Urban living in healthy Tanzanians is associated with an inflammatory status driven by dietary and metabolic changes.

Sub-Saharan Africa currently experiences an unprecedented wave of urbanization, which has important consequences for health and disease patterns. This study aimed to investigate and integrate the immune and metabolic consequences of rural or urban lifestyles and the role of nutritional changes associated with urban living. In a cohort of 323 healthy Tanzanians, urban as compared to rural living was associated with a pro-inflammatory immune phenotype, both at the transcript and protein levels. We identified different food-derived and endogenous circulating metabolites accounting for these differences. Serum from urban dwellers induced reprogramming of innate immune cells with higher tumor necrosis factor production upon microbial re-stimulation in an in vitro model of trained immunity. These data demonstrate important shifts toward an inflammatory phenotype associated with an urban lifestyle and provide new insights into the underlying dietary and metabolic factors, which may affect disease epidemiology in sub-Sahara African countries.

Host genetic regulation of human gut microbial structural variation.

Although the impact of host genetics on gut microbial diversity and the abundance of specific taxa is well established1-6, little is known about how host genetics regulates the genetic diversity of gut microorganisms. Here we conducted a meta-analysis of associations between human genetic variation and gut microbial structural variation in 9,015 individuals from four Dutch cohorts. Strikingly, the presence rate of a structural variation segment in Faecalibacterium prausnitzii that harbours an N-acetylgalactosamine (GalNAc) utilization gene cluster is higher in individuals who secrete the type A oligosaccharide antigen terminating in GalNAc, a feature that is jointly determined by human ABO and FUT2 genotypes, and we could replicate this association in a Tanzanian cohort. In vitro experiments demonstrated that GalNAc can be used as the sole carbohydrate source for F. prausnitzii strains that carry the GalNAc-metabolizing pathway. Further in silico and in vitro studies demonstrated that other ABO-associated species can also utilize GalNAc, particularly Collinsella aerofaciens. The GalNAc utilization genes are also associated with the host's cardiometabolic health, particularly in individuals with mucosal A-antigen. Together, the findings of our study demonstrate that genetic associations across the human genome and bacterial metagenome can provide functional insights into the reciprocal host-microbiome relationship.

A functional genomics approach in Tanzanian population identifies distinct genetic regulators of cytokine production compared to European population.

Humans exhibit remarkable interindividual and interpopulation immune response variability upon microbial challenges. Cytokines play a vital role in regulating inflammation and immune responses, but dysregulation of cytokine responses has been implicated in different disease states. Host genetic factors were previously shown to significantly impact cytokine response heterogeneity mainly in European-based studies, but it is unclear whether these findings are transferable to non-European individuals. Here, we aimed to identify genetic variants modulating cytokine responses in healthy adults of East African ancestry from Tanzania. We leveraged both cytokine and genetic data and performed genome-wide cytokine quantitative trait loci (cQTLs) mapping. The results were compared with another cohort of healthy adults of Western European ancestry via direct overlap and functional enrichment analyses. We also performed meta-analyses to identify cQTLs with congruent effect direction in both populations. In the Tanzanians, cQTL mapping identified 80 independent suggestive loci and one genome-wide significant locus (TBC1D22A) at chromosome 22; SNP rs12169244 was associated with IL-1b release after Salmonella enteritidis stimulation. Remarkably, the identified cQTLs varied significantly when compared to the European cohort, and there was a very limited percentage of overlap (1.6% to 1.9%). We further observed ancestry-specific pathways regulating induced cytokine responses, and there was significant enrichment of the interferon pathway specifically in the Tanzanians. Furthermore, contrary to the Europeans, genetic variants in the TLR10-TLR1-TLR6 locus showed no effect on cytokine response. Our data reveal both ancestry-specific effects of genetic variants and pathways on cytokine response heterogeneity, hence arguing for the importance of initiatives to include diverse populations into genomics research.

