Impairment of B cell trafficking and differentiation during HIV-1 infection

During the course of HIV-1 infection, several B cell dysfunctions occur as result of virus replication and indirect mechanisms of immunopathology. The B cells abnormalities include hypergammaglobulinemia, a decreased number of memory B cells, increased levels of activation markers on B cell surface and plasmacytosis. The molecular bases for these impairments are not fully characterized but may have relevance for designing functional HIV vaccines and improved treatment. In paper I the expression of chemokine receptors/chemokines important for B cell function was determined on cells from HIV-1 infected patients and controls. We studied the CXC chemokine receptor 4 (CXCR4), CXCR5, and CC chemokine receptor 7 (CCR7) and their respective ligands. We found a decreased expression of CXCR5 to be present on blood B cells from patients (P<0.05), in association with low CD4+ T-cell counts. Interestingly, B cells in blood and lymph nodes from HIV-1-infected patients also displayed an increased expression of the CXC chemokine ligand 13 (CXCL13), the ligand for CXCR5. Upon B-cell activation in vitro, CXCL13 was secreted in culture. The findings suggest that altered CXCR5/CXCL13 expression may participate in B-cell dysfunctions during HIV-1 infection. Loss of memory B cells is a regular finding in the blood of HIV-1 infected patients and the possibility exists that increased apoptosis via the Fas death receptor pathway may participate in this pathological mechanism. Interleukin-7 (IL-7), present to high levels in blood of HIV-1 infected patients, was previously reported to lead to increased Fas expression and Fas mediated apoptosis on T cells. In paper II, a novel mechanism responsible for increased B cell apoptosis in presence of the high IL-7 concentration was described. T cells cultured with IL-7 induced high Fas expression on resting B cells together with an increased sensitivity to Fas mediated apoptosis. As the mediator responsible for B cell priming to Fas mediated apoptosis we identified the cytokine IFN-γ that T cells secrete in response to IL-7. These results indicate a potential link between IL-7 and the increased B cell apoptosis in HIV-1 infected individuals. During HIV-1 infection, loss of memory B-cells, together with an altered differentiation of naïve B-cells, result in production of low quality antibodies, which may be due to impaired immunoglobulin affinity maturation. In paper III, we evaluated the effect of HIV-1 infection on class switch recombination and somatic hypermutation, crucial processes for the generation of functional antibodies, by studying the expression of activation-induced cytidine deaminase (AID) in peripheral B-cells from HIV-1 infected patients and healthy controls. We also studied the phenotype of B cells and their ability to produce immunoglobulins in vitro. Cells from HIV-1 infected patients showed higher baseline levels of AID expression and increased IgA production measured ex-vivo and upon CD40 and TLR9 stimulation in vitro. Moreover, the percentage of CD27(-)IgA+ and CD27(-)IgG+ B-cells in blood was significantly increased in HIV-1 infected patients. Interestingly, our results also showed a significantly increased number of somatic hypermutations in the VH genes in CD27(-) cells from patients. Taken together, the results show that during HIV-1 infection, CD27(-) B-cells can produce class switched and somatically hypermutated antibodies. High levels of soluble CD27 (sCD27), a marker of immune activation, are found during HIV-1 infection; whether sCD27 has a biological role on B cells was previously not known. The aim of paper IV was to investigate whether sCD27, by binding to CD70, can induce IgG production from B cells. B cells from healthy and HIV-1-infected individuals were cultured with recombinant human sCD27 (rhsCD27) and IgG production was measured in culture. We demonstrated that rhsCD27 induced IgG production from antigen-primed (CD27+) B cells. This effect was mediated by rhsCD27 binding to CD70 on B cells leading to activation of Blimp-1 and XBP-1, transcription factors associated with plasma cell differentiation. We found a significant correlation between the levels of serum sCD27 and IgG in HIV-1-infected individuals and healthy controls. The sCD27 may act to enhance immunoglobulin production and differentiation of activated memory B cells, thus providing an activation signal to antigen-experienced B cells. This mechanism may operate during HIV-1 infection when continuous immune activation may lead to up-regulation of CD70 expression and increased sCD27 cleavage and account for increased levels of circulating IgG. In conclusion, in this PhD thesis different mechanisms leading to impairments of B cell function observed during HIV-1 infection, in parallel to abnormal events of immune activation, are characterized

