title: Persistent Polyclonal B Cell Lymphocytosis B Cells Can Be Activated through CD40-CD154 Interaction.
abstract: Persistent polyclonal B cell lymphocytosis (PPBL) is a rare disorder, diagnosed primarily in adult female smokers and characterized by an expansion of CD19(+)CD27(+)IgM(+) memory B cells, by the presence of binucleated lymphocytes, and by a moderate elevation of serum IgM. The clinical course is usually benign, but it is not known whether or not PPBL might be part of a process leading to the emergence of a malignant proliferative disorder. In this study we sought to investigate the functional response of B cells from patients with PPBL by use of an optimal memory B cell culture model based on the CD40-CD154 interaction. We found that the proliferation of PPBL B cells was almost as important as that of B cells from normal controls, resulting in high immunoglobulin secretion with in vitro isotypic switching. We conclude that the CD40-CD154 activation pathway is functional in the memory B cell population of PPBL patients, suggesting that the disorder may be due to either a dysfunction of other cells in the microenvironment or a possible defect in another B cell activation pathway.
authors.affiliation: Centre Universitaire d'Hématologie et d'Oncologie de Québec, CHU de Québec, Hôpital de l'Enfant-Jésus, 1401 18ième rue, Québec, QC, Canada G1J 1Z4.
authors.forename: Emmanuelle
authors.identifier: 0000-0002-1801-5433
authors.initials: E
authors.lastname: Dugas-Bourdages
authors.affiliation: Héma-Québec, Recherche et Développement, 1070 avenue des Sciences-de-la-Vie, Québec, QC, Canada G1V 5C3 ; Département de Biochimie, de Microbiologie et de Bio-Informatique, Pavillon Alexandre-Vachon, 1045 avenue de la Médecine, Bureau 3428, Université Laval, Québec, QC, Canada G1V 0A6.
authors.forename: Sonia
authors.initials: S
authors.lastname: Néron
authors.affiliation: Héma-Québec, Recherche et Développement, 1070 avenue des Sciences-de-la-Vie, Québec, QC, Canada G1V 5C3.
authors.forename: Annie
authors.identifier: 0000-0001-7504-6749
authors.initials: A
authors.lastname: Roy
authors.affiliation: Département de Biochimie, de Microbiologie et de Bio-Informatique, Pavillon Alexandre-Vachon, 1045 avenue de la Médecine, Bureau 3428, Université Laval, Québec, QC, Canada G1V 0A6.
authors.forename: André
authors.initials: A
authors.lastname: Darveau
authors.affiliation: Centre Universitaire d'Hématologie et d'Oncologie de Québec, CHU de Québec, Hôpital de l'Enfant-Jésus, 1401 18ième rue, Québec, QC, Canada G1J 1Z4.
authors.forename: Robert
authors.initials: R
authors.lastname: Delage