In addition, Shirakawa et al. found that positive tuberculin responses were associated with a lower prevalence of asthma, a lower total IgE titre, lower Th2 cytokine (i.e. IL-4, IL-10 and IL-13) levels and a higher Th1 cytokine (IFN-γ) level in Japanese school children [27]. This evidence concerns the gene IFNG and asthma.