Resolution of painful trichodysplasia spinulosa with topical cidofovir: case report

Purpose: Trichodysplasia spinulosa (TS) is a rare, disfiguring skin condition which presents with widespread asymptomatic or pruritic, skin-colored papules with white protruding keratin spiculations in immunocompromised individuals. Due to its rarity, there is little data to guide treatment decisions. The purpose of this article is to report a case of TS that completely resolved after treatment with topical cidofovir.Materials and methods: A 19-year-old immunosuppressed female presented with widespread painful, itchy bumps on the nose and face. Upon examination, there were erythematous papules with hyperkeratinized spicules affecting the central face. Biopsy of the lesions was consistent with TS which was confirmed via PCR analysis. The tenderness of this patient's eruption was highly atypical for TS. Once daily topical application of compounded 1% cidofovir cream was prescribed.Results: The patient's symptoms resolved completely after 4 weeks of therapy with topical cidofovir 1% cream, without reduction of immunosuppression.Conclusions: Topical cidofovir 1% cream may be a valuable treatment for this rare disease.

Multidisciplinary Treatment, Including Locoregional Chemotherapy, for Merkel-Polyomavirus-Positive Merkel Cell Carcinomas: Perspectives for Patients Exhibiting Oncogenic Alternative Δ exon 6-7 TrkAIII Splicing of Neurotrophin Receptor Tropomyosin-Related Kinase A

Merkel cell carcinomas (MCCs) are rare, aggressive, cutaneous neuroendocrine tumours, approximately 80% of which are caused by the genomic integration of Merkel cell polyomavirus (MCPyV). MCPyV-positive MCCs carry poor prognosis in approximately 70% of cases, highlighting the need for greater understanding of the oncogenic mechanisms involved in pathogenesis, progression and post-therapeutic relapse, and translation into novel therapeutic strategies. In a previous pilot study, we reported a potential relationship between MCPyV gene expression and oncogenic alternative Δ exon 6–7 TrkAIII splicing in formalin-fixed paraffin-embedded (FFPE) MCC tissues from a 12-patient cohort of >90% MCPyV-positive MCCs, diagnosed at San Salvatore Hospital, L’Aquila, Italy, characterising a new MCC subgroup and unveiling a novel potential MCPyV oncogenic mechanism and therapeutic target. This, however, could not be fully verified due to poor RNA quality and difficulty in protein extraction from FFPE tissues. Here, therefore, we extend our previous observations to confirm the relationship between MCPyV and oncogenic alternative Δ exon 6–7 TrkAIII splicing in fresh, nonfixed, MCPyV-positive MCC metastasis by detecting sequence-verified RT-PCR products, including full-length Δ exon 6–7 TrkAIII, and by Western blot detection of a 100 kDa TrkA protein isoform of identical size to 100 kDa Δ exon 6–7 TrkAIII expressed by stable transfected SH-SY5Y cells. We also report that in three MCC patients submitted for multidisciplinary treatment, including locoregional chemotherapy, MCPyV large T-antigen mRNA expression, Δ exon 6–7 TrkAIII mRNA expression and intracellular indirect immunofluorescence (IF) TrkA and phosphorylation protein isoform(s) immunoreactivity in FFPE tissues were not reduced in postchemotherapeutic-relapsed MCCs compared to pretherapeutic MCCs, extending the possible roles of this novel potential MCPyV oncogenic mechanism from MCC pathogenesis to post-therapeutic relapse and progression. Detection of alternative Δ exon 6–7 TrkAIII splicing in MCC, therefore, not only characterises a new MCPyV-positive MCC subgroup and unveils a novel potential MCPyV oncogenic mechanism but also identifies patients who may benefit from inhibitors of MCPyV T-antigen and/or TrkAIII expression or clinically approved Trk kinase inhibitors such as larotrectinib or entrectinib, which are known to inhibit activated TrkA oncogenes and to elicit durable responses in TrkA-fusion oncogene-driven cancers, supporting the call for a large-scale multicentre clinical study.

The therapeutic effect of switching from tacrolimus to low-dose cyclosporine A in renal transplant recipients with BK virus nephropathy

Background: There is no effective therapy for BK virus (BKV) nephropathy (BKVN). Cyclosporine A (CsA) has a lower immunosuppressive effect than tacrolimus. In vitro studies have shown that CsA inhibits BKV replication. The present study aimed to evaluate the effectiveness of switching from tacrolimus to low-dose CsA in renal transplant recipients with BKVN. Methods: Twenty-four patients diagnosed with BKVN between January 2015 and December 2016 were included. Tacrolimus was switched to low-dose CsA, and patients were followed for 24 months. Primary end points were BKV clearance in blood and graft. Secondary end points were urine specific gravity, serum creatinine, and graft loss. Results: The viremia in all patients cleared at a mean of 2.7 ± 2.0 months after switching to CsA. Urine specific gravity at 3 months after switching to CsA increased significantly compared with that at diagnosis (P=0.002). The timing and trend of urine specific gravity increase was consistent with the timing and trend of blood and urine viral load decrease. Repeated biopsies at a median of 11.2 months (range: 9.1-12.5 months) after switching to CsA showed that 8 patients (42.1%) were negative for BKV, and 11 patients (58.9%) had a decrease in BKV load (P<0.001). There was no statistical difference in the serum creatinine level between the time of diagnosis and 24 months of CsA therapy (P=0.963). The graft survival rate was 100%. Only two patients (8.3%) suffered from acute rejection. Conclusion: Switching from tacrolimus to low-dose CsA may be an effective therapy for BKVN.

