Impact assessment and investigation of factors associated with herpesviruses viremia in the first year of renal transplantation.

The increased risk for opportunistic infections after a renal transplant requires monitoring of viral infections to avoid future complications. Our goal was to investigate the impact and factors associated with Epstein-Barr virus (EBV), human cytomegalovirus (HCMV) and human herpesvirus type 6 (HHV-6) viremia in renal transplant recipients. Whole blood samples were collected monthly from 82 patients during the first semester and then quarterly up to 1 year after transplantation. EBV, HCMV, and HHV-6 were detected and quantified by TaqMan real-time polymerase chain reaction. The results showed that EBV and HCMV viremia were detected in 32 patients (39% each), while HHV-6 viremia in only 3 patients (3.7%). EBV was significantly associated with age (P = .050), thymoglobuline induction (P = .019), mTOR inhibitor-based therapy (P = .003), and female gender (P = .044). HCMV was significantly associated with basiliximab induction (P = .015), mycophenolate mofetil (MMF)-based therapy (P = .003) and allograft acute rejection (P = .033). Moreover, HCMV-disease was correlated with MMF-based therapy (P = .021) and female gender (P = .003). In conclusion, EBV and HCMV viremia were associated with different immunosuppressive induction and maintenance strategies. Additionally, higher HCMV viremia (> 10 4 copies/mL) was related to acute allograft rejection.

A secretion-enhancing cis regulatory targeting element (SECReTE) involved in mRNA localization and protein synthesis.

The localization of mRNAs encoding secreted/membrane proteins (mSMPs) to the endoplasmic reticulum (ER) likely facilitates the co-translational translocation of secreted proteins. However, studies have shown that mSMP recruitment to the ER in eukaryotes can occur in a manner that is independent of the ribosome, translational control, and the signal recognition particle, although the mechanism remains largely unknown. Here, we identify a cis-acting RNA sequence motif that enhances mSMP localization to the ER and appears to increase mRNA stability, and both the synthesis and secretion of secretome proteins. Termed SECReTE, for secretion-enhancing cis regulatory targeting element, this motif is enriched in mRNAs encoding secretome proteins translated on the ER in eukaryotes and on the inner membrane of prokaryotes. SECReTE consists of ≥10 nucleotide triplet repeats enriched with pyrimidine (C/U) every third base (i.e. NNY, where N = any nucleotide, Y = pyrimidine) and can be present in the untranslated as well as the coding regions of the mRNA. Synonymous mutations that elevate the SECReTE count in a given mRNA (e.g. SUC2, HSP150, and CCW12) lead to an increase in protein secretion in yeast, while a reduction in count led to less secretion and physiological defects. Moreover, the addition of SECReTE to the 3'UTR of an mRNA for an exogenously expressed protein (e.g. GFP) led to its increased secretion from yeast cells. Thus, SECReTE constitutes a novel RNA motif that facilitates ER-localized mRNA translation and protein secretion.

Investigation of three oncogenic epitheliotropic viruses shows human papillomavirus in association with non-melanoma skin cancer.

Non-melanoma skin cancers (NMSC) share similar risk factors with other virus-related cancers, despite the lack of proved causal association between viral infection and NMSC development. We investigated the presence of Merkel cell polyomavirus (MCPyV), Epstein-Barr virus (EBV), and human papillomavirus (HPV) DNA in 83 NMSC fresh-frozen and 16 non-cancerous skin biopsies and evaluated viral infection according to demographical data, histopathological diagnosis, and ultraviolet exposure. Our results showed that 75% of NMSC biopsies were positive for at least one out of three viruses, whereas only 38% of non-cancerous skin biopsies were positive (p = 0.02). Notably, HPV detection was frequent in NMSC (43%) and nearly absent (one sample, 6.7%) in non-cancerous biopsies (p = 0.007). MCPyV was associated with sites of higher exposure to ultraviolet radiation (p = 0.010), while EBV was associated with a compromised immune system (p = 0.032). Our study showed that HPV was strongly associated with NMSC while EBV and MCPyV with other risk factors. Though further studies are required to elucidate the role of viral infection in NMSC development and management, this study supports the possible role of oncogenic viruses in skin cancers, especially HPV.

A globally applicable PCR-based detection and discrimination of BK and JC polyomaviruses.

BKV and JCV belong to the Polyomaviridae family and are opportunistic agents associated with complications in immunocompromised individuals. Although a single screening assay for both viruses would be convenient, the diversity of BKV and JCV serotypes and genotypes is a methodological challenge. In this paper, we developed a PCR method able to detect and segregate BKV and JCV, despite these genetic discrepancies. A duplex semi-nested PCR (duplex snPCR) was designed to target a conserved region (639nt-1516nt) within the VP2 gene. In the first PCR, a primer set common to all BKV and JCV serotypes/ genotypes was used, followed by a semi-nested PCR with internal primers for BKV and JCV segregation. The limit of detection of the duplex snPCR was as low as 10 copies of BKV or JCV plasmids/µL. Specific products were observed when JCV and BKV plasmids were mixed in the same reaction. In field sample testing, the duplex snPCR detected and distinguished both viruses in different biological samples. Results were confirmed by Sanger's sequencing. The geographical complexity of BKV and JCV serotypes and genotypes imposes limits to a simple and universal method that could detect each virus. However, we describe here a sensitive and reliable PCR technique for BKV and JCV diagnosis that overcomes these limitations and could be universally applied.

