Diabetes exacerbates SARS-CoV-2 replication through ineffective pulmonary interferon responses, delayed cell-mediated immunity, and disruption of leptin signaling

Comorbidities, including obesity and type 2 diabetes mellitus (T2DM), are associated with increased disease severity and mortality following SARS-CoV-2 infection. Here, we investigated virus-host interactions under the effects of these comorbidities in diet-induced obesity (DIO) and leptin receptor-deficient (T2DM) mice following infection with SARS-CoV-2. DIO mice, as well as their lean counterparts, showed limited susceptibility to SARS-CoV-2 infection. In contrast, T2DM mice showed exacerbated pulmonary SARS-CoV-2 replication and delayed viral clearance associated with down-regulation of innate and adaptative immune gene signatures, ineffective type I interferon response, and delayed SARS-CoV-2-specific cell-mediated immune responses. While T2DM mice showed higher and prolonged SARS-CoV-2-specific immunoglobulin isotype responses compared to their lean counterparts, neutralizing antibody levels were equivalent. By silencing the leptin receptor in vitro using a human alveolar epithelial cell line, we observed an increase in SARS-CoV-2 replication and type I interferons. Altogether, our data provides for the first time evidence that disruption of leptin receptor signaling leading to obesity and T2DM induces altered type I interferon and cell-mediated responses against SARS-CoV-2, mediating increased viral replication and delayed clearance. These data shed light on the alteration of the innate immune pathway in the lung using in-depth transcriptomic analysis and on adaptive immune responses to SARS-CoV-2 under T2DM conditions. Finally, this study provides further insight into this risk factor aggravating SARS-CoV-2 infection and understanding the underlying cellular mechanisms that could help identify potential intervention points for this at-risk population.

Serology supportive of recent coxsackievirus B infection is correlated with multisystem inflammatory syndrome in children (MIS-C)

Rarely, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) will lead to myocarditis associated with multisystem inflammatory syndrome in children (MIS-C). It remains unclear why MIS-C only targets specific children. To explore an association between coxsackievirus infections with MIS-C, we investigated the sero-epidemiology of CV in admitted pediatric patients in relation to the pandemic. This retrospective case-control study was performed by chart review of children (age ≤21 years) admitted to a tertiary care hospital with CV serological testing from January 2017 to August 2023. Clinical, laboratory, and imaging findings were used to classify patients as MIS-C and CV-unlikely or CV-possible for non-MIS-C patients. Out of 182 admissions (179 patients, median age, 6), CVB complement fixation (CF) assay on serotypes B1-B6 and CVA immunofluorescence assay IgG on serotypes A7, A9, A16, and A24 were positive in at least one serotype in 59.2% and 80.7% of cases, respectively. We observed a significant drop in CVB CF seropositivity during the peak of social distancing in 2020. The likelihood of elevated CVB CF titers was significantly higher in MIS-C than the CV-unlikely group (OR: 1.92, 95% CI: 1.02-3.63, P: 0.04) and showed a trend toward higher values in African Americans than Whites (OR: 1.57, 95% CI: 0.98-2.50, P: 0.057). The frequency of MIS-C was considerably higher in African Americans than Whites (18.1% versus 9%, P: 0.1). A higher likelihood of elevated CVB CF titers in patients with MIS-C compared with those unlikely to have acute CV infection along with a relatively higher frequency of MIS-C in African Americans warrants further investigation into the role of CVB infection in MIS-C development.IMPORTANCEThe emergence of multisystem inflammatory syndrome in children (MIS-C) during the SARS-CoV-2 pandemic raised major concerns in providers caring for children. This condition presents a hyper-inflammation state that can lead to severe complications, including myocarditis and cardiogenic shock. The pathogenesis of MIS-C has not been fully understood. Understanding the pathogenesis of this condition is not only important for developing effective treatments but also for applying preventive strategies. A two-hit hypothesis leading to MIS-C has been proposed. Coxsackievirus infections are prevalent during childhood and can also cause myocarditis, and coxsackievirus B specifically has been shown to cause persistent RNA presence in host cells, leading to continued inflammation. Herein, we show that elevated coxsackievirus B titers are associated with MIS-C cases, implying a role of successive infections with these viruses contributing to such a hyperinflammatory state. This study supports the need for larger investigations into this association.

Effect of Inactivated Vaccines Against SARS-CoV-2 on Immunogenicity Outcome

OBJECTIVES

The purpose of this study was to measure and examine the levels of IgG, IgM, and Spike antibody induced by inactivated vaccines, including CoronaVac and BBIBP-CorV.

METHODS

Two groups of healthy adults over 18 years old (50 participants per group), who had previously received 1 dose of either BBIBP-CorV or CoronaVac and receiving either a homologous booster of BBIBP-CorV or a heterologous booster of CoronaVac. Serum IgG, IgM, and Spike antibody levels against SARS-COV-2 were measured using magnetic particle chemiluminescence immunoassay and the ELISA method.

RESULTS

The results showed that both spike antibody and IgG/IgM antibodies elicited by a CoronaVac booster following 1 dose of BBIBP-CorV were significantly higher than those elicited by either a homologous BBIBP-CorV booster or a heterologous BBIBP-CorV booster. The Spike antibody against SARS-COV-2 induced by the heterologous CoronaVac booster reached 200.3, which is substantially greater than that induced by the homologous BBIBP-CorV booster (127.5 pg/mL). Conversely, the Spike antibody against SARS-COV-2 induced by the heterologous BBIBP-CorV booster reached 53.93 pg/mL, which is substantially greater than that induced by the homologous CoronaVac booster (9.60 pg/mL).

CONCLUSIONS

In summary, CoronaVac is immunogenic as a booster dose following 1 dose of BBIBP-CorV and is immunogenically superior to both the homologous booster and the heterologous BBIBP-CorV booster.

Influenza Vaccination of Nurses and Other Health Care Workers in Different Occupational Settings: A Classic and AI Mixed Approach for Time-to-Event Data

Background: Seasonal influenza currently remains a major public health concern for the community and, in particular, the health care worker (HCW). According to the World Health Organization, HCWs are among the high-risk categories for which vaccination is recommended, due to the derived absenteeism, productivity loss, and high probability of transmitting the disease to vulnerable individuals or patients. Therefore, an HCW vaccination policy should be adopted by every health care provider. There is growing evidence that a time effect of the vaccination event is probable, which may influence vaccine effectiveness. We designed and conducted an observational study to investigate the time to anti-influenza vaccination event of different categories of HCWs belonging to different occupational settings in a tertiary hospital during three seasons in order to retrieve some insight about HCW prioritization when designing vaccination campaigns. Materials and Methods: We retrospectively analyzed the results of two HCW anti-influenza vaccination campaigns (2022 and 2023) to assess any difference regarding job typology and unit typology (critical care, surgical, medical, service). We first fitted a classic Cox proportional hazard model and then an AI random forest model to assess variable importance. We used R, RStudio, and the survex package. Results: Overall, other HCWs reported a lower vaccination rate compared to nurses (HR 0.77; 95%CI 0.62-0.97), and service unit personnel appeared to more likely be vaccinated (HR 1.42; 95%CI 1.01-1.99) compared to those belonging to the critical care units. As expected, older workers tended to be vaccinated more frequently (HR 1.70 for the (46, 65] category compared to the younger one; 95%CI 1.39-2.09). The variable importance analysis showed consistent superiority of the ward typology and age category variables with respect to time. During the entire timeline, the ward typology appeared to be more important than the HCW typology. Conclusions: Our results suggest a prioritization policy based firstly on the unit typology followed by the job typology for HCW anti-influenza campaigns.

Pneumococcal Neuraminidases Increase Platelet Killing by Pneumolysin

BACKGROUND

 Platelets prevent extravasation of capillary fluids into the pulmonary interstitial tissue by sealing gaps in inflamed endothelium. This reduces respiratory distress associated with pneumonia. Streptococcus pneumoniae is the leading cause of severe community-acquired pneumonia. Pneumococci produce pneumolysin (PLY), which forms pores in membranes of eukaryotic cells including platelets. Additionally, pneumococci express neuraminidases, which cleave sialic acid residues from eukaryotic glycoproteins. In this study, we investigated the effect of desialylation on PLY binding and pore formation on platelets.

MATERIALS AND METHODS

 We incubated human platelets with purified neuraminidases and PLY, or nonencapsulated S. pneumoniae D39/TIGR4 and isogenic mutants deficient in PLY and/or NanA. We assessed platelet desialylation, PLY binding, and pore formation by flow cytometry. We also analyzed the inhibitory potential of therapeutic immunoglobulin G preparations (IVIG [intravenous immunoglobulin]).

RESULTS

 Wild-type pneumococci cause desialylation of platelet glycoproteins by neuraminidases, which is reduced by 90 to 100% in NanA-deficient mutants. NanC, cleaving only α2,3-linked sialic acid, induced platelet desialylation. PLY binding to platelets then x2doubled (p = 0.0166) and pore formation tripled (p = 0.0373). A neuraminidase cleaving α2,3-, α2,6-, and α2,8-linked sialic acid like NanA was even more efficient. Addition of polyvalent IVIG (5 mg/mL) decreased platelet desialylation induced by NanC up to 90% (p = 0.263) and reduced pore formation >95% (p < 0.0001) when incubated with pneumococci.

CONCLUSION

 Neuraminidases are key virulence factors of pneumococci and desialylate platelet glycoproteins, thereby unmasking PLY-binding sites. This enhances binding of PLY and pore formation showing that pneumococcal neuraminidases and PLY act in concert to kill platelets. However, human polyvalent immunoglobulin G preparations are promising agents for therapeutic intervention during severe pneumococcal pneumonia.

