SARS-CoV-2 uses CD4 to infect T helper lymphocytes.

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the agent of a major global outbreak of respiratory tract disease known as Coronavirus Disease 2019 (COVID-19). SARS-CoV-2 infects mainly lungs and may cause several immune-related complications, such as lymphocytopenia and cytokine storm, which are associated with the severity of the disease and predict mortality. The mechanism by which SARS-CoV-2 infection may result in immune system dysfunction is still not fully understood. Here, we show that SARS-CoV-2 infects human CD4+ T helper cells, but not CD8+ T cells, and is present in blood and bronchoalveolar lavage T helper cells of severe COVID-19 patients. We demonstrated that SARS-CoV-2 spike glycoprotein (S) directly binds to the CD4 molecule, which in turn mediates the entry of SARS- CoV-2 in T helper cells. This leads to impaired CD4 T cell function and may cause cell death. SARS-CoV-2-infected T helper cells express higher levels of IL-10, which is associated with viral persistence and disease severity. Thus, CD4-mediated SARS-CoV-2 infection of T helper cells may contribute to a poor immune response in COVID-19 patients.

Detection of SARS-CoV-2 virus on the ocular surface of an asymptomatic health-care professional / Detecção do vírus SARS-CoV-2 na superfície ocular de um professional de saúde assintomático

ABSTRACT Coronavirus disease (COVID-19) is an infectious disease caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Its main form of transmission is through respiratory droplets. Case reports have described the presence of this virus in biological materials such as blood, feces, urine, and tears, which generate hypotheses about other means thereby the disease is transmitted. In this report, we describe a case of SARS-CoV-2 identified on the eye surface of an asymptomatic health-care professional. The nasopharyngeal reverse transcription polymerase chain reaction test, using a sample collected on the same day, and the serological test, performed 3 months later, did not reveal any evidence of SARS-CoV-2 infection. These results alert on the possibility of a false-positive reverse transcription polymerase chain reaction result for the ocular surface or the presence of the virus in the conjunctival mucosa in individuals without infection.

RESUMO A COVID-19 é uma doença infeciosa causada pelo SARS-CoV-2, sendo sua principal forma de transmissão através de gotículas respiratórias. Já existem relatos de caso descrevendo a presença desse vírus em materiais biológicos como sangue, fezes, urina e lágrima, o que gera hipóteses sobre outros meios de transmissão da doença. Neste estudo, descrevemos um caso de identificação do vírus SARS-CoV-2 na superfície ocular de um profissional de saúde assintomático. A transcrição inversa da reação em cadeia da polimerase da nasofaringe, coletada no mesmo dia, e o teste sorológico, realizado três meses após, não detectaram qualquer evidência de infecção pelo SARS-CoV-2. Esses dados alertam para a possibilidade de resultado falso positivo da transcrição inversa da reação em cadeia da polimerase da superfície ocular ou a presença do vírus na mucosa conjuntival sem infecção.

Morphological, cellular, and molecular basis of brain infection in COVID-19 patients.

Although increasing evidence confirms neuropsychiatric manifestations associated mainly with severe COVID-19 infection, long-term neuropsychiatric dysfunction (recently characterized as part of "long COVID-19" syndrome) has been frequently observed after mild infection. We show the spectrum of cerebral impact of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection, ranging from long-term alterations in mildly infected individuals (orbitofrontal cortical atrophy, neurocognitive impairment, excessive fatigue and anxiety symptoms) to severe acute damage confirmed in brain tissue samples extracted from the orbitofrontal region (via endonasal transethmoidal access) from individuals who died of COVID-19. In an independent cohort of 26 individuals who died of COVID-19, we used histopathological signs of brain damage as a guide for possible SARS-CoV-2 brain infection and found that among the 5 individuals who exhibited those signs, all of them had genetic material of the virus in the brain. Brain tissue samples from these five patients also exhibited foci of SARS-CoV-2 infection and replication, particularly in astrocytes. Supporting the hypothesis of astrocyte infection, neural stem cell-derived human astrocytes in vitro are susceptible to SARS-CoV-2 infection through a noncanonical mechanism that involves spike-NRP1 interaction. SARS-CoV-2-infected astrocytes manifested changes in energy metabolism and in key proteins and metabolites used to fuel neurons, as well as in the biogenesis of neurotransmitters. Moreover, human astrocyte infection elicits a secretory phenotype that reduces neuronal viability. Our data support the model in which SARS-CoV-2 reaches the brain, infects astrocytes, and consequently, leads to neuronal death or dysfunction. These deregulated processes could contribute to the structural and functional alterations seen in the brains of COVID-19 patients.

