Cyclosporin A is a hydrophobic cyclic peptide isolated from several fungal species including Cylindrocarpon, Fusarium, Trichoderma and Tolypocladium. Cyclosporin A inhibits T-cell activation and has been marketed since 1983 as an immunosuppressant in post-allogeneic organ transplant. Cyclosporin A acts by binding to the protein, cyclophilin (immunophilin), in T-lymphocytes causing inhibition of calcineurin (protein phosphatase 2B). Cyclosporin A reduces transcription of interleukin 2, and inhibits lymphokine production, interleukin release and NO synthesis induced by interleukin 1α, lipopolysaccharides and TNFα.