In this study, investigators evaluated whether polymorphisms in the genes involved in host defense are associated with the severity of local infection-inflammation in humans. They used acute appendicitis as a model.
The team studied 134 patients with acute appendicitis treated at an urban hospital.
They looked for associations between the severity of appendicitis, plasma and peritoneal cytokine concentrations, and single nucleotide polymorphisms in genes involved in recognizing bacterial molecules (CD14, TLR4) and in mounting an inflammatory response (IL-6, TNF-alpha, IL-1 beta).
The investigators found that 68% of patients had uncomplicated appendicitis, while 32% had complicated disease.
The team determined that the single nucleotide polymorphisms in the CD14, TLR4, IL-1 beta, and TNF-alpha genes were not associated with the severity of appendicitis.
However, a strong association was found between C-allele carriage at -174 in the IL-6 gene and decreased risk of complicated disease (adjusted odds ratio = 0.24).
The team found evidence to suggest that this polymorphism contributes to decreased IL-6 production in vivo.
Dr Fernando Rivera-Chavez and colleagues concluded, "Polymorphism in the IL-6 gene was associated with the severity of appendicitis, even after adjustment for duration of symptoms".
"The risk for developing appendiceal perforation or gangrene may be determined, in part, by variation in the IL-6 gene".