Expansion of KPC-producing Enterobacterales in four large hospitals in Hanoi, Vietnam

Objectives : The incidence of carbapenem resistance among nosocomial Gram-negative bacteria in Vietnam is high and increasing, including among Enterobacterales. In this study, we assessed the presence of one of the main carbapenemase genes, blaKPC, among carbapenem-resistant Enterobacterales (CRE) from four large hospitals in Hanoi, Vietnam, between 2010 and 2015, and described their key molecular characteristics. Methods : KPC-producing Enterobacterales were detected using conventional PCR and were further analysed using S1 nuclease pulsed-field gel electrophoresis (S1-PFGE), Southern blotting and whole-genome sequencing (WGS) for sequence typing and genetic characterisation. Results : blaKPC genes were detected in 122 (20.4%) of 599 CRE isolates. blaKPC-carrying plasmids were diverse in size. Klebsiella pneumoniae harbouring blaKPC genes belonged to ST15 and ST11, whereas KPC-producing Escherichia coli showed more diverse sequence types including ST3580, ST448, ST709 and ST405. Genotypic relationships supported the hypothesis of circulation of a population of ‘resident’ resistant bacteria in one hospital through the years and of transmission among these hospitals via patient transfer. WGS results revealed co-carriage of several other antimicrobial resistance genes and three different genetic contexts of blaKPC-2. Among these, the combination of ISEcp1–blaCTX-M and ISKpn27–blaKPC–ΔISKpn6 on the same plasmid is reported for the first time. Conclusion : We describe the dissemination of blaKPC-expressing Enterobacterales in four large hospitals in Hanoi, Vietnam, since 2010, which may have started earlier, along with their resistance patterns, sequence types, genotypic relationship, plasmid sizes and genetic context, thereby contributing to the overall picture of the antimicrobial resistance situation in Enterobacterales in Vietnam

Awareness and preparedness of healthcare workers against the first wave of the COVID-19 pandemic: A cross-sectional survey across 57 countries.

BACKGROUND: Since the COVID-19 pandemic began, there have been concerns related to the preparedness of healthcare workers (HCWs). This study aimed to describe the level of awareness and preparedness of hospital HCWs at the time of the first wave. METHODS: This multinational, multicenter, cross-sectional survey was conducted among hospital HCWs from February to May 2020. We used a hierarchical logistic regression multivariate analysis to adjust the influence of variables based on awareness and preparedness. We then used association rule mining to identify relationships between HCW confidence in handling suspected COVID-19 patients and prior COVID-19 case-management training. RESULTS: We surveyed 24,653 HCWs from 371 hospitals across 57 countries and received 17,302 responses from 70.2% HCWs overall. The median COVID-19 preparedness score was 11.0 (interquartile range [IQR] = 6.0-14.0) and the median awareness score was 29.6 (IQR = 26.6-32.6). HCWs at COVID-19 designated facilities with previous outbreak experience, or HCWs who were trained for dealing with the SARS-CoV-2 outbreak, had significantly higher levels of preparedness and awareness (p<0.001). Association rule mining suggests that nurses and doctors who had a 'great-extent-of-confidence' in handling suspected COVID-19 patients had participated in COVID-19 training courses. Male participants (mean difference = 0.34; 95% CI = 0.22, 0.46; p<0.001) and nurses (mean difference = 0.67; 95% CI = 0.53, 0.81; p<0.001) had higher preparedness scores compared to women participants and doctors. INTERPRETATION: There was an unsurprising high level of awareness and preparedness among HCWs who participated in COVID-19 training courses. However, disparity existed along the lines of gender and type of HCW. It is unknown whether the difference in COVID-19 preparedness that we detected early in the pandemic may have translated into disproportionate SARS-CoV-2 burden of disease by gender or HCW type

CD27− B-Cells Produce Class Switched and Somatically Hyper-Mutated Antibodies during Chronic HIV-1 Infection

