Increased IgG Levels Research Articles

Use of serum-free media for peripheral blood mononuclear cell culture and the impact on T and B cell readouts.

As part of a wider programme of work developing next-generation risk assessment approaches (NGRA) using non-animal methods (NAMs) for safety assessment of materials, Unilever SEAC is exploring the use of a peripheral blood mononuclear cell (PBMC) system to investigate how cells from different arms of the human immune system are impacted by different treatments. To maximise human relevance, the cell cultures are supported by human serum, but this came with some challenges, including an inability to measure induced levels of immunoglobulins due to high background levels. Therefore, a study comparing use of human sera containing media with three different chemically defined serum-free media was undertaken. PBMC were isolated from healthy donors and cultured in the absence (media alone) or presence of stimulation reagents (CpG-ODN plus IL-15, Pokeweed Mitogen (PWM) or Cytostim (CS)), in RPMI plus human serum, AIM-V, CTS OpTmizer T cell expansion SFM or X-VIVO 15 media. T cell (CD4+ and CD8+) and B cell proliferation and viability were measured after 6days, along with levels of total IgG in the cell culture supernatants. Each of the serum-free media tested supported good levels of viable and proliferating T cells and B cells over the 6 days of culture, with only a few, small differences across the media, when there was no stimulation. They also enabled detection of a stimulation-evoked increase in IgG levels. There were however some differences in the viability and proliferation responses of T and B cells, to different stimuli, across the different media. The serum-free media formulations tested in this study offer defined systems for. measuring B cell IgG responses, in vitro, in either a 'T cell-independent' (CpG + IL-15) or "T cell-dependent" (PWM or CS) manner and for assessing B cell proliferation, particularly in response to a "T cell-independent" stimulus. However, there are some characteristics and features endowed by human serum that appear to be missing. Therefore, further work is required to optimise animal-free, chemically defined culture conditions for PBMC based assays for inclusion in tiered safety assessments.

Responses of Intestinal Antioxidant Capacity, Morphology, Barrier Function, Immunity, and Microbial Diversity to Chlorogenic Acid in Late-Peak Laying Hens.

This study examined the influence of chlorogenic acid (CGA) on gut antioxidant status, morphology, barrier function, immunity, and cecal microbiota in late-peak laying hens. A total of 240 Hy-Line Brown hens, aged 43 weeks, were randomly assigned to four groups, the basal diet +0, 400, 600, and 800 mg/kg CGA, for 12 weeks. The results revealed that CGA significantly reduced ileal H2O2 and malondialdehyde levels; increased duodenal height, ileal villus height, and villus height-to-crypt depth ratio; while decreasing jejunal crypt depth. The 600 and 800 mg/kg CGA significantly upregulated the duodenal, jejunal, and ileal ZO-1 and occludin gene expression; increased IgG levels in serum and ileum; and upregulated ileal IgA gene expression. The 600 mg/kg CGA significantly upregulated CD3D and CD4 gene expression, while downregulating IL-1β gene expression in duodenum, jejunum, and ileum. Moreover, CGA changed the gut microbiota structure. The SCFA-producing bacteria unclassified_f__Peptostreptococcaceae, unclassified_f_Oscillospiraceae, Pseudoflavonifractor, Lachnospiraceae_FCS020_group, Oscillospira, Elusimicrobium, Eubacterium_ventriosum_group, Intestinimonas, and norank_f_Coriobacteriales_Incertae_Sedis were significantly enriched in the 400, 600, and/or 800 mg/kg CGA groups. The bacteria Lactobacillus, Bacillus, and Akkermansia were significantly enriched in the 600 mg/kg CGA group. Conclusively, dietary CGA (600-800 mg/kg) improved intestinal antioxidant status, morphology, barrier and immune function, and beneficial microbiota growth in late-peak laying hens.

Effects of Alanyl-Glutamine Dipeptide Supplementation on Growth Performance, Nutrient Digestibility, Digestive Enzyme Activity, Immunity, and Antioxidant Status in Growing Laying Hens.

