title: Association between interleukin-6 and carotid atherosclerosis in hemodialysis patients.
abstract: BACKGROUND
  Interleukin-6 (IL-6) is associated with cardiovascular complications in general subjects. Although blood IL-6 is greatly elevated in hemodialysis (HD) patients, the role of IL-6 in the advance of atherosclerosis remains to be determined.
  
  
  METHODS
  We conducted a cross-sectional study to investigate the relationship between circulating IL-6 and carotid atherosclerotic changes in 156 HD patients (age 58 +/- 1 years; time on HD treatment 13 +/- 1 years; 97 males and 59 females). Serum IL-6, IgG and IgA titers of Chlamydia pneumoniae antibodies, the intima-media thickness (IMT) and the cross-sectional intima-media area (IMarea) of the carotid arteries were measured by ultrasonography in each patient.
  
  
  RESULTS
  Serum IL-6 levels were significantly higher in HD patients (2.04 +/- 0.16 pg/mL) compared to normal age-matched control subjects (0.31 +/- 0.06 pg/mL, N = 24). Circulating log IL-6 levels were positively correlated with IMT (r = 0.278, P < 0.01) and IMarea (r = 0.344, P < 0.01), respectively. A stepwise multiple regression analysis revealed that IL-6 became significant predictors for IMT and IMarea but not for aortic wall calcification at L2/3 vertebrae. Serum log IL-6 was significantly correlated with IgG (r = 0.277, P < 0.01) and IgA titers of anti-Chlamydia antibodies (r = 0.192, P < 0.02). Serum IgA anti-Chlamydia titers were also correlated with the maximal diameter of carotid plaque (r = 0.293, P < 0.04).
  
  
  CONCLUSIONS
  These findings suggested that IL-6 is associated with the severity of carotid atherosclerosis in HD patients. Persistent chronic chlamydial infection may be related, in part, to the advance of carotid plaque enlargement in dialysis patients.
authors.affiliation: First Department of Medicine, Hamamatsu University School of Medicine, 1-20-1 Handayama, Hamamatsu, 431-3192 Japan. akato@hama-med.ac.jp
authors.forename: Akihiko
authors.initials: A
authors.lastname: Kato
authors.forename: Mari
authors.initials: M
authors.lastname: Odamaki
authors.forename: Takako
authors.initials: T
authors.lastname: Takita
authors.forename: Yukitaka
authors.initials: Y
authors.lastname: Maruyama
authors.forename: Hiromichi
authors.initials: H
authors.lastname: Kumagai
authors.forename: Akira
authors.initials: A
authors.lastname: Hishida
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000907:Antibodies, Bacterial / Q000097:blood; D002339:Carotid Arteries / Q000000981:diagnostic imaging; D002340:Carotid Artery Diseases / Q000097:blood* / Q000000981:diagnostic imaging / Q000503:physiopathology; D016993:Chlamydophila pneumoniae / Q000276:immunology; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D007070:Immunoglobulin A / Q000097:blood; D015850:Interleukin-6 / Q000097:blood*; D008297:Male; D008875:Middle Aged; D012016:Reference Values; D006435:Renal Dialysis; D012720:Severity of Illness Index; D014463:Ultrasonography
chemical_list: D000907:Antibodies, Bacterial; D007070:Immunoglobulin A; D015850:Interleukin-6