Polyomavirus Nephropathy in Kidney Transplantation

Polyomavirus nephropathy has become an important complication in kidney transplantation, with a prevalence of 1% to 8%. Unfortunately, the risk factors for polyomavirus nephropathy and renal allograft loss are not well defined. The definitive diagnosis is made through assessment of a kidney transplant biopsy. Recently, noninvasive urine and serum markers have been used to assist in polyomavirus nephropathy diagnosis and monitoring. Primary treatment is immunosuppression reduction, but must be balanced with the risks of rejection. No antiviral treatments for polyomavirus nephropathy have been approved by the Food and Drug Administration. Although cidofovir has shown in vitro activity against murine polyomaviruses, and has been effective in some patients, it is associated with significant nephrotoxicity. Graft loss due to polyomavirus nephropathy should not be a contraindication to retransplantation; however, experience is limited. This review presents potential risk factors, screening, diagnostic and monitoring methods, therapeutic management, and retransplantation experience for polyomavirus nephropathy.

BK Virus Infection in Kidney Transplantation: A Case for Early Intervention

The prognosis for renal allograft survival in a patient with BK virus–associated nephropathy is distressing because nearly 50% of affected grafts are lost. With these statistics in mind, attempting clinical intervention before BK virus disease develops seems appropriate. Noninvasive screening tools such as tests to detect decoy cells in urine can enable diagnosis of BK viral infection in its early stages. Although it is not entirely clear which patients with BK infection will have BK disease develop, it may be possible to intervene in this early warning period to prevent the further development of BK virus–associated nephropathy. We present a case of a 50-year-old man in whom asymptomatic BK viruria developed 6 weeks after he received a non-HLA matched kidney from a deceased donor. This BK viruria was accompanied, subsequently, by an unexplained increase in serum creatinine level 2 months after transplantation. Following a change in his immunosuppressive regimen as therapy for presumed renal allograft dysfunction associated with BK viral infection, the decoy cells in his urine disappeared and his creatinine levels stabilized.

Cidofovir in the Treatment of BK Virus-Associated Hemorrhagic Cystitis after Allogeneic Hematopoietic Stem Cell Transplantation

After allogeneic hematopoietic stem cell transplantation (HSCT), BK virus-associated hemorrhagic cystitis (BKV-HC) is a common complication. Although supportive measures have been the standard of care for many years, several studies suggested the efficacy of cidofovir. The aim of this study was to assess the safety profile and efficacy of cidofovir. A retrospective study was conducted on all patients treated with cidofovir in our HSCT unit between March 2011 and May 2013. Data for efficacy (partial [PR] or complete response [CR]), prescription (dose, frequency, number of doses, and administration route), and toxicity were collected from published reports and medical files. Renal toxicity was evaluated using creatinine clearance calculated with the Cockcroft and Gault formula. A parallel literature search using PubMed (last search, May 2015) was performed. From March 2011 to June 2013, 27 of 181 patients undergoing allogeneic HSCT in our department received cidofovir for BKV-HC: 24 (88.9%) intravenously, 1 intravesically, and 2 via both routes. Mean dose was 5 mg/kg per administration, for a median of 4 injections (range, 1 to 11), from twice a week to once every 2 weeks. CR was achieved in 22 patients (81.5%), PR in 2, and no response in 2 patients. Eight patients presented renal failure (29.6%): 6 moderate (creatinine clearance < 60 mL/min) and 2 severe (creatinine clearance < 30 mLmin). Mean decrease in creatinine clearance after cidofovir was 27% (35 mL/min; range, 2 to 159). In 3 cases renal insufficiency and hematologic toxicity led to discontinuation of treatment or switch to intravesical instillation. For 3 patients cidofovir dose was reduced because of nephrotoxicity. Thirteen studies have reported on the use of cidofovir for BKV-HC (204 patients) since 2005. Intravenous cidofovir was used for 91.3% of patients, with doses ranging from .5 to 5 mg/kg. The main toxicity reported was renal failure (9% to 50% in 9 studies). Between 60% and 100% of CRs were observed independently of cidofovir dose or administration route. Cidofovir is an effective therapy for BKV-HC but requires very precise renal function management to avoid toxicity. Cidofovir treatment modalities (high dose, intravesical instillation, or low dose [≤1 mg/kg]) needs to be investigated in randomized controlled trials.

