Cyclosporine A is a cyclic peptide that is naturally obtained from the fungus Beauveria nivea [191]. It is immunosuppressant and calcineurin inhibitor that inhibits T cell activation [192]. It binds to the intracellular receptor cyclophilin-1 producing a cyclosporine-cyclophilin complex. This complex subsequently inhibits calcineurin, which stops the activation of the nuclear factor of activated T cells (NF-AT) that normally causes inflammatory reactions. The inhibition of NF-AT also leads to lower levels of other factors associated with T helper cell function and thymocyte development. Cyclosporine was first approved by the U.S. FDA in 1983 and is orally, parenterally, or topically used to prevent organ transplant rejection, treat/prevent graft-versus-host disease, and treat various inflammatory and autoimmune conditions such as severe rheumatoid arthritis and psoriasis [191,192,193,194,195].