High IgG Research Articles

Study of the state of humoral immunity to COVID-19 in Arkhangelsk residents

The COVID-19 pandemic caused by SARS-CoV-2 has affected healthcare, society and the economy in all countries, including Russia. Several vaccines have been created as the method for COVID-19 prevention. One of the most widespread vaccines in Russia, which has received international recognition, is the Gam-COVID-Vac (Sputnik V) vaccine and its variant Sputnik Light, which represents its first component. This vaccine, like similar vaccines in many countries, was used during the pandemic. The purpose of this work is to study the humoral immunity status of Arkhangelsk city residents and the effect of vaccination on them. Adult residents of Arkhangelsk [N = 281] were enrolled in the randomized study. Samples from vaccinated people and the control group were collected for the study in October 2022.The median from the time of last vaccination/booster to sample collection was 10 months. The samples were tested for the level of IgG to the receptor-binding domain of the SARS-CoV-2 S protein. The work assessed the humoral immunity status among residents of Arkhangelsk. It was shown that in October 2022 high IgG values were recorded among the people in the studied groups, most likely caused by contact with the SARS-CoV-2 virus. The humoral immunity status of unvaccinated residents, for those who have had COVID-19 and those who have not, is described; a significant increase in the level of IgG among those vaccinated compared to unvaccinated people is shown, despite the fact that the average time after vaccination was more than 10 months. A comparative analysis of IgG levels among different age groups was carried out. The study found no difference in post-vaccination antibody levels among people over 65 years old compared to younger age groups. Also there were no statistically significant differences in antibody levels among unvaccinated people over 65 in respect to younger age groups.

Matched oligoclonal bands: Diagnostic utility and clinical characteristics.

To describe patient clinical characteristics associated with matched oligoclonal bands (OCB). A retrospective review at the University of Utah examined patients with matched OCB from 2015 to 2020. Clinical data, diagnosis, and outcomes were collected. Patients were classified with either multiple sclerosis (MS), other inflammatory neurologic disorder (other-IND), or noninflammatory neurologic disorder (NIND). Of 539 identified patients, 436 (53.4% female) were matched-only, while 103 (43.7% female) were matched + unique. Patients with matched-only bands were older (57.4 ± 16 vs. 52 ± 14.2, p < 0.001) and more likely to have a history of autoimmune disease (40.1% vs. 28.2%, p = 0.024) and/or cancer (28.7% vs. 16.5%, p = 0.012). Patients with matched + unique bands were more likely to have CSF pleocytosis (52.4% vs. 25.9%, p < 0.001), high IgG index (52.2% vs. 7.6%, p < 0.001), and an abnormal MRI (86.9% vs. 63.1%, p < 0.001). More than two-thirds of matched-only patients had NIND, while 33% and 41.7% of matched + unique patients had MS and other-IND, respectively. Patients exhibiting matched-only bands and a high IgG index demonstrated a significantly higher incidence of other-IND compared to those with matched-only bands and a normal IgG index (55.6% vs. 30.4%, p = 0.013). While Kaplan-Meier survival curves demonstrated higher mortality in the matched-only cohort compared to the matched + unique cohort (p = 0.02), multivariable Cox regression analysis showed this difference was not statistically significant when adjusting for various factors. A history of cancer was the significant predictor of increased mortality risk (Hazard ratio = 3.147, 95% CI [2.196, 4.51]). Patients with matched only versus matched + unique OCB have distinct clinical profiles.

CD30 influences germinal center B-cell dynamics and the expansion of IgG1-switched B cells.

Initially, identified as a Hodgkin lymphoma marker, CD30 was subsequently detected on a subset of human B cells within and around germinal centers (GCs). While CD30 expression is typically restricted to a few B cells, expansion of CD30-expressing B cells occurs in certain immune disorders and during viral infections. The role of CD30 in B cells remains largely unclear. To address this gap in knowledge, we established a conditional CD30-knockinmouse strain. In these mice, B-cell-specific CD30 expression led to a normal B-cell phenotype in young mice, but most aged mice exhibited significant expansion of B cells, T cells and myeloid cells and increased percentages of GC B cells and IgG1-switched cells. This may be driven by the expansion of CD4+ senescence-associated T cells and T follicular helper cells, which partially express CD30-L (CD153) and may stimulate CD30-expressing B cells. Inducing CD30 expression in antigen-activated B cells accelerates the GC reaction and augments plasma cell differentiation, possibly through the posttranscriptional upregulation of CXCR4. Furthermore, CD30 expression in GC B cells promoted the expansion of IgG1-switched cells, which displayed either a GC or memory-like B-cell phenotype, with abnormally high IgG1 levels compared with those in controls. These findings shed light on the role of CD30 signaling in GC B cells and suggest that elevated CD30+ B-cell numbers lead to pathological lymphocyte activation and proliferation.