Lack of association of the KIR and HLA class I ligands with ZIKV infection in south and southeast of Brazil.

BACKGROUND: Zika virus (ZIKV) is an emerging arbovirus associated with foetal malformations and neurological complications. The infection is usually associated with mild symptoms. The comparison between the allelic frequency of polymorphic genes in symptomatic infected individuals in the population can clarify the pathogenic mechanisms of ZIKV. During ZIKV infection, cytokines are produced and natural killer (NK) cells are recruited, whose activation depends on signaling pathways activated by specific receptors, such as killer cell immunoglobulin-like receptors (KIR). These molecules interact with human leukocyte antigen (HLA) class I ligands and are encoded by polymorphic genes. OBJECTIVES: This study aimed to evaluate the frequency of allelic variants of the genes encoding the KIR receptors and their HLA class I ligands in 139 symptomatic ZIKV-patients and 170 controls negative for the virus, and to evaluate the role of these variants for ZIKV susceptibility. METHODS: KIR and HLA class I genes were genotyped using the polymerase chain reaction-sequence specific oligonucleotide (PCR-SSO) technique. FINDINGS: No significant differences in the frequency distribution of KIRs and KIR-HLA in patients compared to controls were observed. MAIN CONCLUSIONS: KIR and its HLA ligands might play a minor role in ZIKV infection in the south and southeast Brazilian individuals.

Characterization of the Interaction Between SARS-CoV-2 Membrane Protein (M) and Proliferating Cell Nuclear Antigen (PCNA) as a Potential Therapeutic Target.

SARS-CoV-2 is an emerging virus from the Coronaviridae family and is responsible for the ongoing COVID-19 pandemic. In this work, we explored the previously reported SARS-CoV-2 structural membrane protein (M) interaction with human Proliferating Cell Nuclear Antigen (PCNA). The M protein is responsible for maintaining virion shape, and PCNA is a marker of DNA damage which is essential for DNA replication and repair. We validated the M-PCNA interaction through immunoprecipitation, immunofluorescence co-localization, and PLA (Proximity Ligation Assay). In cells infected with SARS-CoV-2 or transfected with M protein, using immunofluorescence and cell fractioning, we documented a reallocation of PCNA from the nucleus to the cytoplasm and the increase of PCNA and γH2AX (another DNA damage marker) expression. We also observed an increase in PCNA and γH2AX expression in the lung of a COVID-19 patient by immunohistochemistry. In addition, the inhibition of PCNA translocation by PCNA I1 and Verdinexor led to a reduction of plaque formation in an in vitro assay. We, therefore, propose that the transport of PCNA to the cytoplasm and its association with M could be a virus strategy to manipulate cell functions and may be considered a target for COVID-19 therapy.

Detection of SARS-CoV-2 virus on the ocular surface of an asymptomatic health-care professional.

Coronavirus disease (COVID-19) is an infectious disease caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Its main form of transmission is through respiratory droplets. Case reports have described the presence of this virus in biological materials such as blood, feces, urine, and tears, which generate hypotheses about other means thereby the disease is transmitted. In this report, we describe a case of SARS-CoV-2 identified on the eye surface of an asymptomatic health-care professional. The nasopharyngeal reverse transcription polymerase chain reaction test, using a sample collected on the same day, and the serological test, performed 3 months later, did not reveal any evidence of SARS-CoV-2 infection. These results alert on the possibility of a false-positive reverse transcription polymerase chain reaction result for the ocular surface or the presence of the virus in the conjunctival mucosa in individuals without infection.