Prevalence and 3-month follow-up of cerebrovascular MRI markers in hospitalized COVID-19 patients: the CORONIS study.

PURPOSE: To investigate the prevalence of cerebrovascular MRI markers in unselected patients hospitalized for COVID-19 (Coronavirus disease 2019), we compared these with healthy controls without previous SARS-CoV-2 infection or hospitalization and subsequently, investigated longitudinal (incidental) lesions in patients after three months. METHODS: CORONIS (CORONavirus and Ischemic Stroke) was an observational cohort study in adult hospitalized patients for COVID-19 and controls without COVID-19, conducted between April 2021 and September 2022. Brain MRI was performed shortly after discharge and after 3 months. Outcomes included recent ischemic (DWI-positive) lesions, previous infarction, microbleeds, white matter hyperintensities (WMH) and intracerebral hemorrhage and were analysed with logistic regression to adjust for confounders. RESULTS: 125 patients with COVID-19 and 47 controls underwent brain MRI a median of 41.5 days after symptom onset. DWI-positive lesions were found in one patient (1%) and in one (2%) control, both clinically silent. WMH were more prevalent in patients (78%) than in controls (62%) (adjusted OR: 2.95 [95% CI: 1.07-8.57]), other cerebrovascular MRI markers did not differ. Prevalence of markers in ICU vs. non-ICU patients was similar. After three months, five patients (5%) had new cerebrovascular lesions, including DWI-positive lesions (1 patient, 1.0%), cerebral infarction (2 patients, 2.0%) and microbleeds (3 patients, 3.1%). CONCLUSION: Overall, we found no higher prevalence of cerebrovascular markers in unselected hospitalized COVID-19 patients compared to controls. The few incident DWI-lesions were most likely to be explained by risk-factors of small vessel disease. In the general hospitalized COVID-19 population, COVID-19 shows limited impact on cerebrovascular MRI markers shortly after hospitalization.

Parental engagement in research on paediatric lower respiratory tract infections in Indonesia.

BACKGROUND: Lower respiratory tract infections (LRTIs) in children are a major concern in Indonesia as it is the leading cause of morbidity and mortality. Therefore, research on LRTIs is crucial to improve children's health. However, clinical research in children is challenging due to parental concerns. This study aims to understand parental considerations for taking part in clinical studies on LRTI in the Indonesian context. METHODS: A cross-sectional study using a validated online questionnaire was conducted from November 2021 to March 2022. This study included parents from two public elementary schools and two private primary schools in Semarang, Indonesia. A total of 1236 responses were analysed. RESULTS: There was a significant association between educational attainment and willingness to participate in general health and LRTI-related research requiring specimen collection; respondents with an advanced educational level were more likely to refuse participation in research. A similar pattern was observed among respondents with smaller families and younger children against participation in LRTI research. Most respondents who indicated not to participate explained that they did not perceive the necessity to take part and expressed their concerns about endangering their child's health as a consequence of the specimen collection. Most respondents expected a personal benefit and prioritized access to the study results for their child. CONCLUSION: Parents' educational background and family composition are important determinants of parental engagement in research on LRTI in Indonesia. Notably, parents with a lower educational level, having large families, and older children were more inclined to participate. The emphasis on concerns about potential harm and personal benefit underscores the need for a targeted communication strategy.

Correction: Immunogenicity and reactogenicity of SARS-CoV-2 vaccines in people living with HIV in the Netherlands: A nationwide prospective cohort study.

[This corrects the article DOI: 10.1371/journal.pmed.1003979.].

OTULIN Haploinsufficiency-Related Fasciitis and Skin Necrosis Treated by TNF Inhibition.

Here, we describe an adult female with severe fasciitis and skin necrosis who carried a private, predicted deleterious missense mutation in OTULIN in heterozygosity. OTULIN is a cellular regulator of deubiquitination that has been shown to play a key role in intrinsic immunity against staphylococcal α-toxin. The patient was treated with broad-spectrum antibiotics, and multiple surgical explorations were conducted without clinical response. Since autoinflammation was the predominant clinical feature, TNF inhibition was started with a good clinical response. We show that excessive inflammation in OTULIN haploinsufficiency can be effectively treated by TNF inhibition.