Inactivated vaccine dosage and serum IgG levels correlate with persistent COVID-19 infections in hematologic malignancy patients during the Omicron Surge in China

PurposeThe essence of this scholarly work was to carefully outline the key factors intensifying the virulence and protracted contagion of COVID-19, particularly among individuals afflicted with hematologic malignancies (HM), in an epoch predominantly governed by the Omicron variant.MethodsAdults with HM diagnosed with COVID-19 from November 2022 to February 2023 were monitored in this retrospective study. Patient blood samples yielded biochemical data, and COVID-19 was confirmed through RNA or antigen testing. The factors affecting severity and infection duration were examined using both univariate and multivariate logistic regression analyses. For calculating the overall survival probabilities, the Kaplan–Meier product limit approach was employed.ResultsIn the examined cohort, 133 individuals diagnosed with HM and concomitantly infected with COVID-19 were scrutinized. Of the participants, 29.3% (39 patients) were classified as Severe/Critical, while the other 70.7% (94 patients) were categorized as Non-severe. A significant difference was observed in vaccination status: 61.7% of patients in the Non-severe group had received at least a two-dose vaccine regimen, whereas 61.5% of the Severe/Critical group had either minimal or only one dose of vaccination. The data analysis revealed that elevated C-reactive protein levels (≥ 100 mg/L) significantly raised the risk of severe/critical conditions in HM patients with COVID-19, as determined by advanced multivariate logistic regression. The odds ratio was 3.415 with a 95% confidence interval of 1.294–9.012 (p = 0.013). Patients who continued to have positive nucleic acid tests and ongoing symptoms beyond 30 days were categorized as having a persistent infection, whereas those who achieved infection control within this timeframe were categorized as having infection recovery. Of the HM cohort, 11 did not survive beyond 30 days after diagnosis. The results from a competing risk model revealed that increased interleukin-6 levels (HR: 2.626, 95% CI: 1.361–5.075; p = 0.004) was significantly associated with persistent infection. Conversely, receiving more than two vaccine doses (HR: 0.366, 95% CI: 0.158–0.846; p = 0.019), and having high IgG levels (≥ 1000 mg/dl) (HR: 0.364, 95% CI: 0.167–0.791; p = 0.011), were associated with infection recovery. There was a notable disparity in survival rates between patients with persistent infections and infection recovery, with those in the non-persistent group demonstrating superior survival outcomes (P < 0.001).ConclusionsIn conclusion, the study determined that HM patients with COVID-19 and increased C-reactive protein levels had a higher likelihood of severe health outcomes. Persistent infection tended to be more prevalent in those with vaccine dosages (< 2 doses), lower IgG levels, and higher interleukin-6 levels.

Characterization of systemic lupus erythematosus subtypes using cluster analysis: insights from lymphocyte subpopulations.

Systemic lupus erythematosus (SLE) is a chronic autoimmune disease, in which lymphocyte subsets were dysregulated. Incorporating lymphocyte subpopulations in cluster analysis offers a pathway for personalized and precise treatment, targeting specific abnormalities for more effective management. We conducted Gaussian clustering analysis on clinical data, serological data, urine test results, and lymphocyte subpopulations for SLE patients hospitalized from September 2008 to December 2019. A total of 1863 SLE patients from Xi'Jing Hospital were included. After excluding those without complete assessments, 1281 patients underwent flow cytometry for lymphocyte subsets. Five SLE clusters emerged: Cluster 1 with severe kidney involvement, high SLEDAI scores, and infection rates, often accompanied by rashes and edema; cluster 2 with high urinary protein but better renal function; cluster 3 with normal lymphocyte count and low positive antibodies; cluster 4 with frequent psychiatric symptoms and pulmonary arterial hypertension (PAH); and cluster 5 with fever, arthritis, hematologic involvement, and high IgG levels despite decreased B cells. All enrolled SLE patients were ultimately categorized into five distinct clinical phenotype groups, with lymphocyte testing being meaningful for patient stratification. This finding shed light on the intricate heterogeneity of SLE, emphasizing the need for a personalized medicine approach. Targeting specific abnormalities in lymphocyte subsets holds promise for more effective and precise management of SLE. Key Points • A comprehensive analysis of SLE patients, including lymphocyte subpopulations, revealed five distinct clusters with varying clinical characteristics, emphasizing the heterogeneity of the disease. • This heterogeneity underscores the need for a personalized medicine approach in SLE management, targeting specific lymphocyte subset abnormalities for more effective and precise treatment.

