Ultrasound findings of BK polyomavirus-associated nephropathy in renal transplant patients

BK polyomavirus (BKV) is an emerging pathogen in immunocompromised patients. BKV infection occurs in 1-9 % of renal transplants and causes chronic nephropathy or graft loss. Diagnosis of BKV-associated nephropathy (BKVAN) is based on detection of viruria then viremia and at least a tubule-interstitial nephritis at renal biopsy. This paper describes the ultrasound and color Doppler (US-CD) features of BKVAN. Seventeen patients affected by BKVAN were studied using a linear bandwidth 7-12 MHz probe. Ultrasound showed a widespread streak-like pattern with alternating normal echoic and hypoechoic streaks with irregular edges from the papilla to the cortex. Renal biopsy performed in hypoechoic areas highlighted the typical viral inclusions in tubular epithelial cells. Our experience suggests a possible role for US-CD in the non-invasive diagnosis of BKVAN when combined with blood and urine screening tests. US-CD must be performed with a high-frequency linear probe to highlight the streak-like pattern of the renal parenchyma.

Prospective study of BK virus infection and nephropathy during the first year after kidney transplantation

INTRODUCTION

The aim of this study was to assess the prevalence and severity of BK virus infection, BK virus nephritis, and related risk factors among kidney transplant recipients.

MATERIALS AND METHODS

BK viremia during the first year of kidney transplantation was assessed prospectively in 32 successive recipients. BK virus DNA was extracted and determined in all samples by real-time polymerase reaction assay for 1 year after kidney transplantation.

RESULTS

The mean age of the patients was 33.3 ± 15.3 years. Sixteen patients (50%) received antithymocyte globulin for induction therapy. Living donor transplant consisted of 75% of the kidney donations. Maintenance immunosuppressive therapy included cyclosporine A in 27 patients (84.4%), plus tapering prednisolone and mycophenolate mofetil. BK viremia was detected in 8 patients (25%). The highest detected plasma viral load was less than 4000 copies per milliliter. BK virus was respectively positive in 5 (62.5%), 2 (25%), and 1 (12.5%) patients during the first 4, 8, and 12 months after transplantation. Biopsy-proven rejection and antirejection therapy by methylprednisolone pulses were 5 and 2.3 times more common in patients with BK virus infection (P = .01 and P = .01), respectively.

CONCLUSIONS

Despite occurrence of BK virus infection in 25% of our patients, BK nephropathy did not develop in any of them. Routine screening of BK virus infection, particularly in centers with low prevalence of BK virus nephritis, may not be cost effective for predicting this disease.

A hamster-derived West Nile virus isolate induces persistent renal infection in mice

Background

West Nile virus (WNV) can persist long term in the brain and kidney tissues of humans, non-human primates, and hamsters. In this study, mice were infected with WNV strain H8912, previously cultured from the urine of a persistently infected hamster, to determine its pathogenesis in a murine host.

Methodology/Principal Findings

We found that WNV H8912 was highly attenuated for neuroinvasiveness in mice. Following a systemic infection, viral RNA could be detected quickly in blood and spleen and much later in kidneys. WNV H8912 induced constitutive IL-10 production, upregulation of IFN-β and IL-1β expression, and a specific IgM response on day 10 post-infection. WNV H8912 persisted preferentially in kidneys with mild renal inflammation, and less frequently in spleen for up to 2.5 months post infection. This was concurrent with detectable serum WNV-specific IgM and IgG production. There were also significantly fewer WNV- specific T cells and lower inflammatory responses in kidneys than in spleen. Previous studies have shown that systemic wild-type WNV NY99 infection induced virus persistence preferentially in spleen than in mouse kidneys. Here, we noted that splenocytes of WNV H8912-infected mice produced significantly less IL-10 than those of WNV NY99-infected mice. Finally, WNV H8912 was also attenuated in neurovirulence. Following intracranial inoculation, WNV persisted in the brain at a low frequency, concurrent with neither inflammatory responses nor neuronal damage in the brain.

Conclusions

WNV H8912 is highly attenuated in both neuroinvasiveness and neurovirulence in mice. It induces a low and delayed anti-viral response in mice and preferentially persists in the kidneys.

West Nile virus (WNV) has been reported to persist long term in the brain and kidney tissues of humans, non-human primates, and hamsters. To define a murine model of persistent WNV renal infection, we characterized infection by WNV H8912, an isolate cultured previously from the urine of a persistently infected hamster. Our findings indicate that WNV strain H8912 is highly attenuated in both neuroinvasiveness and neurovirulence for mice. The virus persisted preferentially in kidneys of the mouse, and less frequently in the spleen and the brain. Moreover, mice infected with WNV H8912 had a delayed induction of IFN- β and IL-1β expression and WNV- specific IgM response, but a constitutive production of serum IL-10. There was a lower proinflammatory response in mouse kidneys when compared to equivalent findings in the spleen. This response may lead to a reduced T cell response in kidneys, which could ultimately contribute to renal-specific WNV persistence. Defining a murine model of WNV persistence by using a well-characterized, hamster-derived WNV urine isolate should provide important insights into understanding the mechanisms of WNV persistence.

[Relationship between B/C genotype of hepatitis B virus and hepatitis B virus related-nephritis in children]

OBJECTIVE

To investigate the relationship between genotype of hepatitis B virus and hepatitis B virus related-glomerular nephritis in (HBV-GN) children.

METHOD

Totally 176 HBV-DNA positive children with chronic hepatitis B were randomly collected. Among the 176 patients, 92 were HBV carriers, 84 were cases with chronic hepatitis. The genotypes of their serum HBV, liver function, and HBV-DNA load were detected. When children showed nephrotic syndrome, renal biopsy was performed.

RESULT

Of the serum samples of 176 cases, 85 (48.3%) were genotype C, 72 (40.9%) were genotype B, 13 (7.4%) were genotype B/C, and 6 (3.4%) were non-B/C genotype which were excluded. Among the analyzed 157 cases, the ratio of HBV-GN in the HBeAg positive group (78.3%) was significantly higher than that in the negative group (21.7%) (χ(2) = 18.301, P < 0.001). And, the ratio of HBV-GN in the genotype C group (73.9%) was significantly higher than that in the genotype B group (26.1%) (P < 0.039). The ratio of hematuria or proteinuria in the genotype C group (20%, 18.8%) was significantly higher than that in the genotype B group (8.3%, 5.6%) (P < 0.039; P value = 0.013); and the alteration of ALT or C3 in the genotype C group (10.2%, 15.3%) was more frequent than those in the genotype B group (2.8%, 2.8%) (P = 0.005; P = 0.008). There were no significant differences in kidney dysfunction or hepatomegaly. Further, the ratio of HBV-GN was more significantly frequent in HBV-DNA highly loading group (79.2%) than which in HBV-DNA lowly loading group (20.8%) (P = 0.000). Finally, in HBV-GN group, genotype C cases (88.2%) more frequently had high HBV-DNA load condition than genotype B cases (11.8%) (P = 0.021).

