Reduction in disialyl-T antigen levels in mice deficient for both St6galnac3 and St6galnac4 results in blood filling of lymph nodes.

Sialic acid (SA) is present at the terminal ends of carbohydrate chains in glycoproteins and glycolipids and is involved in various biological phenomena. The biological function of the disialyl-T (SAα2-3Galß1-3(SAα2-6)GalNAcα1-O-Ser/Thr) structure is largely unknown. To elucidate the role of disialyl-T structure and determine the key enzyme from the N-acetylgalactosaminide α2,6-sialyltransferase (St6galnac) family involved in its in vivo synthesis, we generated St6galnac3- and St6galnac4-deficient mice. Both single-knockout mice developed normally without any prominent phenotypic abnormalities. However, the St6galnac3::St6galnact4 double knockout (DKO) mice showed spontaneous hemorrhage of the lymph nodes (LN). To identify the cause of bleeding in the LN, we examined podoplanin, which modifies the disialyl-T structures. The protein expression of podoplanin in the LN of DKO mice was similar to that in wild-type mice. However, the reactivity of MALII lectin, which recognizes disialyl-T, in podoplanin immunoprecipitated from DKO LN was completely abolished. Moreover, the expression of vascular endothelial cadherin was reduced on the cell surface of high endothelial venule (HEV) in the LN, suggesting that hemorrhage was caused by the structural disruption of HEV. These results suggest that podoplanin possesses disialyl-T structure in mice LN and that both St6galnac3 and St6galnac4 are required for disialyl-T synthesis.

Evidence of BK Polyomavirus Infection in Urothelial but not Renal Tumors from a Single Center Cohort of Kidney Transplant Recipients.

Emerging evidence indicates that reactivation of BK polyomavirus (BKPyV) in the kidney and urothelial tract of kidney transplant recipients (KTRs) may be associated with cancer in these sites. In this retrospective study of a single center cohort of KTRs (n = 1307), 10 clear cell renal cell carcinomas and 5 urinary bladder carcinomas were analyzed from 15 KTRs for the presence of BKPyV infection through immunohistochemistry and fluorescent in situ hybridization (FISH). Three of these patients had already exhibited biopsy-proven polyomavirus-associated nephropathies (PyVAN). Although the presence of BKPyV large-T antigen was evident in the urothelium from a kidney removed soon after PyVAN diagnosis, it was undetectable in all the formalin-fixed and paraffin-embedded (FFPE) blocks obtained from the 10 kidney tumors. By contrast, large-T antigen (LT) labeling of tumor cells was detected in two out of five bladder carcinomas. Lastly, the proportion of BKPyV DNA-FISH-positive bladder carcinoma nuclei was much lower than that of LT-positive cells. Taken together, our findings further strengthen the association between BKPyV reactivation and cancer development in KTRs, especially bladder carcinoma.

Comparison of Immunohistochemical Staining for Large T Antigen and Capsid Protein VP1 in BK Polyomavirus-Associated Nephropathy.

AIM: Most transplant centres use SV40 large T antigen (TAg) staining for the diagnosis and assessment of BK polyomavirus-associated nephropathy (BKPyVAN). This study was performed to evaluate the significance of capsid protein VP1 expression in BKPyVAN. METHODS: We performed immunohistochemical staining using anti-SV40 TAg and anti-BKPyV VP1 antibodies in 16 index biopsies and 12 re-biopsies of BKPyVAN and compared the patterns of positivity and the percentage of positive tubules by counting whole specimens. We investigated the correlation between serum creatinine increase from baseline and the percentage of positive tubules for both markers in 16 index biopsies. RESULTS: In VP1 staining, positive findings were observed not only in the nuclei of tubular epithelial cells but also in the cytoplasm, cells shedding into the lumen, intra-tubular casts, and in the interstitium. Two of 28 biopsies (7.1%) showed TAg-positive and VP1-negative results, in which TAg-positive cells were detected only in a single tubule. The median (interquartile range) percentage of positive tubules was 2.8% (0.7-9.8%) for TAg and 1.4% (0.5-3.9%) for VP1 staining (p = 0.2). In 16 index biopsies, serum creatinine increases significantly correlated with the percentage of VP1-positive tubules (r = 0.49, p = 0.02), while this correlation revealed borderline significance with TAg-positive tubules. CONCLUSIONS: VP1 expression showed various patterns, but was detected in half as many tubules as TAg staining, which might lead to false negatives in the samples with minimal viral replication. However, increased VP1-positive tubules indicate advanced tubular damage and possible association with graft dysfunction.

