title: B-cell subpopulations in children: National reference values.
abstract: Peripheral B-lymphocytes undergo a series of changes during the first few years of life. Encounters with foreign antigens lead to maturation and differentiation. Several primary antibody deficiencies (PADs) affecting B-cell development are associated with abnormalities in the composition and/or differentiation of B-cell compartments. The most recent international classifications of primary immunodeficiencies (PIDs) and common variable immunodeficiencies (CVID) have highlighted the importance of B-cell immunophenotyping and age-specific reference intervals for diagnostic purposes. We established national reference values for memory B-cell subpopulations, on the basis of CD27 and surface IgD expression in the peripheral blood of 242 healthy children. We report here the absolute counts and percentages of naive, switched and non-switched memory B-cells for seven age groups, from neonates to adults. We found that the naive B-cells percentage declined between the ages of 6 months and 8 years, after which it remained stable at about 70-80%. Memory B-cells are already present at birth and their numbers increase throughout childhood, stabilizing between the ages of 12 and 18 years. The definition of reference intervals for pediatric B-cell levels should facilitate the screening and diagnosis of various B-cell immunodeficiencies. This multicenter study, providing national reference values, should thus facilitate immunological diagnosis in children.
authors.affiliation: Study Center of Primary Immunodeficiencies, Assistance Publique-Hôpitaux de Paris (APHP), Necker Hospital Paris, France.
authors.forename: Marie
authors.initials: M
authors.lastname: Duchamp
authors.affiliation: Study Center of Primary Immunodeficiencies, Assistance Publique-Hôpitaux de Paris (APHP), Necker Hospital Paris, France.
authors.forename: Delphine
authors.initials: D
authors.lastname: Sterlin
authors.affiliation: Study Center of Primary Immunodeficiencies, Assistance Publique-Hôpitaux de Paris (APHP), Necker Hospital Paris, France.
authors.forename: Aminata
authors.initials: A
authors.lastname: Diabate
authors.affiliation: Laboratory of Immunology, Nouvel Hôpital Civil Strasbourg, France.
authors.forename: Béatrice
authors.initials: B
authors.lastname: Uring-Lambert
authors.affiliation: Laboratory of Immunology, APHP-Hôpitaux de Paris, Robert Debré Hospital Paris, France.
authors.forename: Valérie
authors.initials: V
authors.lastname: Guérin-El Khourouj
authors.affiliation: Laboratory of Immunology, Caen Hospital, Université de Caen Basse Normandie Caen, France.
authors.forename: Brigitte
authors.initials: B
authors.lastname: Le Mauff
authors.affiliation: Laboratory of Immunology, Cell Therapy and Hematopoiesis, Pontchaillou Hospital Rennes, France.
authors.forename: Delphine
authors.initials: D
authors.lastname: Monnier
authors.affiliation: Laboratory of Immunology, Hospices Civils de Lyon, Edouard Herriot Hospital Lyon, France.
authors.forename: Christophe
authors.initials: C
authors.lastname: Malcus
authors.affiliation: Laboratory of Immunology, Lille Hospital Lille, France.
authors.forename: Myriam
authors.initials: M
authors.lastname: Labalette
authors.affiliation: Study Center of Primary Immunodeficiencies, Assistance Publique-Hôpitaux de Paris (APHP), Necker Hospital Paris, France ; Laboratory of Human Genetics of Infectious Diseases, Necker Branch, INSERM UMR 1163, Necker Medical School, Imagine Institute, Paris Descartes University-Sorbonne Paris Cité Paris, France ; Centre de référence des déficits immunitaires héréditaires (CEREDIH), APHP, Necker Hospital Paris, France.
authors.forename: Capucine
authors.initials: C
authors.lastname: Picard
keywords: B-cells; children; primary immunodeficiency; reference values