Dissecting the COVID-19 Immune Response: Unraveling the Pathways of Innate Sensing and Response to SARS-CoV-2 Structural Proteins

Severe acute respiratory syndrome coronavirus (SARS-CoV), the virus responsible for COVID-19, interacts with the host immune system through complex mechanisms that significantly influence disease outcomes, affecting both innate and adaptive immunity. These interactions are crucial in determining the disease's severity and the host's ability to clear the virus. Given the virus's substantial socioeconomic impact, high morbidity and mortality rates, and public health importance, understanding these mechanisms is essential. This article examines the diverse innate immune responses triggered by SARS-CoV-2's structural proteins, including the spike (S), membrane (M), envelope (E), and nucleocapsid (N) proteins, along with nonstructural proteins (NSPs) and open reading frames. These proteins play pivotal roles in immune modulation, facilitating viral replication, evading immune detection, and contributing to severe inflammatory responses such as cytokine storms and acute respiratory distress syndrome (ARDS). The virus employs strategies like suppressing type I interferon production and disrupting key antiviral pathways, including MAVS, OAS-RNase-L, and PKR. This study also explores the immune pathways that govern the activation and suppression of immune responses throughout COVID-19. By analyzing immune sensing receptors and the responses initiated upon recognizing SARS-CoV-2 structural proteins, this review elucidates the complex pathways associated with the innate immune response in COVID-19. Understanding these mechanisms offers valuable insights for therapeutic interventions and informs public health strategies, contributing to a deeper understanding of COVID-19 immunopathogenesis.

An LNP-mRNA vaccine modulates innate cell trafficking and promotes polyfunctional Th1 CD4+ T cell responses to enhance BCG-induced protective immunity against Mycobacterium tuberculosis

BACKGROUND

Mycobacterium tuberculosis remains the largest infectious cause of mortality worldwide, even with over a century of widespread administration of the only licenced tuberculosis (TB) vaccine, Bacillus Calmette-Guérin (BCG). mRNA technology remains an underexplored approach for combating chronic bacterial infections such as TB.

METHODS

We have developed a lipid nanoparticle (LNP)-mRNA vaccine, termed mRNACV2, encoding for the M. tuberculosis CysVac2 fusion protein, which we have previously formulated as an adjuvanted subunit vaccine. This LNP-mRNA vaccine was administered intramuscularly to female C57BL/6 mice as a standalone vaccine or as booster to BCG to assess immunogenicity and efficacy of the construct.

FINDINGS

Vaccination with mRNACV2 induced high frequencies of polyfunctional, antigen-specific Th1 CD4+ T cells in the blood and lungs, which was associated with the rapid recruitment of both innate and adaptive immune cells to lymph nodes draining the site of immunisation. mRNACV2 vaccination also provided significant pulmonary protection in M. tuberculosis-infected mice, reducing bacterial load and inflammatory infiltration in the lungs. Importantly, mRNACV2 enhanced immune responses and long-term protection when used to boost BCG-primed mice.

INTERPRETATION

These findings of a protective LNP-mRNA vaccine for TB highlight the potential of the LNP-mRNA platform for TB control and support further research to facilitate translation to humans.

FUNDING

This work was supported by the NHMRC Centre of Research Excellence in Tuberculosis Control to JAT and WJB (APP1153493), and MRFF mRNA Clinical Trial Enabling Infrastructure grant to CWP and HAW (MRFCTI000006).

Transfusion-Related Acute Lung Injury: from Mechanistic Insights to Therapeutic Strategies

Transfusion-related acute lung injury (TRALI) is a potentially lethal complication of blood transfusions, characterized by the rapid onset of pulmonary edema and hypoxemia within six hours post-transfusion. As one of the primary causes of transfusion-related mortality, TRALI carries a significant mortality rate of 6-12%. However, effective treatment strategies for TRALI are currently lacking, underscoring the urgent need for a comprehensive and in-depth understanding of its pathogenesis. This comprehensive review provides an updated and detailed analysis of the current landscape of TRALI, including its clinical presentation, pathogenetic hypotheses, animal models, cellular mechanisms, signaling pathways, and potential therapeutic targets. By highlighting the critical roles of these pathways and therapies, this review offers valuable insights to inform the development of preventative and therapeutic strategies and to guide future research efforts aimed at addressing this life-threatening condition.

Antibody prophylaxis may mask subclinical SIV infections in macaques

Broadly neutralizing antibodies (bNAbs) show potential to prevent human immunodeficiency virus (HIV-1) infection in humans1. However, there are limited data on the antibody concentrations required to prevent infection. Clinical trials of bNAb prophylaxis have demonstrated partial efficacy2, but the sampling frequency typically does not allow precise timing of infection events and concurrent antibody levels. Here, using simian immunodeficiency virus (SIV) infection of rhesus macaques, we show that although potent bNAbs can delay the onset of acute viremia, subclinical infections occur while bNAb levels remain high. Serial SIV challenge of monkeys given partially and fully neutralizing bNAbs revealed that 'viral blips'-low and transient plasma viremia-often occur while serum bNAb concentrations are well above currently accepted protective levels. To understand the precise timing of the infections resulting in such blips, we performed plasma viral sequencing on monkeys that were serially challenged with genetically barcoded SIV after bNAb administration. These analyses showed that subclinical infections occurred in most animals that were given potent bNAb prophylaxis. These subclinical infections occurred while antibody concentrations were 2- to 400-fold higher than the levels required to prevent fully viremic breakthrough infection. This study demonstrates that immunoprophylaxis can mask subclinical infections, which may affect the interpretation of prophylactic HIV-1 bNAb clinical trials.

Intra-peritoneal Povidone-iodine Irrigation Decreases Abscesses in a Perforated Appendicitis Murine Model

BACKGROUND

Children with perforated appendicitis frequently form post-operative intra-abdominal abscesses (IAA). Intra-peritoneal irrigation for prevention remains controversial. Using a perforated appendicitis murine model, we sought to determine the effect of intra-peritoneal irrigation on post-operative IAA and adhesion formation.

METHODS

A survival operation was performed where cecal ligation and puncture was used to simulate perforated appendicitis. After 72 h, mice underwent a second operation where a distal cecectomy and intra-peritoneal irrigation was performed. Mice were assigned to a no irrigation group or one of four irrigation groups: normal saline, povidone-iodine (PVI), tacrolimus, or PVI followed by tacrolimus. At 2-weeks or 2-months after the second survival operation, mice were euthanized and IAAs were counted, measured, and cultured. Intra-peritoneal adhesion severity was graded on a 4-point scale. Statistical analysis compared IAA numbers and adhesion grade between the irrigation groups.

RESULTS

In the 2-week cohort, prevalence of IAA was 78 % (n = 129). Type of irrigation solution was associated with abscess development (p < 0.001). Pairwise comparisons demonstrated PVI alone decreased abscess count. PVI irrigation caused more severe adhesions while tacrolimus decreased adhesions and adhesion grade was dependent on irrigation solution (p < 0.001). In the 2-month cohort, similar responses were observed with decreased abscess numbers in the PVI group (p = 0.006) but increased adhesion burden (p = 0.002).

CONCLUSION

Povidone-iodine irrigation decreases intra-abdominal abscess formation, but increases adhesion formation.

LEVEL OF EVIDENCE: 1

Use of Supplemented Medical-Grade Honey to Treat Traumatic Skin Injuries in Geriatric Patients in a Home-Care Setting

Background Traumatic skin injuries (TSI) are more common to geriatric population due to reduced skin elasticity and increased gait instability. This is also associated with an altered wound-healing mechanism thus requires a cost-efficient and effective treatment. Therefore, the aim of the present study is to highlight the efficacy of medical-grade honey (MGH) supplemented with vitamins C and E for the conservative treatment of TSI in a home-care setting. Methodology The present multicenter retrospective case series study included 10 geriatric patients (four men and six women) who sustained TSI of various etiologies. The median age of the patients was 82.5 years (min-max: 65-90 years). Cardiovascular disease was the most frequent concomitant illness (50% of the patients). Previous treatments with povidone-iodine, alginate gel, or simple gauze for 5.5 days (median, min-max: 0-21 days) were ineffective. Treatment with a variety of supplemented MGH products, including ointment, wound gel, gauze, and foam, was commenced upon the initial patients' examination. Results By using MGH products, we achieved effective reduction of the inflammation, removal of the necrotic tissue, and formation of healthy granulation and epithelial tissue. MGH eliminated clinical signs of infection after 7.5 days (median, min-max: 5-35 days). Wounds were completely healed after 21 days (median, min-max: 14-56 days), without evidence of recurrence or complications, and with good functional and aesthetic outcomes. Conclusions Supplemented MGH-based products present high clinical efficacy for the treatment of TSI in older adults in a home-care setting, while demonstrating a safe and easy-to-use profile. Therefore, they can be proposed as an alternative or complementary therapeutic approach to conventional TSI therapies.

More antibodies are not always better: Fc effector functions play a critical role in SARS-CoV-2 infection and protection

Traditional vaccinology has primarily focused on neutralizing antibody titers as the main correlate of vaccine efficacy, often overlooking the multifaceted roles of antibody Fc effector functions in orchestrating protective immune responses. Fc-mediated immune responses play a pivotal role in immune modulation and pathogen clearance. Emerging evidence from natural infections and vaccine studies highlights the critical contribution of Fc effector functions in determining the quality and durability of immunity. This work explores the limitations of current vaccine evaluation paradigms that prioritize neutralization over Fc effector mechanisms. It also describes findings from a study showing an unexpected role for SARS-CoV-2 anti-spike antibodies: both convalescent plasma and patient-derived monoclonal antibodies (mAbs) lead to maximum phagocytic capacity by monocytes at low concentrations, whereas at higher concentrations the phagocytic capacity was reduced. Given that the severity of COVID-19 disease and antibody titers are strongly positively correlated, this work challenges the paradigm that high antibodies offer better protection against severe disease. It is proposed that humoral and cellular responses elicited by vaccination should never be higher than those produced by natural infection. By integrating antibody Fc effector functions into vaccine development, a paradigm shift is proposed that emphasizes synergic antibody responses. Such an approach could transform vaccine efficacy assessment, enhance protection against dangerous pathogens, and drive innovation in vaccine design.