CONCLUSION

Children with HBV infection in Gansu province showed mainly genotypes C or B, while genotype C seemingly predominant. Patients with genotype C more frequently showed proteinuria or hematuria. The high HBV-DNA load may be related with HBV-GN. It is a potential reason in the mechanism of HBV-GN that patients with genotype C had more possibility to have HBV-DNA high load. Analysis of HBV genotype for HBV patients maybe helpful in diagnosis and treatment.

Epizootic occurrence of haemorrhagic nephritis enteritis virus infection of geese

Recent outbreaks of haemorrhagic nephritis enteritis in geese flocks of 3 to 10 weeks in age in Hungary were investigated. Mortality varied between 4% and 67%. Affected birds generally died suddenly. Occasional clinical signs included tremors of the head and neck, subcutaneous haemorrhages and excretion of faeces containing partly digested blood. At necropsy the most frequent findings were a turgid wall and reddish mucosa of the intestines and reddish discolouration of the swollen kidneys, but oedema and haemorrhages of the subcutaneous connective tissue, hydropericardium and ascites were also seen. In subacute cases, visceral gout was frequently observed. Histological examination revealed zonal necrosis of the tubular epithelial cells with haemorrhages in the kidney. Other histological findings were serous hepatitis with fatty infiltration, necrotizing haemorrhagic enteritis and haemorrhages in the different organs including the brain. Experimental geese infected parenterally with crude liver and spleen homogenates prepared from diseased birds died after 8 to 20 days without premonitory signs, and had typical gross and histological lesions. Attempts to isolate cytopathic virus on different tissue cultures failed. The presence of polyomavirus was proven by polymerase chain reaction. Five isolates were further investigated by analysing their complete VP1 gene sequence. All tested strains were very closely related to each other on the basis of the nucleotide sequence, and they were identical at the deduced amino acid level.

[Polyomavirus BK and its role in associated kidney transplantation pathology]

In the last three decades kidney transplantation became a therapeutic approach in Romania but, unfortunately, the increasing of kidney transplantation procedures is related to an increasing rate of associated pathology such as Polyomavirus BK Associated Nephropathy (BKVAN). Studies published recently emphasize that BKVAN is a consequence of different risks factors, particular viral pathogenesis, humoral and cellular immunity and high doses of immunosuppressive drugs used for a long time are the main conditions that influence the BKVAN's evolution. Since there is no specific and effective treatment, optimal medical management is to diagnose nephropathy in early stages, to stop viral replication, limiting tubular lesions and prevent progress toward destruction by decreasing doses of immunosuppressive agents.

Characterization and membrane gene-based phylogenetic analysis of avian infectious bronchitis virus Chinese strain HH06

A Chinese isolate of avian infectious bronchitis virus (IBV) designated HH06 was isolated from the kidney tissues of a chicken flock experiencing an outbreak of nephritis. In vivo pathogenicity of the IBV isolate HH06 was determined by inoculating specific pathogen-free (SPF) chickens. The clinical signs and related gross lesions of HH06 infected chickens were similar with those of the field-infected chickens. SPF embryonated eggs were inoculated with virus suspension for serial passage and their genomic RNA was extracted. RT-PCR technique was utilized to amplify the M gene sequence encoding membrane protein of IBV. Recombinant plasmid named T-vector-M was constructed via inserting the M gene into the TA cloning vector, pMD 18-T. The sequenced M gene and its deduced amino acid (aa) sequences were compared with the published sequences of reference strains. The M gene is of 687 bp in length encoding the M protein of 228 amino acids with a predicted molecular weight of 25.4 kDa. The sequences of the M gene and M protein share 83.9-97.9% and 83.6-96.5% homologous identities, respectively, compared with 29 IBV reference strains derived from different regions or countries, which revealed that there are still significant variations between strains. Furthermore, a phylogenetic tree based on these M DNA sequences was generated, and the tree topology suggests that some Chinese IBV strains may have a common ancestor; however, HH06 is a new local IBV isolate that is responsible for the field outbreak of nephritis.

Aggressive immunosuppression minimization reduces graft loss following diagnosis of BK virus-associated nephropathy: a comparison of two reduction strategies

BACKGROUND AND OBJECTIVES

BK virus-associated nephropathy (BKVAN) has emerged as a leading cause of kidney graft loss, with no known predictors for graft loss and no consensus regarding treatment other than reduction of immunosuppression.

DESIGN, SETTING, PARTICIPANTS AND MEASUREMENTS

A single-center retrospective analysis was performed of all cases of BKVAN from 1999 to 2005 for clinical predictors of graft loss, with evaluation of the impact of immunosuppression withdrawal (3-drug to 2-drug immunosuppression) within the first month versus reduction of immunosuppression.

RESULTS

Of 910 kidney transplants, 35 (3.8%) cases of BKVAN were diagnosed at a median of 15 months after transplant (range, 5.5 to 90 months after transplant), 16 (46%) of which progressed to graft failure at a median of 11 months (range, 2 to 36 months) after diagnosis. Depleting antibody induction was a significant risk factor for graft loss on univariate analysis, whereas early drug withdrawal (<1 mo following diagnosis) protected against graft loss. On multivariate analysis, these findings were independent predictors of graft outcomes. Additionally, when patients were comanaged by referring nephrologists and the transplant center before the diagnosis of BKVAN, the risk of graft loss was 11-fold higher (P = 0.03) than if patients were managed solely by the transplant center.

CONCLUSIONS

Increased awareness and early diagnosis of BKVAN, with aggressive tapering of immunosuppression once established, is critical to preserve kidney graft function. Early drug withdrawal to low-dose two-drug therapy maintenance may be preferable to a general reduction of agents.