Variant morphology and random chromosomal integration of BK polyomavirus in posttransplant urothelial carcinomas.

BK polyomavirus (BKPyV) causes major complications in solid organ transplant recipients but little is known about its role in the development of urothelial carcinoma (UC) during immunosuppression. Immunohistochemistry (IHC) screening for polyomavirus large T antigen (LTag) was performed in 94 micropapillary UC (MPUC), 480 unselected UC, 199 muscle invasive UC (including 83 UC with variant differentiation), 76 cases of plasmocytoid, nested and large nested UC and 15 posttransplant UC. LTag expressing UC were reevaluated regarding their histomorphological features and characterized by IHC for p53 and HER2, chromogenic in situ hybridization for HER2 and SNaPshot analysis of the TERT promoter and HRAS. Real-time PCR and next generation sequencing (NGS) were performed to search for BKPyV-DNA and for variants in the tumor and viral genomes. We detected five LTag expressing UC which were diagnosed between 2 and 18 years after kidney (n = 4) or heart (n = 1) transplantation. 89 MPUC without history of organ transplantation and overall 755 UC (including cases with variant histology) were LTag negative. Of the five LTag expressing UC, three were MPUC, one showed extensive divergent differentiation with Mullerian type clear cell carcinoma, and one displayed focal villoglandular differentiation. All five tumors had aberrant nuclear p53 expression, 2/5 were HER2-amplified, and 3/5 had TERT promoter mutations. Within the 50 most common cancer related genes altered in UC we detected very few alterations and no TP53 mutations. BKPyV-DNA was present in 5/5 UC, chromosomal integration of the BKPyV genome was detectable in 4/5 UC. Two UC with BKPyV integration showed small deletions in the BKPyV noncoding control region (NCCR). The only UC without detectable BKPyV integration had a high viral load of human herpesvirus 6 (HHV-6). Our results suggest that LTag expression of integrated BKPyV genomes and resulting p53 inactivation lead to aggressive high-grade UC with unusual, often micropapillary morphology.

Human polyomavirus 6 and 7 are associated with pruritic and dyskeratotic dermatoses.

BACKGROUND: Human polyomavirus (HPyV)6 and HPyV7 are shed chronically from human skin. HPyV7, but not HPyV6, has been linked to a pruritic skin eruption of immunosuppression. OBJECTIVE: We determined whether biopsy specimens showing a characteristic pattern of dyskeratosis and parakeratosis might be associated with polyomavirus infection. METHODS: We screened biopsy specimens showing "peacock plumage" histology by polymerase chain reaction for HPyVs. Cases positive for HPyV6 or HPyV7 were then analyzed by immunohistochemistry, electron microscopy, immunofluorescence, quantitative polymerase chain reaction, and complete sequencing, including unbiased, next-generation sequencing. RESULTS: We identified 3 additional cases of HPyV6 or HPyV7 skin infections. Expression of T antigen and viral capsid was abundant in lesional skin. Dual immunofluorescence staining experiments confirmed that HPyV7 primarily infects keratinocytes. High viral loads in lesional skin compared with normal-appearing skin and the identification of intact virions by both electron microscopy and next-generation sequencing support a role for active viral infections in these skin diseases. LIMITATION: This was a small case series of archived materials. CONCLUSION: We have found that HPyV6 and HPyV7 are associated with rare, pruritic skin eruptions with a distinctive histologic pattern and describe this entity as "HPyV6- and HPyV7-associated pruritic and dyskeratotic dermatoses."

Polyomavirus large T antigen is prevalent in urothelial carcinoma post-kidney transplant.