Whole sporozoite immunization with Plasmodium falciparum strain NF135 in a randomized trial.

BACKGROUND: Whole sporozoite immunization under chemoprophylaxis (CPS regime) induces long-lasting sterile homologous protection in the controlled human malaria infection model using Plasmodium falciparum strain NF54. The relative proficiency of liver-stage parasite development may be an important factor determining immunization efficacy. Previous studies show that Plasmodium falciparum strain NF135 produces relatively high numbers of large liver-stage schizonts in vitro. Here, we evaluate this strain for use in CPS immunization regimes. METHODS: In a partially randomized, open-label study conducted at the Radboudumc, Nijmegen, the Netherlands, healthy, malaria-naïve adults were immunized by three rounds of fifteen or five NF135-infected mosquito bites under mefloquine prophylaxis (cohort A) or fifteen NF135-infected mosquito bites and presumptive treatment with artemether/lumefantrine (cohort B). Cohort A participants were exposed to a homologous challenge 19 weeks after immunization. The primary objective of the study was to evaluate the safety and tolerability of CPS immunizations with NF135. RESULTS: Relatively high liver-to-blood inocula were observed during immunization with NF135 in both cohorts. Eighteen of 30 (60%) high-dose participants and 3/10 (30%) low-dose participants experienced grade 3 adverse events 7 to 21 days following their first immunization. All cohort A participants and two participants in cohort B developed breakthrough blood-stage malaria infections during immunizations requiring rescue treatment. The resulting compromised immunizations induced modest sterile protection against homologous challenge in cohort A (5/17; 29%). CONCLUSIONS: These CPS regimes using NF135 were relatively poorly tolerated and frequently required rescue treatment, thereby compromising immunization efficiency and protective efficacy. Consequently, the full potential of NF135 sporozoites for induction of immune protection remains inconclusive. Nonetheless, the high liver-stage burden achieved by this strain highlights it as an interesting potential candidate for novel whole sporozoite immunization approaches. TRIAL REGISTRATION: The trial was registered at ClinicalTrials.gov under identifier NCT03813108.

Clonal Hematopoiesis Is Associated With Low CD4 Nadir and Increased Residual HIV Transcriptional Activity in Virally Suppressed Individuals With HIV.

Clonal hematopoiesis, a common age-related phenomenon marked by expansion of cells with clonal hematopoiesis driver mutations, has been associated with all-cause mortality, cancer, and cardiovascular disease. People with HIV (PWH) are at risk for non-AIDS-related comorbidities such as atherosclerotic cardiovascular disease and cancer. In a cross-sectional cohort study, we compared clonal hematopoiesis prevalence in PWH on stable antiretroviral therapy with prevalence in a cohort of overweight individuals and a cohort of age- and sex-matched population controls. The prevalence of clonal hematopoiesis adjusted for age was increased and clone size was larger in PWH compared to population controls. Clonal hematopoiesis is associated with low CD4 nadir, increased residual HIV-1 transcriptional activity, and coagulation factors in PWH. Future studies on the effect of clonal hematopoiesis on the HIV reservoir and non-AIDS-related comorbidities are warranted.

Immunogenicity and reactogenicity of SARS-CoV-2 vaccines in people living with HIV in the Netherlands: A nationwide prospective cohort study.

