Monitoring subtypes of the human polyomavirus BK in Iranian adult kidney transplant patients

BK virus (BKV) is a polyomavirus with seroprevalence in adults, ranging from 60 to 100%. It is considered as usual cause of renal dysfunction after the allograft renal transplantation nephropathy. Potent immunosuppressive therapy in kidney transplantation can lower the rate of acute rejection. Therefore, untreated BKV infections lead to kidney allograft dysfunction or loss. In order to estimate the difference, this study investigated the BKV in urine samples of kidney transplant patients. In this study, we used 220 urine samples from allograft recipients in the time period of 2010-2013. Then, the 287 bp typing region and the PCR increased from the urinary DNA. The PCR products were digested by three limitation enzymes, namely AluI, Cfr13I and RsaI to determine the BKV subtypes. The BKV subtypes are common in the city of Esfahan, Iran. This research showed that 102 (75%) samples were infected by BKV type I. 7 (5%) and BKV subtypes II, 5 (4%) III, and 22 (16%) IV were found in our patients. On the other hand, mixed infections did not clear in the recipients. Our findings showed that BKV replication might occur after kidney transplantation and through the early hours. BKV types II, III and IV are brand new in Iran and previously were not apparent in samples of urine in different kidney transplant patients.