Viral pathogens have been associated with both infectious disease and neoplasia in transplant recipients. Polyomavirus is emerging as a potential causative agent for genitourinary tract cancer in post-kidney transplant patients. Human papillomavirus (HPV) has a proven role in squamous cancers, but has not been studied in genitourinary malignancies in transplantation. Of 2345 kidney transplants performed at our center over the past 20 years, we identified 16 patients with 20 genitourinary cancers (0.7%), including 13 bladder/ureter carcinomas, 5 renal cell carcinomas (RCCs), and 2 prostate carcinomas. We performed immunohistochemical staining for polyomavirus large T antigen and p16, followed by in situ hybridization for HPV in p16+ cases. Four cases of high-grade invasive urothelial bladder carcinomas were positive for large T. Large T+ urothelial carcinomas developed at least 8 years posttransplant in young men, 3 with history of BK polyoma viremia, 2 of whom had native kidney failure due to reflux/obstruction. In situ hybridization for high-risk HPV was negative in all tested cases. Overall, 3 patients died of carcinoma. All 5 RCCs were negative for both large T and p16; 2 prostate cancers were p16 negative and p16+/HPV negative, respectively. Thus, our study shows a relatively high prevalence of large T antigen in urothelial carcinoma in kidney transplant patients (31%), but not in RCC. Although sample size is small, young patients with obstructive disease may be at particular risk for developing large T-positive urothelial carcinoma. Overall, our data further support the necessities of long-term cancer surveillance for renal transplant patients.

Effect of Leflunomide, Cidofovir and Ciprofloxacin on replication of BKPyV in a salivary gland in vitro culture system.

BK polyomavirus (BKPyV) is a known kidney tropic virus that has been detected at high levels in HIV-associated salivary gland disease (HIV-SGD), one of the most important AIDS associated oral lesions. BKPyV has been detected in HIV-SGD patient saliva and replicates in salivary gland cells in vitro. BKPyV antivirals are currently in wide use to guard against BKPyV mediated organ rejection in kidney transplant recipients. The goal of this study was to investigate the inhibitory effects of three such antiviral agents, Ciprofloxacin, Cidofovir, and Leflunomide in BKPyV infected salivary gland cells. Human salivary gland cells, and Vero cells, were infected with BKPyV, treated with antiviral drugs and assessed for BKPyV gene expression and viral replication for up to 5 days post infection. The kinetics of BKPyV replication were different in salivary gland cells compared to kidney cells. Ciprofloxacin and Cidofovir had minimal effect on metabolic activity and host cell DNA replication, however, cell toxicity was detected at the protein level with Leflunomide treatment. Ciprofloxacin decreased BKV T Ag and VP1 mRNA expression by at least 50% in both cell types, and decreased T Ag protein expression at days 3 and 4 post infection. A 2.5-4 log decrease in intracellular DNA replication and a 2-3 log decrease in progeny release were detected with Ciprofloxacin treatment. Cidofovir and Leflunomide also inhibited BKPyV gene expression and DNA replication. The three drugs diminished progeny release by 30-90% and 2- to 6-fold decreases in infectious virus were detected post drug treatment by fluorescence focus assay. Additionally, three clinical BKPyV isolates were assessed for their responses to these agents in vitro. Cidofovir and Leflunomide, but not Ciprofloxacin treatment resulted in statistically significant inhibition of BKPyV progeny release from salivary gland cells infected with HIVSGD BKPyV isolates. All three drugs decreased progeny release from cells infected with a transplant derived viral isolate. In conclusion, treatment of human salivary gland cells with each of the three drugs produced modest decreases in BKPyV genome replication. These data highlight the need for continued studies to discover more effective and less toxic drugs that inhibit BKPyV replication in salivary gland cells.

A new in situ hybridization and immunohistochemistry with a novel antibody to detect small T-antigen expressions of Merkel cell polyomavirus (MCPyV).

