Clinicopathologic Spectrum and Outcomes of Infections Diagnosed on Graft Biopsies and Nephrectomy in Live Renal Allograft Recipients: An Institutional Experience.

OBJECTIVES: Modern immunosuppressive regimens have reduced rejection episodes in renal allograft recipients but have increased the risk of opportunistic infections. Infections are considered to be the second leading cause of death after cardiovascular complications in renal allograft recipients. Data on opportunistic infections affecting the allograft itself are scarce. The present study describes the spectrum of renal opportunistic infections and their outcomes diagnosed on renal allograft biopsies and nephrectomy specimens. MATERIALS AND METHODS: Our retrospective observational study was conducted from December 2011 to December 2021. We analyzed infectious episodes diagnosed on renal allograft biopsies or graft nephrectomy specimens. We obtained clinical, epidemiological, and laboratory details for analyses from hospital records. RESULTS: BK virus nephropathy was the most common opportunistic infection affecting the allograft, accounting for 47% of cases, followed by bacterial graft pyelonephritis (25%). Mucormycosis was the most common fungal infection. The diagnosis of infection from day of transplant ranged from 14 days to 39 months. Follow-up periods ranged from 1 to 10 years. Mortality was highest among patients with opportunistic fungal infection (62%), followed by viral infections, and graft failure rate was highest in patients with graft pyelonephritis (50%). Among patients with BK polyomavirus nephropathy, 45% had stable graft function compared with just 33% of patients with bacterial graft pyelonephritis. CONCLUSIONS: BK polyoma virus infection was the most common infection affecting the renal allograft in our study. Although fungal infections caused the highest mortality among our patients, bacterial graft pyelonephritis was responsible for maximum graft failure. Correctly identifying infections on histology is important so that graft and patient life can be prolonged.

Clinical features of BK-polyomavirus and cytomegalovirus co-infection after kidney transplantation.

BK polyomavirus (BKPyV) and cytomegalovirus (CMV) are the main viral pathogens affecting the graft and recipient outcome after allogenic kidney transplantation. It has recently been found that infection with both viruses has a greater impact on kidney graft function than a single infection. We retrospectively analyzed a cohort of 723 recipients who received kidney transplantation between 2007 and 2015 after living and postmortal donation for differences in risk and outcome parameters regarding BKPyV (DNAemia) and CMV (CMV DNAemia) co-infection compared to sole viremias and to patients without viremia. Of all kidney allograft recipients in our cohort, 8.2% developed co-infection with BKPyV DNAemia and CMV DNAemia, 15.1% showed BKPyV viremia alone and 25.2% sole CMV DNAemia. Acute rejection was closely linked with co-infection (multivariable analysis, p = 0.001). Despite the fact that the estimated glomerular filtration rate of patients with co-infection was noticeably reduced compared to patients with BKV or CMV infection alone, transplant survival and patient survival were not significantly reduced. Co-infection with BKPyV and CMV in kidney transplanted patients is significantly associated with inferior allograft function. Since co-infection is strongly associated with acute rejection, co-infected individuals should be considered a risk collective.

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.

Investigation of simian virus 40 (SV40) and human JC, BK, MC, KI, and WU polyomaviruses in glioma.

The gliomagenesis remains not fully established and their etiological factors still remain obscure. Polyomaviruses were detected and involved in several human tumors. Their potential implication in gliomas has been not yet surveyed in Africa and Arab World. Herein, we investigated the prevalence of six polyomaviruses (SV40, JCPyV, BKPyV, MCPyV, KIPyV, and WUPyV) in 112 gliomas from Tunisian patients. The DNA sequences of polyomaviruses were examined by PCR assays. Viral infection was confirmed by DNA in situ hybridization (ISH) and/or immunohistochemistry (IHC). The relationships between polyomavirus infection and tumor features were evaluated. Specific SV40 Tag, viral regulatory, and VP1 regions were identified in 12 GBM (10.7%). DNA ISH targeting the whole SV40 genome and SV40 Tag IHC confirmed the PCR findings. Five gliomas yielded JCPyV positivity by PCR and DNA ISH (2.7%). However, no BKPyV, KIPyV, and WUPyV DNA sequences were identified in all samples. MCPyV DNA was identified in 30 gliomas (26.8%). For GBM samples, MCPyV was significantly related to patient age (p = 0.037), tumor recurrence (p = 0.024), and SV40 (p = 0.045) infection. No further significant association was identified with the remaining tumor features (p > 0.05) and patient survival (Log Rank, p > 0.05). Our study indicates the presence of SV40, JCPyV, and MCPyV DNA in Tunisian gliomas. Further investigations are required to more elucidate the potential involvement of polyomaviruses in these destructive malignancies.