Class switch recombination and somatic hypermutation occur in mature B-cells in response to antigen stimulation. These processes are crucial for the generation of functional antibodies. During HIV-1 infection, loss of memory B-cells, together with an altered differentiation of naïve B-cells result in production of low quality antibodies, which may be due to impaired immunoglobulin affinity maturation. In the current study, we evaluated the effect of HIV-1 infection on class switch recombination and somatic hypermutation by studying the expression of activation-induced cytidine deaminase (AID) in peripheral B-cells from a cohort of chronically HIV-1 infected patients as compared to a group of healthy controls. In parallel, we also characterized the phenotype of B-cells and their ability to produce immunoglobulins in vitro. Cells from HIV-1 infected patients showed higher baseline levels of AID expression and increased IgA production measured ex-vivo and upon CD40 and TLR9 stimulation in vitro. Moreover, the percentage of CD27−IgA+ and CD27−IgG+ B-cells in blood was significantly increased in HIV-1 infected patients as compared to controls. Interestingly, our results showed a significantly increased number of somatic hypermutations in the VH genes in CD27− cells from patients. Taken together, these results show that during HIV-1 infection, CD27− B-cells can also produce class switched and somatically hypermutated antibodies. Our data add important information for the understanding of the mechanisms underlying the loss of specific antibody production observed during HIV-1 infection

IL-7 Promotes CD95-Induced Apoptosis in B Cells via the IFN-γ/STAT1 Pathway

Interleukin-7 (IL-7) concentrations are increased in the blood of CD4+ T cell depleted individuals, including HIV-1 infected patients. High IL-7 levels might stimulate T cell activation and, as we have shown earlier, IL-7 can prime resting T cell to CD95 induced apoptosis as well. HIV-1 infection leads to B cell abnormalities including increased apoptosis via the CD95 (Fas) death receptor pathway and loss of memory B cells. Peripheral B cells are not sensitive for IL-7, due to the lack of IL-7Ra expression on their surface; however, here we demonstrate that high IL-7 concentration can prime resting B cells to CD95-mediated apoptosis via an indirect mechanism. T cells cultured with IL-7 induced high CD95 expression on resting B cells together with an increased sensitivity to CD95 mediated apoptosis. As the mediator molecule responsible for B cell priming to CD95 mediated apoptosis we identified the cytokine IFN-γ that T cells secreted in high amounts in response to IL-7. These results suggest that the lymphopenia induced cytokine IL-7 can contribute to the increased B cell apoptosis observed in HIV-1 infected individuals

Safety and efficacy of fluoxetine on functional outcome after acute stroke (AFFINITY): a randomised, double-blind, placebo-controlled trial

Background Trials of fluoxetine for recovery after stroke report conflicting results. The Assessment oF FluoxetINe In sTroke recoverY (AFFINITY) trial aimed to show if daily oral fluoxetine for 6 months after stroke improves functional outcome in an ethnically diverse population. Methods AFFINITY was a randomised, parallel-group, double-blind, placebo-controlled trial done in 43 hospital stroke units in Australia (n=29), New Zealand (four), and Vietnam (ten). Eligible patients were adults (aged ≥18 years) with a clinical diagnosis of acute stroke in the previous 2–15 days, brain imaging consistent with ischaemic or haemorrhagic stroke, and a persisting neurological deficit that produced a modified Rankin Scale (mRS) score of 1 or more. Patients were randomly assigned 1:1 via a web-based system using a minimisation algorithm to once daily, oral fluoxetine 20 mg capsules or matching placebo for 6 months. Patients, carers, investigators, and outcome assessors were masked to the treatment allocation. The primary outcome was functional status, measured by the mRS, at 6 months. The primary analysis was an ordinal logistic regression of the mRS at 6 months, adjusted for minimisation variables. Primary and safety analyses were done according to the patient's treatment allocation. The trial is registered with the Australian New Zealand Clinical Trials Registry, ACTRN12611000774921. Findings Between Jan 11, 2013, and June 30, 2019, 1280 patients were recruited in Australia (n=532), New Zealand (n=42), and Vietnam (n=706), of whom 642 were randomly assigned to fluoxetine and 638 were randomly assigned to placebo. Mean duration of trial treatment was 167 days (SD 48·1). At 6 months, mRS data were available in 624 (97%) patients in the fluoxetine group and 632 (99%) in the placebo group. The distribution of mRS categories was similar in the fluoxetine and placebo groups (adjusted common odds ratio 0·94, 95% CI 0·76–1·15; p=0·53). Compared with patients in the placebo group, patients in the fluoxetine group had more falls (20 [3%] vs seven [1%]; p=0·018), bone fractures (19 [3%] vs six [1%]; p=0·014), and epileptic seizures (ten [2%] vs two [<1%]; p=0·038) at 6 months. Interpretation Oral fluoxetine 20 mg daily for 6 months after acute stroke did not improve functional outcome and increased the risk of falls, bone fractures, and epileptic seizures. These results do not support the use of fluoxetine to improve functional outcome after stroke