[Polyomavirus BK-associated nephropathy after kidney transplant]

Advances in immunosuppression have lowered the acute rejection rates in kidney transplant recipients but have impacted negatively on the viral infection rates. Polyomavirus-associated interstitial nephropathy (PyVA N) affects up to 10% of kidney transplant recipients and can progress to irreversible allograft failure in up to 45% of affected cases. Nowadays, thanks to increased awareness of PyVA N and improved diagnostic techniques, the rate of graft loss has decreased, most markedly in centers with active screening and intervention programs. The diagnosis of PyVA N is made by allograft histology. However, systematic screening by quantitative molecular-genetic techniques allows intervention in the early stages of the disease, before the occurrence of irreversible parenchymal changes. So far, the only proven measure affecting PyVA N progression and outcome is the reduction of immunosuppression. Other therapeutic approaches including cidofovir, leflunomide, fluoroquinolones and intravenous immunoglobulins have been explored, but there is no clinical evidence supporting their efficacy. It has been largely demonstrated that BKV-specific T-cell immunity plays a pivotal role in controlling viral replication and disease progression. For this reason viral-specific T-cell immunity can help in monitoring PyVA N. Protocols of adoptive T-cell transfer based on infusion of BKV-specific T cells are the object of many studies and should be considered an innovative treatment approach for PyVA N.

Molecular diagnosis and management of viral infections in hematopoietic stem cell transplant recipients

Viral infections after allogeneic hematopoietic stem cell transplantation (HSCT) are important complications associated with high morbidity and mortality. In this setting, reactivations of persisting latent viral pathogens from donor and/or recipient cells play a central role whereas the sterile environment of transplant units renders new infections less likely. The viruses currently regarded as most relevant in the HSCT setting include particularly the herpes virus family--specifically cytomegalovirus (CMV), Epstein-Barr virus (EBV), and human herpesvirus 6 (HHV-6)--as well as human adenoviruses (AdVs) and the polyoma virus BK (BKV). Timely detection and monitoring of virus copy numbers are prerequisites for successful preemptive treatment approaches. Pre- and post-transplant surveillance by sensitive and quantitative molecular methods has therefore become an essential part of the diagnostic routine. In this review, we discuss diagnostic aspects and the clinical management of the most important viral infections in HSCT recipients, with a focus on pediatric patients.

BK polyomavirus: emerging pathogen

BK polyomavirus (BKPyV) is a small double-stranded DNA virus that is an emerging pathogen in immunocompromised individuals. BKPyV is widespread in the general population, but primarily causes disease when immune suppression leads to reactivation of latent virus. Polyomavirus-associated nephropathy and hemorrhagic cystitis in renal and bone marrow transplant patients, respectively, are the most common diseases associated with BKPyV reactivation and lytic infection. In this review, we discuss the clinical relevance, effects on the host, virus life cycle, and current treatment protocols.

Monitoring and managing viral infections in pediatric renal transplant recipients

Viral infections remain a significant cause of morbidity and mortality following renal transplantation. The pediatric cohort is at high risk of developing virus-related complications due to immunological naiveté and the increased alloreactivity risk that requires maintaining a heavily immunosuppressive environment. Although cytomegalovirus is the most common opportunistic pathogen seen in transplant recipients, numerous other viruses may affect clinical outcome. Recent technological advances and novel antiviral therapy have allowed implementation of viral and immunological monitoring protocols and adoption of prophylactic or preemptive treatment approaches in high-risk groups. These strategies have led to improved viral infection management in the immunocompromised host, with significant impact on outcome. We review the major viral infections seen following kidney transplantation and discuss strategies for preventing and managing these pathogens.

The BK virus in renal transplant recipients-review of pathogenesis, diagnosis, and treatment

The BK virus, a DNA virus from the Polyomavirus group, represents an opportunistic infection of immunosuppressed transplant recipients. Though the virus was discovered approximately 40 years ago, the emergence of BK virus nephropathy since 1995 onwards, with associated high graft loss rates, has revolutionized renal transplantation medicine. Kidney transplant professionals realized that the consequences of over-immunosuppression were as severe as the consequences of under-immunosuppression and we entered the era of immunosuppressive minimization. Despite this recognition, the optimal testing type for BK virus infections and frequency of testing are hotly debated. Similarly, optimal treatment strategies remain sources of intense controversy. The authors review the current strategies of screening, diagnosis, and possible treatment, and also review the amount and quality of evidence in favor or against. Similarities and differences between cytomegalovirus, Epstein-Barr virus, and BV virus, the three major viral infections in kidney transplantation, are highlighted.

Polyomavirus associated nephropathy presenting five years after kidney transplantation

INTRODUCTION

Polyomavirus associated nephropathy (PVAN) is being recognised as an important cause of renal transplant dysfunction. It is a difficult diagnosis to make and requires a high index of suspicion. Here we describe an unusually late presentation of PVAN that responded favourably to reduction of immunosuppression.

CASE REPORT

A 52 year-old male presented with an elevated serum creatinine of 3.8 mg/dl five years after kidney transplantation. He was maintained on tacrolimus, mycophenolate mofetil (MMF), and prednisolone. He had loose motions that subsided when MMF was withdrawn. His tacrolimus trough level was very high and its dose was reduced, with no improvement in creatinine level. Doppler of the transplanted kidney revealed normal perfusion. The patient's urine was negative for decoy cells and his plasma PCR for polyoma BK virus DNA was also negative. Kidney biopsy revealed histological features suggestive of PVAN and this diagnosis was confirmed by immunohistochemistry which was positive for simian virus 40 (SV40) antigen. Tacrolimus was discontinued and the patient maintained on azathioprine and prednisolone. His serum creatinine stabilized at 1.2 mg/dl.

