特異性:FK-506 This item detects FK-506, a macrolide with similar but more potent immunosuppressant activity than cyclosporine. It is a 23-membered lactone produced by the bacteria Streptomyces tsukubaensis . FK-506 inhibits signal transduction and interleukin-2 transcription in CD4+ T helper lymphocytes, and is mainly used after allogenic organ transplantation to reduce organ rejection. Side effects of FK-506 treatment include nephrotoxicity, neurotoxicity, diabetes mellitus and hypertension.