TdT Expression Is a Marker of Better Survival in Merkel Cell Carcinoma, and Expression of B-Cell Markers Is Associated With Merkel Cell Polyomavirus.

OBJECTIVES: Merkel cell carcinoma is a rare but very aggressive cutaneous tumor. We evaluated the prognostic potential of B-cell markers (terminal deoxynucleotidyl transferase [TdT], PAX5, CD117), follicular stem cell markers (CK15, CK19), p63, p53, RB, and Merkel cell polyomavirus (MCPyV; CM2B4) in 136 primary cutaneous Merkel cell carcinomas. METHODS: Clinical, histopathologic, and immunohistochemical analyses were performed. The results were correlated with patient outcomes by Fisher exact test, log-rank tests, and Cox multivariate models. RESULTS: By Fisher exact test, although TdT significantly correlated with both lack of progression (P = .0087) and alive status (P = .0056), MCPyV status correlated only with alive status (P = .031). In univariate analyses, TdT, MCPyV, and RB significantly correlated with improved overall survival, whereas p63 and CK15 correlated with worse overall survival. However, in multivariate analyses, only TdT expression remained as an independent predictor of improved overall survival, Merkel cell carcinoma-specific survival, and progression-free survival. By linear regression analyses, significant correlations between MCPyV vs TdT, PAX5, and CD117 were observed. CONCLUSIONS: TdT expression is a potential marker of better survival in Merkel cell carcinoma. Expression of B-cell markers is associated with MCPyV, suggesting that clonal viral integration might play a role in the expression of these markers.

CD8 T Cells and STAT1 Signaling Are Essential Codeterminants in Protection from Polyomavirus Encephalopathy.

JC polyomavirus (JCPyV), a human-specific virus, causes the aggressive brain-demyelinating disease progressive multifocal leukoencephalopathy (PML) in individuals with depressed immune status. The increasing incidence of PML in patients receiving immunotherapeutic and chemotherapeutic agents creates a pressing clinical need to define biomarkers to stratify PML risk and develop anti-JCPyV interventions. Mouse polyomavirus (MuPyV) CNS infection causes encephalopathology and may provide insight into JCPyV-PML pathogenesis. Type I, II, and III interferons (IFNs), which all signal via the STAT1 transcription factor, mediate innate and adaptive immune defense against a variety of viral infections. We previously reported that type I and II IFNs control MuPyV infection in non-central nervous system (CNS) organs, but their relative contributions to MuPyV control in the brain remain unknown. To this end, mice deficient in type I, II, or III IFN receptors or STAT1 were infected intracerebrally with MuPyV. We found that STAT1, but not type I, II, or III IFNs, mediated viral control during acute and persistent MuPyV encephalitis. Mice deficient in STAT1 also developed severe hydrocephalus, blood-brain barrier permeability, and increased brain infiltration by myeloid cells. CD8 T cell deficiency alone did not increase MuPyV infection and pathology in the brain. In the absence of STAT1 signaling, however, depletion of CD8 T cells resulted in lytic infection of the choroid plexus and ependymal lining, marked meningitis, and 100% mortality within 2 weeks postinfection. Collectively, these findings indicate that STAT1 signaling and CD8 T cells cocontribute to controlling MuPyV infection in the brain and CNS injury.IMPORTANCE A comprehensive understanding of JCPyV-induced PML pathogenesis is needed to define determinants that predispose patients to PML, a goal whose urgency is heightened by the lack of anti-JCPyV agents. A handicap to achieving this goal is the lack of a tractable animal model to study PML pathogenesis. Using intracerebral inoculation with MuPyV, we found that MuPyV encephalitis in wild-type mice causes an encephalopathy, which is markedly exacerbated in mice deficient in STAT1, a molecule involved in transducing signals from type I, II, and III IFN receptors. CD8 T cell deficiency compounded the severity of MuPyV neuropathology and resulted in dramatically elevated virus levels in the CNS. These findings demonstrate that STAT1 signaling and CD8 T cells concomitantly act to mitigate MuPyV-encephalopathy and control viral infection.