Alanyl-glutamine (Aln-Gln), a highly soluble and stable Glutamine-dipeptide, is known to improve the performance of poultry birds. This study aimed to investigate the effect of Aln-Gln during the rearing period on growth performance, nutrient digestibility, digestive enzyme activity, immunity, antioxidant status and relative gene expression of Hy-Line brown hens. A total of 480 healthy day-old Hy-line brown chicks with similar body weights were randomly divided into four dietary groups (8 replicates/group and 15 birds/replicate). Groups A, B, C and D were fed diets containing 0%, 0.1%, 0.2% and 0.3% Aln-Gln, respectively, for 6 weeks. The body weight (BW) and average daily gain (ADG) were higher in hens fed test diets compared with the control (p < 0.05). The feed conversion ratio (FCR) was better in test groups as compared to the control group (p < 0.05). The ADFI showed no significant difference between the groups. Dietary treatments had no effect on dry matter (DM), organic matter (OM) and crude fiber (CF) digestibility. The Aln-Gln also improved gross energy (GE) and crude protein (CP) digestibility (p < 0.05). It has also increased IgG levels in groups C and D. IgM levels were similar to the control in B, C and D. The Aln-Gln increased IL-1 in B and C, IL-2 in C and D, and IL-6 in all test groups (p < 0.05). The supplementation of Aln-Gln had no effect on serum antioxidant indices like CAT, MDA, GSH-PX, GSH, and SOD in 42-day-old growing hens. Aln-Gln supplementation had no significant effect (p > 0.05) on the activity of amylase and lipase, however, a significant improvement (p < 0.05) in the activities of trypsin and chymotrypsin was observed in the test groups. Supplemented Aln-Gln levels in the birds' diets led to an increase in the expression of genes related to growth factors (IGF-1, IGFBP-5), immune markers (IL-1, IL-2, IL-6) and antioxidant status (GSH-Px1), as compared to control group. Aln-Gln supplementation in Hy-Line brown hens during their growing period improved growth, nutrient digestibility, immunity and digestive enzymes activity. These findings suggest that Aln-Gln is a promising dietary additive for enhancing poultry performance.

Immunotherapy and new treatments.

This review comes at a time where new techniques in immunotherapy administration are being developed, new innovations are being incorporated to standard techniques, and new regulations are being adopted regarding the creation and storage of allergen extracts. Prior to the release of updated practice parameters regarding allergic rhinitis and immunotherapies, this review article provides a synopsis of current recommendations, a comparison of the practices in the United States and those of Europe, and an examination of experimental methods that are being studied. This article seeks to review and discuss the various methods of administration, build up schedules, efficacy, effect on other atopic symptoms, and safety associated with allergen immunotherapy. Innovations in standard techniques, such as new allergoids for SCIT, appear to be effective in improving symptoms and increasing IgG levels for grass allergens. Data for newer techniques is less clear. There appears to be increased treatment-related adverse events for ILIT, worse symptom scores compared with placebo for IDIT, and insufficient studies regarding the effectiveness of EPIT for aeroallergens. New regulations seek to standardize the documentation, storage, and creation of allergen extracts.

A multi-epitope protein vaccine encapsulated in alginate nanoparticles as a candidate vaccine against Shigella sonnei

Shigellosis, caused by the Gram-negative bacterium Shigella, is a major global health challenge. Despite extensive research over the past two decades, no commercial vaccine is available to prevent Shigella infection. Developing multi-epitope vaccines offers a promising and innovative approach to tackling infectious diseases. In this study, we produced a multi-epitope vaccine candidate using E. coli BL21 (DE3) plysS bacteria and purified the vaccine protein with Ni-NTA affinity chromatography. We then prepared alginate nanoparticles containing the vaccine protein, with a particle size of 122 ± 6 nm, PDI 0.17, SPAN 0.83, and zeta potential of -27 ± 2 mV. Successful protein loading was confirmed through nanodrop and ATR-FTIR analyses. To evaluate the immunogenicity of the encapsulated vaccine, mice were orally vaccinated, and their serum was analyzed for IgG, IL-4, and IFN-γ levels cytokines. The results showed a significant increase in IgG level in the vaccinated group compared to controls. Additionally, the vaccinated group exhibited a notable increase in IL-4 and IFN-γ cytokines, indicating a robust Th-cell-mediated immune response essential for combating Shigella. Our nano-vaccine demonstrated high efficacy in activating both humoral and cellular immunity, effectively protecting against the bacteria. The alginate-based oral vaccine candidate thus emerges as a promising strategy for developing a multi-epitope vaccine candidate against Shigella.

Evaluation of protective immune responses induced by DNA vaccines encoding Echinococcus granulosus EgM123 protein in Beagle dogs.

