title: Functional class switch recombination may occur 'in vivo' in Waldenström macroglobulinaemia.
abstract: Waldenström macroglobulinaemia (WM) malignant cells have been considered incapable of undergoing class switch recombination (CSR). However, we report a WM patient who developed an IgG M-component 4 years after diagnosis. When the second monoclonal component appeared, reverse transcription-polymerase chain reaction showed the presence of pre (Cmu) and postswitch (Cgamma) clonotypic isotypes; sequencing of these isotypes demonstrated that both corresponded to the single clone amplified at diagnosis, including the same complementarity-determining region 3 and somatic mutation pattern. This proves that WM cells can undergo a functional in vivo CSR.
authors.affiliation: Servicio de Hematología y Hemoterapia, Unidad de Biología Molecular, Hospital Universitario de Salamanca, Salamanca, Spain.
authors.forename: Patricia
authors.initials: P
authors.lastname: Martín-Jiménez
authors.forename: Ramón
authors.initials: R
authors.lastname: García-Sanz
authors.forename: María E
authors.initials: ME
authors.lastname: Sarasquete
authors.forename: Enrique
authors.initials: E
authors.lastname: Ocio
authors.forename: José J
authors.initials: JJ
authors.lastname: Pérez
authors.forename: Marcos
authors.initials: M
authors.lastname: González
authors.forename: Jesús F
authors.initials: JF
authors.lastname: San Miguel
mesh_terms: D022801:Complementarity Determining Regions; D005260:Female; D015321:Gene Rearrangement; D006801:Humans; D017578:Immunoglobulin Class Switching; D007074:Immunoglobulin G; D007075:Immunoglobulin M; D007134:Immunoglobulin Switch Region; D007148:Immunoglobulin mu-Chains; D016130:Immunophenotyping; D008875:Middle Aged; D011995:Recombination, Genetic; D020133:Reverse Transcriptase Polymerase Chain Reaction; D008258:Waldenstrom Macroglobulinemia / Q000235:genetics* / Q000276:immunology*
chemical_list: D022801:Complementarity Determining Regions; D007074:Immunoglobulin G; D007075:Immunoglobulin M; D007148:Immunoglobulin mu-Chains