title: Linkage disequilibrium between tumor necrosis factor (TNF)-alpha-308 G/A promoter and TNF-beta NcoI polymorphisms: Association with TNF-alpha response of granulocytes to endotoxin stimulation.
abstract: OBJECTIVE
  Controversial data have been reported on the association between the tumor necrosis factor (TNF)-alpha-308 G[U279C]A promoter polymorphism or the TNF-alpha I polymorphism with TNF-alpha plasma concentrations. The purpose of this study was to evaluate whether there is a linkage disequilibrium between the two polymorphisms. Moreover, the influence of these polymorphisms on the TNF-alpha synthesis of activated granulocytes was studied.
  
  
  METHODS
  Analysis of TNF-alpha concentrations of human whole blood after endotoxin stimulation.
  
  
  METHODS
  Medical research laboratory.
  
  
  METHODS
  Healthy human volunteers.
  
  
  METHODS
  None.
  
  
  RESULTS
  Healthy human volunteers were genotyped for both TNF polymorphisms by means of polymerase chain reaction. TNF-alpha plasma concentrations were determined with chemiluminescence after incubation of whole blood with endotoxin. A strong (p <.0001) linkage disequilibrium was found for the TNF-beta I and the TNF-alpha-308 genetic polymorphisms. Almost all individuals homozygous for the TNF-B2 allele of the TNF-beta I polymorphism were also TNF-alpha-308 G homozygotes. Carriers of the TNF-alpha-308 genotype AG had a significantly higher TNF-alpha production capacity than G homozygotes. The TNF-beta I genotype TNF-B1/TNF-B2 was associated with significantly higher TNF-alpha concentrations than the genotype TNF-B2/TNF-B2. Individuals homozygous for the TNF-B2 and the TNF-alpha-308 G alleles had a significantly reduced TNF-alpha response compared with individuals heterozygous for both TNF polymorphisms.
  
  
  CONCLUSIONS
  A linkage disequilibrium between the two TNF polymorphisms was found. This study revealed a significant association between genotype and phenotype for both TNF polymorphisms. Heterozygosity for both TNF polymorphisms is associated with an increased TNF-alpha response.
authors.affiliation: Department of Anesthesia, Academic Medical Center, University of Amsterdam, The Netherlands.
authors.forename: Michael
authors.initials: M
authors.lastname: Heesen
authors.forename: Dagmar
authors.initials: D
authors.lastname: Kunz
authors.forename: Bernd
authors.initials: B
authors.lastname: Bachmann-Mennenga
authors.forename: Hans F
authors.initials: HF
authors.lastname: Merk
authors.forename: Brunhilde
authors.initials: B
authors.lastname: Bloemeke
mesh_terms: D006098:Granulocytes / Q000378:metabolism; D006801:Humans; D066298:In Vitro Techniques; D016013:Likelihood Functions; D015810:Linkage Disequilibrium; D008070:Lipopolysaccharides; D008233:Lymphotoxin-alpha / Q000235:genetics*; D011110:Polymorphism, Genetic; D011401:Promoter Regions, Genetic / Q000235:genetics; D012772:Shock, Septic / Q000235:genetics* / Q000378:metabolism; D018709:Statistics, Nonparametric; D014409:Tumor Necrosis Factor-alpha / Q000096:biosynthesis / Q000235:genetics*
chemical_list: D008070:Lipopolysaccharides; D008233:Lymphotoxin-alpha; D014409:Tumor Necrosis Factor-alpha