A novel Kayvirus species phage RuSa1 removes biofilm and lyses multiple clinical strains of methicillin resistant Staphylococcus aureus

The emergence of methicillin-resistant Staphylococcus aureus (MRSA) infection is one of the global healthcare concerns. Here, we report the phenotypic and genotypic characterization of a novel multi-host Staphylococcus phage RuSa1, isolated from wastewater samples derived from a spotted sambar deer (Rusa unicolor) enclosure located at Mangalore, India. Clinical MRSA strains (n = 18) susceptible to RuSa1 were genetically and phenotypically diverse as determined by DNA fingerprinting and in vitro culture assays. RuSa1 displayed a latent period and burst size of 10 min and 50 PFU, respectively, and exhibited efficient biofilm removal activities against S. aureus ATCC BAA-44. The phage exhibited moderate UV stability (3 min) and high titre at 4-37 °C and pH 5‒9. RuSa1 possessed a linear double-stranded genomic DNA with a length of 140 kb. The genome contained 30.18% GC composition and shared 82.0‒94.9% sequence similarity with eleven authentic species of Kayvirus recognized by the International Committee on Taxonomy of Viruses based on VIRIDIC analysis. RuSa1 established distinct phyletic lineage in the maximum likelihood phylogenetic analysis of DNA encoding structural proteins and lacked genes that confer lysogeny. Based on the genotypic, phylogenetic and phenotypic data, RuSa1 is proposed to be a lytic phage and a new species of Kayvirus with a potential therapeutic ability against staphylococcal infections.

Transfusion-Associated Graft-Versus-Host Disease in Pediatric Patients: Clinical Features and Outcomes

BACKGROUND

Transfusion-associated graft-versus-host disease (TA-GVHD) is a rare, usually fatal complication of blood transfusion.

OBJECTIVE

To describe the characteristics of TA-GVHD in children.

METHODS

The clinical records of pediatric patients diagnosed with TA-GVHD between January 2007 and December 2021 were reviewed.

RESULTS

We analyzed 94 clinical records of pediatric patients (0-18 years) with a diagnosis of GVHD, of whom 6 (6.38%) were associated with TA-GVHD; both genders being equally affected. The median age at diagnosis of the underlying disorder was 9 years, 1 month (range 2 months-15 years, 3 months); the median age at diagnosis of TA-GVHD was 9 years, 5.5 months (range 1 year, 7 months-15 years, 7 months). There were 27 grafts; 8 were irradiated and 12 were filtered. All patients presented with Stage 3 cutaneous TA-GVHD and histopathological Grade 2. All cases corresponded to classic acute TA-GVHD with global clinical Grade I-II. Mortality rate was 67%. The median follow-up of our patients was 2 years and 2 months (range 4 months-3 years, 4 months).

CONCLUSIONS

TA-GVHD, although less frequently encountered than in previous years, is still a concern. Early suspicion of TA-GVHD is mandatory due to its high mortality rates and rapid progression. Prevention by using irradiated blood products is the sole effective measure against this condition. Failing to identify and preempt TA-GVHD not only jeopardizes patient survival but also underscores the critical importance of vigilant monitoring and proactive intervention in at-risk patients.

Performance of molecular tests for diagnosis of bloodstream infections in the clinical setting: a systematic literature review and meta-analysis

BACKGROUND

Rapid identification of bloodstream pathogens and associated antimicrobial resistance (AMR) profiles by molecular tests from positive blood cultures (PBCs) have the potential to improve patient management and clinical outcomes.

OBJECTIVES

A systematic review and meta-analysis were conducted to evaluate diagnostic test accuracy (DTA) of molecular tests from PBCs for detecting pathogens and AMR in the clinical setting.

METHODS

.

DATA SOURCES

Medline, Embase, Cochrane, conference proceedings, and study bibliographies were searched.

STUDY ELIGIBILITY CRITERIA

Studies evaluating DTA of commercially available molecular tests vs. traditional phenotypic identification and susceptibility testing methods in patients with PBCs were eligible.

PARTICIPANTS

Patients with PBCs.

TESTS

Commercially available molecular tests.

REFERENCE STANDARD

Traditional phenotypic identification and susceptibility testing methods (standard of care, SOC).

ASSESSMENT OF RISK OF BIAS

Study quality was assessed using Quality Assessment of Diagnostic Accuracy Studies-2.

METHODS OF DATA SYNTHESIS

Summary DTA outcomes were estimated using bivariate random-effects models for gram-negative bacteria (GNB), gram-positive bacteria (GPB), yeast, GNB-AMR, GPB-AMR, and specific targets when reported by ≥ 2 studies (PROSPERO CRD42023488057).

RESULTS

Seventy-four studies including 24 590 samples were analysed, most of which had a low risk of bias. When compared with SOC, molecular tests showed 92-99% sensitivity, 99-100% specificity, 99-100% positive predictive value, and 97-100% negative predictive value for identifying total GNB (43 studies), GPB (38 studies), yeast (24 studies), GNB-AMR (35 studies), and GPB-AMR (39 studies). For individual pathogen targets, 93-100% sensitivity, 98-100% specificity, 86-100% positive predictive value, and 99-100% negative predictive value were estimated. Five of seven AMR genes had 91-99% sensitivity and 99-100% specificity. Sensitivity was lower for IMP (four studies; 62%; 95% CI, 34-83%) and VIM (four studies; 70%; 95% CI, 38-90%) carbapenemases, where genes were not detected or were not harboured in Pseudomonas aeruginosa (i.e. low prevalence). Performance of molecular tests in detecting AMR was generally comparable when grouped by geographical region (Europe, North America, and East Asia).

DISCUSSION

High DTA support the use of molecular tests in identifying a broad panel of pathogens and detecting AMR in GNB and GPB.

Development and validation of a questionnaire to measure COVID-19 vaccine hesitancy within the Romanian industrial laborers

The identification and quantification of sources of vaccine hesitancy among industrial workers in Romania have become crucial for developing effective strategies to facilitate the vaccination process. Our study included employees, both with and without comorbidities, who work in industrial companies. The goal was to develop a scale to assess COVID-19 vaccine hesitancy in Romania. This proposed scale has been designated as the Romanian COVID-19 Vaccine Hesitancy (RO-CVH) scale. The survey encompassed both the demographic characteristics of the respondents and questions related to their perceptions of COVID-19 vaccination. A three-stage process was used to develop the RO-CVH which includes (1) item generation; (2) item-refinement (pilot testing, exploratory factor analysis); and (3) scale validation. The fifteen items loaded onto three factors using exploratory factor analysis, explaining 63% of the total variance. The three factors were labelled as "Confidence in information regarding the COVID-19 vaccine," "Safety and efficacy of the COVID-19 vaccine," and "COVID-19 vaccination as a means of controlling the population." The content validity of the scale was established, and it will be utilized to comprehend the behavior of industrial workers in Romania during similar future outbreaks, particularly regarding the acceptance of mitigatory vaccines. Based on the insights from this scale, future interventions could be designed to reduce vaccine hesitancy.

Impact of immunosuppression on Listeria monocytogenes infection in Spain

INTRODUCTION

Immunosuppression (IS) determines a higher risk of disease severity from Listeria monocytogenes (LM) infection.

METHODS

We examined the epidemiology of IS in all patients hospitalized with LM in Spain from 2000 to 2021 in the National Registry of Hospital Discharges. IS was defined by liver disease (LD), diabetes mellitus (DM), chronic kidney disease (CKD), solid organ transplantation (SOT), bone marrow transplantation (BMT), primary immunodeficiencies (ID), systemic autoimmune diseases (SAD), solid organ neoplasms (SON), and hematological neoplasms (HN).

RESULTS

Among 8,152 admissions with LM, 48% were IS. There was an increase from 39.5% to 60% during the study period, mainly driven by rises in DM (from 12.6% to 26.2%), SON (from 9.9% to 17.5%), CKD (from 4.4% to 16.3%), HN (from 6.6% to 13.4%), and LD (from 4.9% to 6.6%) (p < 0.001 for all trends). IS fatality rate was higher than in non-IS (22.4% vs 11.3%; OR = 2.09). The proportion of LM patients with IS among LM in-hospital deaths increased from 57.1% in 2000 to 67.95% in 2021 (p < 0.001). Fatality risk differed according to baseline IS condition: LD (OR = 2.42), CKD (OR = 1.49), SON (OR 3.01) and HN (OR 1.45).

CONCLUSIONS

The prevalence of IS among patients hospitalized with LM in Spain has risen over the past two decades, with a growing impact on fatality rates. These findings should prompt further efforts to prevent and manage properly LM infection.

