BackgroundBK polyomavirus-associated nephropathy is an important cause of post-transplantation renal failure. We present two cases of BK polyomavirus-associated nephropathy who were submitted to contrasting strategies of clinical follow-up to BK polyomavirus reactivation, but progressed to a similar final outcome.Case presentationCase 1 is a 37-year-old white man whose graft had never presented a good glomerular filtration rate function, with episodes of tacrolimus nephrotoxicity, and no urinary monitoring for BK polyomavirus; stage B BK polyomavirus-associated nephropathy was diagnosed by biopsy at 14 months post-transplant. Despite clinical treatment (dosage decrease and immunosuppressive drug change), he progressed to stage C BK polyomavirus-associated nephropathy and loss of graft function 30 months post-transplant. Case 2 is a 49-year-old mulatto man in his second renal transplantation who was submitted to cytological urinary monitoring for BK polyomavirus; he presented early, persistent, and massive urinary decoy cell shedding and concomitant tacrolimus nephrotoxicity. Even with decreasing immunosuppression, he developed BK polyomavirus-associated nephropathy 1-year post-transplant. Loss of graft function occurred 15 months post-transplant.ConclusionsCytological urinary monitoring was an efficient strategy for monitoring BK virus reactivation. Decoy cell shedding may be related to BK polyomavirus-associated nephropathy when extensive and persistent. The presence of associated tacrolimus nephrotoxicity may be a confounding factor for the clinical diagnosis of BK polyomavirus-associated nephropathy.

SUMMARYThe aim of this study was to investigate the association of EBV and HPV with gingivitis and/or periodontitis according to the immunologic status. To this end, 74 oral biopsies from transplanted and non-transplanted individuals with the abovementioned oral manifestations were submitted to a screening by PCR for both viruses. According to the results, EBV was strongly associated with gingivitis and/or periodontitis in transplanted individuals (p = 0.011) but not HPV (p = 0.766). EBV-HPV co-detections did not enhance the presence of tissue injury as well. Although a causal relationship was not investigated in this study, the higher frequency of these two oncoviruses in lesion tissues must be investigated in follow-up studies, especially among immunocompromised individuals.

BKV and JCV belong to the Polyomaviridae family and are opportunistic agents associated with complications in immunocompromised individuals. Although a single screening assay for both viruses would be convenient, the diversity of BKV and JCV serotypes and genotypes is a methodological challenge. In this paper, we developed a PCR method able to detect and segregate BKV and JCV, despite these genetic discrepancies. A duplex semi-nested PCR (duplex snPCR) was designed to target a conserved region (639nt-1516nt) within the VP2 gene. In the first PCR, a primer set common to all BKV and JCV serotypes/ genotypes was used, followed by a semi-nested PCR with internal primers for BKV and JCV segregation. The limit of detection of the duplex snPCR was as low as 10 copies of BKV or JCV plasmids/μL. Specific products were observed when JCV and BKV plasmids were mixed in the same reaction. In field sample testing, the duplex snPCR detected and distinguished both viruses in different biological samples. Results were confirmed by Sanger's sequencing. The geographical complexity of BKV and JCV serotypes and genotypes imposes limits to a simple and universal method that could detect each virus. However, we describe here a sensitive and reliable PCR technique for BKV and JCV diagnosis that overcomes these limitations and could be universally applied.

The increased risk for opportunistic infections after a renal transplant requires monitoring of viral infections to avoid future complications. Our goal was to investigate the impact and factors associated with Epstein-Barr virus (EBV), human cytomegalovirus (HCMV) and human herpesvirus type 6 (HHV-6) viremia in renal transplant recipients. Whole blood samples were collected monthly from 82 patients during the first semester and then quarterly up to 1 year after transplantation. EBV, HCMV, and HHV-6 were detected and quantified by TaqMan real-time polymerase chain reaction. The results showed that EBV and HCMV viremia were detected in 32 patients (39% each), while HHV-6 viremia in only 3 patients (3.7%). EBV was significantly associated with age (P = .050), thymoglobuline induction (P = .019), mTOR inhibitor-based therapy (P = .003), and female gender (P = .044). HCMV was significantly associated with basiliximab induction (P = .015), mycophenolate mofetil (MMF)-based therapy (P = .003) and allograft acute rejection (P = .033). Moreover, HCMV-disease was correlated with MMF-based therapy (P = .021) and female gender (P = .003). In conclusion, EBV and HCMV viremia were associated with different immunosuppressive induction and maintenance strategies. Additionally, higher HCMV viremia (> 10 4 copies/mL) was related to acute allograft rejection. K E Y W O R D SEpstein-Barr virus, human cytomegalovirus, human herpesvirus type 6, transplant