The control of IL-5 protein production takes place at the level of transcription.[14] IL-10 is a potent anti-inflammatory cytokine that inhibits the synthesis of many inflammatory proteins, including cytokines (TNF-α, granulocyte macrophage colony stimulating factor, IL-5, chemokines) and inflammatory enzymes (inducible nitric oxide synthase) that are over-expressed in asthma.[15] In addition, IL-10 inhibits antigen presentation and sensitisation. This evidence concerns the gene NOS2 and asthma.