B-046 Development and Validation of an Automated Live Cell-Based Flow Cytometry Assay Platform for Measuring AQP4-IgG

Abstract Background Live cell-based assays (CBA) are considered the gold-standard methodology for detecting pathogenic antibodies targeting neural cell surface antigens. However, the adoption of these methods in clinical laboratories has been limited by their manual nature and low throughput. Here, we describe the development and validation of an automated system utilizing a live flow cytometry-based CBA to detect AQP4-IgG. Establishing AQP4-IgG serostatus is a critical component of the diagnostic criteria for Neuromyelitis optica spectrum disorders (NMOSD) as it enables the differentiation of NMOSD from Multiple Sclerosis where there may be significant clinical overlap. The accurate diagnosis of the correct disease state is vital, as the prognosis and treatment approach differ significantly for these two conditions. Two redundant systems were built that automatically receive reagents (live cells in suspension, buffers, diluents, secondary antibodies, and patients’ samples) and generate flow cytometer ready 96-well plates (each containing up to 45 serum or CSF samples tested in duplicate). Methods We assessed the analytical performance of an AQP4-IgG live flow cytometry-based CBA on these new automated systems. We measured intra- and inter-assay imprecision at three levels in 5x5 format and for end-point titer assessment, accuracy (20 positive and 20 negative sera; 5 positive and 5 negative CSF; established on the current manual assay), reference range (20 negative sera and 20 negative CSF from disease controls), analytical sensitivity (LOB and LOD) and specificity (high IgG containing serum specimens), within-plate draft (1 positive sample near the diagnostic cut-off [IgG-binding index of 2.0] that was tested across the entire plate), instrument to instrument correlation (42 positive samples/dilutions tested simultaneously on both systems), and total throughput for both CSF and Serum. Results Imprecision testing yielded the following results: Serum Intra/Inter precision level 1 (IBI = 2) CV% (current method:4.6%/20.7%), (system 1: 3.1%/18.4%), (system 2: 2.6%/22.5%), serum Intra/Inter precision level 2 (IBI=4) CV% (current method:4.9%/23.3%), (system 1: 3.2%/21.9%), (system 2: 2.6%/24.1%), and serum Intra/Inter precision level 3 (IBI =10) pos CV% (current method:6.0%/31.1%), (system 1: 3.8%/27.4%), (system 2: 4.2%/29.4%), and CSF Intra/Inter precision (IBI =2) CV% (System 1: 11.7%/16.8%), (system 2: 6.1%/10.7%). The median end-point titers for all four samples assessed matched within one end-point titer. For accuracy, 100% qualitative agreement between current and both automated systems, and titration accuracy (5 positive serums, 1 positive CSF) all matched within one titer between current and both automated systems. All reference range samples were negative. LOB/LOD in serum (Current: 0.85/1.11), (System 1: 0.82/0.95), (system 2: 0.82/0.96) and CSF (Current: 1.06/1.52), (System 1: 1.02/1.38), (system 2: 1.02/1.64) were comparable. All high IgG samples were negative. Plate drift analysis showed improved whole plate %CV: (Current:6.52%), (system 1: 4.51%), (system 2: 3.46%). Instrument to instrument comparison utilizing linear regression indicated strong agreement across the two systems (slope = 0.93 and R2= 0.95). Assessment of throughput based on real-time timings indicated a maximum output of approximately &amp;gt;700 patient samples per 24hrs per system. Conclusions An automated system for performing live CBAs provides equivalent to superior analytical performance compared to pre-existing manual methods with improved testing capacity.

B-105 Farr Radioimmunoprecipitation Method Enhances Serial Monitoring of Quantitative Anti-dsDNA (double-stranded) Antibody Measurements in Lupus

