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.

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.

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.