BACKGROUND: Vaccines can be less immunogenic in people living with HIV (PLWH), but for SARS-CoV-2 vaccinations this is unknown. In this study we set out to investigate, for the vaccines currently approved in the Netherlands, the immunogenicity and reactogenicity of SARS-CoV-2 vaccinations in PLWH. METHODS AND FINDINGS: We conducted a prospective cohort study to examine the immunogenicity of BNT162b2, mRNA-1273, ChAdOx1-S, and Ad26.COV2.S vaccines in adult PLWH without prior COVID-19, and compared to HIV-negative controls. The primary endpoint was the anti-spike SARS-CoV-2 IgG response after mRNA vaccination. Secondary endpoints included the serological response after vector vaccination, anti-SARS-CoV-2 T-cell response, and reactogenicity. Between 14 February and 7 September 2021, 1,154 PLWH (median age 53 [IQR 44-60] years, 85.5% male) and 440 controls (median age 43 [IQR 33-53] years, 28.6% male) were included in the final analysis. Of the PLWH, 884 received BNT162b2, 100 received mRNA-1273, 150 received ChAdOx1-S, and 20 received Ad26.COV2.S. In the group of PLWH, 99% were on antiretroviral therapy, 97.7% were virally suppressed, and the median CD4+ T-cell count was 710 cells/µL (IQR 520-913). Of the controls, 247 received mRNA-1273, 94 received BNT162b2, 26 received ChAdOx1-S, and 73 received Ad26.COV2.S. After mRNA vaccination, geometric mean antibody concentration was 1,418 BAU/mL in PLWH (95% CI 1322-1523), and after adjustment for age, sex, and vaccine type, HIV status remained associated with a decreased response (0.607, 95% CI 0.508-0.725, p < 0.001). All controls receiving an mRNA vaccine had an adequate response, defined as >300 BAU/mL, whilst in PLWH this response rate was 93.6%. In PLWH vaccinated with mRNA-based vaccines, higher antibody responses were predicted by CD4+ T-cell count 250-500 cells/µL (2.845, 95% CI 1.876-4.314, p < 0.001) or >500 cells/µL (2.936, 95% CI 1.961-4.394, p < 0.001), whilst a viral load > 50 copies/mL was associated with a reduced response (0.454, 95% CI 0.286-0.720, p = 0.001). Increased IFN-γ, CD4+ T-cell, and CD8+ T-cell responses were observed after stimulation with SARS-CoV-2 spike peptides in ELISpot and activation-induced marker assays, comparable to controls. Reactogenicity was generally mild, without vaccine-related serious adverse events. Due to the control of vaccine provision by the Dutch National Institute for Public Health and the Environment, there were some differences between vaccine groups in the age, sex, and CD4+ T-cell counts of recipients. CONCLUSIONS: After vaccination with BNT162b2 or mRNA-1273, anti-spike SARS-CoV-2 antibody levels were reduced in PLWH compared to HIV-negative controls. To reach and maintain the same serological responses as HIV-negative controls, additional vaccinations are probably required. TRIAL REGISTRATION: The trial was registered in the Netherlands Trial Register (NL9214). https://www.trialregister.nl/trial/9214.

Identifying platelet-derived factors as amplifiers of B. burgdorferi-induced cytokine production.

Previous studies have shown that monocytes can be 'trained' or tolerized by certain stimuli to respond stronger or weaker to a secondary stimulation. Rewiring of glucose metabolism was found to be important in inducing this phenotype. As we previously found that Borrelia burgdorferi (B. burgdorferi), the causative agent of Lyme borreliosis (LB), alters glucose metabolism in monocytes, we hypothesized that this may also induce long-term changes in innate immune responses. We found that exposure to B. burgdorferi decreased cytokine production in response to the TLR4-ligand lipopolysaccharide (LPS). In addition, B. burgdorferi exposure decreased baseline levels of glycolysis, as assessed by lactate production. Using GWAS analysis, we identified a gene, microfibril-associated protein 3-like (MFAP3L) as a factor influencing lactate production after B. burgdorferi exposure. Validation experiments proved that MFAP3L affects lactate- and cytokine production following B. burgdorferi stimulation. This is mediated by functions of MFAP3L, which includes activating ERK2 and through activation of platelet degranulation. Moreover, we showed that platelets and platelet-derived factors play important roles in B. burgdorferi-induced cytokine production. Certain platelet-derived factors, such chemokine C-X-C motif ligand 7 (CXCL7) and (C-C motif) ligand 5 (CCL5), were elevated in the circulation of LB patients in comparison to healthy individuals.