Human Polyomaviruses: The Battle of Large and Small Tumor Antigens.

About 40 years ago, the large and small tumor antigens (LT-Ag and sT-Ag) of the polyomavirus (PyVs) simian vacuolating virus 40 have been identified and characterized. To date, it is well known that all the discovered human PyVs (HPyVs) encode these 2 multifunctional and tumorigenic proteins, expressed at viral replication early stage. The 2 T-Ags are able to transform cells both in vitro and in vivo and seem to play a distinct role in the pathogenesis of some tumors in humans. In addition, they are involved in viral DNA replication, transcription, and virion assembly. This short review focuses on the structural and functional features of the HPyVs' LT-Ag and sT-Ag, with special attention to their transforming properties.

Clinical aspects and weight gain reduction in swine infected with porcine circovirus type 2 and torque teno sus virus in Brazil.

Simultaneous Porcine circovirus type 2 (PCV-2) and Torque teno sus virus (TTSuV) infections have been reported around the world, generally linked to severe infections. In the present study, 257 swine plasma samples from 31 swine herds located in Brazil, were PCR screened for PCV-2 and TTSuV-1/2 and correlated with clinical data. PCV-2 was detected in 25%, followed by 38.1% and 42.4% of TTSuV-1 and TTSuV-2, respectively. Co-infections of two or three viruses were found in 32.3% of samples. PCV-2 was more frequently detected in the growing (p=0.030) and finishing phases (p=0.0005) while TTSuV-2 in the nursery (p=0.009). Only TTSuV-1 was statistically associated to clinical disease (multiple signs), in combination or not with PCV-2 or TTSuV-2 (p=0.015). PCV-2/TTSuV co-infections were more frequently related to weight gain reduction in comparison to mono-infections (p=0.049) and no-infections (p=0.027), and also in animals with (p=0.011) or without (p=0.037) clinical signs, being the nursery the most affected phase (p=0.025). Our results uphold the pathogenic potential of TTSuV in naturally infected pigs and the clinical/economical impact of this agent, especially in co-infections. Studies addressing the physiopathological mechanisms of simultaneous infections are needed.

ASSOCIATION OF EPSTEIN-BARR VIRUS (EBV) BUT NOT HUMAN PAPILLOMAVIRUS (HPV) WITH GINGIVITIS AND/OR PERIODONTITIS IN TRANSPLANTED INDIVIDUALS.

The aim of this study was to investigate the association of EBV and HPV with gingivitis and/or periodontitis according to the immunologic status. To this end, 74 oral biopsies from transplanted and non-transplanted individuals with the abovementioned oral manifestations were submitted to a screening by PCR for both viruses. According to the results, EBV was strongly associated with gingivitis and/or periodontitis in transplanted individuals (p = 0.011) but not HPV (p = 0.766). EBV-HPV co-detections did not enhance the presence of tissue injury as well. Although a causal relationship was not investigated in this study, the higher frequency of these two oncoviruses in lesion tissues must be investigated in follow-up studies, especially among immunocompromised individuals.

Phylogenetic and structural analysis of merkel cell polyomavirus VP1 in Brazilian samples.

Our understanding of the phylogenetic and structural characteristics of the Merkel Cell Polyomavirus (MCPyV) is increasing but still scarce, especially in samples originating from South America. In order to investigate the properties of MCPyV circulating in the continent in more detail, MCPyV Viral Protein 1 (VP1) sequences from five basal cell carcinoma (BCC) and four saliva samples from Brazilian individuals were evaluated from the phylogenetic and structural standpoint, along with all complete MCPyV VP1 sequences available at Genbank database so far. The VP1 phylogenetic analysis confirmed the previously reported pattern of geographic distribution of MCPyV genotypes and the complexity of the South-American clade. The nine Brazilian samples were equally distributed in the South-American (3 saliva samples); North American/European (2 BCC and 1 saliva sample); and in the African clades (3 BCC). The classification of mutations according to the functional regions of VP1 protein revealed a differentiated pattern for South-American sequences, with higher number of mutations on the neutralizing epitope loops and lower on the region of C-terminus, responsible for capsid formation, when compared to other continents. In conclusion, the phylogenetic analysis showed that the distribution of Brazilian VP1 sequences agrees with the ethnic composition of the country, indicating that VP1 can be successfully used for MCPyV phylogenetic studies. Finally, the structural analysis suggests that some mutations could have impact on the protein folding, membrane binding or antibody escape, and therefore they should be further studied.

Genetic and structural analysis of Merkel cell polyomavirus large T antigen from diverse biological samples.

