Source and Relevance of the BK Polyomavirus Genotype for Infection After Kidney Transplantation.

BACKGROUND: BK polyomavirus (BKPyV)-associated nephropathy (BKPyVAN) is a major threat for kidney transplant recipients (KTRs). The role of specific BKPyV genotypes/serotypes in development of BKPyVAN is poorly understood. Pretransplantation serotyping of kidney donors and recipients and posttransplantation genotyping of viremic recipients, could reveal the clinical relevance of specific BKPyV variants. METHODS: A retrospective cohort of 386 living kidney donor-recipient pairs was serotyped before transplantation against BKPyV genotype I-IV viral capsid protein 1 antigen, using a novel BKPyV serotyping assay. Replicating BKPyV isolates in viremic KTRs after transplantation were genotyped using real-time polymerase chain reaction and confirmed by means of sequencing. BKPyV serotype and genotype data were used to determine the source of infection and analyze the risk of viremia and BKPyVAN. RESULTS: Donor and recipient BKPyV genotype and serotype distribution was dominated by genotype I (>80%), especially Ib, over II, III and IV. Donor serotype was significantly correlated with the replicating genotype in viremic KTRs (P < .001). Individual donor and recipient serotype, serotype (mis)matching and the recipient replicating BKPyV genotype were not associated with development of viremia or BKPyVAN after transplantation. CONCLUSIONS: BKPyV donor and recipient serotyping and genotyping indicates the donor origin of replicating BKPyV in viremic KTRs but provides no evidence for BKPyV genotype-specific virulence.

Pretransplantation Donor-Recipient Pair Seroreactivity Against BK Polyomavirus Predicts Viremia and Nephropathy After Kidney Transplantation.

Kidney transplant donors are not currently implicated in predicting BK polyomavirus (BKPyV) infection in kidney transplant recipients. It has been postulated, however, that BKPyV infection originates from the kidney allograft. Because BKPyV seroreactivity correlates with BKPyV replication and thus might mirror the infectious load, we investigated whether BKPyV seroreactivity of the donor predicts viremia and BKPyV-associated nephropathy (BKPyVAN) in the recipient. In a retrospective cohort of 407 living kidney donor-recipient pairs, pretransplantation donor and recipient sera were tested for BKPyV IgG levels and correlated with the occurrence of recipient BKPyV viremia and BKPyVAN within 1 year after transplantation. Donor BKPyV IgG level was strongly associated with BKPyV viremia and BKPyVAN (p < 0.001), whereas recipient BKPyV seroreactivity showed a nonsignificant inverse trend. Pairing of high-BKPyV-seroreactive donors with low-seroreactive recipients resulted in a 10-fold increased risk of BKPyV viremia (hazard ratio 10.1, 95% CI 3.5-29.0, p < 0.001). In multivariate analysis, donor BKPyV seroreactivity was the strongest pretransplantation factor associated with viremia (p < 0.001) and BKPyVAN (p = 0.007). The proportional relationship between donor BKPyV seroreactivity and recipient infection suggests that donor BKPyV seroreactivity reflects the infectious load of the kidney allograft and calls for the use of pretransplantation BKPyV serological testing of (potential) donors and recipients.

Viral loads and antiviral resistance of herpesviruses and oral ulcerations in hematopoietic stem cell transplant recipients.

Ulcerative oral mucositis and infection are frequent complications in hematopoietic stem cell transplant (HSCT) recipients. The aim of this study was to investigate the relationship between oral ulcerations and HSV-1, EBV and CMV excretion and the presence of aciclovir-resistant HSV-1 strains in HSCT recipients. This prospective observational study included 49 adult patients who underwent allogeneic HSCT. In total, 26 patients received myeloablative and 23 received non-myeloablative conditioning. Ulcerations on non-keratinized and keratinized oral mucosa were scored and oral rinsing samples were taken twice weekly. Viral loads were determined by real-time PCR. Samples from patients remaining HSV-1 positive despite antiviral treatment were studied for resistance to antivirals. Having an HSV-1 or EBV DNA-positive sample was a significant predictor for ulceration of keratinized mucosa. HSV-1 was a significant predictor for ulcerations on non-keratinized mucosa as well. Persistent HSV-1 infection occurred in 12 of 28 patients treated with antiviral medication and aciclovir-resistant HSV-1 was found in 5 persistent infections. In conclusion, HSV-1 is a predictor of ulcerations on non-keratinized as well as keratinized oral mucosa following HSCT. The role of EBV deserves further study. Persistent HSV-1 replication despite antiviral treatment is common and is due to resistance in 18% of treated patients.

Adenovirus infection in children after allogeneic stem cell transplantation: diagnosis, treatment and immunity.

Human adenoviruses (HAdV) are a frequent cause of potentially fatal infections in patients after allogeneic stem cell transplantation, especially in children. Monitoring of serum/plasma by real-time quantitative PCR is a sensitive tool for the recognition of patients at risk of a potentially fatal infection and for the evaluation of the efficacy of treatment. Data from a retrospective study and from a prospective study demonstrate that recovery of immunity after transplantation is essential for the elimination of HAdV infection. The feasibility of several approaches for the manipulation of immunity in the immunocompromised host to prevent a fatal course of the infection is discussed.