Echinococcus granulosus, known as cystic echinococcosis, is a prominent zoonotic parasitic disease of significant global concern. The definitive hosts serves as the primary reservoir for the transmission of echinococcosis, as well as a main factor in the prevention and control of the disease. Unfortunately, there is currently no commercially available vaccine for these hosts. Nevertheless, DNA vaccines show potential as a feasible strategy for the control and management of parasitic diseases. In this study, the EgM123 antigen was selected for its well-documented immunogenic properties to develop a DNA vaccine aimed at combating E. granulosus infection in canines. The results showed a marked increase in IgG levels in the group vaccinated with pVAX1-EgM123 DNA compared to the PBS group. Additionally, the cytokines IL-1, IFN-γ, IL-4, and IL-6 were significantly upregulated in the pVAX1-EgM123 DNA vaccine group. Furthermore, in comparison to the PBS control group, the EgM123 DNA vaccine group exhibited a notable 87.85% reduction in worm burden and a 65.00% inhibition in segment development. These findings indicate that the pVAX1-EgM123 DNA vaccine shows promising immunogenicity, successfully eliciting a targeted immune response in canines. Moreover, it significantly diminishes the worm burden and hinders the progression of tapeworms in the pVAX1-EgM123 DNA vaccine group. These findings suggest that the pVAX1-EgM123 DNA vaccine holds promise as a potential candidate vaccine for combating E. granulosus infection in dogs.

Association between asthma and IgG levels specific for rhinovirus and respiratory syncytial virus antigens in children and adults

BackgroundViral infections in childhood, especially to rhinovirus (RV) and respiratory syncytial virus (RSV) are associated with asthma inception and exacerbation. However, little is known about the role of RV- and RSV-specific antibodies in childhood versus adult asthma. ObjectiveTo investigate associations between RV- and RSV-specific IgG levels with asthma phenotypes, in children and adults. MethodsThe analysis included 1771 samples from 1501 participants of the Epidemiological Study on the Genetics and Environment of Asthma (EGEA) (530 children (mean(sd) age = 11.1 (2.8) and 1241 adults (mean(sd) age = 43.4(16.7), among which 274 and 498 had ever asthma, respectively). RSV- and RV-specific IgG levels were determined using micro-arrayed virus-derived antigens and peptides. Cross-sectional associations between standardized RSV- and RV-specific IgG levels and asthma phenotypes were estimated by multiple regression models. ResultsIn children, ever asthma was associated with higher IgG levels specific to RV, especially to RV-A, RV-C and to RSV (adj-OR for 1-sd increase in IgG levels = 1.52 (95%CI, 1.16;1.99), 1.42 (1.10;1.83) and 1.24 (0.99;1.54), respectively). These associations were stronger for moderate-to-severe asthma than for mild asthma. Conversely in adults, ever asthma was associated with lower RV-A, RV-B and RV-C IgG levels (adjusted OR = 0.86 (0.74;0.99), 0.83 (0.73;0.95) and 0.85 (0.73;0.99), respectively). ConclusionOur results suggest that the association between respiratory virus specific antibody levels and asthma varies during life, with asthma associated with higher levels of IgG to RSV, RV-A and RV-C in children and lower levels of IgG responses to RV-A/B/C in adults.

Sensory neurons regulate stimulus-dependent humoral immunity.

Sensory neurons sense pathogenic infiltration, serving to inform immune coordination of host defense. However, sensory neuron-immune interactions have been predominantly shown to drive innate immune responses. Humoral memory, whether protective or destructive, is acquired early in life - as demonstrated by both early exposure to streptococci and allergic disease onset. Our study further defines the role of sensory neuron influence on humoral immunity in the lung. Using a murine model of Streptococcus pneumonia pre-exposure and infection and a model of allergic asthma, we show that sensory neurons are required for B-cell and plasma cell recruitment and antibody production. In response to S. pneumoniae, sensory neuron depletion resulted in a larger bacterial burden, reduced B-cell populations, IgG release and neutrophil stimulation. Conversely, sensory neuron depletion reduced B-cell populations, IgE and asthmatic characteristics during allergen-induced airway inflammation. The sensory neuron neuropeptide released within each model differed. With bacterial infection, vasoactive intestinal polypeptide (VIP) was preferentially released, whereas substance P was released in response to asthma. Administration of VIP into sensory neuron-depleted mice suppressed bacterial burden and increased IgG levels, while VIP1R deficiency increased susceptibility to bacterial infection. Sensory neuron-depleted mice treated with substance P increased IgE and asthma, while substance P genetic ablation resulted in blunted IgE, similar to sensory neuron-depleted asthmatic mice. These data demonstrate that the immunogen differentially stimulates sensory neurons to release specific neuropeptides which specifically target B-cells. Targeting sensory neurons may provide an alternate treatment pathway for diseases involved with insufficient and/or aggravated humoral immunity.