Successful pregnancy in renal transplant recipient with previous known polyomavirus nephropathy

Pregnancy after renal transplantation has become increasingly common. Studies in non-immunocompromised patients have shown that pregnant women have increased susceptibility to infection or reactivation of latent virus such as BK virus. To what extent a renal transplant recipient is at risk for reactivation of polyoma virus during pregnancy remains unknown. We hereby report successful pregnancy outcome in a renal transplant recipient with a known history of BK virus nephropathy treated with cidofovir i.v. To our knowledge, this is the first published experience with a successful pregnancy in renal transplant recipients with known history of polyomavirus-associated nephropathy.

Emerging lupus-like manifestations in acute parvovirus B19 infection

We encountered an adult patient with acute parvovirus B19 infection who presented with transient lupus-like symptoms (i.e., polyarthritis, fever, myalgia, pancytopenia, hypocomplementemia, and nephritis). Our case is characterized by the demonstration of acute nephritis as a complication of this infection, making it difficult to distinguish between a viral infection and the first episode of systemic lupus erythematosus.

Caveolar endocytosis is critical for BK virus infection of human renal proximal tubular epithelial cells

In recent years, BK virus (BKV) nephritis after renal transplantation has become a severe problem. The exact mechanisms of BKV cell entry and subsequent intracellular trafficking remain unknown. Since human renal proximal tubular epithelial cells (HRPTEC) represent a main natural target of BKV nephritis, analysis of BKV infection of HRPTEC is necessary to obtain additional insights into BKV biology and to develop novel strategies for the treatment of BKV nephritis. We coincubated HRPTEC with BKV and the cholesterol-depleting agents methyl beta cyclodextrin (MBCD) and nystatin (Nys), drugs inhibiting caveolar endocytosis. The percentage of infected cells (detected by immunofluorescence) and the cellular levels of BKV large T antigen expression (detected by Western blot analysis) were significantly decreased in both MBCD- and Nys-treated HPRTEC compared to the level in HRPTEC incubated with BKV alone. HRPTEC infection by BKV was also tested after small interfering RNA (siRNA)-dependent depletion of either the caveolar structural protein caveolin-1 (Cav-1) or clathrin, the major structural protein of clathrin-coated pits. BKV infection was inhibited in HRPTEC transfected with Cav-1 siRNA but not in HRPTEC transfected with clathrin siRNA. The colocalization of labeled BKV particles with either Cav-1 or clathrin was investigated by using fluorescent microscopy and image cross-correlation spectroscopy. The rate of colocalization of BKV with Cav-1 peaked at 4 h after incubation. Colocalization with clathrin was insignificant at all time points. These results suggest that BKV entered into HRPTEC via caveolae, not clathrin-coated pits, and that BKV is maximally associated with caveolae at 4 h after infection, prior to relocation to a different intracellular compartment.

Treatment of adenovirus disease in stem cell transplant recipients with cidofovir

Invasive adenovirus (AdV) disease is fatal in >50% of allogeneic hematopoietic stem cell transplant (SCT) recipients. Treatment with cidofovir may improve outcomes based on in vitro susceptibility data and case reports. Six consecutive cases of invasive AdV disease treated with cidofovir were reviewed among 84 allogeneic adult SCT recipients (incidence, 7.1%). Cidofovir was administered intravenously at 5 mg/kg per dose (1-7 doses). All patients received intravenous immune globulin. Blood AdV DNA levels (viral loads, VLs) were monitored with a real-time quantitative polymerase chain reaction assay. Published reports of cidofovir treatment of AdV disease in SCT recipients were critically reviewed. The primary manifestations of AdV disease were hepatitis (n = 3), colitis (n = 2), and nephritis (n = 1). All patients had detectable AdV VLs, with peak values from 5 x 10(5) to 2 x 10(8) copies/mL. All patients received CD34+ selected grafts (n = 3) and/or had graft-versus-host disease (n = 4) and had CD4 counts <100 cells/mm3. Only 1 of 5 patients (20%) who received >or=2 doses of cidofovir died with active AdV disease. Four patients exhibited improvement within days of treatment with cidofovir as documented by clinical criteria and declines in AdV VLs (without a change in immunosuppression). In contrast, 1 patient treated late after onset of AdV disease died after 1 dose of cidofovir. In our review of 70 published cases treated with >or=2 doses of cidofovir, 13 (19%) died from AdV disease. In conclusion, early treatment of AdV disease with cidofovir inhibits viral replication in vivo and reduces mortality in allogeneic SCT recipients compared with historical data.

Low incidence of BK virus nephropathy after simultaneous kidney pancreas transplantation

BACKGROUND

BK virus renal allograft nephropathy (BKVAN) in the setting of simultaneous kidney-pancreas transplantation (SKPT) has been inadequately studied and reported. We analyzed our data on the incidence of BKVAN and its outcome in SKPT recipients at University of Pittsburgh Medical Center (UPMC) and affiliated centers and report significant differences compared to previous studies.

METHODS

This study used retrospective review and case studies.

RESULTS

A review of 243 consecutive SKPT recipients from January 1, 1996 to December 31, 2004 identified seven cases (three females; ages = 23-54 yrs) of BKVAN following SKPT (incidence = 2.9%). The immunosuppressive protocols during this period were divided into: Period I (pre-August 2001) with no antibody induction and Period II (post-August 2001) with alemtuzumab or antithymocyte globulin induction with steroid avoidance. One BKVAN case was diagnosed in Period II (incidence = 1.4%). Six of seven patients were treated with intravenous cidofovir (0.20-0.50 mg/kg) every two to four weeks over one to six months. Three patients lost the renal allograft 8-22 months following diagnosis of BKVAN, whereas four patients had prolonged allograft survival. Pancreatic function was well preserved in five; one patient lost the pancreatic function due to surgical complications and one has had partial preservation.

CONCLUSIONS

There was a relatively lower incidence of BKVAN among SKPT patients at our center. Although overall graft loss rate was comparable to other series, BKVAN patients had a slightly prolonged graft life. The BKVAN incidence was further reduced in patients receiving modified immunosuppression with antibody preconditioning. The underlying reasons may include less toxic immunosuppressive protocols, earlier diagnosis and the use of antiviral therapy.