Severe hemorrhagic cystitis caused by the BK polyomavirus is associated with decreased survival post-allogeneic hematopoietic stem cell transplantation.

BACKGROUND: BK polyomavirus reactivation can occur following allogeneic hematopoietic stem cell transplantation (allo-HSCT) and may lead to hemorrhagic cystitis (BKPyV-HC). We hypothesized that development of BKPyV-HC is associated with increased mortality post allo-HSCT. METHODS: We retrospectively reviewed data on 133 adult patients (≥18 years old) who underwent allo-HSCT from 2007 until 2014 at Hospital Israelita Albert Einstein in São Paulo, Brazil. RESULTS: Thirty-six patients presented with BKPyV-HC after a median time of 42 days, with a 1-year cumulative incidence probability of 28.9% (95% CI 21.5%-36.7%). In a multivariate Cox model, risk factors for development of BKPyV-HC included younger age, male sex, development of grade 2-4 acute graft-versus-host disease and recipients of umbilical cord blood grafts. Development of grade 3-4 BKPyV-HC (but not grade 1-2) was associated with a decreased overall survival (OS) in a multivariate Cox model (hazard ratio [HR] 7.51, P < 0.0001) and an increased risk of TRM (HR 3.66, P < 0.0001). Grade 3-4 BKPyV-HC was also associated with an increased risk of relapse that did not reach statistical significance (HR 3.01, P = 0.07). Median overall survival (OS) post-BKPyV-HC was 4.7 months, and cidofovir had no impact on survival. CONCLUSION: Development of BKPyV-HC appears to be associated with decreased survival following allo-HSCT.

Screening for BK Viremia/Viruria and the Impact of Management of BK Virus Nephropathy in Renal Transplant Recipients.

OBJECTIVES: The prevalence of BK-induced nephritis in renal transplant recipients is estimated to be 1% to 10%; the rate of graft loss within 1 year is 30% to 65%. We conducted this study to evaluate screening of BK virus in blood and/or urine among renal transplant recipients and to assess the effects of different therapeutic modalities in renal transplant recipients with BK nephropathy. MATERIALS AND METHODS: Kidney transplant recipients were screened at the time of transplant and then at 1, 2, 3, 6, 9, 12, 18, and 24 months posttransplant. Fiftynine patients were diagnosed with BK virus viremia. Patients were divided into 2 groups according to treatment: group 1 (n = 29) received an active treatment and group 2 (n = 30) received minimized immunosuppression. RESULTS: Most patients required graft biopsies to confirm diagnosis (86.2% in group 1 vs 50% in group 2; P = .03). Both groups were comparable regarding demographic data. Initial posttransplant graft function was significantly better in group 1 (P = .017); ultimately, there was no significant difference between both groups regarding graft survival (P= .51). Fifty percent of patients had biopsy-proven acute T-cell-mediated rejection before BK virus-associated nephropathy diagnosis (significantly higher in group 1). Serum creatinine levels were significantly better in group 2 at 3, 4, and 5 years after BK nephropathy (P = .001, .017, and .003, respectively). CONCLUSIONS: The prevalence of BK nephropathy in our renal transplant recipients was 5.9% with a rate of graft loss ranging from 43% to 51%. Regular screening, less intensive immunosuppressive therapy, and early intervention by reduction of immunosuppressive medications are advisable to obtain early diagnosis and to have better outcomes of BK virus-associated nephropathy with antiviral agents.