Abstract Background Anti-double stranded DNA (anti-dsDNA) antibodies are an important criterion in the diagnosis, classification, and management of systemic lupus erythematous (SLE). High avidity anti-dsDNA IgG may be more clinically relevant and specific for SLE. As such, radioimmunoassay according to the Farr technique (Farr-RIPA) is often considered more sensitive and quantitative than enzyme-linked immunosorbent assay (ELISA) and Crithidia luciliae immunofluorescence assay (CLIFT) methods. Methods Measurements of anti-dsDNA antibodies in 147,016 serum patient samples were obtained by lab-developed Farr-RIPA. Serum with endogenous antibodies binds to 125I-radiolabelled dsDNA and undergoes subsequent immunoprecipitation under high salt conditions which selects for highly avidity anti-dsDNA antibodies. The analytic measurement range (AMR) of the assay is 5.7 to 85 IU/mL, and dilutional linearity is validated to 68,000 IU/mL for results &amp;gt;85 (ULOQ). Inter-assay precision is &amp;lt;10% CV. Results Of 147,016 measured samples, 5.4% (7800) were positive for anti-ds DNA antibodies (mean 251.7) with numeric values, ranging from 8.0 to 55,399 IU/mL. The numeric distribution of all positive results was such that 76% (5859/7800) were between 8.0 - 60 IU/mL, and the median was 19.4 with an interquartile range (IQR) of 36.1. A small percentage (3.9%) had very high anti-dsDNA levels greater than 1000 IU/mL and 0.4% (35/7800) were greater than 10,000 IU/mL. Serial measurements comprised almost half (45.5%) of all positives, occurring in 1016 unique patients an average of 3.5 levels within a 2-year time frame. A fifth of those patients, 200, were more frequently monitored with at least 4 levels. Of patients with the very highest dsDNA (&amp;gt;10,000), we analyzed the results of 17 unique patients who were frequently monitored an average of 6.1 times. Peak and nadir values yielded a mean delta of 20,751 with a mean of 264 days elapsing between peak and nadir. All except one showed a marked decrease in Anti-dsDNA over time with an average decrease of 15,685 IU/mL. Conclusions Here, we performed 147,016 Anti-dsDNA antibody measurements by Farr-RIPA, a precise method with a broad analytic range as compared to other methods which have a limited upper limit of quantitation or are semi-quantitative. Our 7800 positive Farr-RIPA results exhibited quantitative results from 8.0 to 55,399 IU/mL. The median of 19.4 and IQR of 36.1 showed most results to be &amp;lt;55.5 IU/mL. Very high levels &amp;gt;300 and &amp;gt;1000 IU/mL were seen in 10% and 4% of patient samples, respectively. Serial monitoring was frequent. In patients with the very highest levels &amp;gt;10,000, an-eight fold decrease in peak Anti-dsDNA levels was achieved over a mean of 264 days with more than half (9/17) achieving levels &amp;lt;250. The ability to detect and meaningfully monitor these patients is enhanced by the Farr-RIPA method. In conclusion, in 7800 positive samples, we demonstrated a wide range of inter- and intra-patient numeric Anti-dsDNA concentrations that denote the clinical usefulness of serial monitoring by Farr-RIPA.

Serum immunoglobulin A levels: Diagnostic utility in alcoholic liver disease and association with liver fibrosis in steatotic liver disease.

The relationship between immunoglobulin A (IgA) levels and chronic liver disease remains poorly understood. The present study evaluated the clinical significance of IgA in 478 new patients who visited the Outpatient Clinic of Nagasaki Harbor Medical Center (Nagasaki, Japan). Serum IgA levels in comparison to liver stiffness (LS), as measured using a FibroScan® device, were evaluated in 358 patients. Furthermore, in 270 patients, the associations between serum IgA levels and body composition were analyzed using computed tomography. The IgA levels of patients in the groups with Child-Pugh classification B and C (CPGBC), alcoholic liver disease (ALD), steatotic liver disease (SLD) or diabetes were higher than the IgA levels of patients in the groups with CPGA, non-ALD, non-SLD or no diabetes, respectively. Logistic regression analysis showed that CPGBC, ALD, high IgG (>1,700 mg/dl), high macrophage galactose-specific lectin-2 binding protein glycosylation isomer (M2BPGi) (>1 cut-off index) and diabetes were contributing factors for high serum IgA level (>410 mg/dl). The ratio of IgA level divided by IgG level was highest in patients with ALD, followed by those with metabolic dysfunction-associated SLD (MASLD) and non-SLD. In SLD, IgA level was associated more with LS than M2BPGi and fibrosis-4 (FIB-4) in multiple regression analysis. In the receiver operating characteristic analysis, IgA level, M2BPG, and FIB-4 had similar area under the curve values for discriminating high LS (>8 kPa) from low LS (≤8 kPa) in SLD. IgA levels were also associated with visceral fat, and this association was only found in women. In conclusion, elevated IgA is an indicator of liver fibrosis that also reflects the presence of diabetes and an increased visceral fat level. Therefore, IgA is considered a useful marker of liver disease severity in the current era of increased SLD.

Recurrent tick bites induce high IgG1 antibody responses to α-Gal in sensitized and non-sensitized forestry employees in Luxembourg.

The α-Gal syndrome (AGS) is characterized by the presence of specific IgE-antibodies to the carbohydrate galactose-α-1,3-galactose (α-Gal). Sensitization to α-Gal has been associated with tick bites and individuals exposed to ticks have an elevated risk of sensitization. The aim of this study was to analyze IgG and IgE antibody responses to α-Gal in a high-risk cohort of forestry employees (FE) in Luxembourg. Questionnaires and serum samples of FE from Luxembourg (n=219) were retrospectively analyzed. α-Gal specific IgE was quantified by ImmunoCAP, α-Gal specific IgG and subclasses IgG1-4 were determined by ELISA. Additionally, sera from population-based controls (n=150) and two groups of food-allergic patients, patients with AGS (n=45) and fish-allergic patients (n=22) were assessed for IgG antibody responses to α-Gal and cod extract. Twenty-one percent of FE was sensitized to α-Gal (sIgE≥0.1kUA/L). Both sensitized and non-sensitized FE exhibited high levels of α-Gal specific IgG, IgG1 and IgG3 compared with controls, indicating a stimulation of IgG responses by recurrent tick bites, independent of the sensitization status. AGS patients had the highest levels of IgG1 and IgG2 antibodies, whereas the profile of fish-allergic patients was similar to the profile of the controls for which anti-α-Gal responses were dominated by IgG2 antibodies. α-Gal sIgG4 levels were either very low or undetectable in all groups. Our study provides evidence for a continuous stimulation of α-Gal related immune responses by repeated tick bites, translating into highly elevated levels of IgG1 antibodies directed against α-Gal.