Generation of virus-like particles consisting of the major capsid protein VP1 of goose hemorrhagic polyomavirus and their application in serological tests

Goose hemorrhagic polyomavirus (GHPV) is the causative agent of hemorrhagic nephritis and enteritis of geese (HNEG), a fatal disease of young geese with high mortality rates. GHPV cannot be efficiently propagated in tissue culture. To provide antigens for diagnostic tests and vaccines, its major structural protein VP1 was recombinantly expressed in Sf9 insect cells and in the yeast Saccharomyces cerevisiae. As demonstrated by density gradient centrifugation and electron microscopy, GHPV-VP1 expressed in insect cells formed virus-like particles (VLPs) with a diameter of 45 nm indistinguishable from infectious polyomavirus particles. However, efficiency of VLP formation was low as compared to the monkey polyomavirus SV-40-VP1. In yeast cells, GHPV-VP1 alone formed smaller VLPs, 20 nm in diameter. Remarkably, co-expression of GHPV-VP2 resulted in VLPs with a diameter of 45 nm. All three types of GHPV-VLPs were shown to hemagglutinate chicken erythrocytes. ELISA and hemagglutination inhibition tests using the VLPs as antigen detected GHPV-specific antibodies in up to 85.7% of sera derived from flocks with HNEG but in none of the sera of a clinically healthy flock. However, GHPV-specific antibodies were also detected in sera from two other flocks without HNEG indicating a broad distribution of GHPV due to subclinical or unrecognised infections.

Polyomavirus-associated nephropathy: update in diagnosis

The histological diagnosis of BK or JC polyomavirus allograft nephritis (PVAN) requires evaluation of a renal biopsy with demonstration of the polyomavirus cytopathic changes and confirmation with an ancillary technique such as immunohistochemistry. Three histological patterns of PVAN (A, B, and C) are identified in renal biopsies. Pattern A corresponds to the early disease, whereas patterns B and C identify intermediate and very advanced histological changes, respectively. The histological pattern found in the first biopsy correlates with graft outcome. Because PVAN affects the kidney in a random, multifocal manner, a negative biopsy does not rule out the disease. Patients with BK PVAN characteristically have high levels of BK viruria and viremia. Although the cutoff values of viral loads have not been fully determined, there is general agreement that BK viruria of >10(7)/mL and BK viremia of >10(4) are typical of patients with a biopsy showing BK PVAN. Prospective evaluation of viruria with urine cytology (decoy cells) and/or quantitative polymerase chain reaction can aid in the identification of patients at risk for developing PVAN. In addition to histological evaluation, viremia has emerged as the most specific test for the diagnosis of BK PVAN. JC PVAN is very infrequent in comparison with BK PVAN, but is also characterized by large viruria (>10(4)). On the other hand, JC viremia appears to be lower, in the order of 10(3)/mL. The inflammatory changes in PVAN need further characterization. Currently, there are no tools to differentiate acute cellular rejection from viral specific T-cell response.

Renal transplant patient with polyoma virus bladder infection and subsequent polyoma virus nephropathy

Polyoma virus nephropathy (PVN) is a significant cause of renal allograft dysfunction in transplant patients. A 58-year-old male received a cadaveric renal transplant and 12 weeks later presented with fever, diarrhea, and dysuria. He was diagnosed with a polyoma virus infection of the bladder by a transurethral bladder biopsy. One year post-transplant, he presented with renal allograft dysfunction and was diagnosed by biopsy with PVN of the non-native kidney. The diagnosis of a polyoma virus infection was confirmed by immunoreactivity to the polyoma T-antigen. We suggest that polyoma virus infection of the bladder be included in the differential diagnosis of urinary dysfunction in post-transplant patients, as such infections might be an under-recognized comorbidity in individuals with PVN.

BK virus nephritis after renal transplantation

BK viremia and nephritis are increasing problems in renal transplant recipients. The exact cause of the increasing prevalence of this condition remains poorly understood. Increasing prevalence has been correlated with newer immunosuppressive agents and the decline in acute rejection rates in recent years. The clinical manifestation varies from the asymptomatic state of viremia and nephritis to clinical renal dysfunction. The diagnosis of this infection is based on the combination of the presence of urinary decoy cells, virus in the urine/blood, and typical renal histological findings of interstitial nephritis. Routine post-transplant screening for BK viremia and viruria prior to the occurrence of nephritis and the reduction in immunosuppressive therapy for subjects with viremia appear to be attractive approaches. The treatment of BKV nephritis (BKVN) consists of reduction in immunosuppressive therapy and antiviral therapy with cidofovir or leflunomide or a combination of both. Approximately 30-60% of subjects with BKVN experienced irreversible graft failure. However, in recent years, the combinations of early detection, prompt diagnosis, and appropriate reduction in immunosuppressive therapy have been associated with better outcome. The pathogenesis of BK virus infection in renal transplant recipients needs to be explored. The source of BKV infection (donor as opposed to recipient), the role of host humoral, and cellular immunity to BKV, and the role of alloimmune activation in renal graft to the occurrence of nephritis are discussed in this review.

[Expression of NF-kappaB/IkappaB signal pathway in renal tissues of hepatitis B virus-associated nephritis]

AIM

To investigate the expression of nuclear transcription factor-kappa B (NF-kappaB)/IkappaB in renal tissues of hepatitis B virus-associated nephritis (HBVGN) and to study its role in the pathogenesis of HBVGN.

METHODS

The expression of NF-kappaB p65 and IkappaB-alpha in renal tissues was examined in biopsy specimens from 42 HBVGN patients, 20 patients with primary membranous nephropathy and 5 normal subjects by immunohistochemical staining.

RESULTS

The NF-kappaB p65 expression in glomerular and tubular of HBVGN tissues was notably higher than that in normal control tissues (P<0.05) and in primary membranous nephropathy tissues (P<0.01). The IkappaB-alpha expression in glomerular and tubular of HBVGN tissues was lower than that in primary membranous nephropathy tissues (P<0.05).

CONCLUSION

There might be protein degradation of IkappaB-alpha and nuclear translocation of NF-kappaB in renal tissues of HBVGN, which suggests that NF-kappaB/IkappaB signal pathway may play an important role in the pathogenesis of HBVGN.

[A patient with serious viral myositis following flu]

A 16-year-old girl presented at the emergency unit with myalgia following a flu-like episode. Laboratory tests indicated severe rhabdomyolysis and nephritis. Autoimmune-induced myositis was excluded on the basis of negative tests for antinuclear antibodies; prednisolone treatment was discontinued 1 week later. The patient recovered gradually and was discharged with physiotherapy 2 weeks later. High positive titres of complement-binding antibody against influenza B virus were found, i.e. 1:125 and 1:250 on days to and 25 of illness, respectively. Viral myositis is an uncommon disease entity that occurs following a viral infection, especially with influenza virus, that has been experienced for the first time. It usually runs a benign course: children often present with calf tenderness that resolves within a few days. There are cases, however, with a more serious course involving severe rhabdomyolysis and acute renal failure that can be sometimes fatal.