Outcome of renal transplant recipients with cytomegalovirus and BK polyomavirus co-infection nephropathy.

Reactivation of cytomegalovirus (CMV) and BK polyomavirus (BKV) can result in virus-associated tubulointerstitial nephritis in renal allografts. All those renal biopsies reported as viral cytopathic were isolated and examined by two independent renal histopathologists from our institute and classified as CMV, BKV, and CMV-BKV coinfection-associated viral cytopathic changes with confirmation through polymerase chain reaction technology in either serum or urine or both. All twenty patients were categorized as 10 in CMV, four in BKV, and six were in CMV-BKV coinfection. One patient each had received antithymocyte globulin and basiliximab as induction all patients received triple-drug immunosuppression. The mean graft survival was 69, 61, and 59 months in CMV, BKV, and CMV-BKV coinfection group, respectively. At the end of the study period, 10 (50%) patients died. 1-, 3-and 5-year patient survival was 94%, 88% and 76% among CMV group, 75%, 75% and 50% in BKV group, and 96%, 83% and 62%, in CMV-BKV coinfection group (P = 0.157). CMV and BK virus are not so common infections in postrenal transplant patients yet an important cause of graft dysfunction. Coinfection did not pose an increased risk for acute rejection or patients and death-censored and uncensored graft survival among compared groups.

Risk Factors for BK Polyoma Virus Treatment and Association of Treatment With Kidney Transplant Failure: Insights From a Paired Kidney Analysis.

BACKGROUND: Identification of risk factors for BK polyoma virus (BKPyV) without confounding by donor factors and era effects in paired analysis may inform strategies to prevent BKPyV. METHODS: In this analysis of 21,575 mate kidney pairs in the Scientific Registry of Transplant Recipients between 2004 and 2010, the presence of a treatment code for BKPyV virus in follow-up forms was used to identify pairs in which 1 of 2 mate kidneys was treated (discordant treatment) or both mate kidneys were treated (concordant treatment). RESULTS: Among 1975 discordant pairs, younger than 18 years or 60 years or older, male sex, HLA mismatch or 4 greater, acute rejection, and depleting antibody induction had a higher odds of treatment, whereas diabetes and sirolimus had a lower odds of treatment, and treatment was associated with a higher risk of allograft failure (hazards ratio, 2.01; 95% confidence interval, 1.63-2.48). The rate of concordant treatment (0.81%) was 2.8 times higher than expected. Concordant treatment was associated with nonwhite donor ethnicity, donation after circulatory death, transplantation after 2008, and transplantation of mate kidneys in the same center. CONCLUSIONS: This analysis of kidneys from the same donor in which only 1 transplant was treated for BKPyV identifies specific risk factors (age <18 or ≥ 60 years, male sex, depleting antibody, HLA mismatch ≥ 4) for BKPyV and provides an estimate of the BKPyV-associated risk of allograft failure (hazards ratio = 2.01) without confounding by donor factors or era effects. The higher than expected rate of concordant treatment suggests the importance of donor factors in BKPyV pathogenesis and warrants further study.

Reactivation of polyomavirus in the genitourinary tract is significantly associated with severe GvHD and oral mucositis following allogeneic stem cell transplantation.

