title: Serum Immunoglobulin Free Light Chain Assessment in IgG4-Related Disease.
abstract: Immunoglobulin free light chains are produced in excess during normal antibody synthesis. Their evaluation is commonly used in case of a monoclonal gammopathy. In polyclonal hypergammaglobulinemia related to the Sjögren syndrome or systemic lupus, erythematosus serum free light chain levels are increased and could correlate with disease activity. We show here that the κ (P < 0.0001) and λ (P = 0.0003) free light chains and the κ  :  λ ratio (P = 0.0049) are increased in sixteen patients with IgG4-related disease when compared to healthy controls. The increase of κ and λ free light chains probably reflects the marked polyclonal B cell activation of the disease. We could not assess in this small cohort of patients a significative correlation of serum free light chain levels and disease activity or extension.
authors.affiliation: Service de Médecine Interne, Centre Hospitalier Universitaire Hôpital de la Conception, AP-HM, Aix-Marseille Université, 13385 Marseille Cedex 5, France.
authors.forename: Aurélie
authors.initials: A
authors.lastname: Grados
authors.forename: Mikael
authors.initials: M
authors.lastname: Ebbo
authors.forename: José
authors.initials: J
authors.lastname: Boucraut
authors.forename: Frédéric
authors.initials: F
authors.lastname: Vély
authors.forename: Pierre
authors.initials: P
authors.lastname: Aucouturier
authors.forename: Aude
authors.initials: A
authors.lastname: Rigolet
authors.forename: Benjamin
authors.initials: B
authors.lastname: Terrier
authors.forename: David
authors.initials: D
authors.lastname: Saadoun
authors.forename: Pascale
authors.initials: P
authors.lastname: Ghillani-Dalbin
authors.forename: Nathalie
authors.initials: N
authors.lastname: Costedoat-Chalumeau
authors.forename: Jean Robert
authors.initials: JR
authors.lastname: Harlé
authors.forename: Nicolas
authors.initials: N
authors.lastname: Schleinitz