Characteristics of SARS-CoV-2 and Opisthorchis viverrini coinfections: insights into immune responses and clinical outcomes.

The effects of co-infections with SARS-CoV-2 and parasitic diseases have been little investigated in terms of immune response, disease dynamics, and clinical outcomes. This study aimed to explore the impact of co-infection with Opisthorchis viverrini and SARS-CoV-2 on the immune response concerning clinical symptoms and the severity of pulmonary abnormalities. A cross-sectional study was conducted, including healthy participants as controls, participants with opisthorchiasis, SARS-CoV-2 infection, and a co-infection group with both diseases. Characteristics of SARS-CoV-2 infection were assessed based on clinical parameters and severity of pulmonary abnormalities, whereas opisthorchiasis burden was evaluated by eggs-per-gram (EPG) counts. Immune responses were assessed by measuring levels of interferon-γ (IFN-γ), SARS-CoV-2 anti-spike receptor binding domain (RBD) IgG, and neutralizing antibody against SARS-CoV-2. In the co-infected group, clinical parameters and hospitalization rates were lower than in the SARS-CoV-2 group. Pulmonary abnormalities, such as bronchial fibrosis, were commonly observed in the SARS-CoV-2 group, leading to hospitalization in some cases. Participants with opisthorchiasis had higher IFN-γ levels than healthy individuals. IFN-γ levels were significantly lower in the co-infection group compared with the SARS-CoV-2 group (P = 0.002). There was a significant (P = 0.044) positive correlation between RBD-specific IgG and percent neutralization levels in the SARS-CoV-2 group. Levels of both were somewhat lower (not statistically significant) in the co-infection group. A negative correlation was observed between opisthorchiasis burden (EPG counts) and IFN-γ and RBD-specific IgG levels in the co-infected group. Following vaccination, the increase in IgG levels against the RBD protein was significantly lower in the co-infected group than in the SARS-CoV-2 group. These results suggest that O. viverrini infection suppresses immune responses and may lead to a reduction in severity in cases of SARS-CoV-2 co-infection.

Core fucosylation within the Fc-FcγR degradation pathway promotes enhanced IgG levels via exogenous L-fucose

α1,6-Fucosyltransferase (Fut8) is the enzyme responsible for catalyzing core fucosylation. Exogenous L-fucose upregulates fucosylation levels through the GDP-fucose salvage pathway. This study investigated the relationship between core fucosylation and IgG amounts in serum utilizing wild-type (Fut8+/+), Fut8 heterozygous knockout (Fut8+/−), and Fut8 knockout (Fut8−/−) mice. The IgG levels in serum were lower in Fut8+/− and Fut8−/− mice compared with Fut8+/+ mice. Exogenous L-fucose increased IgG levels in Fut8+/− mice, while the ratios of core fucosylated IgG versus total IgG showed no significant difference among Fut8+/+, Fut8+/−, and Fut8+/− mice treated with L-fucose. These ratios were determined by Western blot, lectin blot, and mass spectrometry analysis. Real-time PCR results demonstrated that mRNA levels of IgG Fc and neonatal Fc receptor, responsible for protecting IgG turnover, were similar among Fut8+/+, Fut8+/−, and Fut8+/− mice treated with L-fucose. In contrast, the expression levels of Fc-gamma receptor Ⅳ (FcγRⅣ), mainly expressed on macrophages and neutrophils, were increased in Fut8+/− mice compared to Fut8+/+ mice. The effect was reversed by administrating L-fucose, suggesting that core fucosylation primarily regulates the IgG levels through the Fc-FcγRⅣ degradation pathway. Consistently, IgG internalization and transcytosis were suppressed in FcγRⅣ-knockout cells while enhanced in Fut8-knockout cells. Furthermore, we assessed the expression levels of specific antibodies against ovalbumin and found they were downregulated in Fut8+/− mice, with potential recovery observed with L-fucose administration. These findings confirm that core fucosylation plays a vital role in regulating IgG levels in serum, which may provide insights into a novel mechanism in adaptive immune regulation.

Serological profiling of pneumococcal proteins reveals unique patterns of acquisition, maintenance and waning of antibodies throughout life.