CONCLUSION

This case highlights the propensity of PVAN to present very late after transplantation. Renal biopsy is very valuable in establishing the diagnosis and timely management can prevent graft loss.

Low prevalence of BK virus nephropathy on nonprotocol renal biopsies in Iranian kidney transplant recipients: one center's experience and review of the literature

OBJECTIVES

BK virus-associated nephropathy in renal transplant recipients has been increasing in frequency in recent years. This rise is probably because of widespread use of highly potent immunosuppressive regimens, and increased immunosuppression load leads to inability of the recipients to increase a successful antiviral immune response. The incidence of BK virus-associated nephropathy in different reports is between 1% and 10%, with an allograft loss in significant numbers of patients, especially when timely diagnosis and treatment is not restored. We report our experience on BK virus nephropathy in our institute.

MATERIALS AND METHODS

All renal transplant biopsies performed at our center between 2001 and 2006 were immunohistochemically screened for the presence of PV-specific protein (SV40 Ag). The histologic diagnosis of BK virus-associated nephropathy was made upon the observation of morphologic changes in tubular epithelium and confirmation with immunohistochemical staining. We reviewed the clinical records of the subjects for demographic, clinical, and laboratory data.

RESULTS

BK virus nephropathy was found in 0.93% of all investigated allograft biopsies (1/108) and in 1.04% of all recipients (1/96; mean age of recipients, 36.48±14.10 years; age range, 13-74 years); 54 of them were male (57%). Type of kidney transplant was living-unrelated donor 76 (79%), living-related donor 13 (14%), and deceased donor 7. Seventeen patients (18%) were transplanted for a second time. Immunosuppressive drugs in 87 of recipients (90%) were cyclosporine, mycophenolate mofetil, and prednisolone. Our patient who developed BK virus-associated nephropathy 9 months after transplant was a 37-year-old man on prednisone, cyclosporine, and azathioprine immunosuppresion. He lost his graft 4 months after diagnosis.

CONCLUSIONS

Although BK virus nephropathy after renal transplant is uncommon, it is a serious complication causing loss of the allograft. It should be included in the clinical differential diagnosis of transplant dysfunction.

[BK virus and renal transplantation]

BK virus (BKV) is a subtype of papovaviridae. The latent and asymptomatic infection of BKV is common among healthy people. The incidence of BKV re-activation in renal transplant recipients ranges 10%-68%. About 1%-7% of renal transplant recipients will suffer from BKV-associated nephropathy (BKVAN), and half of them will experience graft failure. This paper summarizes the re-activation mechanism of BKV as well as the risk factors, pathology, diagnosis, and treatment of BKVAN.

Kidney graft loss associated with JC polyomavirus nephropathy

This is the first case of documented treatment failure of JCV nephritis, despite a reduction of immunosuppressive agents and the use of antiviral therapy. We consistently detected high levels of JCV viremia, which correlated with the progressive deterioration of the graft and caused the final loss of the kidney, suggesting that JCV plays an etiological role in the onset of severe nephropathy in kidney transplant patients.

[BK viral infection after renal transplantation]

Viral infections have been a subject of great interest in patients after organ transplantations. Post-transplant immunosuppressive therapy is often associated with transfenction or reactivation of viruses. The human polyomavirus type I, also called BKvirus (BKV), causes polyomavirus-associated nephropathy (PVAN) in 1-10% of renal transplant recipients. Thanks to increased PVAN awareness and improved diagnostic techniques, the rate of graft loss has lowered, more consistently in centres with active screening and intervention programs. The risk factors for PVAN are not conclusively defined and likely involve complementing determinants of recipient, graft, and virus. Central element seems to be the failing balance between BKV replication and BKV-specific immune control, which can result from intense triple immunosuppression, HLA-mismatches, prior rejection and anti-rejection treatment, or BKV-seropositive donor/seronegative recipient pairs. PVAN diagnosis requires the evaluation of a renal biopsy showing polyomavirus cytopathic changes and confirming BKV through an ancillary technique such as immunohistochemistry. The success rate of the intervention is increased with earlier diagnosis. Therefore, it is recommended that all renal transplant recipients should be screened for BKV replication in urine and serum. The treatment of BKVN consists mainly of reduction in immunosuppressive therapy. Currently, in the clinical management of PVAN, no satisfactory antiviral treatment has been defined. Retransplantation after renal allograft loss to PVAN remains a treatment option for patients clearing polyomavirus replication.

[Clinical diagnosis and treatment of BK virus infection in renal transplant recipients]

OBJECTIVE

To explore methods of clinical diagnosis and treatment of BK virus (BKV) infection in renal transplant recipients.