[Polyoma virus BK nephropathy in kidney allograft recipients]

Polyomavirus BK (BKV) infection is a fast growing problem in modern transplantation medicine. Interstitial nephritis is the most important pathology caused by the virus leading to graft failure and the need for dialysis treatment. Ethiopathogenesis of the disease is multifactorial with immunosuppressive treatment playing main role. Many cases of BKV infection have been misdiagnosed and mistreated as steroid-resistant acute rejection. In such cases the infection was spreading what inevitably led to graft failure. Now it is known that the only way to control the disease is close monitoring and decreasing the net state of immunosuppression.

BK virus nephritis: risk factors, timing, and outcome in renal transplant recipients

BACKGROUND

BK virus nephritis (BKVN) has emerged as an important cause of renal transplant failure. Quantified analysis of its timing and clinical course is generally lacking. We have thus quantified the timing, risk factors, evolution of renal function, and transplant graft outcome in renal transplant recipients with BKVN from our center.

METHODS

A total of 41 cases of BKVN were diagnosed in 1001 renal and renal/pancreas transplant recipients. There were 2 groups: group I (N= 16), with diagnosis based on renal biopsy alone from January 1996 to August 2001, and group II (N= 25), with diagnosis based on quantitative blood BKV-PCR and biopsy from September 2001 to December 2003. The demographics, the clinical course, immunosuppressive therapy, renal function, and graft outcome were quantified. Donor, recipient, and transplant risk variables were studied using a univariate analysis. Actuarial graft survival was calculated. An immunosuppressive scale created to evaluate the degree of immunosuppression in these patients and its reduction after the diagnosis of BKVN.

RESULTS

The median time from transplant to BKVN diagnosis was 318 days (range 48-1356). The actuarial graft survival in patients with BKVN at 6 months, 1, 3, and 5 years was 97%, 90%, 58%, and 47%. The corresponding values for those without BKVN were 94%, 92%, 83%, and 76%, respectively, P < 0.001. Graft loss occurred in 46% of patients. The rate of decline of renal function in group II (N= 25) patients in the 4 months preceding BKVN was rapid (4.8 mL/min/month) and this declined to 0.7 mL/min/month at 3 months' post-BKVN diagnosis, P= 0.004. In those who recovered, the time to stabilization of renal function was a median of 112 days. The immunosuppressive scale score was 7 units at the time of diagnosis of BKVN and decreased to 3.5 units at 3 months' post-BKVN. Reduction in the dose of calcineurin inhibitors but not the overall reduction in dose of immunosuppression correlated with recovery of renal function in these patients.

CONCLUSION

BKVN is a relatively late complication of renal transplantation. Despite reduction in immunosuppression, graft loss occurred in 46% of patients. There was a steep decline in renal function in months preceding the diagnosis of BKVN, and reduction in calcineurin inhibitor dose, but not overall immunosuppression, correlated with stabilization of renal function.

BK virus-specific antibodies and BKV DNA in renal transplant recipients with BKV nephritis

We evaluated twenty renal transplant subjects at various stages of BKV nephritis (BKVN) for BKV-specific IgG and IgM antibodies using ELISA technique and BKV-DNA using PCR. They were divided as early onset (n = 7), stabilizing (n = 3), resolved (n = 8) and late onset (n = 2) BKVN. BKV-specific antibodies and BKV-DNA were simultaneously determined. The mean BKV-specific IgG level in early onset and stabilizing BKVN were 64 and 39 EIA units, and were significantly lower than 138 EIA units seen in resolved BKVN, P = 0.007, P = 0.008. The mean BKV-specific IgM levels in stabilizing BKVN was higher than resolved BKVN (130 vs 51 EIA units), P = 0.006. Mean plasma BKV loads for each group were 955,925, 5642 and 42 copies/mL of plasma, respectively. Prospective study in six BKVN cases revealed mean IgG, IgM levels and BKV-DNA at the time of diagnosis of BKVN as 39, 110 EIA units and 586,758 copies/mL of plasma, respectively. After a mean period of 5.2 months, IgG level increased to 120 EIA units (p = 0.0058) and had no detectable viral copies in circulation. Recovery from BKVN and elimination of BKV is associated with the development of BKV-specific IgG antibodies and this provides insight into the role of humoral immunity to BKV in the pathogenesis of BKVN.

Polyomavirus interstitial nephritis and concurrent post-transplant lymphoma in a renal allograft: coincidence or more?

We describe a case of an Epstein-Barr virus (EBV)-negative post-transplant large B-cell non-Hodgkin lymphoma located in the renal allograft, spleen, liver and left inguinal lymph node of a renal recipient and accompanied by a simultaneous polyomavirus-associated nephropathy. To our knowledge, this is the first report of a simultaneous polyomavirus infection and post-transplant lymphoproliferative disorder.

Detection of enteroviruses in renal biopsies from patients with immunoglobulin A nephropathy

Viruses have been suspected to be one of the causes of IgA nephropathy (IgAN). Recent studies have detected viruses in renal tissues of patients with IgAN. Enteroviruses have been reported as pathogenic agents in some renal diseases. We previously reported that group B coxsackieviruses cause pathological changes in experimentally infected mouse kidney. The aim of the present study was to examine the participation of enteroviruses in the pathogenesis of renal diseases including IgAN. Renal biopsies of ten patients with IgAN (group 1) and of 19 patients with non-IgAN renal disease (group 2) were analyzed by polymerase chain reaction (PCR) for the presence of enteroviral RNA. Positive PCR results were obtained for three patients (30%) of group 1. We confirmed by sequencing that the positive PCR products were derived from strains of enteroviruses. One of these three patients also had a positive result for lymphocytes from peripheral blood. In contrast, enteroviral RNA was detected in none of the 19 patients of group 2. The incidence of enteroviral RNA detection in patients of group 1 was higher than that in group 2 (P<0.05). Our findings suggest that enteroviral infection may have the possibility of becoming one of the factors involved in the mechanism of onset or evolution of IgAN.

