Abstract

BK virus (BKV)-associated nephropathy (BKVN) is a complication that can lead to graft loss after kidney transplantation. The primary approach to this disease is reduction of immunosuppressive therapy; however, some cases are non-responsive to this strategy. This case report presents a patient with BKVN that was non-responsive to immunosuppressive reduction and was treated with intravenous immunoglobulin (IVIG). A 62-year-old male patient with a history of kidney transplantation from a living donor 2 years earlier presented with deterioration of renal function. High BKV loads were detected, and the diagnosis of BKVN was confirmed by renal biopsy. Despite discontinuation of mycophenolate mofetil, the viral load continued to increase, and graft function continued to deteriorate. Subsequently, the patient was treated with IVIG. BKV levels in plasma and urine decreased, but renal function showed only minimal improvement. This case highlights the effectiveness of IVIG in resistant BKVN and underscores the role of proactive screening methods in preventing graft rejection.