Abstract
Background
Scrub typhus is caused by Orientia tsutsugamushi and can become severe and potentially life-threatening. It is suggested that specific host factors can modify the host response during O. tsutsugamushi infection. It is known that susceptibility and outcome of infectious disease are associated with genetic polymorphisms of some cytokines.
Materials and Methods
Peripheral blood of 144 patients who were diagnosed with scrub typhus and of 311 unrelated healthy subjects were collected. A diagnosis of scrub typhus was made upon demonstration of a fourfold rise in antibody titer to O. tsutsugamushi in paired serum specimens in an indirect immunofluorescent (IFA) test. Genomic DNAs were extracted from peripheral mononuclear cells and genotypings for IL-1 (-511C/T), IL-1β (+3953T/C), IL-2 (-330T/G), IL-4 (-590C/T), IL-4R(-1902G/A), IL-10 (-1082G/A), IL-10 (-819C/T), TNF-α (-238G/A) and TNF-α (-308G/A) were performed simultaneously using PCR-SSP (sequence specific polymorphisms) assay.
Results
The frequency of IL-1 (-511T/T) (OR=0.53, P<0.01) and IL-2 (-330T/T) (OR=0.56, P<0.01) were significantly decreased, but that of IL-2(-330G/G) (OR=4.49, P<0.01) was increased, in the scrub typhus patients compared to the healthy controls. And, there were no statistically significant differences in the genetic polymorphisms of IL-4 (-590C/T), IL-4Rα (-1902G/A), IL-10 (-1082G/A), IL-10 (-819C/T), TNF-α (-238G/A), TNF-α (-308G/A) genes, in the scrub typhus patients compared to the unrelated healthy controls.
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