IL12A is a gene on chromosome 3, which encodes a subunit of cytokines, acts on T cells and natural killer cells, and has a wide range of biological activities. IL12A cytokine is a disulfide-linked heterodimer composed of the 35 kD subunit encoded by this gene and the 40 kD subunit of the cytokine receptor family member. This cytokine is necessary for T cells to independently induce interferon (IFN) -γ and is important for the differentiation of Th1 and Th2 cells. The response of lymphocytes to this cytokine is mediated by the transcriptional activation protein STAT4. Nitric oxide synthase 2A (NOS2A / NOS 2) is necessary for the signaling process of this cytokine in innate immunity.