title: The interleukin-6 -174 promoter polymorphism is associated with extrapulmonary bacterial dissemination in Streptococcus pneumoniae infection.
abstract: Interleukin-6 (IL-6) is required for the clearance of bacteria in pneumococcal pneumonia. The abundance of endogenous IL-6 production on infectious stimuli is associated with genotypic differences in the -174 promoter region of IL-6 (-174 G-->C), showing increased IL-6 levels in patients carrying the GG genotype. One hundred patients with culturally proven pneumococcal disease were analyzed for distribution of the G-/C-alleles in the IL-6 -174 promoter region in comparison to 50 age-matched controls. Extrapulmonary pneumococcal dissemination, including septic metastasis, endocardial and meningeal infection, was used as parameter for impaired clearance of the bacteria. No significant differences in the allele distribution were observed between patients and controls. Within the patient group, the interleukin-6 GG homozygous carriers were less likely to develop extrapulmonary pneumococcal infection (10.3% versus 30.9%; OR 0.26, 95% CI 0.07-0.94, p=0.04). The IL-6 GG genotype, encoding for enhanced IL-6 secretion on bacterial stimuli, reduces the risk of bacterial spread to extrapulmonary sites in pneumococcal infection, possibly due to a more effective clearance of the pathogen from the blood and the respiratory tract.
authors: III. Department of Medicine, University of Lübeck, Ratzeburger Allee 160, 23538 Lübeck, Germany. schaff@uni-luebeck.de
authors: Bernhard
authors: B
authors: Schaaf
authors: Jan
authors: J
authors: Rupp
authors: Michael
authors: M
authors: Müller-Steinhardt
authors: Jan
authors: J
authors: Kruse
authors: Florian
authors: F
authors: Boehmke
authors: Matthias
authors: M
authors: Maass
authors: Peter
authors: P
authors: Zabel
authors: Klaus
authors: K
authors: Dalhoff
mesh_terms: D005838:Genotype; D006801:Humans; D015850:Interleukin-6 / Q000235:genetics*; D011110:Polymorphism, Genetic; D011401:Promoter Regions, Genetic; D013290:Streptococcal Infections / Q000235:genetics* / Q000382:microbiology; D013296:Streptococcus pneumoniae / Q000472:pathogenicity*
chemical_list: D015850:Interleukin-6