Generation of Primordial Germ Cell-like Cells from iPSCs Derived from Turner Syndrome Patients.

Turner syndrome (TS) is a genetic disorder in females with X Chromosome monosomy associated with highly variable clinical features, including premature primary gonadal failure leading to ovarian dysfunction and infertility. The mechanism of development of primordial germ cells (PGCs) and their connection with ovarian failure in TS is poorly understood. An in vitro model of PGCs from TS would be beneficial for investigating genetic and epigenetic factors that influence germ cell specification. Here we investigated the potential of reprogramming peripheral mononuclear blood cells from TS women (PBMCs-TS) into iPSCs following in vitro differentiation in hPGCLCs. All hiPSCs-TS lines demonstrated pluripotency state and were capable of differentiation into three embryonic layers (ectoderm, endoderm, and mesoderm). The PGCLCs-TS recapitulated the initial germline development period regarding transcripts and protein marks, including the epigenetic profile. Overall, our results highlighted the feasibility of producing in vitro models to help the understanding of the mechanisms associated with germ cell formation in TS.

Field and classroom initiatives for portable sequence-based monitoring of dengue virus in Brazil.

Brazil experienced a large dengue virus (DENV) epidemic in 2019, highlighting a continuous struggle with effective control and public health preparedness. Using Oxford Nanopore sequencing, we led field and classroom initiatives for the monitoring of DENV in Brazil, generating 227 novel genome sequences of DENV1-2 from 85 municipalities (2015-2019). This equated to an over 50% increase in the number of DENV genomes from Brazil available in public databases. Using both phylogenetic and epidemiological models we retrospectively reconstructed the recent transmission history of DENV1-2. Phylogenetic analysis revealed complex patterns of transmission, with both lineage co-circulation and replacement. We identified two lineages within the DENV2 BR-4 clade, for which we estimated the effective reproduction number and pattern of seasonality. Overall, the surveillance outputs and training initiative described here serve as a proof-of-concept for the utility of real-time portable sequencing for research and local capacity building in the genomic surveillance of emerging viruses.

Declining prevalence of hepatitis A and silent circulation of hepatitis E virus infection in southeastern Brazil.

OBJECTIVES: Hepatitis A virus (HAV) infection is considered highly endemic in Brazil, especially in low-income areas. In contrast, only a few human cases of hepatitis E have been reported. This study aimed to estimate the prevalence and potential risk factors of HAV and hepatitis E virus (HEV) infections in an adult population from a rural township of southeastern Brazil. METHODS: We conducted a cross-sectional survey using serum samples from urban and rural residents of Cássia dos Coqueiros, São Paulo state. A total of 990 samples were tested for anti-HAV IgG by chemiluminescent microparticle immunoassay, and a subset of 248 samples tested for anti-HEV IgG, using two commercial ELISA. Variables associated with anti-HAV and anti-HEV positivity were assessed by a multivariate analysis using a binomial logistic regression model. RESULTS: Seroprevalence of HAV and HEV was 89.1% and 20.7%, respectively. Age was significantly associated with HAV infection. Wantai and Mikrogen ELISA yielded comparable HEV seroprevalence results. CONCLUSIONS: Anti-HAV seroprevalence has declined and correlates with age, whereas anti-HEV was significantly higher than that found in previous population-based studies. These results indicate a need for further investigations of the magnitude of HEV infection in Brazil using the currently available, more sensitive diagnostic methods.

Molecular and phylogenetic analyses of human Parvovirus B19 isolated from Brazilian patients with sickle cell disease and ß-thalassemia major and healthy blood donors.

Human Parvovirus B19 (B19V) is a recognized cause of life-threatening conditions among patients with hemoglobinopathies. This study investigates B19V infection in patients with sickle cell disease and ß-thalassemia using different experimental approaches. A total of 183 individuals (144 with sickle cell disease and 39 with ß-thalassemia major) and 100 healthy blood donors were examined for B19V using anti-B19V IgG enzyme immunoassay, quantitative PCR, DNA sequencing, and phylogenetic analysis. Viremia was documented in 18.6% of patients and 1% of donors, and was generally characterized by low viral load (VL); however, acute infections were also observed. Anti-B19V IgG was detected in 65.9% of patients with sickle cell disease and in 60% of donors, whereas the patients with thalassemia exhibited relatively low seroreactivity. The seroprevalence varied among the different age groups. In patients, it progressively increased with age, whereas in donors it reached a plateau. Based on partial NS1 fragments, all isolates detected were classified as subgenotype 1A with a tendency to elicit genetically complex infections. Interestingly, quasispecies occurred in the plasma of not only patients but also donors with even higher heterogeneity. The partial NS1 sequence examined did not exhibit positive selection. Quantitation of B19V with a conservative probe is a technically and practically useful approach. The extensive spread of B19V subgenotype 1A in patients and donors and its recent introduction into the countryside of the São Paulo State, Brazil were demonstrated; however, it is difficult to establish a relationship between viral sequences and the clinical outcomes of the infection.