Preparation of bovine coronavirus virus-like particles and its immunogenicity in mice and cattle

The widespread prevalence of bovine coronavirus (BCoV) disease worldwide has impacted the livestock industry economically. No effective vaccine is available in China. In this study, we produced BCoV virus-like particles (VLPs) containing E, M, N, S, and hemagglutinin-esterase (HE) proteins using a baculovirus expression system. Five recombinant baculoviruses were co-infected with Sf9 cells, and the VLPs were assembled and characterized. Mice and cattle were immunized by VLPs mixed with MF59 and CpG 55.2 adjuvants. Two doses of the VLPs/MF59/CpG vaccine were administered in mice and cattle. The immune effect of the VLPs/MF59/CpG vaccine was measured using indirect ELISA and neutralization assays. After immunization, the serum IgG-specific antibody titer against S protein and neutralization antibody titer increased to 1:1.28 × 104 (p < 0.01) and 1:128 (p < 0.01) in mice, respectively. Interestingly, the high IgG antibody and neutralizing antibody titers were maintained for seven days in mice. In addition, the serum IgG-specific antibody titer against S proteins and neutralization antibody titer increased to 1:1.024 × 105 and 1:512 (p < 0.05) in cattle, respectively. The high IgG antibody and neutralizing antibody titers were maintained for 21 days in cattle. Notably, BCoV VLPs group interferon-gamma (IFN-γ) lymphocytes in spleens were significantly increased (p < 0.01). These findings suggest that BCoV VLPs induced strong cellular and humoral immune responses in mice and cattle. These findings suggest that BCoV VLPs could serve as a potent immunogen for vaccine development.

High Seroprevalence to Aedes-borne arboviruses in Ethiopia: a Cross-sectional Survey in 2024.

Aedes-borne diseases infect millions of people each year. In the last decade several arbovirus outbreaks have been reported in Ethiopia. Arbovirus diagnosis and surveillance is lacking and the true burden is unknown. In this study we conducted a seroprevalence survey using a commercially available test kit that that tests for immunological responses to IgM and IgG for dengue (DENV), Zika (ZIKV), and chikungunya (CHIKV) viruses in Dire Dawa city, eastern Ethiopia. We found a high IgG seroprevalence for DENV (76%), CHIKV (44%), and ZIKV (38%), and <20% IgM seropositivity across all viruses. As a comparison, we conducted serosurveillance in Addis Ababa, the national capital with no reported history of arbovirus outbreaks. The highest seropositivity we found was to IgM for DENGV at approximately 3%. Our results suggest both past and recent widespread exposure to these arboviruses, underscoring the need for improved surveillance and public health interventions in Ethiopia.

Seroprevalence of SARS-CoV-2 infection in pediatric patients in a tertiary care hospital setting.

Globally, cases of children's coronavirus disease 2019 (COVID-19) have been reported since the pandemic started. Most children have an asymptomatic or mild infection. Therefore, the incidence rate of COVID-19 in children might have been underestimated. This study aimed to determine (1) the seroprevalence (and seroconversion rates) of COVID-19, including associated risk factors, in pediatric patients visiting hospitals; and (2) the immunological responses to COVID-19. This was a prospective, cross-sectional study. Patients aged 0-18 years who visited the hospital from September 2020 to February 2022 were included. Demographic, clinical, and laboratory data were reviewed. A total of 1,443 pediatric patients were enrolled. Of these, 323 (22.6%) had a history of COVID-19. In the pre-Delta period, the seroprevalence increased from 4.1% to 70.6% in all included patients and from 0.5% to 10% in patients without a known history of COVID-19 compared with the Delta-Omicron period. The seroconversion rate was 6.8% (19 per 100 person-years) in pediatric patients with COVID-19. Risk factors for COVID-19 seropositivity were respiratory symptoms, being in an outpatient department setting, and infection during the Delta-Omicron period. Exposure to household members with confirmed COVID-19 was a risk factor for seropositivity and seroconversion. Infection during the Delta-Omicron period and testing conducted >2 weeks after the onset of symptoms was associated with spike immunoglobulin (Ig) M and spike and nucleocapsid IgG, respectively. High nucleocapsid IgG levels were associated with pneumonia in pediatric patients with COVID-19. Pediatric patients exposed to household members with COVID-19 and respiratory symptoms should be tested for COVID-19. Nucleocapsid IgG can be used as a surrogate marker to identify patients who may have experienced pneumonia from COVID-19 and as a screening tool for the COVID-19 outbreak, regardless of COVID-19 vaccination status.

