provide new tools for identifying the bone marrow stromal cell-derived molecules necessary for survival and proliferation. Mutations in genes encoding subunits of the pre-B cell receptor and molecules involved in pre-B cell receptor signaling culminate in X-linked and non-X-linked agammaglobulinemia. A cardinal feature of these immunodeficiencies is an apparent apoptotic sensitivity of B-lineage cells at the pro-B to pre-B transition. On the other end of the spectrum is the apoptotic resistance that accompanies the development of B-lineage acute lymphoblastic leukemia, potentially a reflection of genetic abnormalities that subvert normal apoptotic programs. The triad of laboratory models that mimic the bone marrow microenvironment, immunodeficiency diseases with specific defects in B-cell development, and B-lineage acute lymphoblastic leukemia can now be integrated to deepen our understanding of human B-cell development.
authors.affiliation: Department of Laboratory Medicine and Pathology, University of Minnesota Cancer Center, Minneapolis, MN 55455, USA. lebie001@tc.umn.edu
authors.forename: T W
authors.initials: TW
authors.lastname: LeBien
mesh_terms: D000328:Adult; D000361:Agammaglobulinemia / Q000276:immunology; D000818:Animals; D001402:B-Lymphocytes / Q000166:cytology* / Q000276:immunology*; D001854:Bone Marrow Cells / Q000166:cytology / Q000473:pathology; D002051:Burkitt Lymphoma / Q000276:immunology / Q000473:pathology; D006412:Hematopoietic Stem Cells / Q000166:cytology / Q000276:immunology; D006801:Humans; D007153:Immunologic Deficiency Syndromes / Q000276:immunology; D008322:Mammals