title: Serum free light chains of immunoglobulins as biomarkers for systemic sclerosis characteristics, activity and severity.
abstract: Systemic sclerosis (SSc) is a chronic autoimmune connective tissue disease. Humoral immunity and B cells are thought to play an important role in the pathophysiology of the disease. B cells are activated, produce specific autoantibodies and profibrotic cytokines. One way to assess B cell activation is to measure serum free light chains of immunoglobulins (sFLC) levels. We assess here sFLC levels in patients with systemic sclerosis (SSc) and their correlation with the disease characteristics, activity and severity. One hundred and thirty-four SSc patients were prospectively enrolled and compared to 401 age- and sex-matched healthy controls. sFLC levels were measured by a new quantitative immunoassay. sFLC levels were significantly higher in SSc patients than in healthy controls. sFLC levels correlated with modified Rodnan skin score and were independently associated with the presence of interstitial lung disease and its severity. In univariate analysis, sFLC levels correlated with SSc activity, as measured by the European Scleroderma Study Group activity index, and severity, as measured by the Medsger's total severity score. In multivariate analysis, beta2-microglobulin levels correlated with disease activity, BAFF levels with severity and sFLC with neither of these. Other B-cell activation biomarkers (IgG, IgA, beta2-microglobulin and BAFF) were independently correlated with sFLC. sFLC levels are elevated in SSc and are independently associated with lung disease and its severity. B-cell activation biomarkers, including sFLC, beta2-microglobulin and BAFF, correlate with disease severity and activity. These results further support the role of B cell activation in the pathophysiology of SSc.
authors: Université Lille Nord de France, Lille, France; Service de Médecine Interne, Centre National de Référence de la Sclérodermie Systémique, Hôpital Claude-Huriez, CHRU Lille, Lille, France.
authors: Aurélia
authors: A
authors: Lanteri
authors: Université Lille Nord de France, Lille, France; Service de Médecine Interne, Centre National de Référence de la Sclérodermie Systémique, Hôpital Claude-Huriez, CHRU Lille, Lille, France; EA2686, IMPRT IFR 114, Faculté de Médecine, Lille, France.
authors: Vincent
authors: V
authors: Sobanski
authors: Université Lille Nord de France, Lille, France; Unité de Biostatistique, CHRU Lille, Lille, France.
authors: Carole
authors: C
authors: Langlois
authors: Université Lille Nord de France, Lille, France; Service de Médecine Interne, Centre National de Référence de la Sclérodermie Systémique, Hôpital Claude-Huriez, CHRU Lille, Lille, France; EA2686, IMPRT IFR 114, Faculté de Médecine, Lille, France; Institut d'Immunologie, Centre de Biologie-Pathologie-Génétique, CHRU Lille, Lille, France.
authors: Guillaume
authors: G
authors: Lefèvre
authors: Université Lille Nord de France, Lille, France; Institut d'Immunologie, Centre de Biologie-Pathologie-Génétique, CHRU Lille, Lille, France.
authors: Carine
authors: C
authors: Hauspie
authors: Université Lille Nord de France, Lille, France; Service de Médecine Interne, Centre National de Référence de la Sclérodermie Systémique, Hôpital Claude-Huriez, CHRU Lille, Lille, France; EA2686, IMPRT IFR 114, Faculté de Médecine, Lille, France.
authors: Sébastien
authors: S
authors: Sanges
authors: Université Lille Nord de France, Lille, France; Service de Médecine Interne, Centre National de Référence de la Sclérodermie Systémique, Hôpital Claude-Huriez, CHRU Lille, Lille, France.
authors: Marc
authors: M
authors: Lambert
authors: Université Lille Nord de France, Lille, France; Service de Médecine Interne, Centre National de Référence de la Sclérodermie Systémique, Hôpital Claude-Huriez, CHRU Lille, Lille, France.
authors: Sandrine
authors: S
authors: Morell-Dubois
authors: Université Lille Nord de France, Lille, France; Service de Médecine Interne, Centre National de Référence de la Sclérodermie Systémique, Hôpital Claude-Huriez, CHRU Lille, Lille, France.
authors: Pierre-Yves
authors: PY
authors: Hatron
authors: Université Lille Nord de France, Lille, France; Service de Médecine Interne, Centre National de Référence de la Sclérodermie Systémique, Hôpital Claude-Huriez, CHRU Lille, Lille, France; EA2686, IMPRT IFR 114, Faculté de Médecine, Lille, France.
authors: Eric
authors: E
authors: Hachulla
authors: Université Lille Nord de France, Lille, France; Service de Médecine Interne, Centre National de Référence de la Sclérodermie Systémique, Hôpital Claude-Huriez, CHRU Lille, Lille, France; EA2686, IMPRT IFR 114, Faculté de Médecine, Lille, France. Electronic address: david.launay@univ-lille2.fr.
authors: David
authors: D
authors: Launay
authors: Université Lille Nord de France, Lille, France; EA2686, IMPRT IFR 114, Faculté de Médecine, Lille, France; Institut d'Immunologie, Centre de Biologie-Pathologie-Génétique, CHRU Lille, Lille, France.
authors: Sylvain
authors: S
authors: Dubucquoi
mesh_terms: D001402:B-Lymphocytes / Q000276:immunology; D015415:Biomarkers / Q000032:analysis; D006801:Humans; D007147:Immunoglobulin Light Chains / Q000032:analysis* / Q000276:immunology; D008168:Lung / Q000276:immunology; D008213:Lymphocyte Activation / Q000276:immunology; D012595:Scleroderma, Systemic / Q000276:immunology*; D012720:Severity of Illness Index
chemical_list: D015415:Biomarkers; D007147:Immunoglobulin Light Chains
keywords: B cells; BAFF; Beta2-microglobulin; Free light chain; Systemic sclerosis