Autoantibodies to ADAMTS13 in human immunodeficiency virus-associated thrombotic thrombocytopenic purpura.

Thrombotic thrombocytopenic purpura (TTP) is a potentially fatal thrombotic microangiopathic disorder that can result from human immunodeficiency virus (HIV) infection. The pathogenesis involves a deficiency of the von Willebrand factor (vWF) cleaving protease ADAMTS13 (a disintegrin and metalloprotease with thrombospondin motifs member 13) and the presence of anti-ADAMTS13 autoantibodies. However, there is insufficient information regarding the epitope specificity and reactivity of these autoantibodies. This study aimed to perform epitope-mapping analysis to provide novel insights into the specific epitopes on ADAMTS13 domains affected by autoantibodies. The study analysed 59 frozen citrate plasma samples from HIV-associated TTP patients in South Africa, measuring ADAMTS13 activity using Technozyme® ADAMTS13 activity test, total immunoglobulin (Ig) M and IgA antibodies levels using ELISA kit and purifying IgG antibodies using NAb™ Protein G spin columns. A synthetic ADAMTS13 peptide library was used for epitope mapping. Overall, 90% of samples showed anti-ADAMTS13 IgG autoantibodies, with 64% of these antibodies being inhibitory, as revealed by mixing studies. Samples with ADAMTS13 antigen levels below 5% showed high anti-ADAMTS13 IgG autoantibody titres (≥50 IU/mL), whereas those with 5%-10% levels had low autoantibody titres (<50 IU/mL).The metalloprotease, cysteine-rich and spacer domains were 100% involved in binding anti-ADAMTS13 IgG antibodies, with 58% of samples containing antibodies binding to the C-terminal part of the ADAMTS13 disintegrin-like domain, indicating different pathogenic mechanisms. The metalloprotease, cysteine-rich and spacer domains are the primary targets for anti-ADAMTS13 IgG autoantibodies in patients with HIV-associated TTP. These findings suggest potential effects on the proteolytic activity of ADAMTS13, highlighting the complex nature of the pathogenic mechanisms involved.

IgG4-Related Disease: Comprehensive Overview of Pathogenesis, Clinical Manifestations, and Diagnostic Challenges.

Introduction IgG4-related disease (IgG4-RD) is a progressive and potentially life-threatening condition characterized by immune system activation and tissue fibrosis, affecting various organs such as the pancreas, kidneys, and lungs. Initially recognized in 2003, it often presents as mass-like lesions, which can mimic tumors. Despite advancements in understanding its pathology, epidemiological data are limited, and many patients remain undiagnosed due to unfamiliarity with the disease. Aim of the study The aim of this article wast to summarize the latest knowledge on the diagnosis and clinical manifestations of IgG4-related disease. Materiał and methods This review is based on articles from the PubMed and Google Scholar databases, covering the years 2007-2024, using the keywords: IgG4-related disease; autoimmune pancreatitis; retroperitoneal fibrosis; classification criteria. Results The disease's complex pathogenesis involves B and T cell activity, with genetic and environmental factors contributing. While effective treatments, like B cell depletion, exist, the disease's broad clinical manifestations and multi-organ involvement require a multidisciplinary approach for proper diagnosis and management. Conclusion Diagnosing IgG4-RD is challenging due to its varied symptoms, often mimicking other diseases. Key findings include high IgG4 levels and specific histopathological features. Further research is needed to understand its genetic factors, pathogenesis, and epidemiology.

The Effects of Vaccination Status and Age on Clinical Characteristics and Severity of Measles Cases in the United States in the Post-Elimination Era, 2001-2022.

Despite high vaccine-effectiveness, wild-type measles can occur in previously vaccinated persons. We compared the clinical presentation and disease severity of measles by vaccination status and age in the post-elimination era in the United States. We included U.S. measles cases reported from 2001-2022. Breakthrough measles was defined as cases with ≥1 documented dose of measles-containing vaccine, classic measles as the presence of rash, fever, and ≥1 symptoms (cough, coryza, or conjunctivitis), and severe disease as the presence of pneumonia, encephalitis, hospitalization, or death. Vaccinated cases with low and high avidity IgG were classified as primary (PVF) and secondary (SVF) vaccine failures, respectively. Among 4,056 confirmed measles cases, 2,799 (69%) were unvaccinated, 475 (12%) were breakthrough infections, and 782 (19%) had unknown vaccination; 1,526 (38%), 1,174 (29%), and 1,355 (33%) were aged <5, 5-19, and ≥20 years, respectively. We observed a general decline in classic presentation and severe disease with an increase in the number of doses, and less complications among children aged 5-19 years compared to other age-groups. Among 93 breakthrough cases with avidity results, 11 (12%) and 76 (82%) were classified as PVF and SVF, respectively, with a higher proportion of PVFs having a classic measles presentation and severe disease than SVFs. Breakthrough measles cases tended to have milder disease with less complications. A small proportion of breakthrough infections were due to PVF than SVF. It is critical to maintain high MMR vaccination coverage in the United States to prevent serious measles illnesses.

