title: Interleukin-8 is increased in the membrane of circulating erythrocytes in patients with acute coronary syndrome.
abstract: OBJECTIVE
  Studies have shown that erythrocyte membranes are present within necrotic cores in atherosclerotic plaques, and that circulating erythrocytes in patients with acute coronary syndrome (ACS) have increased total cholesterol content (CEM). Interleukin-8 (IL-8) binds to erythrocytes and during intraplaque haemorrhage it is released into the plaque and thus may contribute to inflammatory cascade and atherosclerotic plaque instability. The present study was undertaken to test the hypothesis that erythrocyte membrane IL-8 is elevated in patients with ACS compared with those with chronic stable angina (CSA).
  
  
  RESULTS
  Consecutive patients who presented with CSA (n = 120, 92 men, 62 +/- 9 years), ACS (n = 118, 90 men, 62 +/- 10 years) or with chest pain who had normal coronary arteries (n = 36, 26 men, 60 +/- 7 years), were studied prospectively. IL-8 concentrations in erythrocyte membranes (rIL-8) and in plasma (pIL-8), C-reactive protein (CRP) and CEM were measured. rIL-8 levels [mean +/- 1 SD (standard deviation)] were higher in ACS (102.9 +/- 70.1 pg/mL) compared with CSA (44.7 +/- 22.8 pg/mL) (P < 0.001). No difference in pIL-8 levels between the two coronary artery disease groups was observed (P = 0.280). Serum CRP levels were correlated with rIL-8 levels (r = 0.294, P < 0.001); no association was found between CRP and pIL-8 levels (r = 0.025, P = 0.706). Further, rIL-8 had an independent association with ACS, when CRP and CEM were taken into consideration.
  
  
  CONCLUSIONS
  This study shows for the first time that rIL-8 content was significantly higher in ACS, compared with CSA. These findings endorse results from our previous studies suggesting that erythrocytes may play an important role in the development of unstable atherosclerotic plaque.
authors.affiliation: University Cardiology Department, Medical School, Democritus University of Thrace, Alexandroupolis, Evros, Greece. dtziakas@med.duth.gr
authors.forename: Dimitrios N
authors.initials: DN
authors.lastname: Tziakas
authors.forename: Georgios K
authors.initials: GK
authors.lastname: Chalikias
authors.forename: Ioannis K
authors.initials: IK
authors.lastname: Tentes
authors.forename: Dimitrios
authors.initials: D
authors.lastname: Stakos
authors.forename: Sofia V
authors.initials: SV
authors.lastname: Chatzikyriakou
authors.forename: Konstantina
authors.initials: K
authors.lastname: Mitrousi
authors.forename: Alexandros X
authors.initials: AX
authors.lastname: Kortsaris
authors.forename: Juan Carlos
authors.initials: JC
authors.lastname: Kaski
authors.forename: Harisios
authors.initials: H
authors.lastname: Boudoulas