METHODS

Urine samples were collected from 227 renal transplant recipients who had undergone renal transplantation at most 48 months to detect the decoy cells. Samples of urine and peripheral blood (BP) were collected to undergo real-time PCR to detect the BKV DNA. Part of the renal-recipients received graft biopsy. The recipients with BKV viruria or viremia were divided into 2 groups: intervention group and control group. The 51 patients of the intervention group had the doses of cyclosporine A (CsA) reduced (n=19), had their doses of FK506 reduced (n=22), or underwent replacement of FK506 with CsA (n=10). And other 29 patients in the control group did not receive any intervention. Acute rejection was intensively monitored. The amount of decoy cells, and BKV load in the urine and PB samples were measured again after 3 months.

RESULTS

The positive rates of urine decoy cell, BKV viruria, and viremia in all patients were 33.0%, 33.5%, and 15.4% respectively. In the intervention group, the median levels of decoy cells in urine, and of BKV DNA in urine and PB before intervention were 5.0/10 HP, 1.50 x 10(4) copies/ml and 0 copy/ml respectively ; and the median levels of decoy cell in urine, and of BKV DNA in urine and PB were all 0 after intervention, all significantly lower than those before intervention (all P < 0.01). In the control group, the median levels of decoy cells in urine, and of BKV DNA in urine and PB were 6.0 /10 HP, 0.79 x 10(4) copies/ml, and 0 copy/ml respectively before observation, and the median level of BKV load in urine ofter observation was 2.21 x 10(4) copies/m, significantly higher than that before observation (P < 0.01), however, the median levels of decoy cells in urine and of BKV DNA in PB were 5.0 /10 HP and 0 copy/ml respectively, not significantly different from those before observation ( both P > 0.05). The differences between the levels of urine decoy cells, urine BKV DNA level and blood BKV DNA level of the intervention group were all significantly greater than those of the control group (Z = -2.749, -5.089, -1.996; P = 0.006, 0.000, 0.046 respectively). And during the intervention no acute rejection was observed. Four cases of BKVAN were diagnosed. Treatment of immunosuppression reduction showed effectiveness in 4 BKVAN recipients. The levels of decoy cells in urine, and BKV load in urine and in PB samples were all decreased. The graft functions were improved.

CONCLUSION

Urine cytology is very convenient, useful and sensitive for the evaluation and followup of renal transplant patients, and can reflect renal histological presentation indirectly. Also BKV DNA detection in the urine and peripheral blood is important to screen the evidence of BK reaction in order to prevent irreversible graft damage of BKVAN. The treatment of immunosuppressant reduction and replacement of FK506 with CsA are effective in BKV infection recipients at the early stage.

The influence of immunosuppression on the development of BK virus nephropathy-- does it matter?

In the last decade the incidence of BK virus infection has increased in renal transplant recipients and become an important factor negatively influencing graft outcome. BK virus infection cannot be attributed to a single immunosuppressive agent or regimen. The risk of BKV infection is related to the overall load of immunosuppression, which is determined not only by immunosuppressive drugs but also by the humoral and cellular immunity of the recipient. Reduction in immunosuppression at this time appears to be the best available approach to the treatment of established BKVN. Assays are lacking that are able to measure the degree of immunosuppression in a given patient at a given time after transplantation. The balance between a sufficient yet nontoxic immunosuppressive regimen remains a major problem in preventing complications such as BK virus nephropathy. This article will focus on the influence of immunosuppressive medication on the development of BKVN. The role of other aspects such as viral virulence, humoral and cellular immunity or renal specificity will be shortly discussed.

Herpesviruses and polyomaviruses in renal transplantation

Viral infections remain a significant cause of morbidity and mortality among transplant patients despite recent advances in early detection and treatment. Herpesviruses and polyomaviruses are the most relevant viruses post-transplant as they establish latency in immunocompetent individuals and frequently reactivate in the immunosuppressed transplant recipient. Although we have made significant strides in the early diagnosis and treatment of viral infections in renal transplant recipients over the past five years, many questions remain. Optimization of screening and prophylactic/preemptive protocols, as well as standardization of viral diagnostic testing are still needed. Understanding how viruses modify the host's immune responses, and conversely how variations between hosts' ability to mount an immune response against viruses are important areas of research that might allow for more individualization of immunosuppressive regimens. Other exciting areas of ongoing study include the associations between various HLA loci/mismatches and viral replication/infection, the mechanisms by which certain viruses (i.e., Epstein-Barr virus, human herpes virus 8) are oncogenic, and the development of new therapeutic strategies such as adoptive transfer of antigen-specific T cells to restore immunity and control viral infections.

BK virus-induced tubulointerstitial nephritis in a child with acute lymphoblastic leukemia

We report a case of BK virus-induced tubulointerstitial nephritis in a child with acute lymphoblastic leukemia. Primary BK virus infection was exacerbated by chemotherapy-induced immunodeficiency. Careful administration of chemotherapy and anti-viral therapy prevented further damage. This diagnosis should be considered in children who experience renal dysfunction during cancer treatment.

JC virus granule cell neuronopathy in a child with CD40 ligand deficiency

JC virus infection of the brain typically causes progressive multifocal leukoencephalopathy, a demyelinating disease that rarely involves gray matter. This report presents a case of cerebellar degeneration associated with JC virus infection in a male with CD40 ligand deficiency resulting in hyperimmunoglobulin M type 1. This patient exhibited a progressive cerebellar ataxia with progressive atrophy of the cerebellar cortex in association with the presence of JC virus in the spinal fluid. JC virus infection should be considered in the differential diagnosis of ataxia in children with inherited immunodeficiencies.

