Localization of calcineurin/NFAT in human skin and psoriasis and inhibition of calcineurin/NFAT activation in human keratinocytes by cyclosporin A.

Systemic cyclosporin A and tacrolimus are effective treatments for psoriasis. Cyclosporin A and tacrolimus block T cell activation by inhibiting the phosphatase calcineurin and preventing translocation from the cytoplasm to the nucleus of the transcription factor nuclear factor of activated T cells (NFAT). Inhibition of T cell activation is thought to account for their therapeutic action in psoriasis.