PURPOSE: BK-virus and JC-virus are the most common polyomaviridae associated with hemorrhagic cystitis in the allogeneic transplant setting. Hemorrhagic cystitis and symptomatic viruria caused by these viruses are a major cause of morbidity in patients undergoing allogeneic stem cell transplantation. METHODS: We performed a retrospective evaluation on a highly uniform study population of 73 patients receiving allogeneic stem cell transplantation. Patients were treated according to the FLAMSA-RIC-protocol, and were examined for the incidence of BK-/JC-viruria and late-onset BK-positive hemorrhagic cystitis within a two-year period. RESULTS: The occurrence of BK-viruria was correlated with published risk factors (acute GvHD, oral mucositis, donor type, conditioning, age, gender). Thirty patients (41 %) were found to excrete either BK-virus (n = 17), JC-virus (n = 3) or both (n = 10), of whom 18 patients (60 %) developed higher-grade hemorrhagic cystitis as opposed to none in the virus-negative control group. Higher grade GvHD (grade B-D) was more common in patients with viruria (p = 0.013) and also more common in patients with manifest hemorrhagic cystitis (p = 0.048). Similarly, oral mucositis was associated both with viruria (p = 0.014) and hemorrhagic cystitis (p = 0.005). Manifest cystitis but not viruria was significantly associated with male gender (p = 0.016). No significant correlation was found with age, conditioning with busulfane vs total body irradiation or related vs unrelated donor. CONCLUSIONS: Severe GvHD and oral mucositis are significantly associated with reactivation of polyomaviridae in the genitourinary-tract already at the level of asymptomatic viruria.

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.

Simultaneous pancreas/kidney transplant recipients present with late-onset BK polyomavirus-associated nephropathy.

BACKGROUND: Infections have increased in simultaneous pancreas/kidney transplant recipients (SPKTRs) with BK polyomavirus (BKV)-associated nephropathy (BKVN) being the most important infectious cause of allograft loss. Comparisons of BKVN with kidney transplant recipients (KTRs), however, are lacking. METHODS: We studied all SPKTRs and KTRs at our transplant centre between 2003 and 2012. Eleven of 106 SPKTs (10.4%) and 21 of 1062 KTRs (2.0%) were diagnosed with BKVN with allograft loss in 1 SPKTR (9.1%) and 2 KTRs (9.5%). A control of 95 SPKTRs without BKVN was used for comparison. RESULTS: SPKTRs showed an increased incidence of BKVN compared with KTRs (P < 0.001). Onset of BKVN in SPKTRs was significantly later compared with KTRs (P = 0.033). While 67% of KTRs showed early-onset BKVN, 64% of SPKTRs developed late-onset BKVN. Older recipient age and male gender increased the risk of BKVN in SPKTRs (P < 0.05). No differences were observed for patient and allograft survival (P > 0.05). However, SPKTRs with BKVN showed inferior estimated glomerular filtration rate and a higher incidence of de novo donor-specific antibodies compared with SPKTRs without BKVN in long-term follow-up (P < 0.05). SPKTRs showed higher peak BKV loads, a need for more intense therapeutic intervention and were more likely not to recover to baseline creatinine after BKVN (P < 0.05). CONCLUSIONS: Our results suggest a higher incidence, more severe course and inferior outcome of BKVN in SPKTRs. An increased vulnerability of the allograft kidney due to inferior organ quality may predispose KTRs to early-onset BKVN. In contrast, SPKTRs present with late-onset BKVN in the presence of high-dose immunosuppression.

Symptomatic BK Virus Infection Is Associated With Kidney Function Decline and Poor Overall Survival in Allogeneic Hematopoietic Stem Cell Recipients.

Nephropathy due to BK virus (BKV) infection is an evolving challenge in patients undergoing hematopoietic stem cell transplantation (HSCT). We hypothesized that BKV infection was a marker of kidney function decline and a poor prognostic factor in HSCT recipients who experience this complication. In this retrospective study, we analyzed all patients who underwent their first allogeneic HSCT at our institution between 2004 and 2012. We evaluated the incidence of persistent kidney function decline, which was defined as a confirmed reduction in estimated glomerular filtration rate of at least 25% from baseline using the Chronic Kidney Disease Epidemiology equation. Cox proportional hazard regression was used to model the cause-specific hazard of kidney function decline, and the Fine-Gray method was used to account for the competing risks of death. Among 2477 recipients of a first allogeneic HSCT, BK viruria was detected in 25% (n = 629) and kidney function decline in 944 (38.1%). On multivariate analysis, after adjusting for age, sex, acute graft-versus-host disease (GVHD), chronic GVHD, preparative conditioning regimen, and graft source, BK viruria remained a significant risk factor for kidney function decline (p < 0.001). In addition, patients with BKV infection and kidney function decline experienced worse overall survival. After allogeneic HSCT, BKV infection was strongly and independently associated with subsequent kidney function decline and worse patient survival after HSCT.