Bacterial colonization of the upper airways of children positive and negative for SARS-CoV-2 during the COVID-19 pandemic.

BACKGROUND: Our understanding of the influence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection on bacterial colonization in the children's upper nasopharyngeal tract during the coronavirus infectious disease (COVID-19) pandemic is limited. This study aimed to determine whether there were any differences in bacterial colonization between asymptomatic children with or without a positive SARS-CoV-2 quantitative reverse transcriptase-polymerase chain reaction (RT-qPCR) results in the community setting. METHODS: A cross-sectional community-based exploratory study was conducted from March to May 2021 in Semarang, Central Java Province, Indonesia. Using stored nasopharyngeal swabs collected from children under 18 years as a contact tracing program, we performed a real-time quantitative (qPCR) for the most important bacterial colonizing pathogens: Streptococcus pneumoniae, Haemophilus influenzae, Staphylococcus aureus, and Klebsiella pneumoniae. RESULTS: Swabs from a total of 440 children were included in this study, of which 228 (51.8%) were RT-qPCR-confirmed SARS-CoV-2 positive. In the 440 children, colonization rates were highest for H. influenzae (61.4%), followed by S. pneumoniae (17.5%), S. aureus (12.0%), and K. pneumoniae (1.8%). The co-occurrence of both S. pneumoniae and H. influenzae in the upper respiratory tract was significantly associated with a SARS-CoV-2 negative RT-qPCR. In contrast, colonization with only S. aureus was more common in SARS-CoV-2-positive children. CONCLUSION: Overall, this exploratory study concludes that there is a significant difference in the bacterial nasopharyngeal colonization pattern between SARS-CoV-2 positive and negative in asymptomatic children in the community in Indonesia.

Nasopharyngeal colonisation dynamics of bacterial pathogens in patients with fever in rural Burkina Faso: an observational study.

BACKGROUND: Nasopharyngeal colonisation with clinically relevant bacterial pathogens is a risk factor for severe infections, such as pneumonia and bacteraemia. In this study, we investigated the determinants of nasopharyngeal carriage in febrile patients in rural Burkina Faso. METHODS: From March 2016 to June 2017, we recruited 924 paediatric and adult patients presenting with fever, hypothermia or suspicion of severe infection to the Centre Medical avec Antenne Chirurgicale Saint Camille de Nanoro, Burkina Faso. We recorded a broad range of clinical data, collected nasopharyngeal swabs and tested them for the presence of Streptococcus pneumoniae, Haemophilus influenzae, Moraxella catarrhalis, Staphylococcus aureus and Klebsiella pneumoniae by quantitative polymerase chain reaction. Using logistic regression, we investigated the determinants of carriage and aimed to find correlations with clinical outcome. RESULTS: Nasopharyngeal colonisation with S. pneumoniae, H. influenzae and M. catarrhalis was highly prevalent and strongly dependent on age and season. Females were less likely to be colonised with S. pneumoniae (OR 0.71, p = 0.022, 95% CI 0.53-0.95) and M. catarrhalis (OR 0.73, p = 0.044, 95% CI 0.54-0.99) than males. Colonisation rates were highest in the age groups < 1 year and 1-2 years of age and declined with increasing age. Colonisation also declined towards the end of the rainy season and rose again during the beginning of the dry season. K. pneumoniae prevalence was low and not significantly correlated with age or season. For S. pneumoniae and H. influenzae, we found a positive association between nasopharyngeal carriage and clinical pneumonia [OR 1.75, p = 0.008, 95% CI 1.16-2.63 (S. pneumoniae) and OR 1.90, p = 0.004, 95% CI 1.23-2.92 (H. influenzae)]. S. aureus carriage was correlated with mortality (OR 4.01, p < 0.001, 95% CI 2.06-7.83), independent of bacteraemia caused by this bacterium. CONCLUSIONS: Age, sex and season are important determinants of nasopharyngeal colonisation with S. pneumoniae, H. influenzae and M. catarrhalis in patients with fever in Burkina Faso. S. pneumoniae and H. influenzae carriage is associated with clinical pneumonia and S. aureus carriage is associated with mortality in patients with fever. These findings may help to understand the dynamics of colonisation and the associated transmission of these pathogens. Furthermore, understanding the determinants of nasopharyngeal colonisation and the association with disease could potentially improve the diagnosis of febrile patients.

