C T Nielsen1, O Østergaard2, O P Rekvig3, G Sturfelt4, S Jacobsen5, N H H Heegaard2. 1. Department of Clinical Biochemistry, Immunology and Genetics, Statens Serum Institut, Copenhagen, Denmark Department of Infectious Disease and Rheumatology, University Hospital Rigshospitalet, Copenhagen, Denmark christoffertandrupnielsen@gmail.com. 2. Department of Clinical Biochemistry, Immunology and Genetics, Statens Serum Institut, Copenhagen, Denmark. 3. RNA and Molecular Pathology Research Group, University of Tromsø, Tromsø, Norway. 4. Department of Rheumatology, University Hospital of Lund, Lund, Sweden. 5. Department of Infectious Disease and Rheumatology, University Hospital Rigshospitalet, Copenhagen, Denmark.
Abstract
OBJECTIVE: A high level of galectin-3-binding protein (G3BP) appears to distinguish circulating cell-derived microparticles in systemic lupus erythematosus (SLE). The aim of this study is to characterize the population of G3BP-positive microparticles from SLE patients compared to healthy controls, explore putative clinical correlates, and examine if G3BP is present in immune complex deposits in kidney biopsies from patients with lupus nephritis. METHODS: Numbers of annexin V-binding and G3BP-exposing plasma microparticles from 56 SLE patients and 36 healthy controls were determined by flow cytometry. Quantitation of microparticle-associated G3BP, C1q and immunoglobulins was obtained by liquid chromatography tandem mass spectrometry (LC-MS/MS). Correlations between microparticle-G3BP data and clinical parameters were analyzed. Co-localization of G3BP with in vivo-bound IgG was examined in kidney biopsies from one non-SLE control and from patients with class IV (n = 2) and class V (n = 1) lupus nephritis using co-localization immune electron microscopy. RESULTS: Microparticle-G3BP, microparticle-C1q and microparticle-immunoglobulins were significantly (P < 0.01) increased in SLE patients by LC-MS/MS. Three G3BP-exposing microparticle populations could be discerned by flow cytometry, including two subpopulations that were significantly increased in SLE samples (P = 0.01 and P = 0.0002, respectively). No associations of G3BP-positive microparticles with clinical manifestations or disease activity were found. Immune electron microscopy showed co-localization of G3BP with in vivo-bound IgG in glomerular electron dense immune complex deposits in all lupus nephritis biopsies. CONCLUSIONS: Both circulating microparticle-G3BP numbers as well as G3BP expression are increased in SLE patients corroborating G3BP being a feature of SLE microparticles. By demonstrating G3BP co-localized with deposited immune complexes in lupus nephritis, the study supports cell-derived microparticles as a major autoantigen source and provides a new understanding of the origin of immune complexes occurring in lupus nephritis.
OBJECTIVE: A high level of galectin-3-binding protein (G3BP) appears to distinguish circulating cell-derived microparticles in systemic lupus erythematosus (SLE). The aim of this study is to characterize the population of G3BP-positive microparticles from SLEpatients compared to healthy controls, explore putative clinical correlates, and examine if G3BP is present in immune complex deposits in kidney biopsies from patients with lupus nephritis. METHODS: Numbers of annexin V-binding and G3BP-exposing plasma microparticles from 56 SLEpatients and 36 healthy controls were determined by flow cytometry. Quantitation of microparticle-associated G3BP, C1q and immunoglobulins was obtained by liquid chromatography tandem mass spectrometry (LC-MS/MS). Correlations between microparticle-G3BP data and clinical parameters were analyzed. Co-localization of G3BP with in vivo-bound IgG was examined in kidney biopsies from one non-SLE control and from patients with class IV (n = 2) and class V (n = 1) lupus nephritis using co-localization immune electron microscopy. RESULTS: Microparticle-G3BP, microparticle-C1q and microparticle-immunoglobulins were significantly (P < 0.01) increased in SLEpatients by LC-MS/MS. Three G3BP-exposing microparticle populations could be discerned by flow cytometry, including two subpopulations that were significantly increased in SLE samples (P = 0.01 and P = 0.0002, respectively). No associations of G3BP-positive microparticles with clinical manifestations or disease activity were found. Immune electron microscopy showed co-localization of G3BP with in vivo-bound IgG in glomerular electron dense immune complex deposits in all lupus nephritis biopsies. CONCLUSIONS: Both circulating microparticle-G3BP numbers as well as G3BP expression are increased in SLEpatients corroborating G3BP being a feature of SLE microparticles. By demonstrating G3BP co-localized with deposited immune complexes in lupus nephritis, the study supports cell-derived microparticles as a major autoantigen source and provides a new understanding of the origin of immune complexes occurring in lupus nephritis.
Authors: Felipe L de Oliveira; Mariele Gatto; Nicola Bassi; Roberto Luisetto; Anna Ghirardello; Leonardo Punzi; Andrea Doria Journal: Exp Biol Med (Maywood) Date: 2015-07-03
Authors: Christoffer T Nielsen; Ole Østergaard; Niclas S Rasmussen; Søren Jacobsen; Niels H H Heegaard Journal: Clin Proteomics Date: 2017-04-08 Impact factor: 3.988
Authors: Lotte Hatting Pugholm; Anne Louise Schacht Revenfeld; Evo Kristina Lindersson Søndergaard; Malene Møller Jørgensen Journal: Biomed Res Int Date: 2015-12-03 Impact factor: 3.411