Virologic effects of broadly neutralizing antibodies VRC01LS and VRC07-523LS on chronic HIV-1 infection

BACKGROUNDHIV-1-specific broadly neutralizing monoclonal antibodies (bNAbs) have emerged as promising interventions with the potential to effectively treat and prevent HIV-1 infections. We conducted a phase I clinical trial evaluating the potent CD4-binding site-specific (CD4bs-specific) bNAbs VRC01LS and VRC07-523LS in people with HIV-1 (PWH) not receiving antiretroviral therapy (ART).METHODSParticipants received a single intravenous 40 mg/kg dose of either VRC01LS (n = 7) or VRC07-523LS (n = 9) and did not initiate ART for a minimum of 14 days. The primary study objective was to evaluate safety and tolerability; the secondary study objectives were to evaluate pharmacokinetics (PK) and the impact of administered bNAbs on viral loads (VL) and CD4+ T cell counts in the absence of ART.RESULTSThis trial enrolled 16 PWH aged 20 to 57 years. Both bNAbs were safe and well tolerated. Mild local reactogenicity was only reported in participants who received VRC07-523LS, while both bNAbs were associated with mild systemic symptoms. Maximum serum concentrations (Cmax) following VRC01LS or VRC07-523LS were 1,566 ± 316 and 1,295 ± 376 μg/mL, respectively. VRC07-523LS administration significantly decreased VL in 8 out of 9 participants, with an average decline of 1.7 ± 0.8 log10 copies/mL within 14 days after administration. In contrast, VRC01LS administration resulted in a smaller average decline (0.8 ± 0.8 log10 copies/mL), and 3 out of 7 participants showedno change in VL. Postinfusion maximum decline in VL correlated with post hoc baseline in vitro viral susceptibility results for both bNAbs.CONCLUSIONThe results of this trial support inclusion of potent CD4bs-specific bNAbs, such as VRC07-523LS, into next-generation treatment regimens for HIV-1.TRIAL REGISTRATIONClinicalTrials.gov NCT02840474.FUNDINGNational Institute of Allergy and Infectious Diseases (NIAID)/NIH (grants UM1 AI068634, UM1 AI068636, UM1 AI106701, UM1AI069424, UM1AI069501, UM1AI69415, UM1AI069534, UM1AI69494); the Intramural Research Program of the NIAID/NIH; National Center for Advancing Translational Sciences/NIH (grants UM1TR004548, UL1TR001881, and UL1TR001878); and the National Cancer Institute/NIH (contract 75N91019D00024).

Sex-dependent gastrointestinal colonization resistance to MRSA is microbiota and Th17 dependent

Gastrointestinal (GI) colonization by methicillin-resistant Staphylococcus aureus (MRSA) is associated with a high risk of transmission and invasive disease in vulnerable populations. The immune and microbial factors that permit GI colonization remain unknown. Male sex is correlated with enhanced Staphylococcus aureus nasal carriage, skin and soft tissue infections, and bacterial sepsis. Here, we established a mouse model of sexual dimorphism during GI colonization by MRSA. Our results show that in contrast to male mice that were susceptible to persistent colonization, female mice rapidly cleared MRSA from the GI tract following oral inoculation in a manner dependent on the gut microbiota. This colonization resistance displayed by female mice was mediated by an increase in IL-17A+ CD4+ T cells (Th17) and dependent on neutrophils. Ovariectomy of female mice increased MRSA burden, but gonadal female mice that have the Y chromosome retained enhanced Th17 responses and colonization resistance. Our study reveals a novel intersection between sex and gut microbiota underlying colonization resistance against a major widespread pathogen.

Monitoring and active surveillance of adverse events following the booster dose of AZD1222 vaccine in people vaccinated with Sinopharm BBIBP-CorV: a cohort study

BACKGROUND

Given the limited evidence on the side effects of AZD1222 booster in individuals previously vaccinated with Sinopharm BBIBP-CorV, we conducted a cohort event monitoring study to capture adverse events in those receiving AZD1222 booster doses (first or second) after Sinopharm BBIBP-CorV vaccination in Iran.

METHODS

This active COVID-19 vaccine safety surveillance study was conducted in vaccination centers across 12 provinces in Iran. The study population included individuals who had received two doses of Sinopharm BBIBP-CorV and either a first or second AZD1222 booster dose. Each participant was followed for 13 weeks after their booster dose.

RESULTS

A total of 28,742 participants were included, with 13,428 females (46.72%) and 15,314 males (53.28%). The average age was 43.25 ± 14.90 years. Of the total, 82.46% were recruited retrospectively through vaccination registration. Among 16,944 individuals with available polymerase chain reaction test results, 118 tested positive for COVID-19 between 14 and 90 days post-booster. There were 123 hospital admissions, with 18 cases showing a higher likelihood of being associated with adverse events following immunization (AEFIs) or serious adverse events (SAEs). After excluding deaths unrelated to vaccination, four deaths were potentially linked to AEFIs or SAEs. The cumulative incidence rates for hospital admissions and deaths were 106.40 and 13.90 per 100,000 individuals, respectively.

CONCLUSION

The study indicates that AZD1222 booster doses are safe for individuals previously vaccinated with Sinopharm BBIBP-CorV, with rare adverse events and an acceptable safety profile. This supports the use of heterologous booster strategies, though ongoing monitoring and improved pharmacovigilance are essential to detect any potential long-term effects.

Laboratory Tests in Inflammatory Bowel Disease: An Evidence-Based Approach to Daily Practice

Inflammatory bowel diseases (IBDs) comprise a group of chronic gastrointestinal disorders characterized by periods of relapse and remission. The mainstay of treatment is medical, involving medications such as steroids, immune modulators, monoclonal antibodies (categorized as biologics), and small molecules. These medications can provide profound therapeutic benefits, but they can also cause severe and irreversible toxicities. Clinicians may utilize laboratory tests in the diagnosis and management of IBD including assessment of disease activity, monitoring medication response or toxicity, surveillance of infectious complications, and detection of nutritional deficiencies. Routine use of laboratory tests may help clinicians avoid reactivation of life-threatening infections such as tuberculosis or hepatitis B virus upon initiation of immune suppressive therapy. They can also be used to detect vitamin deficiencies such as B12 deficiency, which has the potential to cause irreversible neurologic damage. While some laboratory tests constitute established practices, the utility of newer tests such therapeutic drug monitoring (TDM) in the era of biologics is an evolving topic. Although clinical assessment with imaging, endoscopic, and histopathological examination is standard practice, laboratory tests serve as valuable adjuncts. We aim to explore the broad range of laboratory tests available to clinicians and to summarize their application in the current management of IBD in daily clinical practice, with special attention to updates in therapeutic drug monitoring.

Interactions with and activation of immune cells by CD41a+ extracellular vesicles

Introduction

The immunological profiles of CD4+ T lymphocytes (TLs) from patients with hematological malignancies differ between patients who have and have not received transfusions. There may be several reasons for these differences, including the presence of extracellular vesicles (EVs) derived from plasma membrane budding and present in the platelet concentrates. Indeed, EVs can modulate the immune system through interactions with many immune cells, but the underlying mechanisms remain incompletely understood.

Methods

We therefore investigated how interactions with CD41a+ EVs cause immune cells to change phenotype and function. CD41a+ EVs were cultured with TLs, B lymphocytes, and monocytes. Given the potential involvement of monocytes in leukemia progression, we performed a new original multi-omics study to confirm the protein changes and gene activation observed following interaction with CD41a+ EVs.

Results

The CD41a+ EVs had immunomodulatory effects on all these cell types but this effect depended on the numbers of EVs. CD4+ TLs required large numbers of CD41a+ EVs for activation, whereas monocytes were the most sensitive. With the new multi-omics technique, we confirmed the direct effects of CD41a+ EVs on protein phenotype and gene activation.

Conclusion

Transfusion EVs should be considered during the immunological follow-up of patients after transfusion to detect immunological effects on malignant hemopathies, and during the development of new immunotherapies.

Staphylococcus aureus colonization and surgical site infections among patients undergoing surgical fixation for acute fractures

OBJECTIVES

To identify risk factors for methicillin-susceptible (MSSA) and methicillin-resistant S. aureus (MRSA) nasal carriage and surgical site infection (SSI) among patients undergoing fracture fixation procedures who were included in a quality improvement protocol involving screening patients for S. aureus nasal carriage and treating carriers with intranasal mupirocin and chlorhexidine bathing.

DESIGN

Retrospective cohort study.

SETTING

Level 1 trauma center.

PARTICIPANTS

1,254 adults who underwent operative fixation of 1,298 extremity or pelvis fractures between 8/1/2014 - 7/31/2017.

METHODS

We calculated rates of S. aureus nasal carriage and SSI. We used multivariable stepwise logistic regression and selected the final models based on Akaike information criterion.

RESULTS

Of the 1,040 screened first procedures, 262 (25.19%) were performed on S. aureus nasal carriers: 211 (20.29%) on MSSA carriers and 51 (4.90%) on MRSA carriers. Long-term care facility residence (odds ratio [OR] 3.38; 95% confidence interval [CI] 1.17-9.76) was associated with MRSA nasal carriage. After adjusting for statistically and clinically significant variables, MRSA carriage was significantly associated with any SSI (OR 4.58; 95% CI 1.63-12.88), S. aureus SSI (OR 10.11; 95% CI 3.25-31.42), and MRSA SSI (OR 27.25; 95% CI 5.33-139.24), whereas MSSA carriage was not. Among S. aureus carriers, any chlorhexidine use was documented for 232 (88.55%), and any intranasal mupirocin was documented for 85 (40.28%) MSSA carriers and 33 (64.71%) MRSA carriers.

CONCLUSIONS

MRSA carriage was associated with a significant risk of SSI after operative fracture fixation. Many carriers did not undergo decolonization, suggesting that a simplified decolonization protocol is needed.

The role of platelets in cancer: from their influence on tumor progression to their potential use in liquid biopsy

Platelets, anucleate blood cells essential for hemostasis, are increasingly recognized for their role in cancer, challenging the traditional notion of their sole involvement in blood coagulation. It has been demonstrated that platelets establish bidirectional communication with tumor cells, contributing to tumor progression and metastasis through diverse molecular mechanisms such as modulation of proliferation, angiogenesis, epithelial-mesenchymal transition, resistance to anoikis, immune evasion, extravasation, chemoresistance, among other processes. Reciprocally, cancer significantly alters platelets in their count and composition, including mRNA, non-coding RNA, proteins, and lipids, product of both internal synthesis and the uptake of tumor-derived molecules. This phenomenon gives rise to tumor-educated platelets (TEPs), which are emerging as promising tools for the development of liquid biopsies. In this review, we provide a detailed overview of the dynamic roles of platelets in tumor development and progression as well as their use in diagnosis and prognosis. We also provide our view on current limitations, challenges and future research areas, including the need to design more efficient strategies for their isolation and analysis, as well as the validation of their sensitivity and specificity through large-scale and rigorous clinical trials. This research will not only enable the evaluation of their clinical viability but could also open new opportunities to enhance diagnostic accuracy and develop personalized treatments in oncology.

