Evaluation of SARS-CoV-2 interferon gamma release assay in BNT162b2 vaccinated healthcare workers.

To predict protective immunity to SARS-CoV-2, cellular immunity seems to be more sensitive than humoral immunity. Through an Interferon-Gamma (IFN-γ) Release Assay (IGRA), we show that, despite a marked decrease in total antibodies, 94.3% of 123 healthcare workers have a positive cellular response 6 months after inoculation with the 2nd dose of BNT162b2 vaccine. Despite the qualitative relationship found, we did not observe a quantitative correlation between IFN-γ and IgG levels against SARS-CoV-2. Using stimulated whole blood from a subset of participants, we confirmed the specific T-cell response to SARS-CoV-2 by dosing elevated levels of the IL-6, IL-10 and TNF-α. Through a 20-month follow-up, we found that none of the infected participants had severe COVID-19 and that the first positive cases were only 12 months after the 2nd dose inoculation. Future studies are needed to understand if IGRA-SARS-CoV-2 can be a powerful diagnostic tool to predict future COVID-19 severe disease, guiding vaccination policies.

Nocardia spp. isolation in chronic lung diseases: Are there differences between patients with pulmonary nocardiosis and Nocardia colonization?

AIMS: Chronic lung diseases are a recognized risk factor for Nocardia spp. INFECTION: Nocardia spp. isolation does not inevitably imply disease, and thus colonization must be considered. Here, we aimed to analyse the differences between pulmonary nocardiosis (PN) and Nocardia spp. colonization in patients with chronic lung diseases. METHODS AND RESULTS: A retrospective study of patients with laboratory confirmation of isolation of Nocardia spp. in at least one respiratory sample was performed. Patients with PN and Nocardia spp. colonization were compared. There were 71 patients with Nocardia spp. identification, 64.8% were male, with a mean age of 67.7 ± 11.2 years. All patients had ≥1 pre-existing chronic lung disease, and 19.7% of patients were immunocompromised. PN and Nocardia spp. colonization were considered in 26.8% and 73.2% of patients, respectively. Symptoms and chest CT findings were significantly more frequent in patients with PN (p < 0.001). During follow-up time, 12 (16.9%) patients died, 6 in PN group. Immunosuppression, constitutional symptoms, haematological malignancy and PN diagnosis were associated with significantly shorter survival times, despite only immunosuppression (HR 3.399; 95% CI 1.052-10.989) and PN diagnosis (HR 3.568; 95% CI 1.078-11.910) remained associated with a higher death risk in multivariate analysis. CONCLUSIONS: PN was associated with clinical worsening, more chest CT findings and worse clinical outcomes. SIGNIFICANCE AND IMPACT OF STUDY: Nocardia spp. isolation in chronic lung disease patients is more common than expected and the differentiation between colonization and disease is crucial.

Dissecting the molecular mechanisms of mitochondrial import and maturation of peroxiredoxins from yeast and mammalian cells.

Peroxiredoxins (Prxs) are cysteine-based peroxidases that play a central role in keeping the H2O2 at physiological levels. Eukaryotic cells express different Prxs isoforms, which differ in their subcellular locations and substrate specificities. Mitochondrial Prxs are synthesized in the cytosol as precursor proteins containing N-terminal cleavable presequences that act as mitochondrial targeting signals. Due to the fact that presequence controls the import of the vast majority of mitochondrial matrix proteins, the mitochondrial Prxs were initially predicted to be localized exclusively in the matrix. However, recent studies showed that mitochondrial Prxs are also targeted to the intermembrane space by mechanisms that remain poorly understood. While in yeast the IMP complex can translocate Prx1 to the intermembrane space, the maturation of yeast Prx1 and mammalian Prdx3 and Prdx5 in the matrix has been associated with sequential cleavages of the presequence by MPP and Oct1/MIP proteases. In this review, we describe the state of the art of the molecular mechanisms that control the mitochondrial import and maturation of Prxs of yeast and human cells. Once mitochondria are considered the major intracellular source of H2O2, understanding the mitochondrial Prx biogenesis pathways is essential to increase our knowledge about the H2O2-dependent cellular signaling, which is relevant to the pathophysiology of some human diseases.

Mycobacterium tuberculosis associated with severe tuberculosis evades cytosolic surveillance systems and modulates IL-1ß production.