[BK virus infection in a pediatric renal transplant recipient]

BK Human Polyomavirus causes an asymptomatic primary infection in children, then establishing latency mainly in the urinary tratt. Viral reactivation can lead to renal pathology in individuals with impaired cellular immune response. This is particularly important in pediatric transplant recipients, who can suffer a primary infection when immunosupressed. We followed up the case of a 5 years old patient who received a renal transplant in October 2003, and presented damaged graft 45 days after the intervention. The patient suffered 3 episodes of renal function failure between October 2003 and June 2004. Blood, urine, renal biopsy and lymphocele liquid samples were analyzed. A differential diagnosis between acute rejection and infectious causes was established by testing for BK, CMV and ADV viruses, and the cytological study of renal tissue. Laboratory findings together with clinical signs suggest the patient was infected by BK virus. As a final consideration, the great importance of differentiating between acute rejection and BK infection is emphasized, since immunosuppressant management is opposite in each case.

Prevalence, characteristics, and outcome of BK virus nephropathy in Japanese renal transplant patients: analysis in protocol and episode biopsies

BACKGROUND

BK virus nephropathy (BKN) is recognized as a cause of graft loss in renal transplant patients. This may be related to the introduction of new and potent immunosuppressive regimens. In Japan, our experience regarding its prevalence, clinical significance, and outcome is still limited. In this study, our primary purpose is to outline the prevalence, outcome, and clinical characteristics of BKN as observed at Osaka University Hospital.

METHODS

We retrospectively analyzed 112 biopsy specimens from 87 renal transplant patients. All transplantations were from living donors. Of the 112 biopsy specimens, 71 were from protocol biopsies and 41 were from episode biopsies. Calcineurin inhibitors and corticosteroid were used in all patients (tacrolimus 32 and cyclosporin 55). In addition, azathioprine was used in 43 patients, mizoribine was used in 24 patients, and mycophenolate mofetil was used in 20 patients. BKN was diagnosed by light microscopic examination and a positive immunohistochemical staining of anti-SV40 antibody in a biopsy specimen. In order to investigate the outcome and potential risk factors of patients with different histological staging, we divided the patients into groups A (mild histological change) and B (moderate or severe histological change).

RESULTS

Of the 87 patients, six were diagnosed with BKN. There were no significant differences between BKN patients and non-BKN patients, except for the number of patients with graft loss (p < 0.001). Of the six BKN patients, three were in group A, and three were in group B. We recognized a significant difference between group A and group B in terms of anti-rejection treatment including glucocorticoid, tacrolimus trough levels of over 8 ng/mL, episode of acute rejection within 1-month post-transplantation, and the time period between transplantation and BKN diagnosis.

CONCLUSIONS

This is the first report of BKN in Japanese renal allograft recipients. In our hospital, the prevalence, risk factors, and outcome were similar to those previously for non-Japanese recipients.

[Nephropathia caused by hantavirus puumala: a case report]

We present a patient from Germany with Hantavirus infection, admitted in the Emergency room of our hospital, with fever, thrombocytopenia, acute renal failure, oliguria, mild proteinuria and hematuria. Percutaneous renal biopsy revealed an acute interstitial nephritis without medulla haemorrhages. The virus infection confirmation was made by detection of IgM against Hantavirus Puumala. This infection should be considered in patients with thrombocytopenia, fever and acute renal failure, over all if they are from North and Central Europe.

BKV-DNA and JCV-DNA Co-Quantification Assay to Evaluate Viral Load in Urine and Serum

Infections from human polyomaviruses BK and JC (BKV and JCV) occur independently, but concomitant infections and the simultaneous persistence of both viruses have been observed in renal transplant recipients. Several studies have disclosed a correlation between BKV and interstitial nephritis in renal transplant recipients, and an association between JCV and some cases of nephropathy has recently been hypothesized. This article describes the development of a semiquantitative-nested polymerase chain reaction (PCR) assay to simultaneously detect BKV and JCV viral load in urine and serum. The first-round amplification step uses primers that amplify a 385-bp DNA fragment from the "large T antigen" region of both viruses. Samples testing positive in the first step are then run in the second step. In the second-round amplification, different inner primers are used to separately quantify BKV-DNA and/or JCV-DNA. The assay offers several advantages including: (1) rapid submission of clinical samples to screening; (2) verification of the absence of Taq polymerase inhibitors with the use of an internal control; (3) a sensitivity threshold of 10 copies/reaction; and (4) assay running is less labor intensive, cheap, and easy to perform. The assay may be easily used to monitor viral loads versus baseline levels in urine and serum samples from renal transplant recipients to detect those at risk of BKV- or JCV-related nephropathy, and to monitor their response to immunosuppression reduction therapy if it occurs.

Pathology of spontaneous and experimental infections by Goose haemorrhagic polyomavirus

Haemorrhagic nephritis enteritis of geese (HNEG) is a fatal disease of geese aged from 3 to 12 weeks. The causative virus, Goose haemorrhagic polyomavirus (GHPV), is a member of the Polyomaviridae family We examined goslings either spontaneously or experimentally infected with GHPV. Tissues were sampled for histology, GHPV DNA detection and electron microscopy. Clinical signs and gross lesions observed in experimentally infected goslings were largely consistent with those noticed in field cases. Histological examination showed that, in the acute phase of HNEG, GHPV replicates in almost all the tissues with a particular tropism for endothelial and lymphoid cells. Haemorrhagic foci were widespread in many tissues, including brain. Ultrastructural features were largely consistent with other polyomavirus infections, with accumulation of virions in the nucleus. Non-typical, double-membraned organelles were observed in the cytoplasm. GHPV DNA distribution was widespread in tissues of infected birds, from day 5 post-infection. GHPV therefore induces a systemic disease in its host, leading to severe vascular dysfunction and immunosuppressive B-cell depletion.