Streptococcus pneumoniae is a leading cause of morbidity and mortality in children and older adults. Yet knowledge on the development of pneumococcal protein-specific antibody responses throughout life is limited. To investigate this, we measured serum IgG levels to 55 pneumococcal proteins in 11-month old infants (n=73), 24-month old children (n=101), parents (n=99), adults without children <6 years of age (n= 99) and older adults aged >60 years (n=100). Our findings revealed low IgG levels in infancy, with distinct development patterns peaking in adults. A decrease in levels was observed for 27 antigens towards older age. Adults and older adults had increased IgG levels during pneumococcal carriage and at increased exposure risk to S. pneumoniae. Carriage was a stronger predictor than exposure or age for antibody responses. These findings highlight the dynamic nature of naturally acquired humoral immunity to pneumococcal proteins throughout life, offering insights for age-targeted interventions.

Phenotypic and Immunological Characterization of Patients with Activated PI3Kδ Syndrome 1 Presenting with Autoimmunity

PurposeAutoimmunity is a significant feature of APDS1 patients. We aimed to explore the pathogenic immune phenotype and possible mechanisms of autoimmunity in APDS1 patients.MethodsThe clinical records and laboratory data of 42 APDS1 patients were reviewed. Immunophenotypes were evaluated by multiparametric flow cytometry. Autoantibodies were detected via antigen microarray analysis.ResultsA total of 42 children with PIK3CD gene mutations were enrolled. Immunological tests revealed increased proportions of effector memory cells (86%) and central memory cells (59%) among CD4+ T cells; increased proportions of effector memory cells (83%) and terminally differentiated effector memory T cells (38%) among CD8+ T cells. Fewer CD3+ T cells and B cells and higher IgG levels were reported in patients with autoimmunity. The proportion of Tregs was decreased, and the proportions of Th9, Tfh, and Tfr cells were increased in APDS1 patients. Among APDS1 patients, higher proportion of Th2 and Tfr cells were found in those with autoimmunity. The proportions of CD11c+ B and CD21lo B cells in patients with autoimmunity were significantly increased. Antigen microarray analysis revealed a wide range of IgG/IgM autoantibodies in patients with APDS1. In patients with autoimmunity, the proportion of Tfr might be positively correlated with autoantibodies.ConclusionsThe pathogenic immune phenotype of APDS1 patients included (1) deceased CD3+ T-cell and B-cell counts and increased IgG levels in patients with autoimmunity, (2) an imbalanced T helper cell subset, (3) increased proportions of autoreactive B cells, and (4) distinct autoantibody reactivities in patients with autoimmunity.

Immune response to vaccination in people with psychotic disorders relative to healthy controls: prospective study of SARS-CoV-2 vaccination.

This prospective study examines the immune response to SARS-CoV-2 vaccination in patients with psychotic disorders compared with healthy volunteers. Participants were recruited naturalistically as part of the UK's COVID-19 vaccination programme. Prior to receiving their first COVID-19 vaccine, blood samples were provided by participants to examine anti-SARS-CoV-2 immunoglobulins (IgG) at baseline, followed by a repeat assay 1 month after receiving their first vaccine to assess vaccine response. The increase of IgG levels from baseline to 1 month post-vaccination was significantly lower in patients compared with controls, supporting evidence of impaired vaccine response in people with psychotic disorders. When excluding patients treated with clozapine from the analysis, this difference was no longer significant, suggesting that effects may be particularly marked in people taking clozapine.

Factors Associated with SARS-CoV-2 Infection in Fully Vaccinated Nursing Home Residents and Workers.

Persons living or working in nursing homes faced a higher risk of SARS-CoV-2 infections during the pandemic, resulting in heightened morbidity and mortality among older adults despite robust vaccination efforts. This prospective study evaluated the humoral and cellular immunity in fully vaccinated residents and workers from two nursing homes in Madrid, Spain, from 2020 to 2021. Measurements of IgG levels were conducted in August 2020 (pre-vaccination) and June and September 2021 (post-vaccination), alongside assessments of neutralizing antibodies and cellular responses in September 2021 among the most vulnerable individuals. Follow-up extended until February 2022 to identify risk factors for SARS-CoV-2 infection or mortality, involving 267 residents (mean age 87.6 years, 81.3% women) and 302 workers (mean age 50.7 years, 82.1% women). Residents exhibited a significantly higher likelihood of experiencing COVID-19 before June 2021 compared with nursing staff (OR [95% CI], 7.2 [3.0 to 17.2], p < 0.01). Participants with a history of previous COVID-19 infection showed more significant increases in IgG levels in August 2020, June 2021 and September 2021, alongside an increased proportion of neutralizing antibodies in the most vulnerable individuals. However, IgG decay remained the same between June and September 2021 based on the previous COVID-19 status. During the Omicron variant wave, residents and staff showed a similar rate of SARS-CoV-2 infection. Notably, preceding clinical or immunological factors before receiving three vaccination doses did not demonstrate associations with COVID-19 infection or overall mortality in our participant cohort.