Lack of association of the KIR and HLA class I ligands with ZIKV infection in south and southeast of Brazil

BACKGROUND Zika virus (ZIKV) is an emerging arbovirus associated with foetal malformations and neurological complications. The infection is usually associated with mild symptoms. The comparison between the allelic frequency of polymorphic genes in symptomatic infected individuals in the population can clarify the pathogenic mechanisms of ZIKV. During ZIKV infection, cytokines are produced and natural killer (NK) cells are recruited, whose activation depends on signaling pathways activated by specific receptors, such as killer cell immunoglobulin-like receptors (KIR). These molecules interact with human leukocyte antigen (HLA) class I ligands and are encoded by polymorphic genes. OBJECTIVES This study aimed to evaluate the frequency of allelic variants of the genes encoding the KIR receptors and their HLA class I ligands in 139 symptomatic ZIKV-patients and 170 controls negative for the virus, and to evaluate the role of these variants for ZIKV susceptibility. METHODS KIR and HLA class I genes were genotyped using the polymerase chain reaction-sequence specific oligonucleotide (PCR-SSO) technique. FINDINGS No significant differences in the frequency distribution of KIRs and KIR-HLA in patients compared to controls were observed. MAIN CONCLUSIONS KIR and its HLA ligands might play a minor role in ZIKV infection in the south and southeast Brazilian individuals.

Microbiota-derived short-chain fatty acids do not interfere with SARS-CoV-2 infection of human colonic samples.

Microbiota-derived molecules called short-chain fatty acids (SCFAs) play a key role in the maintenance of the intestinal barrier and regulation of immune response during infectious conditions. Recent reports indicate that SARS-CoV-2 infection changes microbiota and SCFAs production. However, the relevance of this effect is unknown. In this study, we used human intestinal biopsies and intestinal epithelial cells to investigate the impact of SCFAs in the infection by SARS-CoV-2. SCFAs did not change the entry or replication of SARS-CoV-2 in intestinal cells. These metabolites had no effect on intestinal cells' permeability and presented only minor effects on the production of anti-viral and inflammatory mediators. Together our findings indicate that the changes in microbiota composition of patients with COVID-19 and, particularly, of SCFAs do not interfere with the SARS-CoV-2 infection in the intestine.

Elevated Glucose Levels Favor SARS-CoV-2 Infection and Monocyte Response through a HIF-1α/Glycolysis-Dependent Axis.

COVID-19 can result in severe lung injury. It remained to be determined why diabetic individuals with uncontrolled glucose levels are more prone to develop the severe form of COVID-19. The molecular mechanism underlying SARS-CoV-2 infection and what determines the onset of the cytokine storm found in severe COVID-19 patients are unknown. Monocytes and macrophages are the most enriched immune cell types in the lungs of COVID-19 patients and appear to have a central role in the pathogenicity of the disease. These cells adapt their metabolism upon infection and become highly glycolytic, which facilitates SARS-CoV-2 replication. The infection triggers mitochondrial ROS production, which induces stabilization of hypoxia-inducible factor-1α (HIF-1α) and consequently promotes glycolysis. HIF-1α-induced changes in monocyte metabolism by SARS-CoV-2 infection directly inhibit T cell response and reduce epithelial cell survival. Targeting HIF-1ɑ may have great therapeutic potential for the development of novel drugs to treat COVID-19.

Adequate Placental Sampling for the Diagnosis and Characterization of Placental Infection by Zika Virus.

The detection of Zika virus (ZIKV) in immunoprivileged anatomical sites, potential sites for viral persistence, may guide the confirmation of undefined cases of ZIKV infection and also bring to light unknown pathways of viral transmission. Thus, this study aimed to characterize ZIKV infection in stratified, standardized placental samples in women with exanthematic febrile manifestations during pregnancy and compare findings to the standard investigation protocol of official health agencies. To this end, a case series of placental findings within a prospective cohort study was conducted over a period of 24 months. Serum/urine were obtained at the time of clinical case identification. Placental sampling was performed following standard investigation protocol (samples of 1.0 cm sent to a reference laboratory) and in a systematic way at various regions, such as chorionic plate, chorionic villi, basal plate, amniotic membrane, and umbilical cord, for subsequent ZIKV identification and quantification. Clinical information was obtained and histological preparation with hematoxylin-eosin staining for morphological evaluation was performed. This case series included 17 placentas systematically collected. Of these, 14 were positive by qRT-PCR for ZIKV, 5 in the umbilical cord, 7 in the amniotic membrane, 7 in the chorionic plate, 13 in the chorionic villi, and 7 in the basal plate, whereas none were reported by the reference laboratory. The most common morphological and anatomopathological findings were increased stromal cellularity, villitis, calcification, maternal vascular malperfusion, placental hypoplasia, and maternal-fetal hemorrhage (intervillous thrombi). Seven women presented positive testing for ZIKV in serological and/or molecular tests during gestation in urine. While viral quantification in urine ranged from 101 to 103 FFU eq/ml, that in different placental regions ranged from 103 to 108 FFU eq/g. Thus, ZIKV can infect different regions of the placenta and umbilical cord of pregnant women, showing that the systematic collection and adequate storage of the placenta is fundamental for the detection of ZIKV in this organ. The detection of ZIKV in the placenta after several months of initial symptoms suggests that this tissue may be a site for viral persistence during pregnancy.