Polyomavirus infection in pediatric renal transplant recipients: evaluation using a quantitative real-time PCR technique

Polyomavirus infection and related nephropathy is being increasingly recognized as an important cause of allograft dysfunction in adult renal transplant recipients. We prospectively monitored pediatric renal transplant recipients for the presence of BK and JC polyomavirus in urine and blood using a quantitative PCR assay to evaluate the prevalence and clinical relevance of polyomavirus infection in the pediatric renal transplant population. Of 46 pediatric renal recipients who were evaluated, nine (20%) demonstrated isolated BKV viruria, while five (11%) had concomitant BKV viremia and viruria. JCV viruria was found in eight (17%) patients. BKV viremia was associated with a significantly higher urinary BKV viral load: median urinary viral load 1.9 x 10(9) copies/mL (range 6.7 x 10(2)-1.8 x 10(11)) for the group with concomitant viremia and viruria vs. 1.8 x 10(3) copies/mL (range 2.5 x 10(2)-4.5 x 10(6)) for the group with isolated viruria (p < 0.0001). In children that were followed prospectively since their transplantation, the BKV urinary viral load increased markedly before viremia became detectable a few weeks later. None of the patients with JCV viruria or isolated BKV viruria had renal dysfunction. Among the five patients with BKV in both urine and blood, two developed biopsy-proven BKV nephropathy associated with deterioration of the renal function. Management of the BKV nephropathy consisted of reduction of immunosuppression alone or in combination with antiviral treatment with cidofovir. This study shows that polyomavirus infection and related interstitial nephritis is a relevant clinical issue in the pediatric renal transplant population. Monitoring the polyomaviral load in the urine and the blood of the patients using a quantitative PCR technique is a useful tool in the diagnosis and subsequent management of this infection. Even before viremia is present, an important rise in the urinary viral load should draw the attention of the transplant clinician and raise the issue of adapting the immunosuppression.

[Pathomorphology of West Nile fever]

8 patients, aged from 61 to 70 years, died from serous meningoencephalitis during the outburst of the West Nile fever in Volgograd in 1999-2001, were studied morphologically. Serous meningoencephalitis with necrotic vasculitis is a characteristic feature of this fever with degenerative changes and destructive foci in the brain. Proteinic and fatty inflammatory and lymphomacrophageal reactions were observed in the liver, serous productive myocarditis and cardiomyocytic necrosis dystrophy. Desquamative pneumonia, intracapillary nephritis were also seen. Immunohistochemical reaction against virus of this fever was positive in the vascular endothelium of parenchymal organs, hepatocytes, neurons of the brain.

Characterization of an avian infectious bronchitis virus isolated in China from chickens with nephritis

One IBV isolate, SC021202, was isolated from the kidneys of the infected young chickens by inoculating embryonated eggs, and its morphology, physiochemical and haemagglutonating properties were detected. Virulence of the isolate SC021202 was determined with specific pathogen‐free (SPF) chicken inoculation. Nucleotide acid sequence of S1 gene of the isolate SC021202 was further sequenced and analysed. The physiochemical and morphological properties of the isolate SC021202 were in accordance to that of typical infectious bronchitis virus (IBV). In a pathogenicity experiment, the clinical signs and related gross lesions resembling those of field outbreak were reproduced and the virus isolate SC021202 was re‐isolated from the kidneys of the infected chicken. Sequence data demonstrated that the full length of the amplified S1 gene of the isolate SC021202 was composed of 1931 nucleotides, coding a polypeptide of 543 amino acid residues. Compared with IBV strains from GenBank, the nucleotide and deduced amino acid sequence of S1 gene of the isolate SC021202 shared 60.0–91.4% and 49.1–88.9% identities, respectively. A nucleotide fragment of ′CTTTTTAATTATACTAACGGA′ was inserted at nucleotide site 208 in the S1 gene of the isolate. These results indicated that IBV isolate SC021202 was a new variant IBV isolate and responsible for field outbreak of nephritis.

Risk factors for BK polyomavirus nephritis in renal allograft recipients1

Recurrent episodes of acute rejection (AR) and/or the intense immunosuppression used for their treatment have been proposed as risk factors for BK nephritis (BKN; BK refers to the initials of the first patient from whom this polyomavirus was isolated). To further examine the relationship between AR and BKN, we analyzed all kidney transplants performed at our center between January 1999 and August 2001 (n = 286). After a mean follow-up of 737 +/- 22 d, we identified nine cases of BKN (3.1%). The mean time to diagnosis of BKN was 326 +/- 56 d. No patient with BKN had a prior history of AR. During the same period, 62 patients were diagnosed with AR (22%). The mean time to diagnosis of AR was 197 +/- 40 d (p = 0.01 vs. time to diagnosis of BKN). Despite aggressive therapy with methylprednisolone and, in some cases, anti-lymphocyte antibody, none of these patients with AR developed BKN. We compared the baseline characteristics of patients in both groups and found that BKN patients were more likely to be white people (78 vs. 44%, p = 0.05) and male (89 vs. 53%, p = 0.04). Moreover, the mean tacrolimus (TAC) levels before diagnosis were higher in BKN than in AR patients (11.7 +/- 0.5 vs. 6.5 +/- 0.6 ng/mL, p < 0.001). In summary, our study shows that BKN often occurs in the absence of prior episodes of AR. In addition, our findings suggest that white males exposed to higher TAC levels are at greater risk of developing BKN.

Urinary excretion of interleukin-6 correlates with proteinuria in acute Puumala hantavirus-induced nephritis

BACKGROUND

Nephropathia epidemica (NE) is a mild type of hemorrhagic fever with renal syndrome caused by Puumala Hantavirus. Cytokines are thought to have an important role in the pathogenesis of NE. The aim of this study is to evaluate whether cytokines contribute to renal involvement in NE.

METHODS

Overnight urinary excretion of interleukin-1beta (IL-1beta), IL-1 receptor antagonist (IL-1Ra), IL-6, tumor necrosis factor-alpha (TNF-alpha), albumin, immunoglobulin G (IgG), and alpha1-microglobulin and quantitative 24-hour urinary protein excretion were measured for 3 consecutive days from 70 hospitalized patients with acute NE (49 men, 21 women; age, 15 to 70 years; median age, 39 years). Plasma levels of the respective cytokines also were measured. Urinary collections were repeated after 1 year. The control group for blood samples included 400 healthy blood donors.

RESULTS

Maximum median urinary IL-6 excretion in the acute phase of NE was increased compared with values detected after 1 year (49.5 versus 0.7 pg/min; P < 0.001). Correspondingly, maximum median plasma IL-6 concentration in patients was increased compared with controls (14.6 versus 1.2 pg/mL; P < 0.001). Urinary IL-6 excretion correlated with urinary albumin, IgG, and protein excretion (r = 0.79; P < 0.001; r = 0.76; P < 0.001; and r = 0.65; P < 0.001, respectively), but not plasma IL-6 levels (r = 0.18; P = 0.148).