Immunoglobulins As a Predictor of Chronicity in Pediatric Immune Thrombocytopenia

Introduction: Immune thrombocytopenia (ITP) is the most common acquired bleeding disorder in children, but predictors of chronicity at the time of diagnosis remain largely unknown. Small studies have previously indicated predictive value of baseline immunoglobulin levels, but without definitive clinically applicable conclusions. We aim to further investigate the utility of immunoglobulin levels obtained at the time of diagnosis in predicting the development of chronic ITP (cITP) in children. Methods: We completed a retrospective review of patients aged 6 months - 21 years diagnosed with ITP at tertiary referral centers from 2015 - 2022 in accordance with IRB-approved protocols. Patients with immunoglobulin levels obtained within 3 months of ITP diagnosis and prior to any treatment were included in the study. cITP was defined as ITP duration &amp;gt;12 months. ITP resolution was defined as achieving a platelet count &amp;gt; 150 x 10 9/L on 2 occasions, or on 1 occasion in the presence of normalized MPV, absent of therapy. Patients who were lost to follow-up or had ongoing disease &amp;lt;1 year duration were excluded. Immunoglobulins were recorded by continuous variable as well as by age-related reference values. The two groups (“spontaneously resolved” and “cITP”) were compared using Pearson's Chi-squared test for nonparametric categorical variables, Fisher's exact test for parametric categorical variables, and Wilcoxon rank sum test for nonparametric categorical variables. A multivariable logistic regression model was built to determine independent associations between immunoglobulin levels and the development of cITP after adjusting for age. R (version 4.2.1) was used for analysis. A p-value &amp;lt;0.05 was considered to be statistically significant. Results: We identified 497 patients for inclusion in the study. Among these, 336 patients (67.6%) had ITP resolution prior to 12 months, while 161 patients (32.4%) developed cITP. Within the full cohort, 257 (51.7%) were male and 218 (43.9%) were Hispanic. Median age of diagnosis was 4.1 years among those with resolution, and 9.4 years among those with cITP. Patients were more likely to have secondary ITP in the cITP group vs the resolved group (37 patients [23.0%] vs 10 patients [6.2%]). Low and high IgG levels were more prevalent in cITP (5% vs 3% and 16% vs 5.7%, respectively). The median IgG level was higher in the cITP group (991 vs 838 mg/dL). Low IgA levels were more prevalent in cITP (7% vs 2.4%) and high IgA levels more prevalent in spontaneously resolving ITP (7.8% vs. 5.7%), although the median IgA level was higher in cITP (116 vs 88 mg/dL), likely attributable to older age in the cITP group. Both low and high IgM levels were more prevalent in cITP (8.9% vs 6.6% and 20% vs 16%, respectively), with the median IgM level being similar in both groups (89 vs 85 mg/dL). The age-adjusted multivariable logistic regression analysis demonstrated independent predictive value of IgG, IgA, and IgM for development of cITP (See Table, Figure). Each 100 mg/dL increase in IgG level was associated with a 17% increase in the odds of developing cITP (p=0.001); while each 100 mg/dL increase in IgA or IgM level was associated with decreased odds of developing cITP (37% [p=0.025] and 56% [p&amp;lt;0.001] decrease, respectively). Additionally, every 1-year increase in age was associated with a 16% increase in the odds of developing cITP (p&amp;lt;0.001). We also found that patients with a known secondary cause of ITP at the time of diagnosis had increased likelihood of developing cITP (p&amp;lt;0.001). Performance scores for the predictive model include a C-index of 0.72 and Nagelkerke R 2 of 0.21. Conclusions: We utilized pre-treatment immunoglobulin values obtained within 3 months of diagnosis from 497 children with ITP to investigate the predictive value of immunoglobulin measurements for the development of cITP. We found that IgG, IgA, and IgM values are predictive of cITP development after accounting for age. Increasing age was also associated with increased risk of cITP. In future work, we plan to evaluate the value of additional variables for predicting the development of cITP and then validate the predictions in an external cohort. Better defining the predictive value of clinical data available at the time of ITP diagnosis will allow hematologists to provide improved prognostication and individualized management much earlier in a patient's disease course, ultimately improving the quality of care for children with ITP.

Longitudinal study of humoral immunity against SARS-CoV-2 of health professionals in Brazil: the impact of booster dose and reinfection on antibody dynamics.

