Molecular characterization of BK polyomavirus subtypes in renal transplant recipients in Brazil

Abstract

BK polyomavirus (BKV) is highly prevalent in the world population. Different reports indicate that BKV subtypes and subgroups present an uneven geographical distribution which might be correlated with human migration. However, there is a lack of data on the BKV subtype distribution in the South American population. The occurrence of BKV subtypes and subgroups detected in 51 kidney transplant recipients in Rio de Janeiro, Brazil is described. According to genetic studies, the population in this region descends mainly from European or African immigrants, with a relatively low genetic background from the Amerindians. By sequencing the VP1 region of BKV, subgroups Ib1 and Ia of subtype I were found in 34 (67%) and 15 (29%), respectively, of samples, while subtype II was present in 2 (4%) of the samples. Subtypes III and IV were not detected. Phylogenetic analysis indicated similarities between Brazilian BKV subgroup Ia and East African lineages; and subgroup Ib-1 with Asian and North American lineages, while subtype II samples were similar to sequences from Japan and the UK. This is the first report that describes distribution of BKV subtypes in South America. The high prevalence of BKV subgroup Ia probably reflects the high proportion of African descendants in this population. On the other hand, the predominance of subgroup Ib-1 and the absence of Ib-2 in an area with a high proportion of European ancestry was unexpected. Further studies in South American populations are needed to provide a better understanding of the epidemiology of BKV in this region.

Molecular detection and characterization of BK and JC polyomaviruses in urine samples of renal transplant patients in Southern Brazil

“…These data support previous results on JCPyV genotyping obtained in other regions of the country [Fink et al, ; Fumian et al, ]. In addition, subtypes I and II of BKPyV were found in our study, corroborating the results shown by Zalona et al []; who found BKPyV subtypes I, II, and III in samples collected from Brazilian renal transplant patients.…”

Variable sources of Bk virus in renal allograft recipients

“…Also, four other pairs presented variable shedding throughout months, with virus similar to the donor's only at 1st month after the transplantation (pairs #6 and #13) or few months after transplantation (pairs #9 and 10). Unfortunately, the method used here for sequencing (Sanger) is not capable to detect minor variants.Therefore, we cannot exclude the possibility that both donor and recipient viruses could be present in particular time points as it would be expected in patients experiencing mixed infection through the time.Still, the data presented here challenge the accepted concept that the donor is the main source for the recipient infection since 60% of our donor-recipient pairs showed the opposite.Consistent with a previous study undertaken in Brazil where 96% of BKPyV from renal transplant recipients in Rio de Janeiro belonged to subtype I,19 all individuals analyzed here harbor BKPyV subtype Ia(except for the recipient #9). Also, the variability observed among the sequences was extremely low, as already observed by others when analyzing BKPyV from the same subtype.…”

“…Consistent with a previous study undertaken in Brazil where 96% of BKPyV from renal transplant recipients in Rio de Janeiro belonged to subtype I, all individuals analyzed here harbor BKPyV subtype Ia (except for the recipient #9). Also, the variability observed among the sequences was extremely low, as already observed by others when analyzing BKPyV from the same subtype .…”

A Qualitative Seminested PCR Assay as an Alternative to Urine Cytology for BK Polyomavirus Screening after Renal Transplantation

“…In a previous study designed to assess the prevalence of BKV subtypes among renal transplant recipients in Brazil, we developed a qualitative seminested PCR ( snPCR) assay to detect BKV in urine samples [11] . In the present report, we analyzed follow-up data to compare the accuracy of snPCR and urine cytology as an initial screening method to detect patients at risk of developing PVAN.…”

“…For snPCR, each urine sample was submitted to DNA extraction using a Wizard TM Genomic DNA Purification kit (Promega, Madison, Wisc., USA) according to the manufacturer's instructions. snPCR targeting a conserved region of BKV VP1 was performed as described previously [11] .…”