BACKGROUND: Approximately 80% of Merkel cell carcinomas (MCCs) harbor Merkel cell polyomavirus (MCPyV) which monoclonally integrates into the genome and has prognostic significance. The presence or absence of MCPyV is usually diagnosed using CM2B4 immunohistochemistry (IHC) for MCPyV-large T antigen (LT) protein. However, this method poses a risk of misdiagnosis. METHODS: In this study, we determined MCPyV infection in MCCs using real-time PCR for MCPyV-LT DNA and prepared 16 cases of MCPyV-DNA-positive and -negative groups. Diagnostic sensitivity and specificity of conventional PCR for MCPyV-small T antigen (MCPyV-ST), IHC using a newly developed polyclonal antibody (ST-1) for MCPyV-ST protein (MCPyV-ST) (aa: 164-177), and in situ hybridization (ISH) as well as real-time PCR for MCPyV-ST mRNA were compared against CM2B4-IHC for sensitivity (0.94, 15/16) and specificity (0.94, 15/16). RESULTS: The followings are the respective sensitivity and specificity results from examinations for MCPyV-ST gene: conventional PCR for the MCPyV-ST (0.94, 1.0), ST-1-IHC (0.69, 1.0), real-time PCR for ST mRNA (1.0, no data), ST mRNA ISH (0.94, 1.0). Each of the MCPyV-pseudonegative (1/16) and -pseudopositive (1/16) diagnoses evaluated using CM2B4-IHC were accurately corrected by examinations for MCPyV-ST or its expression as well as real-time PCR for MCPyV-LT. Sensitivity of CM2B4-IHC (0.94) was superior to that of ST-1-IHC (0.69) but equal to that of ST mRNA-ISH (0.94). Specificities of ST-1-IHC (1.0) and ST mRNA-ISH (1.0) were superior to that of CM2B4-IHC (0.94). CONCLUSIONS: Therefore, combined application of ST mRNA-ISH and ST-IHC as well as CM2B4-IHC is recommended and will contribute to the diagnostic accuracy for MCPyV infection in MCCs. VIRTUAL SLIDES: The virtual slide(s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/9966295741144834.

[A case report of Streptococcus pneumoniae-induced hemolytic uremic syndrome: appropriate transfusional management by T-antigen determination]. / Un cas de syndrome hémolytique et urémique à Streptococcus pneumoniae : prise en charge transfusionnelle adaptée par la recherche de l'antigène T.

Pediatric hemolytic uremic syndrome (HUS) is a rare complication of infections usually caused by Escherichia coli; Streptococcus pneumoniae may be a causative agent in 5% of cases and is often more serious in terms of morbidity and mortality. We report a case of pediatric HUS following an infection by a serotype of S. pneumoniae not included in the vaccine administered to the child. Bacterial neuraminidase revealed a T-antigen and a Tk-antigen and red blood cells polyagglutinability in the laboratory test. Transfusion has been reoriented by an indication of secondary preparations: deplasmatisation of red blood cells and platelets and abstention of therapeutic plasma administration. HUS evolved favorably in a few days but the child retains consequences of meningitis cerebral anoxia.

Characterization of an early passage Merkel cell polyomavirus-positive Merkel cell carcinoma cell line, MS-1, and its growth in NOD scid gamma mice.

Merkel cell carcinoma (MCC) is an aggressive skin cancer with a high mortality rate. The majority of MCC (70-80%) harbor clonally integrated Merkel cell polyomavirus (MCV) in the tumor genome and express viral T antigen oncoproteins. The characterization of an early passage MCV-positive MCC cell line MS-1 is described, and its cellular, immunohistochemical, and virological features to MCV-negative (UISO, MCC13, and MCC26) and MCV-positive cell lines (MKL-1 and MKL-2) were compared. The MS-1 cellular genome harbors integrated MCV, which preserves an identical viral sequence from its parental tumor. Neither VP2 gene transcripts nor VP1 protein are detectable in MS-1 or other MCV-positive MCC cell lines tested. Mapping of viral and cellular integration sites in MS-1 and MCC tumor samples demonstrates no consistent viral or cellular gene integration locus. All MCV-positive cell lines show cytokeratin 20 positivity and grow in suspension. When injected subcutaneously into NOD scid gamma (NSG) mice, MS-1 forms a discrete macroscopic tumor. Immunophenotypic analysis of the MS-1 cell line and xenografts in mice show identical profiles to the parental tumor biopsy. Hence, MS-1 is an early passage cell line that provides a useful in vitro model to characterize MCV-positive MCC.

Does JC virus have a role in the etiology and prognosis of Egyptian colorectal carcinoma?