Prognostic value of antibodies to Merkel cell polyomavirus T antigens and VP1 protein in patients with Merkel cell carcinoma.

BACKGROUND: Merkel cell polyomavirus (MCPyV) is the main aetiological agent of Merkel cell carcinoma (MCC). Serum antibodies against the major MCPyV capsid protein (VP1) are detected in the general population, whereas antibodies against MCPyV oncoproteins (T antigens) have been reported specifically in patients with MCC. OBJECTIVES: The primary aim was to assess whether detection of serum antibodies against MCPyV proteins at baseline was associated with disease outcome in patients with MCC. The secondary aim was to establish whether evolution of these antibodies during follow-up was associated with the course of the disease. METHODS: Serum T-antigen and VP1 antibodies were assessed by enzyme-linked immunosorbent assay using recombinant proteins in a cohort of 143 patients with MCC, including 84 patients with serum samples available at baseline. RESULTS: Low titres of VP1 antibodies at baseline (< 10 000) were significantly and independently associated with increased risk of recurrence [hazard ratio (HR) 2·71, 95% confidence interval (CI) 1·13-6·53, P = 0·026] and death (HR 3·74, 95% CI 1·53-9·18, P = 0·004), whereas T-antigen antibodies were not found to be associated with outcome. VP1 antibodies did not differ between patients in remission and those with recurrence or progression during follow-up. However, T-antigen antibodies were more frequently detected in patients with recurrence or progression at 12 months (P = 0·020) and 24 months (P = 0·016) after diagnosis. CONCLUSIONS: VP1 antibodies constitute a prognostic marker at baseline, whereas T-antigen antibodies constitute a marker of disease recurrence or progression if detected > 12 months after diagnosis.

Outcomes of kidney transplant tourism and risk factors for de novo urothelial carcinoma.

BACKGROUND: To date, the outcomes of transplant tourism have not been reported extensively. In addition, data about the accuracy of urine cytology for the detection and the role of the BK virus (BKV) in the carcinogenesis of urothelial carcinoma (UC) after renal transplantation are lacking. METHODS: Three hundred seven patients who received deceased donor kidney transplants between January 2003 and December 2009 were retrospectively studied. The clinical parameters and outcomes between the domestic and tourist groups were compared. We also investigated the risk factors and role of BKV in the carcinogenesis of de novo UC by quantitative real-time polymerase chain reaction. RESULTS: The subjects in the tourist group were older at transplantation and had a shorter dialysis time before transplantation. There were significantly higher incidence rates of BKV viruria, Pneumocystis jiroveci pneumonia, and malignancy in the tourist group. Graft and patient survival were superior in the domestic group. A total of 43 cancers were identified, and the most common type of malignancy was UC (23 patients, 53.5%). The tourist group had a significantly higher incidence of tumors. The sensitivity and specificity of urine cytology for detecting UC were 73.9% and 94.7%, respectively. Independent predictors of UC included female sex, use of Chinese herbal medicine, and transplant tourism. Only two patients (8.7%) with UC had detectable BKV. CONCLUSIONS: Transplant tourism was a risk factor for infection and de novo malignancy. Urothelial carcinoma was the most common malignancy after kidney transplantation. Regular screening for the early detection of UC by urine cytology or periodic sonographic surveys is mandatory, especially for those at high risk.

Transient versus persistent BK viremia and long-term outcomes after kidney and kidney-pancreas transplantation.

