American Journal of Medical Sciences and Medicine, 2014, Vol. 2, No. 5, 85-88 Available online at http://pubs.sciepub.com/ajmsm/2/5/1 © Science and Education Publishing DOI:10.12691/ajmsm-2-5-1 BK Virus in Allogeneic and Autologous Bone Marrow Transplantation: Review Article Ilhami BERBER 1,* , Mehmet Ali ERKURT 1 , Funda YETKIN 2 , Irfan KUKU 1 , Emin KAYA 1 , Emin BODAKCI 3 , Mustafa KOROGLU 1 , Ilknur NIZAM 1 1 Department of Hematology, Bone Marrow Transplantation Unit, Faculty of Medicine, Inonu University, Malatya, Turkey 2 Department of Infection Disease, Faculty of Medicine, Inonu University, Malatya, Turkey 3 Department of Internal Medicine, Faculty of Medicine, Inonu University, Malatya, Turkey *Corresponding author: drilhamiberber@hotmail.com Received September 10, 2014; Revised September 17, 2014; Accepted September 21, 2014 Abstract The BK virus is a member of the polyomavirus family. When the immune system is compromised, as in patients undergoing chemotherapy after hematopoietic stem cell and solid organ transplantation, the virus is reactivated, leading to haemorrhagic cystitis. While the BK virus is one of the most common causes of morbidity and mortality in patients after allogeneic stem cell transplantation, it rarely occurs after autologous stem cell transplantation. The early diagnosis and treatment of viral cystitis may prevent significant morbidity and mortality associated with haemorrhagic cystitis caused by the BK virus. It is not entirely clear how the BK virus affects prognosis in patients undergoing allogeneic and autologous hematopoietic stem cell transplantation. Keywords: BK Virus, Allogeneic and Autologous Bone Marrow Transplantation Cite This Article: Ilhami BERBER, Mehmet Ali ERKURT, Funda YETKIN, Irfan KUKU, Emin KAYA, Emin BODAKCI, Mustafa KOROGLU, and Ilknur NIZAM, “BK Virus in Allogeneic and Autologous Bone Marrow Transplantation: Review Article.” American Journal of Medical Sciences and Medicine, vol. 2, no. 5 (2014): 85-88. doi: 10.12691/ajmsm-2-5-1. 1. Introduction The BK virus (BKV) was first isolated as a new human papovavirus from the urine of a renal transplant patient by Gardner et al. in 1971. Polyomavirus hominis 1 (genus Polyomaviridae), the BKV, is a non-encapsulated DNA virus that is highly prevalent in healthy adults, with up to 90% seropositivity. Past infection with the BKV is common, but significant consequences of the infection are uncommon. In contrast, the BKV frequently causes mortality and morbidity in immunocompromised and immunosuppressed patients, and it can also be identified in the non-transplant setting in patients with B-cell lymphoproliferative disorders [1]. The BKV is a well-known cause of graft dysfunction following renal transplantation and it has been reported in the native kidneys of other solid organ recipients. BKV infection has been connected with the development of haemorrhagic cystitis (HC) after allogeneic transplant; it occurs in up to 70% of hematopoietic stem cell transplant (HSCT) recipients and is associated with prolonged hospitalisation [2]. However, HC caused by BKV rarely occurs in autologous HSCT [3]. This virus can be diagnosed by a BKV blood test or a urine test for decoy cells. Polymerase chain reaction (PCR) techniques are often carried out to identify the virus [4]. The cornerstone of therapy is the reduction of immunosuppression. A recent surge in BKV nephropathy correlates with the use of potent immunosuppressant drugs [5]. Topical anaesthetics such as phenazopyridine, antispasmodic agents, and narcotic analgesics can use in treatment of HC [6,7]. Insertion of a large-bore three-way Foley’s urethral catheter to decompress the bladder and saline solution irrigation of the bladder is recommended for HC [8]. However, no drug is yet licensed for use in BKV infection. Other therapeutic options include cidofovir, leflunomide, intravenous immunoglobulin (IVIG), fluoroquinolones, hyperbaric oxygen, and cytotoxic T lymphocytes [9,10,11,12,13]. 2. Diagnosis and Treatment of BK Virus in Allogeneic and Autologous Bone Marrow Transplantation Many people who are infected with the BKV are asymptomatic, but in rare cases, it causes disease such as respiratory infection or fever, especially during early childhood. These are known as primary BK infections. After the first infection, polyomavirus can be latent in the kidneys, urothelium, and other organs, until the body undergoes some form of immunosuppression. In cases of immunosuppression, it persists for the life of the individual [14,15,16]. The BK virus is rarely seen in autologous HSCT compared to allogeneic HSCT. In a study of 132 patients in which 19% of the patients underwent autologous