Preeti Zanwar

Detection of polyomavirus SV40 in tonsils from immunocompetent children.

BACKGROUND BK virus (BKV), JC virus (JCV) and simian virus 40 (SV40) are nonenveloped DNA viruses, members of the family Polyomaviridae. BK and JC viruses establish persistent infections in humans, and evidence suggests that SV40 can infect humans, as well. Whether persistence occurs in the lymphoid system is unknown. METHODS Paraffin-embedded tonsils from 220 immunocompetent children (mean age 9.3 years) were examined by polymerase chain reaction (PCR) to detect viral DNA of BKV, JCV, SV40, and Epstein-Barr virus (EBV). RESULTS Polyomavirus-specific DNA sequences were detected in 8.3% (29/351) of specimens collected from 220 children. Twenty-one (9.5%) children had polyomavirus DNA present in at least one tonsil, with sequences identified as SV40 (n=20) and BKV (n=1). Polyomavirus JCV was not detected. Among patients positive for SV40, 8 of 14 (57%) contained viral DNA in both available tonsils. EBV DNA was detected in 99 (28.2%) samples from 67 (30.5%) patients. Eleven samples (3.1%) from 8 (3.6%) children were positive for both polyomavirus and EBV. SV40-positive children were significantly older than the SV40-negative subjects (P<0.001). T-antigen expression was detected in an SV40 DNA-positive tonsil by immunohistochemistry. CONCLUSIONS These results suggest that SV40 can infect tonsils, that lymphoid tissue may represent a site for polyomavirus persistence, and that immunohistochemistry is not a useful detection assay when there are very few virus-infected cells in a tissue.

A prospective longitudinal study of polyomavirus shedding in lung-transplant recipients.

BACKGROUND Polyomavirus infection causes renal dysfunction after kidney transplantation, but it has not been thoroughly investigated in nonrenal solid-organ transplantation. METHODS Fifty lung-transplant recipients provided prospective urine and blood samples over the course of 17 months. Samples were analyzed for BK virus (BKV), JC virus (JCV), and simian virus 40 (SV40) using conventional polymerase chain reaction (PCR), sequence analysis, and quantitative real-time PCR. RESULTS Thirty-one (62%) of 50 patients had polyomavirus detected in at least 1 urine specimen, including 16 (32%) for BKV, 12 (24%) for JCV, and 6 (12%) for SV40. Mean BKV loads (5.0 log(10) copies/mL) did not differ from those of JCV (5.7 log(10) copies/mL; P=.38), but SV40 loads (2.5 log(10) copies/mL) were lower than those of BKV (P=.006) and JCV (P=.002). Blood samples were negative. Infection with individual polyomaviruses or polyomavirus infection in aggregate was not associated with reduced creatinine clearance. Patients not shedding polyomavirus had better survival than patients shedding polyomavirus (P=.049). CONCLUSIONS Polyomaviruses BKV and JCV were commonly detected in urine from lung-transplant recipients. SV40 was found in 12% of patients but was shed at a lower frequency and with lower viral loads than the other viruses. Polyomavirus infection was not associated with renal dysfunction.

Polyomavirus Infection and Its Impact on Renal Function and Long-Term Outcomes after Lung Transplantation

