Cyclosporin A, commonly known as cyclosporine or CsA, is a medication used primarily in organ transplant recipients to prevent the rejection of transplanted organs. It is an immunosuppressive drug that works by suppressing the activity of the immune system, specifically T cells, which are responsible for mounting an immune response against foreign substances or transplanted organs.
Cyclosporin A is commonly used in cases of kidney, liver, heart, lung, and pancreas transplants, as well as in some autoimmune diseases like rheumatoid arthritis and psoriasis. By dampening the immune system response and inhibiting the production of certain cytokines, it helps to prevent the destruction of transplanted organs or the progression of certain autoimmune disorders.