After receiving a kidney transplant, the body recognizes the donated kidney as a foreign invader and triggers the immune system to attack the kidney. This can lead to rejection of the new kidney and a failed transplant. To help reduce the risk of kidney rejection, transplant patients are given immunosuppressant drugs, which reduce the body's normal immune response and allow the transplanted organ to function. CsA or tacrolimus are two drugs that are often given to transplant patients. However, these are powerful drugs, and it can cause serious side effects and put a patient at increased risk for infections. SRL is a new drug that has been shown to reduce a transplant patient's chance of rejecting a new kidney, without serious side effects. This study is necessary to test the safety and effectiveness of SRL in children.