IFNG and viral infectious disease: During viral infections, the expression pattern of cytokines is changed and IL-12 and IFN-γ are increased.[13] Studies showed that polymorphisms in specific regions of these cytokines also influence the expression pattern of cytokines.[14] For example, the +1188 polymorphism of P40 subunit of IL-12 gene is believed to be involved in regulation of IL-12 expression.[10] It is not clear which mechanisms are being affected in OBI patients that make them unable to completely recover from viral infections.