title: The significance and predictive value of free light chains in the urine of patients with chronic inflammatory rheumatic disease.
abstract: In patients with rheumatic diseases, reliable markers for determining disease activity are scarce. One potential parameter is the level of immunoglobulin free light chains (FLCs), which is known to be elevated in the blood of patients with certain rheumatic diseases. Few studies have quantified FLCs in urine, a convenient source of test sample, in patients with different rheumatic diseases. We carried out a retrospective analysis of patients with rheumatic disease attending the University hospital of Goettingen, Germany. Subjects were included if they had urine levels of both κ and λ FLCs available and did not have myeloma. Data regarding systemic inflammation and kidney function were recorded, and FLC levels were correlated with inflammatory markers. Of the 382 patients with rheumatic disease, 40.1 % had chronic polyarthritis, 21.2 % connective tissue disease, 18.6 % spondyloarthritis and 15.7 % vasculitis. Elevated levels of κ FLCs were found for 84 % of patients and elevated λ for 52.7 %. For the patients with rheumatoid arthritis, FLCs correlated with C-reactive protein (κ, r = 0.368, p < 0.001; λ, r = 0.398, p < 0.001) and erythrocyte sedimentation rate (κ, r = 0.692, p < 0.001; λ, r = 0.612, p < 0.001). Patients being treated with rituximab displayed FLC levels similar to those of the reference group. There were clear elevations in both κ and λ FLCs in patients with rheumatic disease, but not in κ/λ ratio. The correlation between FLCs and inflammatory markers in patients with rheumatoid arthritis demonstrates their potential for predicting disease activity.
authors.affiliation: Department of Nephrology and Rheumatology, Georg-August-University Goettingen, Robert-Koch-Str. 40, 37075, Göttingen, Germany. c.bramlage@med.uni-goettingen.de.|Institute for Pharmacology and Preventive Medicine, Cloppenburg, Germany. c.bramlage@med.uni-goettingen.de.
authors.forename: Carsten Paul
authors.initials: CP
authors.lastname: Bramlage
authors.affiliation: Department of Nephrology and Rheumatology, Georg-August-University Goettingen, Robert-Koch-Str. 40, 37075, Göttingen, Germany.
authors.forename: Britta
authors.initials: B
authors.lastname: Froelich
authors.affiliation: Department of Nephrology and Rheumatology, Georg-August-University Goettingen, Robert-Koch-Str. 40, 37075, Göttingen, Germany.
authors.forename: Manuel
authors.initials: M
authors.lastname: Wallbach
authors.affiliation: Institute for Pharmacology and Preventive Medicine, Cloppenburg, Germany.
authors.forename: Joan
authors.initials: J
authors.lastname: Minguet
authors.affiliation: Department of Medicine III, Hospital Bamberg, Bamberg, Germany.
authors.forename: Clemens
authors.initials: C
authors.lastname: Grupp
authors.affiliation: Institute for Pharmacology and Preventive Medicine, Cloppenburg, Germany.
authors.forename: Cornelia
authors.initials: C
authors.lastname: Deutsch
authors.affiliation: Institute for Pharmacology and Preventive Medicine, Cloppenburg, Germany.
authors.forename: Peter
authors.initials: P
authors.lastname: Bramlage
authors.affiliation: Department of Nephrology and Rheumatology, Georg-August-University Goettingen, Robert-Koch-Str. 40, 37075, Göttingen, Germany.
authors.forename: Michael
authors.initials: M
authors.lastname: Koziolek
authors.affiliation: Department of Nephrology and Rheumatology, Georg-August-University Goettingen, Robert-Koch-Str. 40, 37075, Göttingen, Germany.
authors.forename: Gerhard Anton
authors.initials: GA
authors.lastname: Müller
mesh_terms: D000328:Adult; D000368:Aged; D001799:Blood Sedimentation; D002097:C-Reactive Protein / Q000378:metabolism; D005260:Female; D006801:Humans; D007145:Immunoglobulin kappa-Chains / Q000737:chemistry / Q000652:urine*; D007146:Immunoglobulin lambda-Chains / Q000737:chemistry / Q000652:urine*; D007249:Inflammation / Q000175:diagnosis / Q000276:immunology / Q000652:urine*; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D012189:Retrospective Studies; D012216:Rheumatic Diseases / Q000175:diagnosis / Q000276:immunology / Q000652:urine*; D000069283:Rituximab / Q000008:administration & dosage
chemical_list: D007145:Immunoglobulin kappa-Chains; D007146:Immunoglobulin lambda-Chains; D000069283:Rituximab; D002097:C-Reactive Protein
keywords: Autoimmune; C-reactive protein; Erythrocyte sedimentation rate; Free light chains; Inflammation; Rheumatic disease; Rituximab