Merkel cell polyomavirus (MCPyV) large T antigen (LT-ag) is frequently found truncated in Merkel cell carcinomas (MCC) and it is considered a major tumor-specific signature. Nonetheless, the biological role of LT-ag nontruncated mutations is largely unknown. In this study, MCPyV LT-ag second exon from 11 non-MCC oral samples and NCBI sequences derived from different anatomical sites were studied from the genetic and structural standpoint. As expected, the LT-ag mutation profile was influenced by the geographical origin of the sample, although nonsynonymous mutations were more frequent in lesional tissues. Our in silico study suggests that the mutations found would not significantly affect protein functions, regardless of sample category. This work presents a thorough investigation of the structural and functional properties of LT-ag nontruncated mutations in MCPyV. Our results sustain the geographical influence of the MCPyV genetic profile, but do not discard genetic tissue specificities. Further investigation involving other genetic segments in healthy and lesional tissues are necessary to improve our knowledge on MCPyV pathogenesis.

Detection of Merkel cell polyomavirus in oral samples of renal transplant recipients without Merkel cell carcinoma.

Merkel cell carcinoma (MCC) is a rare but aggressive neuroendocrine cancer, with approximately 80% of cases associated with Merkel cell polyomavirus (MCPyV). The lack of information concerning its occurrence in non-MCC immunosuppressed populations led to the investigation of MCPyV DNA in saliva and oral biopsies from 60 kidney allograft recipients and 75 non-transplanted individuals (control group). In contrast to herpesviruses, which was also investigated (CMV, HHV-6A, and B, HHV-7) MCPyV was detected predominantly in patients with oral lesions (gingivitis and/or periodontitis) of both transplanted and non-transplanted groups (P=0.016) and in the saliva of the transplanted group (P=0.009). MCPyV co-detection with CMV (P=0.048), and HHV-6 (P=0.020) in the saliva of transplanted patients requires further investigation on a possible role of co-infection.

Human papillomavirus infections and renal transplantation: a review / Infecções causadas por papilomavírus humanos e transplante renal: uma revisão

The immune suppressive therapy in renal allograft recipients provides a favorable environment to the development of viral infections. Among them,human papillomavirus (HPV) infections are usually related to potential life-threatening mucocutaneous neoplasias. Data from clinical surveys suggestthat transplant recipients may have up to 5-fold increased risk of developing multiple malignancies due to the increased susceptibility to persistent HPV infection. High risk HPV induced oncogenesis is a multi-step process in which a persistent infection is the initiating causative event, though subsequentgenetic and epigenetic alterations may be necessary for malignant transformation. The main tumoral types associated with persistent HPV infection areanogenital, oral and skin cancers, common conditions in transplant recipients and responsible for substantial morbidity and mortality. Since prophylactic vaccines with high rates of efficacy have been approved for human population, studies to evaluate its immunogenicity and efficacy should be considered forlong-term survivors after allogeneic transplantation. Hence, we conducted an extensive revision published data for the last 10 years regarding the theme.To achieve our objectives, we searched in diverse data basis such as Lilacs, ScIELO, Medline, Scopus. We concluded that, concerning the increase in thepopulation of transplant recipients as well as in the incidence of HPV associated diseases, measures for prevention and control are necessary, and includecapaciting human resources and the use of last generation methodologies of diagnosis and prophylaxis.

A terapia imunossupressora em pacientes receptores de transplante renal fornece um ambiente favorável ao desenvolvimento de infecções virais. Dentreestas infecções, aquelas causadas pelos papilomavírus humanos (HPV) são geralmente associadas a neoplasias mucocutâneas que podem ameaçar asobrevida pós-transplante. Pesquisas clínicas sugerem que receptores de transplante podem apresentar um risco até cinco vezes maior de desenvolverem quadros de doenças malignas múltiplas, devido à maior frequência da persistência do HPV. A oncogênese induzida por HPV de alto risco é um processo demúltiplos estágios, no qual a infecção persistente é o evento fundamental, apesar de alterações genéticas e epigenéticas adicionais serem necessárias para a transformação maligna. Os principais tipos tumorais relacionados à infecção persistente por HPV são os cânceres anogenitais, orais e de pele, comunsem receptores de transplante e responsáveis por grande morbidade e mortalidade. Uma vez que vacinas profiláticas de alta eficácia contra a infecçãopelo HPV foram aprovadas para uso na população humana, estudos para avaliar a imunogenicidade e eficácia destas vacinas em imunossuprimidos são recomendáveis. Assim, objetivamos fazer extensa revisão sobre o tema. Para tal, pesquisamos o assunto nas bases de dados Lilacs, ScIELO, Medline,Scopus nos últimos 10 anos. Concluímos que, com o aumento na população de receptores de transplantes e a crescente incidência das doenças associadasao HPV, medidas de prevenção e controle se fazem necessárias e englobam desde a formação de profissionais capacitados até a aplicação de metodologias de diagnóstico e profilaxia, de última geração.