CONCLUSION

Plasma IL-6 concentrations and urinary IL-6 excretion were markedly increased in patients with acute NE, but there was no correlation between plasma and urinary IL-6 levels. The high urinary IL-6 levels might reflect local production of this proinflammatory cytokine in the kidneys during acute infection.

BK polyoma virus allograft nephropathy: ultrastructural features from viral cell entry to lysis

BK virions must enter the host cell and target their genome to the nucleus in order to complete their life cycle. The mechanisms by which the virions accomplish these tasks are not known. In this morphological study we found that BK virions localized beneath the host cell cytoplasmic membrane in 60-70-nm, smooth (non-coated) monopinocytotic vesicles similar to, or consistent with, caveolae. In the cytoplasm, the monopinocytotic vesicles carrying virions appeared to fuse with a system of smooth, vesicles and tubules that communicated with the rough endoplasmic reticulum and was continuous with the Golgi system. Membrane-bound single virions and large tubulo-reticular complexes loaded with virions accumulated in paranuclear locations. Occasional nuclei displayed virions within the perinuclear cisterna in association to the perinuclear viral accumulations. Tubular cells with mature productive infection had large nuclei, distended by daughter virions, whereas they lacked significant numbers of cytoplasmic virions. In addition to virally induced cell necrosis, there was extensive tubular cell damage (apoptosis and necrosis) in morphologically non-infected tubules. The observed ultrastructural interactions between the BK virions and host cells are remarkably similar to viral cell entry and nuclear targeting described for SV40 virus.

Polyomavirus allograft nephropathy: sequential assessment of histologic viral load, tubulitis, and graft function following changes in immunosuppression

Our initial cases of polyoma virus allograft nephropathy (PVAN) received pulse steroids due to anxiety about concomitant acute rejection triggered by the presence of tubulitis. However, our current policy is to reduce immunosuppression in all cases. The aim of this study was to determine whether clinical follow-up in these patient categories shows any differences in: (a) histologic viral load, (b) grade of tubulitis, and (c) graft function. Reduced viral load assessed within 8 weeks was seen in 4/20 (20.0%) biopsies treated initially by increased immunosuppression, compared to 15/19 (83.3%) biopsies treated with reduced immunosuppression (p = 0.001, Fisher's exact test). Yet, >70% reversal of the rise in serum creatinine occurred in only 3/19 (15.8%) and 1/19 (5.3%) patients, respectively, in these two groups. Improved tubulitis was seen in 11/20 (55%) of biopsies treated with steroids, despite the lack of beneficial effect on serum creatinine in 12/19 (63.1%) instances. In biopsies not treated with any change in immunosuppression, the serum creatinine remained stable in 1/5 (20%) and worsened in 4/5 (80%) biopsies. These data demonstrate that in biopsies with PVAN and tubulitis, reduced immunosuppression is more effective in lowering viral load than steroid therapy. Lack of parallelism between viral load, tubulitis grade, and serum creatinine illustrates a complex interplay of viral and alloimmune factors leading to graft injury.

Polyomavirus nephropathy in renal transplantation: a clinico-pathological study

Polyomavirus (PV) nephropathy is a rare cause of graft dysfunction, but it may accompany acute rejection (AR), resulting in complications with respect to its diagnosis and treatment. To examine the validity of tubulitis and inflammatory phenotype in the diagnosis of concurrent AR, we reviewed the renal histology of ten biopsy samples from nine patients with PV nephropathy, and the immunohistochemistry from eight samples. Tubulitis was present in seven patients and was associated with AR in six. The degrees of tubulitis and interstitial inflammation were higher in biopsy samples with AR than in those without, but the degree of tubulitis was not related to the degree of interstitial inflammation. Virally infected cells were rare in the samples with no, or mild, tubulitis, but did not increase with the degree of interstitial inflammation. Immuno-phenotyping of inflammatory cells did not show any T-cell dominance in AR: T cells were dominant over B cells in three of six samples with AR and both samples without AR. Although the degrees of tubulitis and interstitial inflammation were higher in the AR subjects, the presence of tubulitis or inflammatory phenotype was not helpful in the diagnosis of concurrent AR. Further studies will be required to find a better marker for coexisting AR in patients with PV nephropathy and to establish strategies for treatment.

The genome of goose hemorrhagic polyomavirus, a new member of the proposed subgenus Avipolyomavirus

The full-length genome of goose hemorrhagic polyomavirus (GHPV), the ethiologic agent of hemorrhagic nephritis and enteritis of geese, was cloned and sequenced. Transfection of the circular ds DNA with a size of 5256 bp and an organisation typical of polyomaviruses produced viral progeny in cultured goose cells. According to the splicing sites determined by RT-PCR, five open reading frames (ORFs) were found to encode putative proteins with significant similarities to large T antigen and small t antigen as well as VP1, VP2, and VP3 of other polyomaviruses. An additional ORF located in the 5' region of late mRNA, with a coding capacity for 169 amino acids, shows a low degree of homology to VP4 of avian polyomavirus (APV). The alignment of nucleotide sequences and amino acid sequences revealed a relatively close relationship between GHPV and APV. Therefore, grouping of this new polyomavirus into the proposed subgenus Avipolyomavirus is suggested.

[Renal damage during type II cryoglobulinemia]

THE CONTEXT: Type II cryoglobulinemia, composed of a monoclonal IgM rheumatoid factor directed against polyclonal IgG, is associated in most cases with chronic hepatitis C viral infection. THE CHARACTERISTICS OF RENAL DAMAGE: Frequent, the renal damage usually occurs after the onset of various systemic manifestations and is expressed by moderate renal failure, microscopic haematuria, proteinuria lower than 3 g/d and hypertension difficult to control. More severe aspects are possible such as acute nephrotic or nephritic syndromes, or even multi-organ failure with anuria. A renal biopsy confirms the diagnosis by revealing a membranoproliferative glomerulonephritis, characterized by the intensity of the monocyte infiltration and glomerular deposits, often arranged in curved microtubules under electronic microscopy and often associated with vasculitis lesions. Progression towards terminal renal failure is rare.

THERAPEUTIC MODALITIES

Treatment, unclearly defined, relies on anti-virals (interferon a and ribavirin), which are partially effective when the viral replication is inhibited, associated with corticosteroids and immunosuppressors or even plasma exchange in the severe forms. The management and treatment of the cardiovascular complications condition the vital prognosis.