John Cunningham virus (JCV) encodes an oncogenic T-antigen, which is capable of interacting with key growth regulatory pathways. JCV definite role as causal agent of human cancer, still awaits final confirmation. The present study was conducted to assess the possible role of JCV in Egyptian colorectal carcinoma (CRC) and correlate the expression with the clinicopathological features and survival. JCV in situ hybridization (ISH) signals and large T antigen immunoreactivity were examined in 87 colonic specimens. Positive glandular JCV ISH signals were detected in 20%, 25% and 40% of normal, adenoma and CRC cases respectively. Stromal JCV ISH signals were identified in 26% of CRC cases and 5% of adenoma however, normal mucosa did not show stromal positivity with significant difference (p = 0.03). Glandular JCV expression was significantly associated with high grade (p = 0.03), high mitotic index (p=0.02) and low apoptotic index (p = 0.00). Positive stromal signals were significantly associated with low apoptosis (p = 0.00). No positive nuclear immunostaining of JCV large T antigen was detected in all specimens. JCV stromal expression was the 2nd most powerful indicator of short survival and bad prognosis (p = 0.03) in CRC patients. JCV might play an etiological role in CRC tumorogenesis and short survival in Egyptian CRC patients.

Prevalence of human polyomaviruses in common and rare types of non-Merkel cell carcinoma skin cancer.

BACKGROUND: Little is known about the association of human polyomaviruses (HPyVs) other than Merkel cell polyomavirus (MCPyV) with nonmelanoma skin cancer. OBJECTIVES: To evaluate the presence of HPyV6, HPyV7, trichodysplasia spinulosa-associated polyomavirus (TSV), also called HPyV8, and the recently discovered HPyV9 in basal cell carcinoma (BCC), actinic keratosis (AK), squamous cell carcinoma in situ (SCCis), squamous cell carcinoma (SCC), keratoacanthoma (KA), microcystic adnexal carcinoma (MAC) and atypical fibroxanthoma (AFX). METHODS: Archival paraffin-embedded samples (n = 193: 41 BCC, 31 AK, 8 SCCis, 52 SCC, 42 KA, 5 MAC and 14 AFX) were analysed for the presence of the respective HPyV by polymerase chain reaction (PCR). HPyV DNA loads (HPyV DNA copies per ß-globin gene copy) were determined in all HPyV-positive samples by quantitative real-time PCR. Immunohistochemical analysis of MCPyV large T-antigen (LTA) expression was performed using the monoclonal antibody CM2B4. RESULTS: MCPyV DNA was found in 29% of BCC, 19% of AK, 25% of SCCis, 27% of SCC, 29% of KA, 0% of MAC and 29% of AFX. MCPyV DNA loads never exceeded 0·3 MCPyV DNA copies per ß-globin gene copy (median 0·004). In the immunohistochemical analysis of MCPyV LTA expression, all evaluated samples (32 MCPyV DNA-positive samples) were LTA negative. HPyV6 DNA was found in 7% of BCC, 3% of AK, 12% of SCCis, 4% of SCC, 5% of KA, and 0% of MAC and AFX. HPyV6 DNA loads never exceeded 0·7 HPyV6 DNA copies per ß-globin gene copy (median 0·015). None of the 193 samples was positive for HPyV7, TSV or HPyV9 DNA. CONCLUSIONS: Our findings argue against a pathogenic role for MCPyV, HPyV6, HPyV7, TSV and HPyV9 in the analysed types of non-Merkel cell carcinoma skin cancer.

JC virus T-antigen regulates glucose metabolic pathways in brain tumor cells.