Maternal Cytomegalovirus (CMV) Serology: The Diagnostic Limitations of CMV IgM and IgG Avidity in Detecting Congenital CMV Infection.

Congenital cytomegalovirus (cCMV) is a common congenital viral infection. Testing for cCMV usually begins with assessing maternal CMV serology, specifically IgM and IgG antibodies. A negative maternal CMV IgM suggests a low risk of recent maternal CMV infection, thereby suggesting a low risk of cCMV in the fetus. Consequently, cCMV is often ruled out when maternal CMV IgM is negative. In our perinatal autopsy and placental pathology database, we identified 5 cases of cCMV despite negative maternal CMV IgM results in the second trimester. In all 5 cases, fetal abnormalities were first detected by ultrasound in the second trimester, prompting maternal CMV testing. Since second trimester maternal CMV IgM was negative in all cases, cCMV was considered unlikely, thus precluding further prenatal CMV testing in 4 of these cases. The diagnosis of cCMV was subsequently made through placental and/or autopsy examinations. Following this diagnosis, retrospective CMV serology and IgG avidity testing was performed on stored frozen first-trimester maternal blood samples in 3 cases. Among these, the first-trimester samples in 2 cases were IgG+, IgM+, and exhibited low IgG avidity, suggesting a primary maternal CMV infection around the time of conception. In the third case, both first and second-trimester maternal blood samples were IgG+, IgM-, and showed high IgG avidity, suggesting a non-primary maternal CMV infection (i.e., reactivation or reinfection of CMV). A negative maternal CMV IgM in the second trimester cannot exclude cCMV infection. While CMV IgG avidity testing and analysis of stored frozen first-trimester maternal blood samples provide valuable insights, they have limitations. CMV PCR performed on amniotic fluid is a useful prenatal diagnostic tool. For cases of unexplained fetal abnormalities or death, autopsy and placental examination are recommended.

Kinetics of humoral and cellular immune responses 5 months post-COVID-19 booster dose by immune response groups at the peak immunity phase: An observational historical cohort study using the Fukushima vaccination community survey

BackgroundUnderstanding the waning of immunity after booster vaccinations is important to identify which immune-low populations should be prioritized. MethodsWe investigated longitudinal cellular and humoral immunity after the third vaccine dose in both high- and low-cellular and humoral immunity groups at the peak immunity phase after the booster vaccination in a large community-based cohort. Blood samples were collected from 1045 participants at peak (T1: median 54 days post-third dose) and decay (T2: median 145 days post-third dose) phases to assess IgG(S), neutralizing activity, and ELISpot responses. Participants were categorized into high/low ELISpot/IgG(S) groups at T1. Cellular and humoral responses were tracked for approximately five months after the third vaccination. ResultsIn total, 983 participants were included in the cohort. IgG(S) geometric mean fold change between timepoints revealed greater waning in the >79 years age group (T2/T1 fold change: 0.27) and higher IgG(S) fold change in the low-ELISpot group at T1 (T2/T1 fold change: 0.32–0.33) than in the other groups, although ELISpot geometric mean remained stable. ConclusionsAntibody level of those who did not respond well to third dose vaccination waned rapidly than those who responded well. Evidence-based vaccine strategies are essential in preventing potential health issues caused by vaccines, including side-effects.

A genetically engineered mouse/human chimeric antibody targeting CD99 enhances antibody-dependent cellular phagocytosis against human mantle cell lymphoma Z138 cells