BACKGROUND AND OBJECTIVES: The objective was to study the long-term impact of transient versus persistent BK viremia on kidney transplant outcomes. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS: In total, 609 recipients who underwent kidney transplant from 2007 to 2011 were screened at months 1-12 for the occurrence of polyomavirus BK viremia; 130 patients (21.7%) developed BK viremia during the first year post-transplant. BK viremia patients were classified according to duration of infection (more or less than 3 months), and BK viral loads (more or less than 10,000 copies/ml) were classified as transient low viremia (n=42), transient high viremia (n=18), persistent low viremia (n=23), and persistent high viremia (n=47). All patients were followed a median of 36 (3-66) months. The rates of BK polyomavirus-associated nephropathy, acute rejection, and 1-year graft function were compared with the polyomavirus BK-negative control group. RESULTS: Patient and graft survival were not significantly different among the groups. Graft function (creatinine; milligrams per deciliter) at 1 year was significantly worse in the persistent high viremia (1.75±0.6) and transient high viremia (1.85±0.7) groups compared with aviremic controls (1.47±0.4; P=0.01 and P=0.01, respectively). The incidence of BK polyomavirus-associated nephropathy was limited to the persistent high viremia group (1.3%, P<0.001). The transient high viremia (50%) and persistent high viremia (34%) groups showed significantly (P=0.01) increased incidence of acute rejection versus aviremic controls (21.5%), transient low viremia (19%), or persistent low viremia (17.3%) groups. CONCLUSION: Low viral load BK viremia, either transient or persistent, was not associated with long-term transplant outcomes. Persistent high viremia was associated with a greater risk for BK polyomavirus-associated nephropathy and subsequent graft dysfunction. Although transient high viremia was not associated with BK polyomavirus-associated nephropathy, it was associated with worse graft function. These data support the role of surveillance for BK viremia after transplant.

Distinct gene expression profiles of viral- and nonviral-associated merkel cell carcinoma revealed by transcriptome analysis.

Merkel cell carcinoma (MCC) is an aggressive cutaneous neuroendocrine tumor with high mortality rates. Merkel cell polyomavirus (MCPyV), identified in the majority of MCCs, may drive tumorigenesis via viral T antigens. However, the mechanisms underlying pathogenesis in MCPyV-negative MCCs remain poorly understood. To nominate genes contributing to the pathogenesis of MCPyV-negative MCCs, we performed DNA microarray analysis on 30 MCCs. The MCPyV status of MCCs was determined by PCR for viral DNA and RNA. A total of 1,593 probe sets were differentially expressed between MCPyV-negative and MCPyV-positive MCCs, with significant differential expression defined as at least a 2-fold change in either direction and a P-value 0.05. MCPyV-negative tumors showed decreased RB1 expression, whereas MCPyV-positive tumors were enriched for immune response genes. Validation studies included immunohistochemistry demonstration of decreased RB protein expression in MCPyV-negative tumors and increased peritumoral CD8+ T lymphocytes surrounding MCPyV-positive tumors. In conclusion, our data suggest that loss of RB1 expression may have an important role in the tumorigenesis of MCPyV-negative MCCs. Functional and clinical validation studies are needed to determine whether this tumor-suppressor pathway represents an avenue for targeted therapy.

Significant overexpression of the Merkel cell polyomavirus (MCPyV) large T antigen in Merkel cell carcinoma.

BACKGROUND: The purpose of this study was to determine the expression pattern of the Merkel cell polyomavirus (MCPyV) large T-protein antigen in patients with Merkel cell carcinoma. METHODS: A tissue microarray (TMA) containing 30 specimens was constructed and stained for the MCPyV large T protein. Immunohistochemical expression was determined semiquantitively and was compared to patients' outcome. RESULTS: Nuclear expression of MCPyV large T protein was detected in 29 of 30 specimens (97%). In particular, 60% to 100%, 30% to 60%, and 10% to 30% of tumor cells were positive in 27 specimens (90%), 1 (3%), and 1 (3%), respectively. There was no difference in positivity between primary and metastatic lesions. Clinical data could not be correlated to MCPyV large T-protein expression. CONCLUSION: MCPyV large T protein was significantly overexpressed in 97% of all specimens. Although we could not demonstrate a predictive effect, MCPyV large T protein may represent a molecular marker with utility in pathological diagnosis as well as a potential new therapeutic target in patients with Merkel cell carcinoma.