Activation of the Coagulation Cascade as a Universal Danger Sign

Hemostasis is a mechanism that stops bleeding from an injured vessel, involves multiple interlinked steps, culminating in the formation of a "clot" sealing the damaged area. Moreover, it has long been recognized that inflammation also provokes the activation of the coagulation system. However, there has been an increasing amount of evidence revealing the immune function of the hemostasis system. This review collects and analyzes the results of the experimental studies and data from clinical observations confirming the inflammatory function of hemostasis. Here, we summarize the latest knowledge of the pathways in immune system activation under the influence of coagulation factors. The data analyzed allow us to consider the components of hemostasis as receptors recognizing «foreign» or damaged «self» or/and as «self» damage signals that initiate and reinforce inflammation and affect the direction of the adaptive immune response. To sum up, the findings collected in the review allow us to classify the coagulation factors, such as Damage-Associated Molecular Patterns that break down the conventional concepts of the coagulation system.

Case report: The value of early application of mNGS technology in the diagnosis and treatment of severe Legionnaires' disease: reports of two cases with different outcomes

Background

Legionnaires' disease has a high clinical mortality rate, and early diagnosis and treatment are critical. Increasing evidence shows that metagenomic next-generation sequencing (mNGS) has excellent potential for the early identification of pathogens. To help clinicians better recognize Legionnaires' disease in its early stage and to illustrate the diagnostic value of mNGS technology, we reviewed and summarized two cases of severe Legionnaires' disease.

Methods and analysis

We selected two patients with severe Legionnaires' disease who were admitted to our department in recent years. We discuss experience with them and the shortcomings in their treatment by summarizing their medical history, disease evolution, tests, and diagnostic and therapeutic processes.

Results

In both patients, the diagnosis of Legionnaires' disease was confirmed through analysis of the bronchoalveolar lavage fluid (BALF). The middle-aged male patient was cured and discharged due to early detection and diagnosis. The elderly immunocompromised patient died due to a delay in diagnosis.

Conclusion

This study highlights the importance of the early recognition and diagnosis of severe Legionnaires' disease and the advantages of mNGS in identifying the pathogen.

Listeria monocytogenes use multiple mechanisms to disseminate from the intestinal lamina propria to the mesenteric lymph nodes

Listeria monocytogenes are facultative intracellular bacterial pathogens that cause foodborne disease in humans. The bacteria can use the surface protein InlA to invade intestinal epithelial cells or transcytose across M cells in the gut, but it is not well understood how the bacteria traffic from the underlying lamina propria to the draining mesenteric lymph nodes (MLN). Previous studies indicated that L. monocytogenes associated with both monocytes and dendritic cells in the intestinal lamina propria. We show here that CCR2-/- mice had a significant reduction in Ly6Chi monocytes in the MLN but no change in bacterial burden following foodborne infection; thus, dissemination of L. monocytogenes associated with monocytes is not required for colonization of the MLN. To block CCR7-mediated trafficking of dendritic cells from the lamina propria, we treated mice with anti-VEGFR3 antibody (clone AFL4) prior to and during infection but did not see a change in dendritic numbers in the MLN as had been previously reported with other anti-VEGFR3-specific antibodies. However, increasing the number of circulating dendritic cells by treating mice with rFlt3L resulted in a significant increase in L. monocytogenes in the lymph nodes that drain the small intestine and the spleen. Whole-mount fluorescent microscopy of lymphatic vessels following ligated loop infection revealed both free-floating L. monocytogenes and cell-associated bacteria within lymphatic vessels. Together, these results suggest that L. monocytogenes can use multiple, redundant mechanisms to disseminate from the gut tissue to the MLN.

IMPORTANCE

Consumption of the foodborne bacterial pathogen Listeria monocytogenes results in a wide spectrum of human disease from mild self-limiting gastroenteritis to life-threatening infections of the bloodstream, brain, and placenta. It is not well understood how the bacteria migrate from the intestines to the draining mesenteric lymph nodes, which are thought to serve as the last barrier to prevent systemic infections. Results presented here reveal multiple redundant mechanisms L. monocytogenes can use to disseminate from the ileum or colon to the mesenteric lymph nodes.

A common form of dominant human IFNAR1 deficiency impairs IFN-α and -ω but not IFN-β-dependent immunity

Autosomal recessive deficiency of the IFNAR1 or IFNAR2 chain of the human type I IFN receptor abolishes cellular responses to IFN-α, -β, and -ω, underlies severe viral diseases, and is globally very rare, except for IFNAR1 and IFNAR2 deficiency in Western Polynesia and the Arctic, respectively. We report 11 human IFNAR1 alleles, the products of which impair but do not abolish responses to IFN-α and -ω without affecting responses to IFN-β. Ten of these alleles are rare in all populations studied, but the remaining allele (P335del) is common in Southern China (minor allele frequency ≈2%). Cells heterozygous for these variants display a dominant phenotype in vitro with impaired responses to IFN-α and -ω, but not -β, and viral susceptibility. Negative dominance, rather than haploinsufficiency, accounts for this dominance. Patients heterozygous for these variants are prone to viral diseases, attesting to both the dominance of these variants clinically and the importance of IFN-α and -ω for protective immunity against some viruses.

A novel virulent core genome multilocus sequence type CT 11424 of Listeria monocytogenes isolate causing stillbirth in Bangladesh

BACKGROUND

Listeria monocytogenes is a foodborne pathogen that can lead to severe pregnancy outcomes. This study reports the clinical and genomic characteristics of a Listeria-mediated stillbirth identified in January 2022 through the Child Health and Mortality Prevention Surveillance (CHAMPS) project in Bangladesh. The Lm-BD-CHAMPS-01 isolate was recovered from the blood and cerebrospinal fluid (CSF) of a male stillborn. Maternal history, clinical, and demographic data were collected by the CHAMPS surveillance platform. An expert panel evaluated all reports to determine the role of L. monocytogenes infection in the causal chain of stillbirth. Genomic characterization included multilocus sequence typing (MLST), core genome MLST (cgMLST), serotyping, and the presence or absence of virulence genes. Genetic divergence and phylogenetic analyses were conducted to determine the relationship with other reported isolates globally.

RESULTS

The isolate Lm-BD-CHAMPS-01 was identified as a novel cgMLST CT11424. It belonged to ST 308, Serotype 4b, Clonal Complex 1, and Phylogenetic Lineage 1. Key L. monocytogenes virulence genes facilitating the crossing of the placental barrier, including full-length inlA, LIPI-1, and LIPI-3, were detected. The isolate was closely related to clinical L. monocytogenes isolates, as determined by GrapeTree based on cgMLST. SNP-based phylogenetic analysis found Lm-BD-CHAMPS-01 to be the most distant from other CC1 isolates in the database. Possible sources of infection included the consumption of contaminated raw vegetables or exposure to pigeons.

CONCLUSIONS

This is the first genome sequence of clinical L. monocytogenes from Bangladesh, which also caused stillbirth. Rural healthcare professionals should be aware of L. monocytogenes infection risks during pregnancy. Pregnant women should be counseled on the dangers of exposure to animals or birds and consumption of potentially contaminated raw food to prevent adverse pregnancy outcomes due to L. monocytogenes infection.

Cytomegalovirus-Reactive IgG Correlates with Increased IL-6 and IL-1β Levels, Affecting Eating Behaviours and Tactile Sensitivity in Children with Autism

BACKGROUND/OBJECTIVES

Elevated cytokine levels, including IL-6 and IL-1β, can contribute to persistent brain inflammation in children with autism and cytomegalovirus (CMV) infection, exacerbating autism-related behaviours and symptoms. This study evaluates the impact of CMV-induced cytokine increases on the eating behaviours and sensory profiles of children with autism.

METHODS

A cross-sectional design was employed, involving children aged two to five years (CMV-reactive IgG), with ASD (n= 98) and TD (n = 96). Serological tests using ELISA were conducted to measure IgG CMV, IL-6, and IL-1β biomarkers. Eating behaviours were evaluated using the BAMBI (Brief Autism Mealtime Behaviour Inventory), and sensory profiles were assessed using the SSP (Short Sensory Profile). Statistical analyses were performed using Spearman's rank and chi-square tests.

RESULTS

The results show that autism significantly affects children's eating behaviours and sensory profiles (p < 0.001), with notable differences found between the groups. Correlation analysis revealed a significant association between IgG CMV and IL-6 (p = 0.026) and IL-1β (p = 0.014) in the ASD group. Additionally, eating behaviours (food refusal and limited variety) in ASD correlated with IL-6 and IL-1β. Sensory characteristics, such as tactile sensitivity, were found to correlate with IL-6 (p = 0.027) and IL-1β (p = 0.002) in the ASD group.

CONCLUSIONS

These findings suggest that CMV-infected children with autism are at increased risk of IL-6 and IL-1β dysregulation, contributing to sensory processing issues and eating behaviours. Further research is needed to enhance CMV testing protocols and better understand the virus's role in the development of sensory and behavioural issues in children with autism.