Molecular and clinical perspectives of polyomaviruses: emerging evidence of importance in non-kidney transplant populations

JC virus (JCV), BK virus (BKV) and simian virus 40 (SV40) are deoxyribonucleic acid (DNA) viruses, members of the family Polyomaviridae. These viruses establish persistent infections, and reactivate from latency in their host under immunosuppression. During the last few years there has been recognition of the morbidity related to polyomaviruses, particularly BKV in kidney transplant recipients. More importantly, recent studies indicate the potential implication of JCV, BKV, and SV40 in renal dysfunction among nonrenal organ transplant patients. Polyomaviruses are tumor-inducing viruses and animal models have provided evidence of the oncogenicity of these pathogens. Although data are not conclusive, molecular studies suggest an association of BKV and SV40 with malignancies among solid organ transplant patients. As new and potent immunosuppressive agents are introduced into clinical practice, it is believed that the incidence of polyomavirus-related diseases in organ transplantation might increase. This review evaluates the biologic and epidemiologic features of these 3 viruses, the data regarding their infections in nonkidney organ transplant patients and describes future directions in the management and research of these opportunistic pathogens.

BK virus infection in transplant recipients: an overview and update

BK virus infection after kidney transplantation has been a subject of great interest in the past decade. This article traces the discovery of BK virus and the subsequent development of our knowledge about this emerging pathogen. The pathobiology of the virus is summarized with particular reference to epidemiology, interactions with host cell receptors, cell entry, cytoplasmic trafficking and targeting of the viral genome to the nucleus. This is followed by a discussion of clinical features, laboratory monitoring and therapeutic strategies. Finally, we present potential cellular mechanisms that explain the basis of virus-mediated damage to the human kidney.

Cellular and molecular parameters of mesothelioma

Malignant mesotheliomas (MM) are neoplasms arising from mesothelial cells that line the body cavities, most commonly the pleural and peritoneal cavities. Although traditionally recognized as associated with occupational asbestos exposures, MMs can appear in individuals with no documented exposures to asbestos fibers, and emerging data suggest that genetic susceptibility and simian virus 40 (SV40) infections also facilitate the development of MMs. Both asbestos exposure and transfection of human mesothelial cells with SV40 large and small antigens (Tag, tag) cause genetic modifications and cell signaling events, most notably the induction of cell survival pathways and activation of receptors, and other proteins that favor the growth and establishment of MMs as well as their resistance to chemotherapy. Recent advances in high-throughput technologies documenting gene and protein expression in patients and animal models of MMs can now be validated in human MM tissue arrays. These have revealed expression profiles that allow more accurate diagnosis and prognosis of MMs. More importantly, serum proteomics has revealed two new candidates (osteopontin and serum mesothelin-related protein or SMRP) potentially useful in screening individuals for MMs. These mechanistic approaches offer new hope for early detection and treatment of these devastating tumors.

Cidofovir bladder instillation for the treatment of BK hemorrhagic cystitis after allogeneic stem cell transplantation

We report a case of severe hemorrhagic cystitis after allogeneic transplantation in association with high BK viral load. After failure of aggressive hydration, platelet and blood transfusions, continuous bladder irrigation, and tapering of the immune suppression, we instilled cidofovir into the bladder, which resulted in decreased BK viral load and significant clinical improvement. Our case suggests that local cidofovir therapy for viral hemorrhagic cystitis is effective and well tolerated with no observed side effects.

[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.

[Polyomavirus BK infection in renal transplant recipients]

Beside acute rejection or immunosuppressive therapy toxicity, infection by Polyomavirus BK, usually not aggressive in immunoactive patients, has emerged as an important factor affecting graft function in renal transplant recipients. Indeed, one of the most important complications of BK infection is nephropathy. Viral replication in the urinary tract as assessed by the presence of "decoy cells", or by a positive PCR for BK virus has been detected in up to half of the recipients but only 5% will present nephropathy which is usually the only sign. The most common risk factors for this emerging new cause are new immunosuppressive drugs and rejection episodes. The gold standard to diagnose BK nephropathy is immunohistochemical staining for large T antigen in graft biopsy specimens. Urine cytology examination and DNA BK PCR are used as a screening test. The prognosis in BK nephropathy has been considered to be poor. The early reduction of immunosuppression can improve the prognosis and perhaps also cidofovir or leflunomide use.

Malignant mesothelioma in 2004: How advanced technology and new drugs are changing the perspectives of mesothelioma patients. Highlights from the VIIth Meeting of the International Mesothelioma Interest Group

Malignant mesothelioma (MMe) is a seemingly uncommon tumour whose incidence has in fact increased steadily and progressively over the last 30 years. Indeed, an actual "epidemic" is expected in the next 20 years, with over 1300 new cases a year till 2020 at least. Despite unquestionable improvement in the diagnostic methods at our disposal and the availability of new treatment strategies, the prognosis of MMe patients remains dramatically poor. For all the above reasons, translational research is the key to success; indeed, ever increasing knowledge of the molecular mechanisms underlying MMe pathogenesis could lead (and is actually leading) to new, hopefully more active, treatment options. To foster discussion among investigators working in this field, and to exchange different viewpoints concerning the newest advances in MMe pathogenesis and treatment, the VII International Mesothelioma Interest Group (IMIG) meeting was held in Brescia (Italy) between 24 and 26 June 2004 in cooperation with the Italian Group for the Study and Therapy of MMe (GIMe). The aim of this report is to summarize the most significant advances in the different disciplines applied to MMe presented and discussed during the IMIG meeting and how these advances will be changing the perspective of patients with MMe.

