 The overall goal of this study is to rapidly improve clearance of BK viremia with Immunoglobulin Privigen thereby decreasing the potential for formation of alloantibodies in renal transplant recipients that have had immunosuppression reduction due to BK viremia. Our approach is to perform a prospective, randomized, placebo controlled trial intravenous immune globulin IVIg; Privigen plus protocolized immunosuppression reduction versus placebo and protocolized immunosuppression reduction in patients with BK viremia post-kidney transplantation. 