title: Primary B cell immunodeficiencies: comparisons and contrasts.
abstract: Sophisticated genetic tools have made possible the identification of the genes responsible for most well-described immunodeficiencies in the past 15 years. Mutations in Btk, components of the pre-B cell and B cell receptor (lambda5, Igalpha, Igbeta), or the scaffold protein BLNK account for approximately 90% of patients with defects in early B cell development. Hyper-IgM syndromes result from mutations in CD40 ligand, CD40, AID, or UNG in 70-80% of affected patients. Rare defects in ICOS or CD19 can result in a clinical picture that is consistent with common variable immunodeficiency, and as many as 10% of patients with this disorder have heterozygous amino acid substitutions in TACI. For all these disorders, there is considerable clinical heterogeneity in patients with the same mutation. Identifying the genetic and environmental factors that influence the clinical phenotype may enhance patient care and our understanding of normal B cell development.
authors.affiliation: Department of Pediatrics, University of Tennessee College of Medicine, Memphis, Tennessee 38163, USA. maryellen.conley@stjude.org
authors.forename: Mary Ellen
authors.initials: ME
authors.lastname: Conley
authors.forename: A Kerry
authors.initials: AK
authors.lastname: Dobbs
authors.forename: Dana M
authors.initials: DM
authors.lastname: Farmer
authors.forename: Sebnem
authors.initials: S
authors.lastname: Kilic
authors.forename: Kenneth
authors.initials: K
authors.lastname: Paris
authors.forename: Sofia
authors.initials: S
authors.lastname: Grigoriadou
authors.forename: Elaine
authors.initials: E
authors.lastname: Coustan-Smith
authors.forename: Vanessa
authors.initials: V
authors.lastname: Howard
authors.forename: Dario
authors.initials: D
authors.lastname: Campana
mesh_terms: D048868:Adaptor Proteins, Signal Transducing / Q000235:genetics / Q000276:immunology / Q000378:metabolism; D000077329:Agammaglobulinaemia Tyrosine Kinase; D000818:Animals; D018941:Antigens, CD19 / Q000235:genetics / Q000276:immunology / Q000378:metabolism; D000945:Antigens, Differentiation, T-Lymphocyte / Q000235:genetics / Q000276:immunology / Q000378:metabolism; D001402:B-Lymphocytes / Q000276:immunology* / Q000378:metabolism; D051925:CD79 Antigens / Q000235:genetics / Q000276:immunology / Q000378:metabolism; D006801:Humans; D007153:Immunologic Deficiency Syndromes / Q000235:genetics / Q000276:immunology*; D060889:Inducible T-Cell Co-Stimulator Protein; D009154:Mutation; D054448:Precursor Cells, B-Lymphoid / Q000276:immunology* / Q000378:metabolism; D011505:Protein-Tyrosine Kinases / Q000235:genetics / Q000276:immunology / Q000378:metabolism; D053303:Transmembrane Activator and CAML Interactor Protein / Q000235:genetics / Q000276:immunology / Q000378:metabolism
chemical_list: D048868:Adaptor Proteins, Signal Transducing; D018941:Antigens, CD19; D000945:Antigens, Differentiation, T-Lymphocyte; C113939:B cell linker protein; D051925:CD79 Antigens; C556692:ICOS protein, human; D060889:Inducible T-Cell Co-Stimulator Protein; C108467:TNFRSF13B protein, human; D053303:Transmembrane Activator and CAML Interactor Protein; D011505:Protein-Tyrosine Kinases; D000077329:Agammaglobulinaemia Tyrosine Kinase; C000625949:BTK protein, human