Platelets Modulate IFN-γ Production against Candida albicans in Peripheral Blood Mononuclear Cells via Prostaglandins.

Platelets are known to have immunomodulatory properties. They modulate immune responses of leukocytes against various pathogens, including fungi. Candida albicans can cause systemic infection in immunocompromised individuals that is associated with a high mortality and morbidity. In the current study, we explored the role of platelets in antifungal host defense against C. albicans PBMCs were stimulated with heat-killed (HK) C. albicans in the presence or absence of isolated washed platelets. Cytokines were quantified from culture supernatants by ELISA. Inhibition of platelet receptors and cytokine pathways were used to elucidate the mechanisms involved in platelet-leukocyte interaction. In the presence of platelets, PBMCs produced less IFN-γ upon stimulation with HK C. albicans This effect was dependent on the direct contact between platelets and leukocytes but was independent of the platelet GPIb and P-selectin receptors. The attenuation of IFN-γ was not a direct effect on T cells but was dependent on the presence of APC and T cells. Platelets did not modulate the Th-1-polarizing cytokines IL-12 and IL-18. The addition of PG (PGE2) further diminished IFN-γ levels in PBMCs, and supplementation of cells with nonsteroidal anti-inflammatory drugs was able to restore the level of IFN-γ. Overall, we show that modulation of the Th1 response against C. albicans by platelets is dependent on PGs.

Outcome in Patients after Autologous Femoral Vein Reconstruction for Primary Aortic Infection and Aortic Graft Infection: A Case Series.

BACKGROUND: For surgical treatment of primary aortic infection and aortic graft infection, in situ reconstruction with autologous vein(s) has the lowest rates of re-infection and of graft thrombosis. In this study, we have assessed the outcome after autologous femoral vein reconstruction in patients with aortic (graft) infection and we provide insights into the specific technical surgical considerations of the procedure. METHODS: In this retrospective single-center study, all patients who underwent autologous femoral vein reconstruction because of primary aortic infection or aortic graft infection between January 2012 and January 2020 were included. The primary outcome parameter was 30-day mortality. RESULTS: Twenty-nine patients with autologous femoral vein reconstruction for a primary aortic infection (n = 3) or aortic graft infection (n = 26) were included. An aorto-enteral fistula was detected in 13 patients (49%). Venous reconstruction of the aorta was performed with a single femoral vein in 17 patients (59%), and two femoral veins in 12 patients (41%). Thirty-day mortality was 17%. Relapse of infection occurred in two patients (7%) and no amputations were needed. One year after surgery, only three patients (10%) still needed stockings and after 2 years none of the patients used stockings. CONCLUSIONS: Central aortic reconstruction with femoral veins is a durable solution for primary aortic and aortoiliac graft infections with a low incidence of reinfections, amputations, and venous hypertension.

A Randomized Clinical Trial to Compare Plasmodium falciparum Gametocytemia and Infectivity After Blood-Stage or Mosquito Bite-Induced Controlled Malaria Infection.