Background. Polyomavirus infection causes nephropathy after kidney transplantation but has not been thoroughly investigated in nonrenal organ transplantation. Methods. Ninety lung transplant recipients were enrolled, and they provided urine samples for over 4.5 years. Samples were analyzed for BK virus (BKV), JC virus (JCV), and simian virus 40 (SV40) by conventional and quantitative real-time polymerase chain reaction. Results. Fifty-nine (66%) patients had polyomavirus detected at least once, including 38 patients (42%) for BKV, 25 patients (28%) for JCV, and six patients (7%) for SV40. Frequency of virus shedding in serial urine samples by patients positive at least once varied significantly among viruses: JCV, 64%; BKV, 48%; and SV40, 14%. Urinary viral loads for BKV (105.4 copies/mL) and JCV (106.0 copies/mL) were higher than for SV40 (102.5 copies/mL; P=0.001 and 0.0003, respectively). Polyomavirus infection was associated with a pretransplant diagnosis of chronic obstructive pulmonary disease (odds ratio 6.0; P=0.016) but was less common in patients with a history of acute rejection (odds ratio 0.28; P=0.016). SV40 infection was associated with sirolimus-based immunosuppression (P=0.037). Reduced survival was noted for patients with BKV infection (P=0.03). Patients with polyomavirus infection did not have worse renal function than those without infection, but in patients with BKV infection, creatinine clearances were lower at times when viral shedding was detected (P=0.038). Conclusions. BKV and JCV were commonly detected in the urine of lung transplant recipients; SV40 was found at low frequency. No definite impact of polyomavirus infection on renal function was documented. BKV infection was associated with poorer survival.

Polyomavirus JC Urinary Shedding in Kidney and Liver Transplant Recipients Associated with Reduced Creatinine Clearance

BACKGROUND Polyomavirus reactivation can cause significant morbidity in solid organ transplant recipients, particularly BK virus (BKV) in kidney transplant patients. Less is known about dynamics of John Cunningham virus (JCV) in nonkidney organ transplant patients. METHODS We examined the frequency of urinary shedding of polyomaviruses BKV and JCV and their relationship to creatinine clearance (CrCl) in a longitudinal study of 41 kidney and 33 liver transplant recipients. RESULTS Any polyomavirus urinary shedding was more frequent in liver than kidney recipients (64% vs 39%; P= .03). JCV was excreted more frequently by liver than kidney recipients (71% vs 38%), whereas BKV was shed more often by kidney than liver patients (69% vs 52%). Mean JCV loads were significantly higher than those of BKV in both patient groups (P< .0001). Lower mean CrCl values were significantly associated with JCV shedding in both kidney and liver recipients (P< .001). CONCLUSIONS These findings suggest that BKV and JCV display different patterns of reactivation and shedding in kidney and liver transplant patients and that JCV may have a role in renal dysfunction in some solid organ transplant recipients.

Viral microRNA effects on pathogenesis of polyomavirus SV40 infections in syrian golden hamsters.

Effects of polyomavirus SV40 microRNA on pathogenesis of viral infections in vivo are not known. Syrian golden hamsters are the small animal model for studies of SV40. We report here effects of SV40 microRNA and influence of the structure of the regulatory region on dynamics of SV40 DNA levels in vivo. Outbred young adult hamsters were inoculated by the intracardiac route with 1×107 plaque-forming units of four different variants of SV40. Infected animals were sacrificed from 3 to 270 days postinfection and viral DNA loads in different tissues determined by quantitative real-time polymerase chain reaction assays. All SV40 strains displayed frequent establishment of persistent infections and slow viral clearance. SV40 had a broad tissue tropism, with infected tissues including liver, kidney, spleen, lung, and brain. Liver and kidney contained higher viral DNA loads than other tissues; kidneys were the preferred site for long-term persistent infection although detectable virus was also retained in livers. Expression of SV40 microRNA was demonstrated in wild-type SV40-infected tissues. MicroRNA-negative mutant viruses consistently produced higher viral DNA loads than wild-type SV40 in both liver and kidney. Viruses with complex regulatory regions displayed modestly higher viral DNA loads in the kidney than those with simple regulatory regions. Early viral transcripts were detected at higher levels than late transcripts in liver and kidney. Infectious virus was detected infrequently. There was limited evidence of increased clearance of microRNA-deficient viruses. Wild-type and microRNA-negative mutants of SV40 showed similar rates of transformation of mouse cells in vitro and tumor induction in weanling hamsters in vivo. This report identified broad tissue tropism for SV40 in vivo in hamsters and provides the first evidence of expression and function of SV40 microRNA in vivo. Viral microRNA dampened viral DNA levels in tissues infected by SV40 strains with simple or complex regulatory regions.