title: Increased prevalence of vulnerable atherosclerotic plaques and low levels of natural IgM antibodies against phosphorylcholine in patients with systemic lupus erythematosus.
abstract: BACKGROUND
  The risk of cardiovascular disease (CVD) and atherosclerosis is reported to be increased in systemic lupus erythematosus (SLE). We recently reported a negative association between natural IgM-antibodies against phosphorylcholine (anti-PC) in the general population, high anti-PC levels leading to decreased atherosclerosis development and low levels to increased risk of CVD. Potential mechanisms include anti-inflammatory properties and inhibition of uptake of oxidized low density lipoprotein (LDL) in macrophages. The objective herein was to study atherosclerosis in SLE in detail and in relation to traditional and non-traditional risk factors.
  
  
  METHODS
  A total of 114 patients with SLE were compared with 122 age- and sex-matched population-based controls. Common carotid intima-media thickness (IMT), calculated intima-media area (cIMa) and plaque occurrence were determined by B-mode ultrasound as a surrogate measure of atherosclerosis. Plaques were graded according to echogenicity and grouped as 1 to 4, with 1 being echoluscent, and considered most vulnerable. Anti-PC was studied by ELISA.
  
  
  RESULTS
  Hypertension, triglycerides and insulin resistance (determined by homeostasis model assessment of insulin resistance) and C-reactive protein (CRP) were increased in SLE (P < 0.01) while smoking, LDL, high density lipoprotein (HDL) did not differ between groups. Low levels of anti-PC IgM (lowest tertile) were more common in SLE patients than in controls (P = 0.0022). IMT and cIMa did not differ significantly between groups. However, plaques were more often found in SLE patients (P = 0.029). Age, LDL and IgM anti-PC (lowest tertile) were independently associated with plaque occurrence in SLE. Further, in the left carotid arteries echoluscent plaques (grade 1) were more prevalent in SLE as compared to controls (P < 0.016).
  
  
  CONCLUSIONS
  Plaque occurrence in the carotid arteries is increased in SLE and is independently associated with age, LDL and low anti-PC levels. Vulnerable plaques were more common in SLE. Anti-PC could be a novel risk marker also with a therapeutic potential in SLE.
authors.affiliation: Department of Medicine, Karolinska University Hospital, Huddinge, 141 86 Stockholm, Sweden.
authors.forename: Cristina
authors.initials: C
authors.lastname: Anania
authors.forename: Thomas
authors.initials: T
authors.lastname: Gustafsson
authors.forename: Xiang
authors.initials: X
authors.lastname: Hua
authors.forename: Jun
authors.initials: J
authors.lastname: Su
authors.forename: Max
authors.initials: M
authors.lastname: Vikström
authors.forename: Ulf
authors.initials: U
authors.lastname: de Faire
authors.forename: Mikael
authors.initials: M
authors.lastname: Heimbürger
authors.forename: Tomas
authors.initials: T
authors.lastname: Jogestrand
authors.forename: Johan
authors.initials: J
authors.lastname: Frostegård
mesh_terms: D001323:Autoantibodies / Q000097:blood*; D001324:Autoantigens / Q000276:immunology; D002339:Carotid Arteries / Q000000981:diagnostic imaging / Q000473:pathology; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D006801:Humans; D007075:Immunoglobulin M / Q000097:blood; D008180:Lupus Erythematosus, Systemic / Q000097:blood / Q000150:complications* / Q000276:immunology*; D008297:Male; D008875:Middle Aged; D010767:Phosphorylcholine / Q000276:immunology*; D058226:Plaque, Atherosclerotic / Q000453:epidemiology / Q000209:etiology / Q000276:immunology*; D015995:Prevalence; D014463:Ultrasonography
chemical_list: D001323:Autoantibodies; D001324:Autoantigens; D007075:Immunoglobulin M; D010767:Phosphorylcholine