Enhanced expression and fucosylation of ficolin3 in plasma of RA patients

ObjectivesThe aim of this work was to detect low abundant proteins, which may be potential biomarkers of rheumatoid arthritis (RA) at the early stage. We compared plasma protein profiles of RA patients with healthy individuals in two dimensional gel electrophoresis after removal of abundant proteins (albumin and IgG) using depletion kit and Aleuria aurantia lectin (AAL) affinity chromatography.Design and MethodsForty plasma samples each from healthy control individuals and RA patients were used in this study.ResultsWe found ficolin 3, haptoglobin alpha chain, IgM chain, alpha-1-antitrypsin and hemopexin precursor to be up regulated in the plasma of RA patients. These proteins were identified by matrix assisted laser desorption ionization-time of flight (MALDI-TOF) from several reproducible 2D gels. Ficolin 3, which was not at all visible in albumin and IgG depleted gels, but detected in AAL bound fractions, was further verified by immunobloting and enzyme immunoassay. Elevated fucosylation in ficolin 3 was detected using high performance anion exchange chromatography–pulse amperometric detection (HPAEC–PAD), lectin blotting and enzyme linked lectin binding assay.ConclusionsAltered fucosylation and elevated level of Ficolin 3 might be exploited to be a potential marker for diagnosis of RA.

► Proteomic analysis of albumin and IgG depleted and AAL bound plasma of RA patients.
► MALDI-TOF analysis of differentially expressed proteins.
► Increased fucosylation of ficolin 3 in plasma of RA patients.