Background: Mantle cell lymphoma (MCL) is an aggressive form of B-cell nonHodgkin lymphoma. The elimination of MCL cells via phagocytosis is essential for cancer eradication. Therefore, discovering novel targeted antibodies that can induce phagocytosis is needed. We have demonstrated that our in-houseproduced mouse anti-CD99 mAb clone MT99/3 could induce potent anticancer activities against MCL cell lines in both in vitro and in vivo mouse xenograft models. Nevertheless, for use in humans, the mouse mAb needs to be transformed into a mouse/human chimeric mAb that contains a human Fc region to activate human immune effector functions, especially macrophage-mediated phagocytosis. Antibody-dependent cellular phagocytosis (ADCP) mediated by mouse/human chimeric mAb MT99/3 against MCL has not been previously reported. Objective: This study aimed to genetically engineer a mouse/human chimeric antibody against human CD99 derived from mouse mAb MT99/3 and to evaluate its effect in mediating the ADCP mechanism for eradicating MCL cells in vitro using monocyte-derived macrophages. Materials and methods: The expression plasmid to produce chimeric anti-CD99 antibody, ChAbMT99/3, was constructed by fusing the variable domains of mouse mAb MT99/3 with the constant domains of human IgG1 and the constant domains of kappa light chain. ChAbMT99/3 was expressed in the stable human expression system based on HEK293T cells. ChAbMT99/3 was purified from the culture supernatant of ChAbMT99/3-expressing HEK293T cells using Protein G chromatography. The purity and structure of ChAbMT99/3 were verified by SDS-PAGE and western blotting. The binding specificity and activity were determined by staining with cells expressing recombinant and native human CD99. The anticancer activity of ChAbMT99/3 in mediating the ADCP mechanism against MCL cell line Z138 using human monocytederived macrophages was evaluated. Results: We successfully constructed the plasmid to produce ChAbMT99/3. Human HEK293T cells stably expressing ChAbMT99/3 were established. The ChAbMT99/3- expressing HEK293T cells could secrete ChAbMT99/3 into the culture supernatant. The high purity and complete IgG structure of ChAbMT99/3 were obtained from the purification process. Crucially, this chimeric antibody retained its binding reactivity to recombinant and native human CD99. In addition, the produced ChAbMT99/3, upon binding to MCL cells, significantly enhanced ADCP against MCL cell line Z138 in a dose-dependent manner. Conclusion: The production of a mouse/human chimeric antibody against human CD99 derived from mouse mAb MT99/3 was successful. The engineered antibody could mediate ADCP activity against MCL cells. The produced ChAbMT99/3 might be a promising therapeutic candidate for MCL treatment.

Clinical characteristics and IgG antibody response against SARS-CoV-2 among COVID-19 patients in the POYUN factory (Hai Duong) outbreak, 2021

We conducted a cross - sectional study, from Jan 2021 to May 2021, on COVID-19 cases of the POYUN factory outbreak in Hai Duong province, to describe clinical features and explore IgG antibodies against SARS-CoV-2 status. Data from COVID-19 patients were extracted from the National Notifiable Infectious Disease Information System, and 137 blood samples were collected for ELISA testing; statistical analyses were conducted using STATA version 16.0. Among 182 COVID-19 patients, females accounted for 73.6%, the mean age was 30.2 ± 6.1. Approximately 40% of patients had onset symptom(s); the incubation period was 7.6 (95%CI: 6.5 - 8.7) days. Clinical symptoms included fatigue (36.3%), cough (34.6%), sore throat (32.4%), and fever (31.3%); other symptoms such as muscle/joint pain, and chill,… ranged from 24% - 30%. Nearly 65% of blood samples were IgG-positive; higher IgG (+) proportions were seen among patients with onset symptoms (77.4%), fever (82.4%), chill (85.7%), muscle/joint pain (84.8%), and loss of taste/smell (96.1%). The median time of IgG antibody response was 50 days post-infection, and 65.5% of patients who contracted COVID-19 ≥ 45 days had IgG (+) in their blood samples. COVID-19 patients presented with fever, muscle/joint pain, cough, and loss of taste/smell were more likely to be IgG positive. The limitations of our research included small sample size, using the convenient sampling method, and using one cut point for ELISA testing… which may lead to potential bias. In conclusion, patients in the POYUN outbreak showed specific symptoms of SARS-CoV-2 infection. The IgG antibody response among COVID-19 patients was not prolonged and was associated with presented symptoms.

Intranasal Administration of Recombinant Newcastle Disease Virus Expressing SARS-CoV-2 Spike Protein Protects hACE2 TG Mice against Lethal SARS-CoV-2 Infection.

Coronavirus disease 2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), emerged as a global outbreak in 2019, profoundly affecting both human health and the global economy. Various vaccine modalities were developed and commercialized to overcome this challenge, including inactivated vaccines, mRNA vaccines, adenovirus vector-based vaccines, and subunit vaccines. While intramuscular vaccines induce high IgG levels, they often fail to stimulate significant mucosal immunity in the respiratory system. We employed the Newcastle disease virus (NDV) vector expressing the spike protein of the SARS-CoV-2 Beta variant (rK148/beta-S), and evaluated the efficacy of intranasal vaccination with rK148/beta-S in K18-hACE2 transgenic mice. Intranasal vaccination with a low dose (106.0 EID50) resulted in an 86% survival rate after challenge with the SARS-CoV-2 Beta variant. Administration at a high dose (107.0 EID50) led to a reduction in lung viral load and 100% survival against the SARS-CoV-2 Beta and Delta variants. A high level of the SARS-CoV-2 spike-specific IgA was also induced in vaccinated mice lungs following the SARS-CoV-2 challenge. Our findings suggest that rK148/beta-S holds promise as an intranasal vaccine candidate that effectively induces mucosal immunity against SARS-CoV-2.