Probiotic and postbiotic interference exhibit anti-adhesion effects against clinical methicillin-resistant Staphylococcus aureus (MRSA) and impede MRSA-induced intestinal epithelial hyper-permeability in HT-29 cell line

This study investigates the dynamics of MRSA de-colonization on HT-29 cell line using effective strategies like probiotics and postbiotics. Exploring novel alternatives to combat infections caused by antibiotic-resistant pathogens is an urgent need. Harnessing the antagonistic properties of live probiotics and their heat-killed preparations (postbiotics) to curb the growth of AMR pathogens represents a promising and essential area of contemporary research. This study was designed to evaluate the anti-adhesion properties of indigenous probiotics (Limosilactobacillus fermentum Lf1 and Lactiplantibacillus plantarum A5), as well as standard reference strains (Lacticaseibacillus rhamnosus GG and Lactobacillus acidophilus NCFM), and their heat-killed postbiotic preparations against clinical MRSA isolates (MRSA12/206 and 5/255) on the HT-29 cell line. ATR-FTIR-based functional group characterization of the postbiotic preparations revealed the heat-induced alterations in cell surface molecules and architecture. Both probiotic and postbiotic preparations were non-cytotoxic to HT-29 cells. The probiotic intervention, via protective, competitive, and displacement modes, significantly (p < 0.05) reduced the adhesion of MRSA isolates to HT-29 cells, with the protective and competitive modes showing greater efficacy. In contrast, heat-killed probiotics demonstrated notable anti-MRSA adhesion effects across all three modes (protective, competitive, and displacement). In comparison, heat-killed cells exhibited a superior anti-adhesion capability compared to live cells, likely due to the enhanced accessibility of microbe-associated molecular patterns and adhesion sites following heat treatment. Furthermore, co-treatment of MRSA with probiotic strains substantially (p < 0.05) reduced FITC-dextran transflux across the HT-29 cell monolayer. In conclusion, this study highlights the superior anti-adhesion efficacy of heat-killed postbiotics over live probiotic cells against MRSA isolates. It underscores the further need for pre-clinical and in-vivo investigations to validate the anti-MRSA colonization and gut barrier prophylactic or therapeutic potential of the investigated probiotics and postbiotics. Thus, the present study documents and supports the alternative to antibiotics potential of probiotics and postbiotics.

New Developments and Therapeutic Drug Monitoring Options in Costimulatory Blockade in Solid Organ Transplantation: A Systematic Critical Review

PURPOSE

In this review, the authors summarized the latest developments in costimulatory blockade to prevent rejection after solid organ transplantation (SOT) and discussed possibilities for future research and the need for therapeutic drug monitoring (TDM) of these agents.

METHODS

Studies about costimulatory blockers in SOT in humans or animal transplant models in the past decade (2014-2024) were systematically reviewed in PubMed, European Union clinical trials (EudraCT), and ClinicalTrials.gov .

RESULTS

Seventy-five registered clinical trials and 58 published articles were found on costimulation blockade of the CD28-CD80/86, CD40-CD40L, and OX40-OX40L pathways. Belatacept, an antagonist of the CD28-CD80/86 pathway, is the only approved costimulatory agent in SOT, hence accounting for most of the research. Other identified costimulatory blocking agents included abatacept and CD28 antagonists tegoprubart, dazodalibep, and TNX-1500. Although tegoprubart was unsuccessful in pancreas transplantation in nonhuman primates, trials in human kidney transplantation are underway. Dazodalibep trials faced recruitment challenges. TNX-1500 was unsuccessful in animal studies and is currently not pursued in humans. After discontinuation of iscalimab (CD40-CD154 pathway antagonist) in SOT, the alternatives, bleselumab and KPL404, showed promising results in kidney transplantation and cardiac xenotransplantation. Studies on secondary costimulatory pathway antagonists, such as OX40-OX40L, have only used animal models. Despite the low interindividual variability in pharmacokinetics (PK) in all studied agents, TDM could be useful for optimizing dosing in PK/pharmacodynamic (PD) studies.

CONCLUSIONS

The routine use of costimulation blockade in SOT is hindered by problems in efficacy compared with the standard of care. Costimulatory inhibitors could be combined in a calcineurin inhibitor-free regimen. Future PK/pharmacodynamic studies in costimulatory agents and personalized medicine could warrant TDM of these agents.

Myocarditis diagnosis: From light microscope to molecular analysis and cardiac magnetic resonance

Telling story of myocarditis is characterized by discoveries and inventions. The invention of the microscope opened new avenues in medicine, with the observation of myocardial inflammation by Carl Ludwig Alfred Fiedler. Rudolph Virchow discovered that cells are the elementary units. Karl Albert Ludwig Aschoff first reported rheumatic pancarditis. Gilbert Dallford found enterovirus in the faeces of children, who died suddenly in the village of Coxsackie. Werner Forssmann entered in his own right ventricle with a urologic catheter via the left radial vein. Endomyocardial biopsy, via the femoral or jugular veins, made possible to take away myocardial samples in vivo, for diagnosis of myocarditis or cardiac rejection of transplanted heart. The invention of polymerase chain reaction by Kary Mullis allowed to achieve diagnosis of concealed infections and genetically determined cardiomyopathies. Myocarditis, a significant cause of sudden death, was found to be frequently ascribed to viruses. Cytotoxicity of Coxsackievirus B was proved to consist on released protease 2, encoded by virus genome and cleaving dystrophin. RNA (Coxsackie) and DNA (adenovirus) viruses share a common receptor. Cardiac magnetic resonance revealed to be sensitive and specific in the diagnosis of myocarditis by detecting myocardial oedema. However, it is unable to establish the histotype. The onset of myocarditis may be fulminant; however, extracorporeal membrane oxygenation, invented by Robert Bartlett, allows heart rest, while replacing cardiac contractility. High rates of survival have been achieved, probably because of mild myocardial damage.

Insights Into Enterovirus D68 Immunology: Unraveling the Mysteries of Host-Pathogen Interactions

BACKGROUND

Enterovirus D68 (EV-D68) has emerged as a significant respiratory and neurological pathogen, particularly affecting children with severe respiratory illnesses and acute flaccid myelitis. Understanding the interaction between EV-D68 and the host immune system is crucial for developing effective prevention and treatment strategies.

OBJECTIVES

This review aims to examine the immune response to EV-D68, its mechanisms of immune evasion, and the current progress in vaccine and antiviral development while identifying gaps in knowledge and future research directions.

METHODS

A comprehensive review of the literature was conducted, focusing on the innate and adaptive immune responses to EV-D68, its strategies for immune evasion, and advancements in therapeutic interventions.

RESULTS

Pattern recognition receptors detect EV-D68 and trigger antiviral defenses, including interferon production and activation of natural killer cells. B cells generate antibodies, while T cells coordinate a targeted response to the virus. EV-D68 employs mechanisms such as antigenic variation and disruption of host antiviral pathways to evade immune detection. Progress in vaccine and antiviral research shows promise but remains in the early stages.

CONCLUSIONS

EV-D68 represents a complex and evolving public health challenge. Although the immune system mounts a robust response, the virus's ability to evade these defenses complicates efforts to control it. Continued research is essential to develop effective vaccines and antivirals and to address gaps in understanding its pathogenesis and immune interactions.

IMPLICATIONS

A multidisciplinary approach is critical to improving diagnostic, preventive, and therapeutic strategies for EV-D68, ensuring better preparedness for future outbreaks.

Initial antigen encounter determines robust T-cell immunity against SARS-CoV-2 BA.2.86 variant three years later

OBJECTIVES

We aimed to evaluate the adaptive immune responses cross-recognition of the hypermutated SARS-CoV-2 BA.2.86 variant and identify the determinants influencing this recognition.

METHODS

We measured BA.2.86 neutralizing antibodies and T-cell responses cross-reactivity in previously exposed participants. We investigated clinical-demographic factors and used a novel in silico analysis to assess viral genetic determinants affecting T-cell responses.

RESULTS

Despite notable escape from neutralizing antibodies, T-cell responses remained generally preserved, albeit with a significant but small loss in T-cell cross-recognition (7.5%, 14.2%, and 10.8% average loss for IFN-γ, IL-2, and IFN-γ + IL-2, respectively, p<0.05). This is consistent with the prediction of 6 out of 10 immunodominant T-cell epitopes (TCEs) altered by BA.2.86 mutations to have reduced peptide presentation. This effect is expected to be mitigated by total TCEs across the genome. Remarkably, T-cell responses and cross-recognition were 3.5 (IFN-γ), 2 (IL-2) and 2.4 (IFN-γ + IL-2) times higher when first induced by infection rather than by vaccination three years earlier, by increasing number of infections, and by ancestral/Delta than Omicron infections.

CONCLUSIONS

Our findings underscore the critical role and factors influencing T-cell immunity against evolving SARS-CoV-2 variants, such as first antigen encounter (vaccination or infection), as it is essential for developing effective control strategies.

NOD1 Agonist Induces Proliferation and Plasma Cell Differentiation of Mouse B Cells Especially CD23high B Cells

BACKGROUND

Like innate cells, B cells also express Pattern Recognition Receptors (PRRs) to detect danger signal such as tissue damage or pathogen intrusion. Production of specific antibodies by plasma cells results from the activation and differentiation of B cells following three signals: (i) antigen recognition by B Cell Receptors, (ii) recognition of danger and (iii) T-cell help. However, it is unclear whether T-cell help is dispensable for B cell activation and differentiation or not. Few studies have investigated the role of cytosolic PRRs such as NOD1 in B cell differentiation.

METHODS

We used splenic C57BL6J B cells to evaluate NOD1 expression and then assessed the effect of stimulation with C12-iE-DAP, a NOD1 ligand, with or without CD40L as a T-cell help signal on B-cell responses globally or according to their CD23 expression level.

RESULTS

We showed that murine B cells express NOD1 and that the presence of C12-iE-DAP induces activation, proliferation and initiates differentiation in plasma cells even in the absence of a T-dependent signal. Surprisingly, CD23high B cells are more sensitive than CD23low B cells to stimulation.

CONCLUSION

Our results suggest that the NLR pathway could induce antibody development during infections and be exploited to develop more effective vaccination.

Acceptability of an annual tenofovir alafenamide implant for HIV prevention in South African women: findings from the CAPRISA 018 Phase I clinical trial

INTRODUCTION

Long-acting HIV pre-exposure prophylaxis promises to improve uptake, adherence and persistence challenges experienced with daily oral tablets. We assessed the acceptability of an annual tenofovir alafenamide (TAF) implant in South African women enrolled from 9 July 2020 until 31 May 2022 in a Phase I trial.