Genetic diversity of Mycobacterium tuberculosis affects immune responses and clinical outcomes of tuberculosis (TB). However, how bacterial diversity orchestrates immune responses to direct distinct TB severities is unknown. Here we study 681 patients with pulmonary TB and show that M. tuberculosis isolates from cases with mild disease consistently induce robust cytokine responses in macrophages across multiple donors. By contrast, bacteria from patients with severe TB do not do so. Secretion of IL-1ß is a good surrogate of the differences observed, and thus to classify strains as probable drivers of different TB severities. Furthermore, we demonstrate that M. tuberculosis isolates that induce low levels of IL-1ß production can evade macrophage cytosolic surveillance systems, including cGAS and the inflammasome. Isolates exhibiting this evasion strategy carry candidate mutations, generating sigA recognition boxes or affecting components of the ESX-1 secretion system. Therefore, we provide evidence that M. tuberculosis strains manipulate host-pathogen interactions to drive variable TB severities.

Nontuberculous mycobacteria in a tertiary Hospital in Portugal: A clinical review.

BACKGROUND: Nontuberculous mycobacteria (NTM) form a heterogeneous group regarding their ability to cause disease. To further understand their clinical relevance, the characteristics of patients who had positive cultures for NTM at a tertiary hospital in Portugal were reviewed. METHODS: Retrospective analysis of patients assessed at the Infectious Diseases (ID) Department of the São João Hospital Center, from January 2007 to December 2014, from whom at least one biological sample was tested culture positive for NTM. RESULTS: A total of 74 patients with at least one positive culture for NTM were identified. Forty-nine (66.2%) were infected by the human immunodeficiency virus, 4 (5.4%) had cancer, and 7 (9.5%) were under immunosuppressive medication. A total of 13 patients (17.6%) fulfilled the American Thoracic Society/ID Society of America criteria for pulmonary NTM disease and treatment was initiated in 12 other patients (16.2%), all of which were immunocompromised. Mycobacterium avium complex was more frequently associated with disease, responsible for 56% of the patients treated. Patients were treated with antituberculosis drugs adjusted for the species isolated, and cure was achieved in 13 patients (52%). CONCLUSION: The present study highlights the importance of understanding the epidemiology of NTM to better comprehend their clinical impact.

Effect of Syzygium cumini and Bauhinia forficata aqueous-leaf extracts on oxidative and mitochondrial parameters in vitro.

Aqueous-leaf extract of Syzygium cumini and Bauhinia forficata are traditionally used in the treatment of diabetes and cancer, especially in South America, Africa, and Asia. In this study, we analyzed the effects of these extracts on oxidative and mitochondrial parameters in vitro, as well as their protective activities against toxic agents. Phytochemical screenings of the extracts were carried out by HPLC analysis. The in vitro antioxidant capacities were compared by DPPH radical scavenging and Fe(2+) chelating activities. Mitochondrial parameters observed were swelling, lipid peroxidation and dehydrogenase activity. The major chemical constituent of S. cumini was rutin. In B. forficata were predominant quercetin and gallic acid. S. cumini reduced DPPH radical more than B. forficata, and showed iron chelating activity at all tested concentrations, while B. forficata had not similar property. In mitochondria, high concentrations of B. forficata alone induced a decrease in mitochondrial dehydrogenase activity, but low concentrations of this extract prevented the effect induced by Fe(2+)+H2O2. This was also observed with high concentrations of S. cumini. Both extracts partially prevented the lipid peroxidation induced by Fe(2+)/citrate. S. cumini was effective against mitochondrial swelling induced by Ca(2+), while B. forficata alone induced swelling more than Ca(2+). This study suggests that leaf extract of S. cumini might represent a useful therapeutic for the treatment of diseases related with mitochondrial dysfunctions. On the other hand, the consumption of B. forficata should be avoided because mitochondrial damages were observed, and this possibly may pose risk to human health.

Reactividad de sueros de pacientes chagásicos crónicos con extractos de aislamientos mexicanos de Trypanosoma cruzi / Reactivity of sera from Chagas patients to extracts of mexican Trypanosoma cruzi isolates

An antigenic extract prepared from four different Mexican isolates of Trypanosoma cruzi cultured on BHI (three came from human cases-Agripina, Fidelfa and Ninoa, and other from triatoma-Cocula) were assayed with human sera. ELISA results always were consistent with clinical diagnosis. Sera from patients with a diagnosis of Chagas disease were reactive and non-chagasic sera were negative. Western blot of chagasic sera recognized antigens of molecular weight > 81 kd, 81 kd, 54 kd, 42 kd, and 26 kd. Sera with high OD in ELISA reacted with more peptide bands. The soluble extract antigens prepared from Mexican isolates of T. cruzi and from the Brazilian Y strain have an homogenous and similar reactivity.