Recent studies have reported the detection of the human neurotropic virus, JCV, in a significant population of brain tumors, including medulloblastomas. Accordingly, expression of the JCV early protein, T-antigen, which has transforming activity in cell culture and in transgenic mice, results in the development of a broad range of tumors of neural crest and glial origin. Evidently, the association of T-antigen with a range of tumor-suppressor proteins, including p53 and pRb, and signaling molecules, such as ß-catenin and IRS-1, plays a role in the oncogenic function of JCV T-antigen. We demonstrate that T-antigen expression is suppressed by glucose deprivation in medulloblastoma cells and in glioblastoma xenografts that both endogenously express T-antigen. Mechanistic studies indicate that glucose deprivation-mediated suppression of T-antigen is partly influenced by 5'-activated AMP kinase (AMPK), an important sensor of the AMP/ATP ratio in cells. In addition, glucose deprivation-induced cell cycle arrest in the G1 phase is blocked with AMPK inhibition, which also prevents T-antigen downregulation. Furthermore, T-antigen prevents G1 arrest and sustains cells in the G2 phase during glucose deprivation. On a functional level, T-antigen downregulation is partially dependent on reactive oxygen species (ROS) production during glucose deprivation, and T-antigen prevents ROS induction, loss of ATP production, and cytotoxicity induced by glucose deprivation. Additionally, we have found that T-antigen is downregulated by the glycolytic inhibitor, 2-deoxy-D-glucose (2-DG), and the pentose phosphate inhibitors, 6-aminonicotinamide and oxythiamine, and that T-antigen modulates expression of the glycolytic enzyme, hexokinase 2 (HK2), and the pentose phosphate enzyme, transaldolase-1 (TALDO1), indicating a potential link between T-antigen and metabolic regulation. These studies point to the possible involvement of JCV T-antigen in medulloblastoma proliferation and the metabolic phenotype and may enhance our understanding of the role of viral proteins in glycolytic tumor metabolism, thus providing useful targets for the treatment of virus-induced tumors.

No evidence for a causal role of Merkel cell polyomavirus in keratoacanthoma.

BACKGROUND: Merkel cell polyomavirus (MCPyV) is a recently discovered virus that is monoclonally integrated into the genome of approximately 80% of all Merkel cell carcinomas (MCCs). While some evidence exists that MCPyV does not play a pathogenic role in other nonmelanoma skin cancers, such as basal cell carcinoma and squamous cell carcinoma (SCC), little is known about the presence of MCPyV in keratoacanthoma (KA). OBJECTIVES: To evaluate the prevalence, viral DNA-load, and large T(umor)-antigen expression of MCPyV in KA of immunocompetent patients and to compare the results with those found in SCC and MCC. METHODS: Paraffin-embedded tissue samples were analyzed for the presence of MCPyV-DNA by polymerase chain reaction (PCR). MCPyV-DNA load (MCPyV-DNA copies per beta-globin gene copy) was determined by using quantitative real-time PCR. Immunohistochemical analysis of the MCPyV large T-antigen was performed with the monoclonal antibody CM2B4. RESULTS: A total of 137 samples (42 KA, 52 SCC, and 43 MCC) were analyzed. MCPyV-DNA was found significantly more frequently in MCC (37/43, 86.0%) compared with KA (12/42, 28.6%) and SCC (14/52, 26.9%). Moreover, MCPyV-DNA loads were more than two orders of magnitude lower in KA and SCC compared with MCC (median/mean loads 0.005/0.015 [KA] vs 0.023/0.059 [SCC] vs 2.613/56.840 [MCC] MCPyV-DNA copies per beta-globin gene copy). All MCC analyzed (n = 3) expressed MCPyV large T-antigen, whereas 8 KA and 7 SCC were negative in immunohistochemistry. LIMITATIONS: The relatively small number of samples is a limitation. CONCLUSIONS: Our findings argue against a pathogenic role of MCPyV in KA and SCC.

Soft tissue Rosai-Dorfman disease: 29 new lesions in 18 patients, with detection of polyomavirus antigen in 3 abdominal cases.