METHODS

Six women received one TAF implant for 4 weeks (Group 1), after which 30 women were randomized (4:1, TAF to placebo ratio) to receive 1 or 2 TAF or placebo implants for 48 weeks (Group 2), before trial discontinuation. Acceptability assessments were conducted pre- and post-implant removal. Implant attributes (size, quantity, insertion site, palpability, visibility) and physical experiences (insertion/removal procedures, implant site reactions [ISRs]) were rated on a scale of 1 (highly unacceptable) to 6 (highly acceptable), with 4 being the acceptability threshold. The mean (range) of the mean acceptability scores across all pre-removal visits were calculated, including stratification by removal timing (early vs. scheduled). Implant likes and dislikes were also assessed.

RESULTS

The median participant age was 26 years. Prior to implant removal, the mean (range) acceptability scores were 5.4 (3.6-6.0) for product attributes and 5.1 (1.7-6.0) for physical experiences. Eleven (31%) participants had early implant removals, occurring on average 19 weeks (range 2-27 weeks) after insertion. The proportion of study visits reporting adherence measure as unacceptable in early versus scheduled removals: ISRs (50% vs. 19%), visibility (30% vs. 15%), palpability (14% vs. 8%), pain (16% vs. 4%) and implant quantity (13% vs. 1%). Pre-removal acceptability scores for ISRs (p = 0.003) and physical experiences (p = 0.05) were significantly associated with early removal. Overall, mean (range) acceptability scores were 5.8 (4.0-6.0) and 5.9 (4.7-6.0) for lifestyle compatibility and likelihood of recommendation, respectively. After removal, 39% of participants found ISRs unacceptable, followed by 22% citing implant visibility. Potential for long-term HIV protection, followed by discreet and convenient use, were most liked, while ISRs were the most disliked aspect.

CONCLUSIONS

While implant attributes, physical experiences and insertion/removal procedures were largely acceptable, local ISRs significantly reduced tolerability and acceptability, resulting in higher-than-expected early removals. The potential benefits of an annual TAF implant may be undermined unless tolerability is improved.

Revisiting the potential of natural antimicrobial peptides against emerging respiratory viral disease: a review

This review assesses the antiviral capabilities of antimicrobial peptides (AMPs) against SARS-CoV-2 and other respiratory viruses, focussing on their therapeutic potential. AMPs, derived from natural sources, exhibit promising antiviral properties by disrupting viral membranes, inhibiting viral entry, and modulating host immune responses. Preclinical studies demonstrate that peptides such as defensins, cathelicidins, and lactoferrin can effectively reduce SARS-CoV-2 replication and inhibit viral spread. In addition, AMPs have shown potential in enhancing the host's antiviral immunity. Despite these promising outcomes, several challenges require assessments before transforming into clinical translation. Several issues related to peptide stability, cytotoxicity, and efficient delivery systems pose significant limitations to their therapeutic application. Recent advancements in peptide engineering, nanotechnology-based delivery systems, and peptide conjugation strategies have improved AMPs stability and bioavailability; however, further optimization is essential. Moreover, whilst AMPs are safe, their effects on host cells and tissues need a thorough investigation to minimise potential adverse reactions. This review concludes that whilst AMPs present a promising route for antiviral therapies, particularly in targeting SARS-CoV-2, extensive clinical trials and additional studies are required to overcome current limitations. Future research should focus on developing more stable, less toxic AMPs formulations with enhanced delivery mechanisms, aiming to integrate AMPs into viable therapeutic options for respiratory viral diseases, including COVID-19 and other emerging infections.

An agent-based model to simulate the transmission dynamics of bloodborne pathogens within hospitals

Mathematical models are powerful tools to analyze pathogen spread and assess control strategies in healthcare settings. Nevertheless, available models focus on nosocomial transmission through direct contact or aerosols rather than through blood, even though bloodborne pathogens remain a significant source of iatrogenic infectious risk. Herein, we propose an agent-based SEI (Susceptible-Exposed-Infected) model to reproduce the transmission of bloodborne pathogens dynamically within hospitals. This model simulates the dynamics of patients between hospital wards, from admission to discharge, as well as the dynamics of the devices used during at-risk invasive procedures, considering that patient contamination occurs after exposure to a contaminated device. We first illustrate the use of this model through a case study on hepatitis C virus (HCV) in Egypt. Model parameters, such as HCV upon-admission prevalence and transition probabilities between wards or ward-specific probabilities of undergoing different invasive procedures, are informed with data collected in Ain Shams University Hospital in Cairo. Our results suggest a low risk of HCV acquisition for patients hospitalized in this university hospital. However, we show that in a low-resource hospital, frequent device shortages could lead to increased risk. We also find that systematically screening patients in a few selected high-risk wards could significantly reduce this risk. We then further explore potential model applications through a second illustrative case study based on HBV nosocomial transmission in Ethiopia. In the future, this model could be used to predict the potential burden of emerging bloodborne pathogens and help implement effective control strategies in various hospital contexts.

[Community acquired bacterial meningitis in adults]

Bacterial meningitis is a rare but severe disease with a high mortality. The most frequent pathogens in adults are pneumococcus, meningococcus and Listeria. The most important key symptoms are headache, meningism and fever; however, the absence of individual cardinal symptoms does not exclude the diagnosis. The empirical treatment consists of ceftriaxone and ampicillin, supplemented with dexamethasone as needed. It should be initiated without delay if bacterial meningitis is suspected. Before this, two pairs of blood cultures should be obtained followed by a lumbar puncture. An elevated intracranial pressure must be excluded via cerebral computed tomography before performing a lumbar puncture only in patients with confirmation of impaired consciousness, focal neurological deficits or epileptic seizures. In such cases treatment is initiated immediately after obtaining blood cultures but before the lumbar puncture. The identification and management of a focus are essential and should be conducted on the day of admission.

Seasonal shifts in respiratory pathogen co-infections and the associated differential induction of cytokines in children

In the post-pandemic era, research on respiratory diseases should refocus on pathogens other than the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Respiratory pathogens, highly infectious to children, with to different modes of infection, such as single-pathogen infections and co-infections. Understanding the seasonal patterns of these pathogens, alongside identifying single infections and co-infections and their impact on the pediatric immune status, is crucial for clinical diagnosis, treatment, and prognosis in children. Our study found that from December 2023 to April 2024, the main co-infection combinations in children shifted from Mycoplasma pneumonia and influenza virus A (MP + IVA) to Bordetella pertussis and rhinovirus (BP + RhV). To explore the impact of these infections, two cohorts were established to analyze the effects of single and co-infections of four respiratory pathogens, MP, IVA, BP, and RhV, on the immune status of pediatric patients. Using multi-cytokine analysis, cytokines, such as PDGF-BB, that were differentially expressed between patients with single and co-infections were identified. Additionally, we observed that children with single-pathogen infections generally exhibited more severe conditions, as evidenced by higher overall cytokine expression than those with co-infections. Our findings provide an important theoretical basis for understanding the pathogenic mechanisms of single and co-infections of respiratory pathogens and clinically differentiating pediatric patients with various respiratory infections.

Embolic risk management in infective endocarditis: predicting the 'embolic roulette'

Life-threatening complications of infective endocarditis (IE,) are heart failure, uncontrolled infection and embolic events (EE), which pose significant morbidity and mortality risks. EE from vegetation rupture are frequent, occurring in more than 50% of patients and can lead to ischaemic stroke and systemic organ infarctions, contributing to poor patient outcomes. Early identification and characterisation of embolic risk factors, including vegetation size, mobility and echogenicity assessed through transthoracic and transoesophageal echocardiography, but also certain pathogens and biomarkers are important for guiding clinical decisions. The latest European Guidelines recommendations emphasise the role of imaging modalities like CT and MRI in detecting silent emboli and guiding therapeutic interventions, including the timely consideration of surgical options to mitigate embolic risks. In this regard, embolic vascular dissemination-including asymptomatic cases detected through multimodality imaging-has been introduced as a new minor criterion for the diagnosis of IE.Depending on the location and severity of the embolism, the embolic risk can either escalate or alternatively, complicate and delay cardiac surgery. The decision to proceed with surgery should not hinge solely on the occurrence of an embolic event, although current guidelines often emphasise this criterion. Therefore, future perspectives should focus on identifying high-risk profiles for EE and investigating whether early surgical intervention benefits these patients, even if they respond favourably to antibiotic therapy. This review explores current literature on echocardiographic and biomarker predictors of EE in IE, aiming to enhance clinical strategies for mitigating embolic complications and improving patient outcomes.

Executive functioning in subjects post COVID-19 infection in Mexico

Over the past three years, conflicting evidence has emerged regarding the impact of COVID-19 on executive functions and the frontal lobe. In this study, we evaluated executive functions in individuals from the state of Jalisco who had contracted COVID-19. Sixty individuals with a history of mild COVID-19 were included and compared to historical controls from the Mexican population, who had been assessed prior to the pandemic during the validation of the Trail Making Test Form B, the Stroop Color and Word Test, and the Modified Wisconsin Card Sorting Test (M-WCST). The post-infection group exhibited lower scores only on the M-WCST. Therefore, we concluded that individuals who have recovered from mild COVID-19 do not display widespread impairments in executive functions, with the exception of deficits observed on the M-WCST. This suggests possible neurophysiological alterations in the prefrontal cortex during SARS-CoV-2 infection, given that cognitive flexibility is primarily mediated in this region. These findings contribute to the growing body of evidence indicating that even non-hospitalized COVID-19 patients can experience executive function deficits, providing a foundation for further neurophysiological research into the mechanisms underlying this phenomenon.

Listeria Meningitis as an Indication of Undiagnosed Primary Immune Deficiency, Activated Phosphoinositide 3-Kinase Delta Syndrome: A Case Report

INTRODUCTION

Listeria monocytogenes is a Gram-positive bacillus that causes severe infections mainly in newborns, pregnant women, immunocompromised individuals, and elderly. In this report, we present a case of immune dysregulation that presented with invasive Listeria infection despite the absence of these risk factors.

