Andréa Nazaré Monteiro Rangel da Silva

Coinfection between hepatitis C virus (HCV) and human T-lymphotropic virus 1/2 (HTLV-1/2) remains poorly investigated in the Northern Region of Brazil despite its clinically important condition. The objective of this study was to determine the prevalence and describe the epidemiological and behavioral risk factors for HCV/HTLV-1/2 coinfection in Belém, Pará. This observational, descriptive, and cross-sectional study analyzed 192 samples from patients previously diagnosed with HCV: 127 participants recruited between May 2023 and June 2025 and 65 samples previously stored in the Virology Laboratory of UFPA. Data were collected through a structured survey. Serological screening for HTLV-1/2 was performed by enzyme-linked immunosorbent assay (ELISA) and confirmed by INNO-LIA and molecular biology (qPCR). HCV/HTLV-1/2 coinfection was observed in 4 individuals (2.1%), of whom 1.6% had HCV/HTLV-1 coinfection and 0.5% HCV/HTLV-2. There was no statistically significant association when comparing the sociodemographic, clinical characteristics, or risk factors of HCV monoinfected and HCV/HTLV-1/2 coinfected individuals. Although the results show a low prevalence of HTLV-1/2 and HCV coinfection in Belém do Pará, they still reinforce the importance of including HTLV in testing protocols for patients with hepatitis C in the North region of Brazil.

The first case of coronavirus disease 2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), in Brazil was diagnosed on February 26, 2020. Due to the important epidemiological impact of COVID-19, the present study aimed to analyze the specificity of IgG antibody responses to the S1, S2 and N proteins of SARS-CoV-2 in different COVID-19 clinical profiles. This study enrolled 136 individuals who were diagnosed with or without COVID-19 based on clinical findings and laboratory results and classified as asymptomatic or as having mild, moderate or severe disease. Data collection was performed through a semistructured questionnaire to obtain demographic information and main clinical manifestations. IgG antibody responses to the S1 and S2 subunits of the spike (S) protein and the nucleocapsid (N) protein were evaluated using an enzyme-linked immunosorbent assay (ELISA) according to the manufacturer’s instructions. The results showed that among the participants, 87.5% (119/136) exhibited IgG responses to the S1 subunit and 88.25% (120/136) to N. Conversely, only 14.44% of the subjects (21/136) displayed S2 subunit responses. When analyzing the IgG antibody response while considering the different proteins of the virus, patients with severe disease had significantly higher antibody responses to N and S1 than asymptomatic individuals (p ≤ 0.0001), whereas most of the participants had low antibody titers against the S2 subunit. In addition, individuals with long COVID-19 showed a greater IgG response profile than those with symptomatology of a short duration. Based on the results of this study, it is concluded that levels of IgG antibodies may be related to the clinical evolution of COVID-19, with high levels of IgG antibodies against S1 and N in severe cases and in individuals with long COVID-19.

Human T lymphotropic virus 1 (HTLV-1) is a retrovirus associated with inflammatory diseases, including HTLV-1-associated myelopathy (HAM), and host genetic factors may be involved in disease evolution. The forkhead Box P3 (FOXP3) transcription factor is linked to homeostasis of the immune system, and the presence of polymorphisms in the promoter region of the FOXP3 gene should reflect its expression levels and consequent activation of regulatory T cells, which may contribute to severe inflammatory disorders, such as HAM. This study evaluated the rs2232365 polymorphism (−924 A/G) located in the promoter region of the FOXP3 gene and its association with HAM. Forty DNA samples from asymptomatic carriers and 25 samples from HAM patients were used, in addition to 130 control samples. The polymorphism was genotyped by conducting real-time polymerase chain reaction (PCR) (quantitative PCR [qPCR]) on extracted DNA. The proviral loads (PVLs) and CD4⁺ and CD8⁺ T lymphocyte counts were determined by qPCR and FACSCalibur flow cytometry, respectively. The PVLs, CD4⁺ T lymphocyte concentrations, and tumor necrosis factor-α dosages were considered predictive factors of the clinical profiles of HTLV-1 infection, all of which had higher levels in the HAM group. Carriers of the GG genotype for the polymorphism rs2232365 had high PVLs and CD4⁺ T lymphocyte concentrations.

O presente estudo objetivou caracterizar o perfil clinico-epidemiológico de pessoas vivendo com HIV (PVHIV) residentes no estado do Pará. Foram incluídos todos os indivíduos, independente de idade ou sexo, cujas amostras, de 2013 a 2015, foram encaminhadas ao Laboratório Central do Pará (LACEN-PA) para a realização do teste de genotipagem do HIV. Os dados foram obtidos por meio da coleta de informações nos laudos do teste de genotipagem guardados no LACEN. Foram coletadas informações como sexo, idade, nível de escolaridade, raça, ano de diagnóstico, motivos relacionados a mudança de esquema terapêutico e presença de mutações. O gênero masculino foi predominante, com faixa etária entre 40 e 50 anos ou mais, pardos e com ensino fundamental. A maioria teve o diagnóstico para o HIV entre os anos 2000 e 2009, tendo a maior parte apresentado mudanças de esquema terapêutico. Tal fato se deu em grande parte pela presença de falha terapêutica e intolerância, corroborando assim com a presença de mutações. No presente estudo observamos um perfil epidemiológico de PVHIV condizente com a literatura, caracterizado pela prevalência do gênero masculino, com faixa etária entre 40 e 50 anos ou mais, pardo e escolaridade em nível fundamental. Foi possível observar também um alto índice de mudanças nos regimes terapêuticos, de falha terapêutica, além de elevadas taxas de mutações. Demonstrando assim, a importância do exame de genotipagem não só para a escolha da terapia mais adequada como também para a adoção de estratégias que busquem melhorar a adesão de PVHIV ao tratamento com antirretrovirais. Novos estudos que possam contribuir com a compreensão e identificação das mudanças dos regimes terapêuticos assim como a contribuição destes para o aparecimento de mutações e consequente falha terapêutica são necessários.

