The interferon gamma gene polymorphism+874 A/T is associated with severe acute respiratory syndrome

Background: Cytokines play important roles in antiviral action. We examined whether polymorphisms of IFN-gamma, TNF-alpha and IL-10 affect the susceptibility to and outcome of severe acute respiratory syndrome (SARS). Methods: A case-control study was carried out in 476 Chinese SARS patients and 449 healthy controls. We tested the polymorphisms of IFN-gamma, TNF-alpha and IL-10 for their associations with SARS. Results: IFN-gamma + 874A allele was associated with susceptibility to SARS in a dose-dependent manner ( P < 0.001). Individuals with IFN-gamma + 874 AA and AT genotype had a 5.19- fold (95% Confidence Interval [CI], 2.78-9.68) and 2.57-fold ( 95% CI, 1.35-4.88) increased risk of developing SARS respectively. The polymorphisms of IL- 10 and TNF-alpha were not associated with SARS susceptibility. Conclusion: IFN-gamma + 874A allele was shown to be a risk factor in SARS susceptibility.