Plasma Extracellular Vesicles Derived from Pediatric COVID-19 Patients Modulate Monocyte and T Cell Immune Responses Based on Disease Severity.

BACKGROUND: The COVID-19 pandemic has caused significant morbidity and mortality globally. The role of plasma-derived extracellular vesicles (EVs) in pediatric COVID-19 patients remains unclear. METHODS: We isolated EVs from healthy controls (n = 13) and pediatric COVID-19 patients (n = 104) with varying severity during acute and convalescent phases using serial ultracentrifugation. EV effects on healthy PBMCs, naïve CD4+ T cells, and monocytes were assessed through in vitro assays, flow cytometry, and ELISA. RESULTS: Our findings indicate that COVID-19 severity correlates with diverse immune responses. Severe acute cases exhibited increased cytokine levels, decreased IFNγ levels, and lower CD4+ T cell and monocyte counts, suggesting immunosuppression. EVs from severe acute patients stimulated healthy cells to express higher PDL1, increased Th2 and Treg cells, reduced IFNγ secretion, and altered Th1/Th17 ratios. Patient-derived EVs significantly reduced proinflammatory cytokine production by monocytes (p < .001 for mild, p = .0025 for severe cases) and decreased CD4+ T cell (p = .043) and monocyte (p = .033) populations in stimulated healthy PBMCs. CONCLUSION: This study reveals the complex relationship between immunological responses and EV-mediated effects, emphasizing the impact of COVID-19 severity. We highlight the potential role of plasma-derived EVs in early-stage immunosuppression in severe COVID-19 patients.

Development and preclinical evaluation of virus-like particle vaccine against COVID-19 infection.

BACKGROUND: Vaccines that incorporate multiple SARS-CoV-2 antigens can further broaden the breadth of virus-specific cellular and humoral immunity. This study describes the development and immunogenicity of SARS-CoV-2 VLP vaccine that incorporates the four structural proteins of SARS-CoV-2. METHODS: VLPs were generated in transiently transfected HEK293 cells, purified by multimodal chromatography, and characterized by tunable-resistive pulse sensing, AFM, SEM, and TEM. Immunoblotting studies verified the protein identities of VLPs. Cellular and humoral immune responses of immunized animals demonstrated the immune potency of the formulated VLP vaccine. RESULTS: Transiently transfected HEK293 cells reproducibly generated vesicular VLPs that were similar in size to and expressing all four structural proteins of SARS-CoV-2. Alum adsorbed, K3-CpG ODN-adjuvanted VLPs elicited high titer anti-S, anti-RBD, anti-N IgG, triggered multifunctional Th1-biased T-cell responses, reduced virus load, and prevented lung pathology upon live virus challenge in vaccinated animals. CONCLUSION: These data suggest that VLPs expressing all four structural protein antigens of SARS-CoV-2 are immunogenic and can protect animals from developing COVID-19 infection following vaccination.

Assessment of ventricular functions by tissue Doppler echocardiography in children with asthma.

Patients with asthma develop pulmonary hypertension due to recurrent hypoxia and chronic inflammation, leading to right heart enlargement with ventricular hypertrophy. Patients with severe asthma can experience cor pulmonale later in life, but little is known about ventricular function during the early stages of the disease. This study aimed to investigate ventricular functions in asymptomatic children with asthma as detected by conventional echocardiography and tissue Doppler echocardiography (TDE). Fifty-one pediatric patients (mean age 10.4 ± 2.2 years) with asthma and 46 age- and sex-matched healthy children (mean age 10.9 ± 2.4 years) were studied. All subjects were examined by conventional echocardiography and TDE, and they had pulmonary function tests on spirometry. The right-ventricular (RV) wall was statistically (p = 0.01) thicker among asthmatic patients (4.7 ± 1.5 mm) compared with healthy children (3.6 ± 0.4 mm). However, conventional pulsed-Doppler indices of both ventricles did not differ significantly between asthmatic patients and healthy children (p > 0.05). The results of TDE examining RV diastolic function showed that annular peak velocity during early diastole (E'), annular peak velocity during late diastole (A') (16.4 ± 1.8 and 5.1 ± 1.4 cm/s, respectively), E'/A' ratio (3.2 ± 0.7), isovolumetric relaxation time (67.7 ± 10.2 ms) and myocardial performance index (48.1 % ± 7.0 %) of the lateral tricuspid annulus among asthmatic patients differed significantly (p = 0.01) from those of healthy children (13.2 ± 2.3, 8.2 ± 2.0 cm/s, 1.6 ± 0.5, 46.2 ± 8.7 ms, and 42.0 % ± 5.7 %, respectively). Only peak expiratory flow (PEF) rate from the pulmonary function tests was negatively correlated with the E'/A' ratio of the tricuspid annulus (r = -0.38, p = 0.01). This study showed that although the findings of clinical and conventional echocardiography were apparently normal in children with asthma, TDE showed subclinical dysfunction of the right ventricle, which is negatively correlated with PEF. These findings signify the diagnostic value of TDE in the early detection and monitoring of such deleterious effects among asthmatic patients.

Improved nitrogen nutrition enhances root uptake, root-to-shoot translocation and remobilization of zinc ((65) Zn) in wheat.

This study focussed on the effect of increasing nitrogen (N) supply on root uptake and root-to-shoot translocation of zinc (Zn) as well as retranslocation of foliar-applied Zn in durum wheat (Triticum durum). Nutrient solution experiments were conducted to examine the root uptake and root-to-shoot translocation of (65) Zn in seedlings precultured with different N supplies. In additional experiments, the effect of varied N nutrition on retranslocation of foliar-applied (65) Zn was tested at both the vegetative and generative stages. When N supply was increased, the (65) Zn uptake by roots was enhanced by up to threefold and the (65) Zn translocation from roots to shoots increased by up to eightfold, while plant growth was affected to a much smaller degree. Retranslocation of (65) Zn from old into young leaves and from flag leaves to grains also showed marked positive responses to increasing N supply. The results demonstrate that the N-nutritional status of wheat affects major steps in the route of Zn from the growth medium to the grain, including its uptake, xylem transport and remobilization via phloem. Thus, N is a critical player in the uptake and accumulation of Zn in plants, which deserves special attention in biofortification of food crops with Zn.

Accelerated idioventricular rhythm associated with propranolol treatment in a child.

Accelerated idioventricular rhythm (AIVR) is a ventricular arrhythmia most commonly seen in adults with underlying cardiac disease. It is important to establish the diagnosis when it occurs to differentiate this benign phenomenon from dangerous ventricular tachycardia. We present the case of a healthy child who developed episodes of AIVR associated with propranolol treatment. Her 24-hour electrocardiography recording showed AIVR with difference between sinus and ventricular beats. The arrhythmia resolved with the discontinuation of propranolol, and eventually the case was in sinus rhythm. This patient is the first case of AIVR associated with propranolol treatment in the literature.

Hepatitis a with pleural effusion, ascites and acalculous cholecystitis.

BACKGROUND: Hepatitis A virus (HAV) infection constitutes an important health problem in developing countries. It is usually a benign self-limiting disease, but may present with atypical clinical findings. CASE PRESENTATION: A twelve-year-old male with ascites, pleural effusion, and acalculous cholecystitis during the course of HAV infection is reported. He was managed conservatively and clinical improvement was observed with resolution of HAV infection. CONCLUSION: To our knowledge, this is the first case in which all these three rare complications were observed in a single patient in the early period of disease.