CASE

A previously healthy 5-year-old girl developed L. monocytogenes meningitis, which is unusual given her age and lack of typical risk factors. The patient initially presented with fever, diarrhea and altered mental status, unresponsive to empiric antibiotic treatment. Besides clinical diagnosis of meningitis, laboratory tests revealed pleocytosis and positive polymerase chain reaction test for L. monocytogenes in cerebrospinal fluid. Despite initial improvement, the patient developed proteinuria and hypertension and was later diagnosed with focal class 3 lupus nephritis following a renal biopsy. Given the atypical nature of her L. monocytogenes infection, persistent organomegaly, and lupus nephritis, further immunological evaluation was conducted. Genetic testing revealed a de-novo gain-of-function mutation in the PIK3CD gene, confirming the diagnosis of Activated Phosphoinositide 3-Kinase Delta Syndrome 1 (APDS1), a rare primary immunodeficiency characterized by lymphoproliferation and autoimmunity. The patient was started on immunoglobulin replacement therapy and prophylactic trimethoprim-sulfamethoxazole. No recurrence of severe infection occurred during 2 years of follow-up.

CONCLUSION

This case underscores the importance of considering underlying immune dysregulations in pediatric patients with atypical presentation of Listeria infections.

Refractory and Resistant Herpes Simplex Virus Mucocutaneous Infections in Immunocompromised Patients: Literature Review and Proposed Definitions for Use in Clinical Trials

Herpes simplex virus (HSV) infection is one of the most prevalent viral infections worldwide. In general, host immunity is sufficient to clear viral shedding and recurrences, although it is insufficient to prevent subsequent virologic reactivations. In immunocompromised patients, prolonged and difficult-to-treat HSV infections may develop. The diagnosis of refractory HSV infection is based on the lack of clinical response to nucleoside analogs. Antiviral resistance is confirmed via genotypic and/or phenotypic testing. To provide consensus definitions of refractory and/or resistant (R/R) HSV mucocutaneous infections for clinical trial use, the HSV Resistance Working Group of the Transplant Associated Viral Infections Forum, which includes international clinicians, scientists, industry representatives, and regulatory officials, conducted a literature review of previously published data related to R/R HSV infections in immunocompromised patients. We propose definitions of R/R HSV mucocutaneous infections, which will be subject to re-evaluation and revision based on forthcoming data and future studies.

Prevalence of Nasal Staphylococcus aureus Carriage in Patients Undergoing Hemodialysis and Assessment of Risk Factors: A Cross-Sectional Study of Outpatients at a University Hospital

Background/Objectives: Infection poses a significant threat of mortality in patients with chronic kidney disease (CKD) undergoing hemodialysis. Staphylococcus aureus (S. aureus) is a common etiological agent, with prior nasal colonization identified as a risk factor for infection. The aim of the present cross-sectional study was to determine the prevalence of nasal S. aureus carriage among patients with CKD undergoing dialysis at a university hospital and identify potential factors associated with colonization. Methods: Nasal swabs were obtained, and bacterial isolates were identified using matrix-assisted laser desorption/ionization time-of-flight spectrometry and antibiogram testing with the Vitek 2 system. Demographic and clinical data were collected for the investigation of risk factors associated with colonization. Results: Among the 96 patients analyzed, 34 were carriers of S. aureus. Among these carriers, three (8.8%) harbored oxacillin-resistant strains. More than half of the S. aureus strains exhibited resistance to clindamycin but susceptibility to oxacillin. Colonization was associated with age and the use of corticosteroids/immunosuppressants. Conclusions: The prevalence of nasal S. aureus carriage was high among patients undergoing dialysis at the university hospital, exceeding that found in the general population. Nasal colonization by S. aureus was linked to corticosteroid use and age. Understanding factors associated with S. aureus nasal colonization in patients on dialysis can assist healthcare providers in preventing the spread of infection and cross-contamination, while reducing risk in this population.

A practical approach to investigating nosocomial acquisition of Aspergillus

Invasive mould disease (IMD) has a high mortality in immunosuppressed patients. Invasive aspergillosis (IA) is the most common IMD. A guideline for preventing IA has been published jointly by the Centers for Disease Control and Prevention, the Infectious Disease Society of America, and the American Society of Blood and Marrow Transplantation. Use of high-efficiency particulate air filters, adequate air exchange rates, sealing of patient rooms, and preventing exposure to moulds by nursing patients in areas away from construction sites are recommended by the guideline. However, there is limited information in relation to the actions to be undertaken by infection prevention and control teams in the event of one or more cases of nosocomial aspergillosis. In this review, we describe a systematic approach to aspergillosis by defining possible and probable nosocomial acquisition based on the number of days since hospital admission. We advocate an incremental response to the investigation of nosocomial aspergillosis in patients in protective isolation taking into account the number of cases and the likelihood of nosocomial origin. For single cases of nosocomial IA, we suggest that infection control investigations should focus on case surveillance and walk-through inspection escalating in a stepwise manner to enhanced case surveillance, verification of environmental controls, environmental monitoring, genotyping of clinical and environmental isolates, and review of antifungal prophylaxis for multiple cases and outbreaks. Where applicable, the construction site should be inspected with the aim to reduce the dispersal of conidia. Surveillance systems need to be strengthened to better understand the epidemiology of IA.

Airborne Staphylococcus aureus Exposure Induces Depression-like Behaviors in Mice via Abnormal Neural Oscillation and Mitochondrial Dysfunction

Airborne Staphylococcus aureus exists widely in the natural environment and is closely related to human health. Growing evidence indicates that environmental air pollution elevates the risk of depressive disorders. However, the potential role of airborne S. aureus in the development of depression remains unclear. This study aims to elucidate the neurotoxic effects and potential mechanisms associated with depression caused by airborne S. aureus. Mice were randomly divided into four groups, and the experimental groups with environmental S. aureus were at 4.89 × 102, 8.89 × 105, and 1.27 × 108 CFU/m3 during four consecutive weeks. Airborne S. aureus exposure contributed to depression-like behaviors in mice, especially in the high-concentration group. The electroencephalography signal analysis identified uncoupling of theta and gamma bands and a shift of the beta rhythm toward delta oscillation in the medial prefrontal cortex of mice. Neuropathological analysis showed uplifted neuroinflammation and elevated levels of oxidative stress in the brain. Neuroinflammation and oxidative stress resulted in mitochondrial dysfunction, which could lead to apoptosis. Together, this study provides a strong basis for understanding the adverse outcomes of airborne S. aureus on mental health disorders.

Human genetic and immunological determinants of SARS-CoV-2 infection and multisystem inflammatory syndrome in children

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) induces pneumonia and acute respiratory failure in coronavirus disease 2019 (COVID-19) patients with inborn errors of immunity to type I interferon (IFN-I). The impact of SARS-CoV-2 infection varies widely, ranging from mild respiratory symptoms to life-threatening illness and organ failure, with a higher incidence in men than in women. Approximately 3-5% of critical COVID-19 patients under 60 and a smaller percentage of elderly patients exhibit genetic defects in IFN-I production, including X-chromosome-linked TLR7 and autosomal TLR3 deficiencies. Around 15-20% of cases over 70 years old, and a smaller percentage of younger patients, present with preexisting autoantibodies neutralizing type I interferons. Additionally, innate errors affecting the control of the response to type I interferon have been associated with pediatric multisystem inflammatory syndrome (MIS-C). Several studies have described rare errors of immunity, such as XIAP deficiency, CYBB, SOCS1, OAS1/2, and RNASEL, as underlying factors in MIS-C susceptibility. However, further investigations in expanded patient cohorts are needed to validate these findings and pave the way for new genetic approaches to MIS-C. This review aims to present recent evidence from the scientific literature on genetic and immunological abnormalities predisposing individuals to critical SARS-CoV-2 infection through IFN-I. We will also discuss multisystem inflammatory syndrome in children (MIS-C). Understanding the immunological mechanisms and pathogenesis of severe COVID-19 may inform personalized patient care and population protection strategies against future serious viral infections.

Thromboelastometry-Based Profiling of Haemostatic Alterations in Neonatal Sepsis by Causative Pathogens

Background: Neonatal sepsis is a serious condition with high mortality, especially in premature and low-birth-weight neonates. This study aims to examine whether the haemostatic profile of neonates with sepsis defers depending on the type of bacteria (Gram-positive or Gram-negative), by using the method of Rotational Thromboelastometry (ROTEM). Methods: This single-centre prospective cohort study was conducted on 128 neonates with sepsis, including 95 cases caused by Gram-negative pathogens and 33 cases caused by Gram-positive bacteria. All participants were hospitalised in the Neonatal Intensive Care Unit (NICU). ROTEM parameters were compared between neonates with Gram-positive and Gram-negative infections. Results: The ROTEM parameters were found to be significantly different between neonates suffering from Gram-positive versus Gram-negative infections, with Gram-positive pathogens associated with an increased clotting potential compared to Gram-negative pathogens. This is reflected in the higher ROTEM values such as A10, α-angle, and MCF in the EXTEM and INTEM assays. Multivariant analysis showed that Gram-positive infections were linked to increased clot thickness at 10 min (coefficient: 8.9, CI: 2.8-15.0, p = 0.004), higher maximum clot stability (coefficient: 10.4, CI: 4.3-16.6, p = 0.001), and a bigger α-angle (coefficient: 8.0, CI: 2.7-13.2, p = 0.003). Similar findings were observed in the INTEM assay parameters. Conclusions: Neonatal sepsis caused by Gram-positive bacteria leads to a hypercoagulable haemostatic state, whereas neonates with sepsis caused by Gram-negative bacteria exhibit a more hypocoagulable profile and a higher incidence of haemorrhagic episodes. These findings provide valuable insights into the haemostatic disorders associated with sepsis, and may aid in developing an individualised approach for the treatment of those disorders, dependent on and adapted for the specific type of causative organism.