Studies have shown that the human T-lymphotropic virus 2 (HTLV-2) is endemic in several indigenous populations of the Brazilian Amazon and molecular analyses have shown the exclusive presence of HTLV-2 subtype 2c among the indigenous groups of this geographical region. The present study characterizes the prevalence of HTLV-2 infection in three new villages of the Xikrin tribe, in the Kayapo group, according to their distribution by sex and age. The study included 263 samples from individuals from the Kateté, Djujeko and Oodjã villages. Plasma samples were tested for the presence of anti-HTLV-1/2 antibodies using enzyme-linked immunosorbent assays (ELISA). Seropositive samples were confirmed using real-time PCR, nested PCR and sequencing. The serological and molecular results confirmed the sole presence of HTLV-2 in 77 (29%) samples, with a prevalence of 38% among women and 18% among men. In these communities, it was found that the prevalence of HTLV-2 infection increased with age. Nucleotide sequences (642 bp, 5’LTR) from eight samples were subjected to phylogenetic analysis by the neighbor-joining method to determine the viral subtype, which confirmed the presence of HTLV-2c. The results of the present study establish the presence of HTLV-2 infection in three new villages of the Xikrin tribe and confirm the high endemicity of the infection in the Kayapo indigenous group of the Brazilian Amazon.

A terapia gênica tem como princípio a transferência de material genético para dentro das células de um indivíduo, com o intuito de corrigir genes responsáveis por características patológicas e, assim, tratar doenças. Desse modo, a entrega eficiente e a expressão apropriada dos genes terapêuticos são requisitos fundamentais para a eficiência da terapia gênica. Diante disso, os vírus se apresentam como importantes sistemas para a transferência de genes, sendo utilizados como uma excelente estratégia para o tratamento de doenças monogênicas e não monogênicas. Os vetores virais baseados em retrovírus, adenovírus, vírus adenoassociados, herpesvírus e poxvírus têm sido estudados para o tratamento de doenças monogênicas, incluindo a doença granulomatosa crônica, a imunodeficiência combinada grave ligada ao X e a deficiência da enzima adenosina desaminase, assim como para as doenças não monogênicas como o câncer. A presente revisão objetiva explorar os aspectos mais relevantes do uso de vetores virais na terapia gênica. Embora sejam eficientes na entrega do material genético, os vetores virais apresentam risco de infecção, ativam a resposta imune do hospedeiro e podem apresentar um potencial oncogênico. Assim, para que a terapia gênica possa ser aplicada na rotina clínica, muitas pesquisas ainda são necessárias para o refinamento e aperfeiçoamento da técnica, incluindo o desenvolvimento dos vetores virais.

Yellow fever (YF) is a viral disease transmitted by mosquitoes and endemic mostly in South America and Africa with 20–50% fatality. All current licensed YF vaccines, including YF-Vax^® (Sanofi-Pasteur, Lyon, France) and 17DD-YFV (Bio-Manguinhos, Rio de Janeiro, Brazil), are based on live attenuated virus produced in hens’ eggs and have been widely used. The YF vaccines are considered safe and highly effective. However, a recent increase in demand for YF vaccines and reports of rare cases of YF vaccine-associated fatal adverse events have provoked interest in developing a safer YF vaccine that can be easily scaled up to meet this increased global demand. To this point, we have engineered the YF virus envelope protein (YFE) and transiently expressed it in Nicotiana benthamiana as a stand-alone protein (YFE) or as fusion to the bacterial enzyme lichenase (YFE-LicKM). Immunogenicity and challenge studies in mice demonstrated that both YFE and YFE-LicKM elicited virus neutralizing (VN) antibodies and protected over 70% of mice from lethal challenge infection. Furthermore, these two YFE-based vaccine candidates induced VN antibody responses with high serum avidity in nonhuman primates and these VN antibody responses were further enhanced after challenge infection with the 17DD strain of YF virus. These results demonstrate partial protective efficacy in mice of YFE-based subunit vaccines expressed in N. benthamiana. However, their efficacy is inferior to that of the live attenuated 17DD vaccine, indicating that formulation development, such as incorporating a more suitable adjuvant, may be required for product development.

GB virus C (GBV-C) is a lymphotropic virus with a low level or non-existent replication in the liver. The interaction between HIV-1 and GBV-C apparently reduces the progression of HIV-1 infection to AIDS and improves the quality of life of HIV-1 infected individuals. A cross-sectional study was established to determine the possible effect of HIV-1/GBV-C coinfection on HIV-1 viral load and CD4⁺ T lymphocyte counts. Samples from 313 HIV-1 infected persons from the Virus Laboratory of the Federal University of Pará as well as demographic and clinical information were obtained from medical records. This study used a nested PCR method to determine GBV-C viremia. The prevalence of HIV-1/GBV-C coinfection was 17%. There were no significant differences in the distribution according to age, sex or ethnicity between the groups. The differences in HIV-1 viral load and CD4⁺ T lymphocyte count between the HIV-1 and HIV-1/GBV-C groups were highly significant, indicating that coinfection results in lower viral loads and higher CD4⁺ T lymphocyte counts compared to HIV-1 mono-infection. The results indicate a protective effect among coinfected individuals.