The pandemic caused by SARS-CoV-2 has had a major impact on health systems. Vaccines have been shown to be effective in improving the clinical outcome of COVID-19, but they are not able to fully prevent infection and reinfection, especially that caused by new variants. Here, we tracked for 450 days the humoral immune response and reinfection in 52 healthcare workers from Brazil. Infection and reinfection were confirmed by RT-qPCR, while IgM and IgG antibody levels were monitored by rapid test. Of the 52 participants, 19 (36%) got reinfected during the follow-up period, all presenting mild symptoms. For all participants, IgM levels dropped sharply, with over 47% of them becoming seronegative by the 60th day. For IgG, 90% of the participants became seropositive within the first 30 days of follow-up. IgG antibodies also dropped after this period reaching the lowest level on day 270 (68.5 ± 72.3, p<0.0001). Booster dose and reinfection increased the levels of both antibodies, with the interaction between them resulting in an increase in IgG levels of 130.3 arbitrary units. Overall, our data indicate that acquired humoral immunity declines over time and suggests that IgM and IgG antibody levels are not associated with the prevention of reinfection.

Immunomodulatory effects of testosterone and letrozole during Plasmodium berghei ANKA infection.

Malaria is one of the leading health problems globally. Plasmodium infection causes pronounced sexual dimorphism, and the lethality and severity are more remarkable in males than in females. To study the role of testosterone in the susceptibility and mortality of males in malaria, it is common to increase its concentration. However, this strategy does not consider the enzyme CYP19A1 aromatase, which can transform it into oestrogens. To avoid the interference of oestrogens, we inhibited in vivo CYP19A1 aromatase with letrozole and increased the testosterone level by exogen administration before infection with Plasmodium berghei ANKA. We measured the impact on free testosterone, 17β-oestradiol and dehydroepiandrosterone levels in plasma; additionally, we evaluated parasitaemia, body temperature, body mass, glucose levels and haemoglobin concentration. Furthermore, we evaluated the effects of testosterone on the immune response; we quantified the CD3+/CD4+, CD3+/CD8+, CD19+, Mac-3+ and NK cells in the spleen and the plasma concentrations of the cytokines IL-2, IL-4, IL-6, IFN-, IL-10, TNF-α and IL-17A. Finally, we quantified the levels of antibodies. We found that mice treated with the combination of letrozole and testosterone and infected with Plasmodium berghei ANKA had increased concentrations of free testosterone and DHEA but decreased levels of 17β-oestradiol. As a result, parasitaemia increased, leading to severe anaemia. Interestingly, testosterone increased temperature and decreased glucose concentration as a possible testosterone-mediated regulatory mechanism. The severity of symptomatology was related to critical immunomodulatory effects generated by free testosterone; it selectively increased CD3+CD8+ T and CD19+ cells but decreased Mac-3+. Remarkably, it reduced IL-17A concentration and increased IL-4 and TNF-α. Finally, it increased IgG1 levels and the IgG1/IgG2a ratio. In conclusion, free testosterone plays an essential role in pathogenesis in male mice by increasing CD8+ and decreasing Mac3+ cells and mainly reducing IL-17A levels, which is critical in the development of anaemia. Our results are important for understanding the mechanisms that regulate the exacerbated inflammatory response in infectious diseases and would be useful for the future development of alternative therapies to reduce the mortality generated by inflammatory processes.

IgG4 Antibodies Induced by Repeated Vaccination May Generate Immune Tolerance to the SARS-CoV-2 Spike Protein.

Less than a year after the global emergence of the coronavirus SARS-CoV-2, a novel vaccine platform based on mRNA technology was introduced to the market. Globally, around 13.38 billion COVID-19 vaccine doses of diverse platforms have been administered. To date, 72.3% of the total population has been injected at least once with a COVID-19 vaccine. As the immunity provided by these vaccines rapidly wanes, their ability to prevent hospitalization and severe disease in individuals with comorbidities has recently been questioned, and increasing evidence has shown that, as with many other vaccines, they do not produce sterilizing immunity, allowing people to suffer frequent re-infections. Additionally, recent investigations have found abnormally high levels of IgG4 in people who were administered two or more injections of the mRNA vaccines. HIV, Malaria, and Pertussis vaccines have also been reported to induce higher-than-normal IgG4 synthesis. Overall, there are three critical factors determining the class switch to IgG4 antibodies: excessive antigen concentration, repeated vaccination, and the type of vaccine used. It has been suggested that an increase in IgG4 levels could have a protecting role by preventing immune over-activation, similar to that occurring during successful allergen-specific immunotherapy by inhibiting IgE-induced effects. However, emerging evidence suggests that the reported increase in IgG4 levels detected after repeated vaccination with the mRNA vaccines may not be a protective mechanism; rather, it constitutes an immune tolerance mechanism to the spike protein that could promote unopposed SARS-CoV2 infection and replication by suppressing natural antiviral responses. Increased IgG4 synthesis due to repeated mRNA vaccination with high antigen concentrations may also cause autoimmune diseases, and promote cancer growth and autoimmune myocarditis in susceptible individuals.

