title: Interleukin-6 and interleukin-8 blood levels' poor association with the severity and clinical profile of ex-smokers with COPD.
abstract: BACKGROUND
  The role of interleukins in the severity and clinical profile of chronic obstructive pulmonary disease (COPD) is not known, but evidence supports the contribution of systemic inflammation to disease pathophysiology. This study evaluated the relationship of serum biomarkers to the severity and clinical parameters of COPD.
  
  
  RESULTS
  Serum levels of high-sensitivity C-reactive protein, interleukin-6 (IL-6), and interleukin-8 (IL-8) were measured in 50 patients with stable COPD and in 16 controls. The levels of these biomarkers were compared with parameters of severity, such as the grading of flow obstruction using the recommendations of the Global initiative for chronic Obstructive Lung Disease, the BMI (body mass index), obstruction, dyspnea, exercise capacity (health index) index, the number of exacerbations within the last year, and peripheral oxygen saturation after the six-minute walk test, and with clinical parameters, such as bronchitis and non-bronchitis phenotypes, the number of associated comorbidities, and the smoking burden. COPD patients exhibited higher levels of IL-6 and IL-8 compared to the control group. Higher levels of IL-6 occurred in COPD groups with body mass index <21 kg/m(2), with more than two exacerbations in the past year, with a higher smoking burden, and with bronchitis. The increase in serum IL-8 was found only in the group with the highest number of exacerbations within the previous year.
  
  
  CONCLUSIONS
  Increased IL-6 was mainly associated with smoking burden, in patients who had smoked for more than 30 pack-years and exhibited a bronchitis phenotype. No direct association was observed for both IL-6 and IL-8 blood levels with the severity of COPD in ex-smokers.
authors.affiliation: Health Sciences of Federal University of Goiás, Federal University of Goiás, Goiânia, Goiás, Brazil.
authors.forename: Maria Rosedália
authors.initials: MR
authors.lastname: de Moraes
authors.affiliation: Institute of Tropical Pathology and Public Health, Federal University of Goiás, Goiânia, Goiás, Brazil.
authors.forename: Adeliane Castro
authors.initials: AC
authors.lastname: da Costa
authors.affiliation: Institute of Tropical Pathology and Public Health, Federal University of Goiás, Goiânia, Goiás, Brazil.
authors.forename: Krislainy de Sousa
authors.initials: Kde S
authors.lastname: Corrêa
authors.affiliation: Institute of Tropical Pathology and Public Health, Federal University of Goiás, Goiânia, Goiás, Brazil.
authors.forename: Ana Paula
authors.initials: AP
authors.lastname: Junqueira-Kipnis
authors.affiliation: Faculty of Medicine, Federal University of Goiás, Goiânia, Goiás, Brazil.
authors.forename: Marcelo Fouad
authors.initials: MF
authors.lastname: Rabahi
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015415:Biomarkers / Q000097:blood; D002097:C-Reactive Protein / Q000032:analysis; D016022:Case-Control Studies; D003430:Cross-Sectional Studies; D005080:Exercise Test; D005260:Female; D006801:Humans; D018836:Inflammation Mediators / Q000097:blood*; D015850:Interleukin-6 / Q000097:blood*; D016209:Interleukin-8 / Q000097:blood*; D008168:Lung / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D011379:Prognosis; D029424:Pulmonary Disease, Chronic Obstructive / Q000097:blood / Q000175:diagnosis / Q000209:etiology* / Q000276:immunology / Q000503:physiopathology; D012129:Respiratory Function Tests; D012307:Risk Factors; D012720:Severity of Illness Index; D012907:Smoking / Q000009:adverse effects / Q000097:blood / Q000276:immunology / Q000503:physiopathology; D016540:Smoking Cessation; D000074606:Smoking Prevention
chemical_list: D015415:Biomarkers; C508606:CXCL8 protein, human; C508600:IL6 protein, human; D018836:Inflammation Mediators; D015850:Interleukin-6; D016209:Interleukin-8; D002097:C-Reactive Protein
keywords: C-reactive protein; COPD; interleukin-6; interleukin-8
references.citation: Chest. 2002 May;121(5 Suppl):121S-126S
references.pmid: 12010839
references.citation: Eur Respir J. 2009 May;33(5):1165-85
references.pmid: 19407051
references.citation: Respir Res. 2013 Feb 20;14:24
references.pmid: 23425215
references.citation: Respir Res. 2010 May 25;11:63
references.pmid: 20500811
references.citation: Cancer Epidemiol Biomarkers Prev. 2011 Aug;20(8):1760-9
references.pmid: 21708936
references.citation: Toxicol Appl Pharmacol. 2011 Jul 15;254(2):72-85
references.pmid: 21296096
references.citation: Eur Respir J. 2008 Mar;31(3):492-501
references.pmid: 18310396
references.citation: Chest. 2009 Oct;136(4):1039-1046
references.pmid: 19542257
references.citation: Lancet. 2004 Aug 14-20;364(9434):613-20
references.pmid: 15313363
references.citation: Rev Med Chil. 2010 Aug;138(8):957-64
references.pmid: 21140052
references.citation: Respir Res. 2010 Apr 22;11:41
references.pmid: 20412595
references.citation: Respiration. 2009;78(2):191-6
references.pmid: 19270439
references.citation: N Engl J Med. 2009 Jun 4;360(23):2445-54
references.pmid: 19494220
references.citation: Am J Respir Crit Care Med. 2008 Dec 15;178(12):1211-8
references.pmid: 18836149
references.citation: Respir Res. 2012 Aug 20;13:71
references.pmid: 22906131
references.citation: Chest. 2005 Oct;128(4):1995-2004
references.pmid: 16236847
references.citation: Am J Respir Crit Care Med. 2003 Feb 1;167(3):418-24
references.pmid: 12426229
references.citation: Chest. 2008 Jun;133(6):1336-1343
references.pmid: 18339787
references.citation: Circulation. 2003 Mar 25;107(11):1514-9
references.pmid: 12654609
references.citation: Am J Respir Crit Care Med. 2012 Jul 15;186(2):155-61
references.pmid: 22561964
references.citation: Thorax. 2011 May;66(5):430-7
references.pmid: 21177668
references.citation: Am J Respir Crit Care Med. 2002 Jul 1;166(1):111-7
references.pmid: 12091180
references.citation: Arch Bronconeumol. 2006 Jul;42(7):332-7
references.pmid: 16945263
references.citation: Am J Respir Crit Care Med. 1998 Mar;157(3 Pt 1):822-6
references.pmid: 9517597
references.citation: Eur Respir J. 2005 Aug;26(2):319-38
references.pmid: 16055882
references.citation: Respir Med. 2011 Jul;105(7):1046-53
references.pmid: 21367591
references.citation: PLoS One. 2012;7(5):e37483
references.pmid: 22624038
references.citation: N Engl J Med. 2004 Mar 4;350(10):1005-12
references.pmid: 14999112
references.citation: Respirology. 2010 Apr;15(3):478-84
references.pmid: 20210891
references.citation: Am J Respir Crit Care Med. 2012 Nov 15;186(10):982-8
references.pmid: 22983959
references.citation: Am J Respir Crit Care Med. 2012 May 15;185(10):1065-72
references.pmid: 22427534
references.citation: Respir Res. 2005 Mar 01;6:22
references.pmid: 15740629
references.citation: Lancet. 2004 Aug 21-27;364(9435):709-21
references.pmid: 15325838
references.citation: Respir Res. 2005 Apr 25;6:38
references.pmid: 15850494
references.citation: J Bras Pneumol. 2007 Jul-Aug;33(4):397-406
references.pmid: 17982531