Human adenovirus replication and persistence in hypertrophic adenoids and palatine tonsils in children.

The role of human adenovirus (HAdV) infection in different acute diseases, such as febrile exudative tonsillitis, conjunctivitis, and pharyngoconjunctival fever is well established. However, the relationships, if any, of HAdV persistence and reactivation in the development of the chronic adenotonsillar disease is not fully understood. The present paper reports a 3-year cross-sectional hospital-based study aimed at detecting and quantifying HAdV DNA and mRNA of the HAdV hexon gene in adenoid and palatine tonsil tissues and nasopharyngeal secretions (NPS) from patients with adenotonsillar hypertrophy or recurrent adenotonsillitis. HAdV C, B, and E were detectable in nearly 50% of the patients, with no association with the severity of airway obstruction, nor with the presence of recurrent tonsillitis, sleep apnea or otitis media with effusion (OME). Despite the higher rates of respiratory viral coinfections in patients with HAdV, the presence of other viruses, including DNA and RNA viruses, had no association with HAdV replication or shedding in secretions. Higher HAdV loads in adenoids showed a significant positive correlation with the presence of sleep apnea and the absence of OME. Although this study indicates that a significant proportion (~85%) of individuals with chronic adenotonsillar diseases have persistent nonproductive HAdV infection, including those by HAdV C, B, and E, epithelial and subepithelial cells in tonsils seem to be critical for HAdV C production and shedding in NPS in some patients, since viral antigen was detected in these regions by immunohistochemistry in four patients, all of which were also positive for HAdV mRNA detection.

A Machine Learning Application Based in Random Forest for Integrating Mass Spectrometry-Based Metabolomic Data: A Simple Screening Method for Patients With Zika Virus.

Recent Zika outbreaks in South America, accompanied by unexpectedly severe clinical complications have brought much interest in fast and reliable screening methods for ZIKV (Zika virus) identification. Reverse-transcriptase polymerase chain reaction (RT-PCR) is currently the method of choice to detect ZIKV in biological samples. This approach, nonetheless, demands a considerable amount of time and resources such as kits and reagents that, in endemic areas, may result in a substantial financial burden over affected individuals and health services veering away from RT-PCR analysis. This study presents a powerful combination of high-resolution mass spectrometry and a machine-learning prediction model for data analysis to assess the existence of ZIKV infection across a series of patients that bear similar symptomatic conditions, but not necessarily are infected with the disease. By using mass spectrometric data that are inputted with the developed decision-making algorithm, we were able to provide a set of features that work as a "fingerprint" for this specific pathophysiological condition, even after the acute phase of infection. Since both mass spectrometry and machine learning approaches are well-established and have largely utilized tools within their respective fields, this combination of methods emerges as a distinct alternative for clinical applications, providing a diagnostic screening-faster and more accurate-with improved cost-effectiveness when compared to existing technologies.

Efficient detection of Zika virus RNA in patients' blood from the 2016 outbreak in Campinas, Brazil.

Infection with Zika virus (ZIKV), a mosquito-borne flavivirus has been casually linked with increased congenital microcephaly in Brazil from 2015 through 2016. Sensitive and specific diagnosis of patients with Zika fever (ZIKF) remains critical for patient management. We developed a ZIKV NS5 qRT-PCR assay by combining primers described by Balm et al. and a new Taqman probe. The assay was evaluated and compared with another assay described by Lanciotti et al. (ZIKV 1107) using 51 blood and 42 urine samples from 54 suspected ZIKV patients. ZIKV NS5 performed better in terms of sensitivity with more samples detected as ZIKV-positive (n = 37) than ZIKV 1107 (n = 34) for urine, and ZIKV-positive (n = 29) than ZIKV 1107 (n = 26) for blood. Both assays displayed good overall agreement for urine (κappa = 0.770) and blood (κappa = 0.825) samples. Improved availability of validated diagnostic tests, such ZIKV NS5 qRT-PCR, will be critical to ensure adequate and accurate ZIKV diagnosis.