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Abstract
Background: BK virus is an increasingly recognized pathogen in transplant recipient patients associated with nephropathy and emerged as a cause of allograft failure linked to immunosuppressive regimens in renal transplant recipients. This study develops a sensitive PCR method to detect the viremia and viruria as well as the incidence of BK virus infection in renal transplant recipients.
Methods: A nested PCR method was developed and a total of 45 paired serum and urine samples from renal transplant recipient patients were collected and tested with the developed assay.
Results: The threshold of the developed detection assay was 10 copies/µl of BKV DNA in samples. Our results also indicated that about 40% of the urine and 26.7% of serum samples were positive for BKV in renal transplant patients in this study.
Conclusion: This Nested-PCR method was found a specific, sensitive and simple procedure for detection of viruria and viremia of BK virus in renal transplant recipients.
Keywords: BK virus; Renal transplant recipients; Prevalence; Iran
Introduction
BK virus (BKV) was described in 1971.1 BKV is a non-enveloped icosahedral deoxyribonucleic acid (DNA) virus and represents a discrete species within the genus Polyoma virus of the family of Polyomaviridae. 2 Different studies have estimated that about 80% of the adult population worldwide are sero-positive for BKV with the exception of some segregated populations in South American and Southeast Asia.3 Rates of BKV sero-positivity are significantly related to age, and sero-prevalence was shown to reach 91% at 5 to 9 years of age.3,4 The BK virus is acquired during childhood, through the respiratory or gastrointestinal route.5 The primary infections are trivial and resolve with the development of specific humoral and cellular immunities. After the primary infection, BKV has the tendency to remain latent in the reno-urinary epithelium.4,6
In the past decade, this virus has been recognized as an increasingly important cause of renal allograft dysfunction particularly in renal transplant recipients. 7-9 The relatively recent recognition of this condition probably reflects an increase in reactivation of latent BK virus infection as a consequence of the use of newer and more potent immunosuppressive agents such as tacrolimus or mycophenolate mofetil (MMF).10,11 Most cases of BKV nephropathy "BKVN" have been diagnosed about 40 weeks posttransplantation. 8 Over the last few years...