Soft tissue Rosai-Dorfman disease (STRDD) is rare, previously reported only as single cases and few series. Simian virus 40 (SV40), a polyomavirus, has been identified in lymphoid processes and has a controversial role in neoplasia etiology. Occasional cytoplasmic pink granular inclusions and nuclear changes led us to explore a viral etiology. Only unpublished STRDD from our files with adequate material, soft tissue location, and diagnostic confirmation were included. Immunohistochemistry and follow-up were obtained. Eighteen STRDD patients, 4 male and 14 female, had 29 lesions; 5 with 2 or more lesions. Ages ranged from 8 to 81 years (mean 42.6 years and median 42.5 years). Soft tissue Rosai-Dorfman disease locations include trunk or proximal extremity (n = 19), distal extremity (n = 5), "abdominal" (n = 3), face (n = 1), and unknown subcutaneous site (n = 1). Sizes ranged from 0.5 to 13.7 cm (median, 2.4 cm). Previous disease included lymphoma, buttocks injection site, diabetes and hypothyroidism, and radiation for chronic dermopathy. No patients had a preceding or concurrent known viral infection; none had lymphadenopathy at present. None were known to be immunocompromised. Soft tissue Rosai-Dorfman disease was rapidly progressing. Initial pathologic diagnosis ranged from Rosai-Dorfman disease or inflammatory pseudotumor to inflammatory malignant fibrous histiocytoma. Grossly STRDDs were multilobulated, tan-yellow, and firm; morphologically, circumscribed, and subcutaneous-based. All had sheets of polygonal histiocytes with abundant pale eosinophilic cytoplasm, emperipolesis, plasma cells, and lymphocytes scattered and within clusters. Focal spindle cell change and mild pleomorphism were each observed in 3 patients; 2 had focal necrosis, none with mitoses. Small granular pink cytoplasmic inclusions and nuclear viral-like changes were observed. By immunohistochemistry, all STRDDs were positive for S100 protein, negative for CD1a, Epstein-Barr virus, and latent membrane protein, yet 3 (all abdominal, 1 multicentric) of the 9 studied were focally positive for cytoplasmic and nuclear SV40 polyomavirus. All were treated by local excision. Follow-up on 14 patients older than 8 to 16 years revealed recurrence in 3 patients with persistent multiple lesions, one with abdominal location. There were no metastases or death from disease. Soft tissue Rosai-Dorfman disease is a rapidly evolving, mostly solitary and nonrecurrent trunk and proximal extremity subcutaneous lesion in middle-aged females. More than one third can have persistent multicentric disease. It is important to recognize STRDD, to separate it from malignancy. Epstein-Barr virus/latent membrane protein was negative but polyomavirus was positive in 3 patients with abdominal STRDD, one with multicentric persistent disease. The relationship of polyomavirus to the evolution of abdominal STRDD should be further explored.

Decoy cells in the urine cytology of a renal transplant recipient: an immunohistochemical study.

Human polyoma virus causes renal dysfunction and graft loss as a result of tubulo-interstial nephritis in renal transplant recipients after reactivation of latent virus in renal epithelium. The infected cells in the urinary sediments are characterized by large homogenous inclusions, which may cause diagnostic error in urine cytology. The epithelial cells with polyoma viral inclusions in urine cytology specimens are termed Decoy cells to caution pathologists not to misdiagnose these cells as cancer cells. We present a case of polyoma viral changes detected the first time in our laboratory in the urine of a 46year old male who underwent renal transplantation six months back and followed by immunotherapy. Urine cytological examination showed decoy cells and subsequently revealed on histopathology. Immunoperoxidase staining for SV-40 LT antigen (LT ag), expression of proliferating cell nuclear antigen (PCNA), p53 and Rb genes were also studied in the tissue sections for further observation. The expression of SV40 LT ag was negative, while PCNA showed strong positivity; p53 and Rb were expressed moderately in the nuclei of cells in the tubules. The report of a case of decoy cells in the urine of a patient with renal transplantation focuses the importance of cytologic analysis of urine as a diagnostic tool for screening renal transplant recipients at risk of polyoma viral infection.

Detection of human polyomavirus proteins, T-antigen and agnoprotein, in human tumor tissue arrays.

Expression of the human polyomavirus JCV genome in several experimental animals induces a variety of neural origin tumors. The viral proteins, T-antigen and Agnoprotein, contribute to the oncogenesis of JCV by associating with several tumor suppressor proteins and dysregulating signaling pathways, which results in uncontrolled cell proliferation. In addition, T-antigen and Agnoprotein have been associated with DNA damage and interfering with DNA repair mechanisms. In this study, we have utilized commercially available tissue arrays of human tumors of various origins and demonstrated the expression of both T-antigen and Agnoprotein in some, but not all, tumors of neural and non-neural origin. Most notably, more than 40% of human glioblastomas and greater than 30% of colon adenocarcinomas express viral proteins. The detection of viral transforming proteins, T-antigen and Agnoprotein in the absence of viral capsid proteins suggests a role for JCV in the development and/or progression of human tumors. These results invite further large-scale investigation on the role of polyomaviruses, particularly JCV in the pathogenesis of human cancer.