Prevalence of BK virus in renal allograft recipients pre and post transplantation in Iran

BK virus, a member of polyomaviridae, infects humans asymptomatically in their early infancy and remains latent in the kidney and urinary tract cells. Reactivation of BK virus in renal-transplanted patients occurs frequently and sometimes leads to nephropathy and rejection of grafted organ. In this study, prevalence of this virus in renal allograft recipients is discussed before and after transplantation. This cross-sectional study performed on 78 renal recipient cases. Blood and urine samples of patients were collected three times; before graft, one month following operation and four months after receiving the graft. All the patients were taking similar drug regimen. The extracted DNA of the samples was investigated by double PCR and semi-nested-PCR. PCR results were analyzed by SPSS software version 11.5 and Mac Nemar test. Out of 78 samples collected from kidney transplanted cases, five urine specimens (6.4%) were positive for BK virus, 10 urine samples (12.8%) turned out as positive for this virus one month after operation and 30 of urine specimens (38.5%) became positive for BK virus four months post-transplantation. Of 78 plasma samples of the same cases, none of them was positive for BK virus before transplantation. One plasma specimen (1.3%) turned out as positive for BK virus and 16 plasma samples (20.5%) were positive for this virus four months after grafted kidney. The difference between the results of the urine samples collected before and four months after kidney transplantation from the patients, was statistically significant (P<0.05). Based on the gleaned data it is concluded that BK virus infection increased in a considerable fraction of kidney transplant patients. Therefore, investigation for reactivation of BK virus is recommended in these patients after kidney graft.