BACKGROUND: For malaria elimination efforts, it is important to better understand parasite transmission to mosquitoes and develop models for early-clinical evaluation of transmission-blocking interventions. METHODS: In a randomized open-label trial, 24 participants were infected by bites from Plasmodium falciparum 3D7-infected mosquitoes (mosquito bite [MB]; n = 12) or by induced blood-stage malaria (IBSM) with the same parasite line (n = 12). After subcurative piperaquine treatment, asexual parasite and gametocytes kinetics were assessed, and mosquito feeding experiments were performed. RESULTS: Study procedures were well tolerated. The median peak gametocyte density was 1304/mL (interquartile range, 308-1607/mL) after IBSM, compared with 14/mL (10-64/mL) after MB inoculation (P < .001), despite similar peak asexual parasite densities (P = .48). Peak gametocyte density was correlated with preceding pfap2-g transcripts, indicative of gametocyte commitment (ρ = 0.62; P = .002). Direct feeding assays resulted in mosquito infections from 9 of 12 participants after IBSM versus 0 of 12 after MB inoculation (P < .001). CONCLUSIONS: We observed a striking effect of inoculation method on gametocyte production, suggesting higher gametocyte commitment after IBSM. Our direct comparison of MB and IBSM establishes the controlled human malaria infection transmission model, using intravenous administration of P. falciparum-infected erythrocytes as a model for early-clinical evaluation of interventions that aim to interrupt malaria transmission. CLINICAL TRIAL REGISTRATION: NCT03454048.

Dysregulated Innate and Adaptive Immune Responses Discriminate Disease Severity in COVID-19.

The clinical spectrum of COVID-19 varies and the differences in host response characterizing this variation have not been fully elucidated. COVID-19 disease severity correlates with an excessive proinflammatory immune response and profound lymphopenia. Inflammatory responses according to disease severity were explored by plasma cytokine measurements and proteomics analysis in 147 COVID-19 patients. Furthermore, peripheral blood mononuclear cell cytokine production assays and whole blood flow cytometry were performed. Results confirm a hyperinflammatory innate immune state, while highlighting hepatocyte growth factor and stem cell factor as potential biomarkers for disease severity. Clustering analysis revealed no specific inflammatory endotypes in COVID-19 patients. Functional assays revealed abrogated adaptive cytokine production (interferon-γ, interleukin-17, and interleukin-22) and prominent T-cell exhaustion in critically ill patients, whereas innate immune responses were intact or hyperresponsive. Collectively, this extensive analysis provides a comprehensive insight into the pathobiology of severe to critical COVID-19 and highlights potential biomarkers of disease severity.

Desialylation of platelets induced by Von Willebrand Factor is a novel mechanism of platelet clearance in dengue.

Thrombocytopenia and platelet dysfunction are commonly observed in patients with dengue virus (DENV) infection and may contribute to complications such as bleeding and plasma leakage. The etiology of dengue-associated thrombocytopenia is multifactorial and includes increased platelet clearance. The binding of the coagulation protein von Willebrand factor (VWF) to the platelet membrane and removal of sialic acid (desialylation) are two well-known mechanisms of platelet clearance, but whether these conditions also contribute to thrombocytopenia in dengue infection is unknown. In two observational cohort studies in Bandung and Jepara, Indonesia, we show that adult patients with dengue not only had higher plasma concentrations of plasma VWF antigen and active VWF, but that circulating platelets had also bound more VWF to their membrane. The amount of platelet-VWF binding correlated well with platelet count. Furthermore, sialic acid levels in dengue patients were significantly reduced as assessed by the binding of Sambucus nigra lectin (SNA) and Maackia amurensis lectin II (MAL-II) to platelets. Sialic acid on the platelet membrane is neuraminidase-labile, but dengue virus has no known neuraminidase activity. Indeed, no detectable activity of neuraminidase was present in plasma of dengue patients and no desialylation was found of plasma transferrin. Platelet sialylation was also not altered by in vitro exposure of platelets to DENV nonstructural protein 1 or cultured DENV. In contrast, induction of binding of VWF to glycoprotein 1b on platelets using the VWF-activating protein ristocetin resulted in the removal of platelet sialic acid by translocation of platelet neuraminidase to the platelet surface. The neuraminidase inhibitor oseltamivir reduced VWF-induced platelet desialylation. Our data demonstrate that excessive binding of VWF to platelets in dengue results in neuraminidase-mediated platelet desialylation and platelet clearance. Oseltamivir might be a novel treatment option for severe thrombocytopenia in dengue infection.