Basic and clinical research in polyomavirus nephropathy

Over the last decade, polyomavirus nephropathy (PVN) has emerged as an important cause of renal allograft dysfunction and graft loss. PVN occurs with a prevalence of 1%-8% in renal transplant recipients and is most commonly reported within the first 12 months posttransplant. The human polyomavirus, BK virus, is thought to be the primary etiologic agent of PVN. Risk factors for PVN are not well defined and are most likely a result of a complex interaction between multiple donor and recipient factors. Definitive diagnosis of PVN is made through histological assessment of a renal allograft biopsy. Recent studies have also evaluated noninvasive urine and serum markers for screening of BK virus replication and as adjunct tools in PVN diagnosis and monitoring. The principal treatment for PVN is immunosuppression reduction, but this must be balanced against the risks of rejection. If rejection occurs concurrently with PVN, a brief increase in immunosuppression to treat the rejection episode followed by a subsequent reduction in immunosuppression is recommended. No antiviral treatments for PVN have been approved by the Food and Drug Administration. Although the antiviral drug cidofovir has shown in vitro activity against murine polyomaviruses, and has been effective in some patients, it is associated with significant nephrotoxicity. Small series of patients treated with leflunomide and intravenous immune globulin therapy for PVN have also recently been reported. Retransplantation after graft loss due to PVN is feasible, but experience is limited. Current research is focusing on identifying PVN risk factors, refining screening, diagnostic and monitoring methods, and developing therapy for prophylaxis and treatment of PVN with the goals of decreasing the prevalence of PVN and improving allograft outcomes in renal transplant recipients diagnosed with PVN. This review will present recent advances in basic and clinical research related to PVN and renal transplantation.

BK polyomavirus: a newly recognized threat to transplanted kidneys

Reactivation of latent infection with BK polyomavirus is now being recognized as a cause of failure of renal allografts. An increasing serum creatinine concentration in a kidney transplant recipient should prompt a referral for reevaluation by the transplant center.

Polyomavirus BK infection in pediatric kidney-allograft recipients: a single-center analysis of incidence, risk factors, and novel therapeutic approaches

BACKGROUND

Although a growing body of literature regarding polyoma BK virus (BKV) infection and associated interstitial nephritis in kidney-allograft recipients is becoming available, the impact of BKV infection in the pediatric population has not been fully evaluated.

METHODS

In a retrospective analysis, we performed polymerase chain reaction (PCR) assays for BKV DNA in serum and urine samples from 100 pediatric kidney-allograft recipients referred to our institution in the last 5 years.

RESULTS

BKV viruria was observed in 26 of 100 patients, whereas BKV viremia was demonstrated in 5 patients. Serum creatinine was significantly higher in recipients with positive BK viremia compared with BKV DNA-negative patients (mean 2.66 vs. 1.14 mg/100 mL). Renal biopsy performed in 3 of 5 patients showed graft damage consistent with interstitial nephropathy. In the univariate analysis, negative antibody status of the recipient and the presence of mycophenolate mofetil in baseline immunosuppression were the two factors predictive of active BKV infection.

CONCLUSIONS

Our study shows that BKV-associated nephropathy is a relevant complication in the pediatric kidney transplantation setting also. Identification of patients at risk of developing virus-associated nephropathy, through prospective quantification of viral load, could improve clinical outcome by allowing the use of timely preemptive therapy guided by BKV DNA levels.

Pathogenesis and management of polyomavirus infection in transplant recipients

Polyomaviruses (JC virus [JCV], BK virus [BKV], and simian virus 40 [SV40]) establish subclinical and persistent infections and share the capacity for reactivation from latency in their host under immunosuppression. JCV establishes latency mainly in the kidney, and its reactivation results in the development of progressive multifocal leukoencephalopathy. BKV causes infection in the kidney and the urinary tract, and its activation causes a number of disorders, including nephropathy and hemorrhagic cystitis. Recent studies have reported SV40 in the allografts of children who received renal transplants and in the urine, blood, and kidneys of adults with focal segmental glomerulosclerosis, which is a cause of end-stage renal disease and an indication for kidney transplantation. Clinical syndromes related to polyomavirus infection are summarized in the present review, and strategies for the management of patients who receive transplants are discussed.

Polyoma virus in renal transplant recipients

Infection and rejection have been the most critical complications following renal transplantation. Rejection rates have decreased recently with the advent of new and more powerful immunosuppressive agents. However, infection continues to be a serious complication. The use of broad-spectrum antibiotics and the development of antiviral agents have provided effective tools to combat the infectious processes traditionally seen in renal transplant recipients. Recently, a new viral illness has been identified in this population. Polyoma virus infection has been identified as the cause of allograft dysfunction and graft loss. This paper reviews the current prevalence and outcome of renal transplant patients infected with polyoma virus.

