title: The interleukin-6 -147 g/c polymorphism is associated with increased risk of coronary artery disease in young South African Indian men.
abstract: BACKGROUND
  Interleukin-6 (IL-6) is a proinflammatory cytokine involved in the pathogenesis of chronic inflammatory diseases such as coronary artery disease (CAD). The -174 IL-6 G/C promoter polymorphism influences mRNA levels and protein expression and is implicated in CAD. The Indian population in South Africa, unlike the black community, has a high prevalence of premature CAD. This polymorphism has not been fully explored in this population. The present study assessed the -174 IL-6 G/C polymorphism in young Indian patients with angiographically documented CAD and compared them with age- and gender-matched Indian and black control subjects.
  
  
  METHODS
  Polymorphic variants were assessed by polymerase chain reaction-restriction fragment length polymorphism, and IL-6 levels were measured using enzyme-linked immunosorbent assay (ELISA).
  
  
  RESULTS
  The -174 IL-6 C allele was found with a higher frequency (23%) in the total Indian group compared to 2% in the black participants [P<0.0001, odds ratio (OR)=0.05, 95% confidence interval (CI) 0.018-0.14). The difference in frequency was more pronounced when Indian controls were compared to black controls (29% vs. 2%, respectively) (P<0.0001, OR=0.05, 95% CI 0.02-0.17). A significant association between the -174 IL-6 G allele and CAD was found in Indian patients compared to Indian controls (84% in cases vs. 71% in Indian controls; P=0.043, OR=0.47 95% CI 0.23-0.95). Levels of IL-6 in circulation were higher in black controls (6.62±0.63 pg/mL) compared to Indian controls (2.51±0.57 pg/mL) and CAD patients (1.46±0.36 pg/mL) (P<0.0001). Levels of IL-6 were higher in all groups with homozygous -174 IL-6 C alleles, but only significant in the healthy Indian control group (GG 3.73±0.94 pg/mL vs. GC/CC 0.89±0.5 pg/mL, P=0.0001).
  
  
  CONCLUSIONS
  The presence of the IL-6 -174 G allele influences levels of IL-6 and increases the risk of CAD in South African Indians.
authors: Department of Medical Biochemistry and Chemical Pathology, Nelson R. Mandela School of Medicine, University of KwaZulu-Natal, Congella, Durban, South Africa.
authors: Alisa
authors: A
authors: Phulukdaree
authors: Sajidah
authors: S
authors: Khan
authors: Prithiksha
authors: P
authors: Ramkaran
authors: Rishalan
authors: R
authors: Govender
authors: Devapregasan
authors: D
authors: Moodley
authors: Anil A
authors: AA
authors: Chuturgoon
mesh_terms: D000328:Adult; D017668:Age of Onset; D044383:Black People / Q000208:ethnology / Q000235:genetics; D016022:Case-Control Studies; D003324:Coronary Artery Disease / Q000208:ethnology* / Q000235:genetics*; D056726:Genetic Association Studies; D020022:Genetic Predisposition to Disease; D006801:Humans; D015850:Interleukin-6 / Q000235:genetics*; D008297:Male; D008875:Middle Aged; D012150:Polymorphism, Restriction Fragment Length / Q000502:physiology; D020641:Polymorphism, Single Nucleotide; D015995:Prevalence; D011401:Promoter Regions, Genetic / Q000235:genetics; D012307:Risk Factors; D013019:South Africa / Q000453:epidemiology; D055815:Young Adult
chemical_list: D015850:Interleukin-6