BK nephropathy in the native kidneys of patients with organ transplants: Clinical spectrum of BK infection

Abstract

Nephropathy secondary to BK virus, a member of the Papoviridae family of viruses, has been recognized for some time as an important cause of allograft dysfunction in renal transplant recipients. In recent times, BK nephropathy (BKN) of the native kidneys has being increasingly recognized as a cause of chronic kidney disease in patients with solid organ transplants, bone marrow transplants and in patients with other clinical entities associated with immunosuppression. In such patients renal dysfunction is often attributed to other factors including nephrotoxicity of medications used to prevent rejection of the transplanted organs. Renal biopsy is required for the diagnosis of BKN. Quantitation of the BK viral load in blood and urine are surrogate diagnostic methods. The treatment of BKN is based on reduction of the immunosuppressive medications. Several compounds have shown antiviral activity, but have not consistently shown to have beneficial effects in BKN. In addition to BKN, BK viral infection can cause severe urinary bladder cystitis, ureteritis and urinary tract obstruction as well as manifestations in other organ systems including the central nervous system, the respiratory system, the gastrointestinal system and the hematopoietic system. BK viral infection has also been implicated in tumorigenesis. The spectrum of clinical manifestations from BK infection and infection from other members of the Papoviridae family is widening. Prevention and treatment of BK infection and infections from other Papovaviruses are subjects of intense research.

Keywords: BK viral infection, BK nephropathy, Cardiac transplant, Bone marrow transplant, Liver transplant, Pancreatic transplant, Lung transplant

Core tip: BK virus (BKV) is a member of a family of viruses that cause various diseases in animals and humans. Severe disease in transplanted kidneys was the first recognized human disease caused by BKV. In more recent times, BKV was also recognized as a cause of disease in the native kidneys of patients who had received bone marrow, heart, lung, liver and pancreas transplants, as well as in the kidneys of patients with loss of resistance to infection, such as patients with acquired immune deficiency syndrome or patients treated for malignant tumors. In addition to disease of the kidneys, BKV has also caused severe disease of the urinary bladder, the brain, the lungs, the gut and the blood. The diagnosis and particularly the management of infection by BKV present difficulties. Research for new medications specific for treating this infection is imperative.