BK virus infection in renal transplant recipients

BK virus (BKV) is increasingly being recognized as an important pathogen among renal transplant recipients. To date, only limited information is known about BKV infections in this population; definitive data regarding the epidemiology, diagnosis, treatment, and outcome of BKV infection are lacking. Therefore, further investigations are needed. This article reviews our current understanding of BKV infections among renal transplant patients.

Polyomavirus BK nephropathy in a kidney transplant recipient: critical issues of diagnosis and management

Diagnosis of polyomavirus BK nephropathy and treatment by low-dose immunosuppression may be optimized by using surrogate markers, such as the detection of viral inclusion bearing cells in the urine and polyomavirus BK DNA in plasma by polymerase chain reaction. These markers were used prospectively in the management of a 44-year-old woman and led to the diagnosis of polyomavirus BK nephropathy at an early stage. The management was complicated by the concurrence of acute allograft rejection. Two treatment steps were initiated: antirejection therapy consisting of methylprednisolone for 3 days followed by lowering of the maintenance immunosuppression. This treatment resulted in a return of the serum creatinine concentration to the baseline of 1.6 mg/L, clearance of polyomavirus BK from plasma, and disappearance of viral inclusion bearing cells from the urine. After 2 months of stable allograft function, a control biopsy confirmed the resolution of polyomavirus BK nephropathy. Histologic signs of acute interstitial rejection were found and preemptively treated by methylprednisolone without altering the baseline regimen. Allograft function remained stable without evidence of recurrent polyomavirus BK nephropathy. This case shows the value of surrogate markers used in a prospective fashion for diagnosis and management of polyomavirus BK nephropathy with concurrent rejection.

Diagnosis and management of BK polyomavirus interstitial nephritis in renal transplant recipients

BACKGROUND

Interstitial nephritis caused by BK polyomavirus is a recognized complication of renal transplantation. A study of renal transplant recipients at Duke University Medical Center was undertaken to evaluate diagnostic modalities and assess clinical outcomes in transplant polyomavirus infections.

METHODS

Polyomavirus nephritis was identified in 6 of 240 patients who received renal transplants between January 1996 and June 1998 and an additional patient who underwent transplantation in 1995. The clinical records of these seven patients were reviewed, as were all renal biopsy and nephrectomy specimens. Electron microscopy (EM) was performed on negatively stained urine samples from 6 patients with polyomavirus infection and 23 patients with other diagnoses.

RESULTS

Patients with polyomavirus infection shared several clinical features, including ureteral obstruction (5/7 patients), lymphocele (3/7), bacterial urinary tract infection (3/7), hematuria (3/7), cytomegalovirus infection (3/7), and immunosuppression with mycophenolate mofetil (6/7). All patients experienced elevations in serum creatinine, which stabilized or decreased in four patients with altered or decreased immunosuppression. The diagnosis of polyomavirus infection was established by renal biopsy and EM of urine in five patients, by biopsy alone in one, and by EM alone in one. Sequential examinations of urine by EM were used to monitor the course of infection in six patients.

CONCLUSIONS

Interstitial nephritis due to BK polyomavirus occurred in 2.5% of patients receiving renal transplants at our center since 1996. Polyomavirus infection can cause transplant dysfunction and graft loss, but progression of the infection can frequently be abrogated with alterations in immunosuppressive therapy. Both renal biopsy and EM of urine samples are useful in the diagnosis and monitoring of polyomavirus infections.

Urological treatment and clinical course of BK polyomavirus-associated hemorrhagic cystitis in children after bone marrow transplantation

Hemorrhagic cystitis (HC) is a major complication of bone marrow transplantation (BMT). We describe the clinical course and urological management of BK polyomavirus-associated HC in children after bone marrow transplantation. From 8/88 to 11/95, a total of 117 consecutive pediatric patients received BMT. Nine patients (7. 7%) developed HC after transplantation. HC in all 9 patients was characterized by late onset (day +24 to +50 post-BMT), long duration (1-7 weeks) and the excretion of BK polyomavirus in the urine as confirmed by electron microscopy, DNA hybridization and PCR techniques. Six children developed mild HC (grade 1-2) and were treated successfully by hyperhydration. In 3 patients, severe HC (grade 3-4) over 6 weeks required surgical interventions. In these 3 patients, cystoscopy revealed circumscript papulous tumors as the source of hematuria. Severe and persistent hematuria required blood transfusions, insertion of large suprapubic catheters and permanent bladder irrigation because of recurrent blood clot retention. Attempts to stop the hematuria in 2 of these patients by coagulation and laser vaporization (Nd:YAG) failed to stop the bleeding. Differential diagnosis of hematuria after BMT includes urinary tract infection, cyclophosphamide-induced chemical cystitis and bleeding due to BMT-induced thrombocytopenia. With the increasing number of BMTs in children, urologists may be confronted with BK polyomavirus-associated HC and must consider this in the differential diagnosis of hematuria after BMT.