The prevalence of depression and associated risk factors among medical students: An untold story in Vietnam.

BackgroundDepression is a common mental health problem in medical students worldwide. The association between depression and motivation in Vietnamese medical students is not well-documented.ObjectivesTo estimate the prevalence of self-reported depression and to identify associated risk factors among medical students at Hanoi Medical University (HMU).MethodA cross-sectional study was conducted on medical students with clinical experience at HMU from November 2015 to January 2016. We used the multistage cluster random sampling technique to select and invite students to complete a questionnaire including demographic characteristics, Patient Health Questionnaire 9 (PHQ-9), Academic Motivation Scale (AMS), and International Physical Activity Questionnaire Short Form (IPAQ).ResultsAmong 494 participants (78.8% response rate), the prevalence of self-reported depression was 15.2% (95%CI:12.0%-19.0%), and suicidal ideation was 7.7% (95%CI:6.2%-9.5%). Self-reported depression was significantly associated with perceived financial burden, physical inactivity, being senior student, perceived negative influence of night shifts, and non-self-determined motivation profile. Suicidal ideation was significantly associated with perceived financial burden and non-self-determined motivation profile. In the multivariable regression models, significant risk factors for self-reported depression were non-self-determined motivation (PR = 2.62, 95%CI:1.68-4.07), perceived financial burden (PR = 1.95, 95%CI:1.39-2.73), and vigorous level of physical activity (PR = 0.43, 95%CI:0.20-0.942). For suicidal ideation, non-self-determined motivation (PR = 2.33, 95%CI:1.13-4.80) and perceived financial burden (PR = 1.91, 95%CI:1.16-3.13) were significant risk factors.Strengths and limitationsThe strengths of our study included a representative sample, a good response rate, and using a good depression screening tool. However, the PHQ-9 only allowed us to screen for depression, and the translation of the AMS and IPAQ into Vietnamese could potentially decrease these tools' validity.ConclusionThe prevalence of self-reported depression and suicidal ideation in medical students is notably higher compared to the general population in Vietnam. Non-self-determined motivation and financial burden were the prominent risk factors for both the depression and suicidal ideation in medical students

Molecular genotypes of gag sequences in HIV-1 infected children treated with antiretroviral therapy in Vietnam

Background: Gag protein of human immunodeficiency virus (HIV) has been reported to play a crucial role in establishing infection, viral replication, and disease progression; thus, gag might be related to treatment response. The objective of this study was to investigate molecular genotypes of the gag gene, particularly the important functional binding domains in relation to treatment outcomes. Methods: HIV-infected children enrolled and treated at Vietnam National Children’s Hospital were recruited in the study. A total of 25 gag sequences were generated and used to construct phylogenetic trees and aligned with a reference sequence comparing 17 functional domains. Results: We found that all patients in a treatment failure (TF) group belonged to one cluster of the phylogenetic tree. In addition, the rate of mutations was significantly higher in TF compared with a treatment success (TS) group, specifically the PIP2 recognition motif, and the nucleocapsid basic and zinc motif 2 domains [median and (interquartile range (IQR): 12.5 (6.25–12.5) versus 50 (25–50), p < 0.01; 0 (0–0) versus 0 (0–21.43), p = 0.03 and 0 (0–7.14) versus 7.14 (7.14–7.14), p = 0.04, respectively]. When analyzing gag sequences at different time points in seven patients, we did not observe a consistent mutation pattern related to treatment response. Conclusion: Gag mutations in certain domains might be associated with increased viral load; therefore, studying the molecular genotype of the gag gene might be beneficial in monitoring treatment response in HIV-infected children