Chiang et al. demonstrated significantly lower ratios of IFN-γ/IL-4, IFN-γ/IL-10, IL-2/IL-4, and TNF-α/IL-4 in patients with schizophrenia compared to healthy controls, suggesting that Th2 predominance may constitute a distinct immunological feature of schizophrenia [32]. This evidence concerns the gene IL4 and schizophrenia.