Neutralizing Antibodies against SARS-CoV-2 Beta and Omicron Variants Inhibition Comparison after BNT162b2 mRNA Booster Doses with a New PETIA sVNT Assay.

Monitoring antibody response following SARS-CoV-2 vaccination is strategic, and neutralizing antibodies represent the gold standard. The neutralizing response to Beta and Omicron VOCs was evaluated versus the gold standard by a new commercial automated assay. Serum samples from 100 healthcare workers from the Fondazione Policlinico Universitario Campus Biomedico and the Pescara Hospital were collected. IgG levels were determined by chemiluminescent immunoassay (Abbott Laboratories, Wiesbaden, Germany) and serum neutralization assay as the gold standard. Moreover, a new commercial immunoassay, the PETIA test Nab (SGM, Rome, Italy), was used for neutralization evaluation. Statistical analysis was performed with R software, version 3.6.0. Anti-SARS-CoV-2 IgG titers decayed during the first ninety days after the vaccine second dose. The following booster dose significantly (p < 0.001) increased IgG levels. A correlation between IgG expression and neutralizing activity modulation was found with a significant increase after the second and the third booster dose (p < 0.05. Compared to the Beta variant of the virus, the Omicron VOC was associated with a significantly larger quantity of IgG antibodies needed to achieve the same degree of neutralization. The best Nab test cutoff for high neutralization titer (≥1:80) was set for both Beta and Omicron variants. This study correlates vaccine-induced IgG expression and neutralizing activity using a new PETIA assay, suggesting its usefulness for SARS-CoV2 infection management.

Comparative assessment of the immunogenicity of various revaccination regimens against the SARS-CoV-2

Along with efficacy and safety, it is extremely important to study the severity of humoral and cellular immunity during not only vaccination, but also revaccination against the Severe Acute Respiratory Syndromerelated CoronaVirus 2 (SARS-CoV-2).Aim. To compare the immunogenicity (humoral and cellular immunity) of various (heterologous and homologous) revaccination regimens against coronavirus disease 2019 (COVID-19) in a prospective observational study.Material and methods. In individuals aged ≥18 years, in the absence of contraindications to vaccination, two following types of vaccines were used for primary vaccination and revaccination: Gam-COVIDVac and CoviVac. Group I patients received Gam-COVID-Vac at each stage of primary and secondary vaccination; patients of group II — Gam-COVID-Vac at each stage of primary vaccination, CoviVac at each stage of re-vaccination; patients of group III — CoviVac at each stage of primary vaccination and Gam-COVID-Vac at each stage of revaccination; patients of group IV — CoviVac at each stage of primary and secondary vaccination. All participants (at each stage of vaccination, revaccination and 12 months after the primary vaccination) were determined the level of IgG to the receptor-binding domain of SARS-CoV-2 spike (S) protein and T-cell immunity to SARSCoV-2.Results. The maximum level of IgG at the second stage of revaccination was observed in groups I and III. In addition, in groups I, III and IV, a significant (p&lt;0,0001) increase in IgG level by the second stage of revaccination was noted, the most pronounced in group III. In addition, there was a significantly (p&lt;0,05) higher level of IgG at I and II stages of revaccination (Visit 3 and 4) among those vaccinated with Gam-COVID-Vac — 520 and 540 BAU/ml, respectively, compared with group IV vaccinated with CoviVac — 467 and 478 BAU/ml, respectively. The maximum and significant increase in active T-cells by the second stage of revaccination (Visit 4) was noted in groups I (p&lt;0,0001) and III (p&lt;0,0022) of vaccinated individuals, where it amounted to 11 and 12, respectively, which allows to consider the result positive (&gt;8). At the same time, the level of active T cells responding to SARS-CoV-2 nucleocapsid Ag stimulation by Visit 4 (stage II of revaccination) was noted in groups II (14,5) and IV (12).Conclusion. The use of the Gam-COVID-Vac vaccine as a booster dose in both homologous and heterologous vaccination regimens against the SARS-CoV-2 virus is most effective for stimulation and humoral and T-cell post-vaccination response.