title: Aberrant levels of natural IgM antibodies in osteoarthritis and rheumatoid arthritis patients in comparison to healthy controls.
abstract: Natural IgM antibodies (nIgM) are polyreactive autoantibodies that have diverse roles in regulating autoimmunity, systemic inflammation and removal of oxidized low-density lipoproteins (oxLDL). We hypothesized that aberrant states of nIgM may exist in persons with osteoarthritis (OA) and rheumatoid arthritis (RA). Herein, we characterized and compared the levels of nIgM specific for phosphorylcholine (anti-PC), double-stranded DNA (anti-dsDNA), and galactosyl (anti-Gal) in persons with OA, RA and healthy controls (HC). Levels of anti-PC nIgM in OA patients were significantly lower than both HC and RA patients in an age-adjusted analysis (P<0.05). In contrast, anti-Gal nIgM levels were significantly higher in RA patients than OA patients (P<0.05) and markedly increased in comparison to HC. Anti-PC nIgM significantly correlated with anti-dsDNA and anti-Gal nIgM levels in HC and RA (P<0.05) but not in OA patients. Elevated CRP levels were associated with RA conditions and old ages in general. There was no significant correlation between anti-PC nIgM and CRP or oxLDL levels. Our study highlights for the first time the evidence of aberrant state of nIgM in human OA compared to healthy individuals that implicates a deficiency in immune responses to oxLDL which may contribute to the metabolic syndromes in the development of OA.
authors.affiliation: Autoimmunity and Immunotherapy Research, Royal North Shore Hospital, Sydney, NSW 2065, Australia; Perinatal Research, Royal North Shore Hospital, Sydney, NSW 2065, Australia. Electronic address: tommie.nguyen@sydney.edu.au.
authors.forename: Tue G
authors.initials: TG
authors.lastname: Nguyen
authors.affiliation: Perinatal Research, Royal North Shore Hospital, Sydney, NSW 2065, Australia; Sutton Arthritis Research Laboratory, Kolling Institute, Royal North Shore Hospital, Sydney, NSW 2065, Australia.
authors.forename: Kelly J
authors.initials: KJ
authors.lastname: McKelvey
authors.affiliation: Institute of Bone and Joint Research, Royal North Shore Hospital, Sydney, NSW 2065, Australia; Department of Rheumatology, Royal North Shore Hospital, Sydney, NSW 2065, Australia.
authors.forename: Lyn M
authors.initials: LM
authors.lastname: March
authors.affiliation: Institute of Bone and Joint Research, Royal North Shore Hospital, Sydney, NSW 2065, Australia; Department of Rheumatology, Royal North Shore Hospital, Sydney, NSW 2065, Australia.
authors.forename: David J
authors.initials: DJ
authors.lastname: Hunter
authors.affiliation: Sutton Arthritis Research Laboratory, Kolling Institute, Royal North Shore Hospital, Sydney, NSW 2065, Australia; Institute of Bone and Joint Research, Royal North Shore Hospital, Sydney, NSW 2065, Australia.
authors.forename: Meilang
authors.initials: M
authors.lastname: Xue
authors.affiliation: Sutton Arthritis Research Laboratory, Kolling Institute, Royal North Shore Hospital, Sydney, NSW 2065, Australia; Institute of Bone and Joint Research, Royal North Shore Hospital, Sydney, NSW 2065, Australia.
authors.forename: Christopher J
authors.initials: CJ
authors.lastname: Jackson
authors.affiliation: Perinatal Research, Royal North Shore Hospital, Sydney, NSW 2065, Australia; Northern Clinical School, University of Sydney, Royal North Shore Hospital, Sydney, NSW 2065, Australia.
authors.forename: Jonathan M
authors.initials: JM
authors.lastname: Morris
mesh_terms: D000328:Adult; D000368:Aged; D001172:Arthritis, Rheumatoid / Q000097:blood / Q000175:diagnosis / Q000276:immunology*; D001323:Autoantibodies / Q000097:blood / Q000276:immunology; D015415:Biomarkers; D016022:Case-Control Studies; D005260:Female; D006801:Humans; D007074:Immunoglobulin G / Q000097:blood / Q000276:immunology; D007075:Immunoglobulin M / Q000097:blood / Q000276:immunology*; D018836:Inflammation Mediators / Q000097:blood; D008297:Male; D008875:Middle Aged; D010003:Osteoarthritis / Q000097:blood / Q000175:diagnosis / Q000276:immunology*
chemical_list: D001323:Autoantibodies; D015415:Biomarkers; D007074:Immunoglobulin G; D007075:Immunoglobulin M; D018836:Inflammation Mediators
keywords: Anti-dsDNA; Anti-galactosyl; Anti-phosphorylcholine; Natural IgM; Osteoarthritis; Rheumatoid arthritis