Substance use, Unlike Dolutegravir, is Associated with Mood Symptoms in People Living with HIV.

Contradictory data have been reported concerning neuropsychiatric side effects of the first-line antiretroviral drug dolutegravir, which may be partly due to lack of control groups or psychiatric assessment tools. Using validated self-report questionnaires, we compared mood and anxiety (DASS-42), impulsivity (BIS-11), and substance use (MATE-Q) between dolutegravir-treated and dolutegravir-naive people living with HIV (PLHIV). We analyzed 194, mostly male, PLHIV on long-term treatment of whom 82/194 (42.3%) used dolutegravir for a median (IQR) of 280 (258) days. Overall, 51/194 (26.3%) participants reported DASS-42 scores above the normal cut-off, 27/194 (13.5%) were classified as highly impulsive, and 58/194 (29.9%) regularly used recreational drugs. Regular substance use was positively associated with depression (p = 0.012) and stress scores (p = 0.045). We observed no differences between dolutegravir-treated and dolutegravir-naive PLHIV. Our data show that depressed and anxious moods and impulsivity are common in PLHIV and associate with substance use and not with dolutegravir use.

Presence of Genetic Variants Among Young Men With Severe COVID-19.

Importance: Severe coronavirus disease 2019 (COVID-19) can occur in younger, predominantly male, patients without preexisting medical conditions. Some individuals may have primary immunodeficiencies that predispose to severe infections caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Objective: To explore the presence of genetic variants associated with primary immunodeficiencies among young patients with COVID-19. Design, Setting, and Participants: Case series of pairs of brothers without medical history meeting the selection criteria of young (age <35 years) brother pairs admitted to the intensive care unit (ICU) due to severe COVID-19. Four men from 2 unrelated families were admitted to the ICUs of 4 hospitals in the Netherlands between March 23 and April 12, 2020. The final date of follow-up was May 16, 2020. Available family members were included for genetic variant segregation analysis and as controls for functional experiments. Exposure: Severe COVID-19. Main Outcome and Measures: Results of rapid clinical whole-exome sequencing, performed to identify a potential monogenic cause. Subsequently, basic genetic and immunological tests were performed in primary immune cells isolated from the patients and family members to characterize any immune defects. Results: The 4 male patients had a mean age of 26 years (range, 21-32), with no history of major chronic disease. They were previously well before developing respiratory insufficiency due to severe COVID-19, requiring mechanical ventilation in the ICU. The mean duration of ventilatory support was 10 days (range, 9-11); the mean duration of ICU stay was 13 days (range, 10-16). One patient died. Rapid clinical whole-exome sequencing of the patients and segregation in available family members identified loss-of-function variants of the X-chromosomal TLR7. In members of family 1, a maternally inherited 4-nucleotide deletion was identified (c.2129_2132del; p.[Gln710Argfs*18]); the affected members of family 2 carried a missense variant (c.2383G>T; p.[Val795Phe]). In primary peripheral blood mononuclear cells from the patients, downstream type I interferon (IFN) signaling was transcriptionally downregulated, as measured by significantly decreased mRNA expression of IRF7, IFNB1, and ISG15 on stimulation with the TLR7 agonist imiquimod as compared with family members and controls. The production of IFN-γ, a type II IFN, was decreased in patients in response to stimulation with imiquimod. Conclusions and Relevance: In this case series of 4 young male patients with severe COVID-19, rare putative loss-of-function variants of X-chromosomal TLR7 were identified that were associated with impaired type I and II IFN responses. These preliminary findings provide insights into the pathogenesis of COVID-19.