Detection of IgM and IgG antibodies in patients with coronavirus disease 2019

CLIA immunoassay as an alternative and accurate method to detect Sars-Cov-2 antigen compared to ELISA

BACKGROUND

COVID-19 has caused moderately severe infections in humans over the past few years, leading to >759 million confirmed cases. This situation highlights an urgent need to develop accurate diagnostic tests to monitor infectious disease and to adopt alternative methods such as CLIA to achieve low detection levels of proteins on diagnostic platforms.

OBJECTIVES

Develop in-house immunoassay for ELISA and CLIA to diagnose COVID-19.

METHODS

200 nasopharyngeal samples were collected using swabs, placed in tubes with 3 mL of PBS. 1 mL from each sample was used to perform qRT-PCR and was considered positive in samples with CT < 38. The remaining volume was used for in-house sandwich immunoassay ELISA and CLIA.

RESULTS

The results showed that CLIA was able to detect active disease in samples containing N protein concentrations greater than 16 ng/mL, with a sensitivity of 90 % and specificity of 94.5 %, and an area under the ROC curve (AUROC) of 0.943 (95 % CI: 0.909-0.977). ELISA showed an AUROC = 0.709 (95 % CI: 0.639-0.778), with a sensitivity of 54.4 % and specificity of 87.2 %.

CONCLUSIONS

The CLIA results in this study outperformed the traditional ELISA and proved to be a suitable platform for monitoring the progression of disease stages, including the diagnosis of active COVID-19 infection.

Genetic parameter estimation for traits related to the immune system against sheep red blood cells in Japanese quail

1. Improving resistance against disease is important in the animal and poultry industry. Besides drugs and vaccines, genetic selection for improved immune systems may be an effective approach.2. Traits related to the immune system were studied in a 938 pedigreed Japanese quail population infected by sheep red blood cells (SRBC). Besides body weight at 35 d of age (BW35), weight of the gizzard (G), liver (Li), lungs (Lu), bursa (Bu), spleen (S), heart (H), and digestive track (D) and length of ileum (I) and caecum (C) were recorded. Total antibody (TA), mercaptoethanol-resistant (IgG), mercaptoethanol-sensitive titres (IgM), the number of monocyte (M), basophil (B) and eosinophil (E) and the ratio of heterophil to lymphocyte (H/L) were measured. Co-variance components were estimated via Gibbs sampling using GIBBS3F90 software. Five univariate animal models, including simple forms, were used for genetic parameter estimations, and the best model was determined by the deviance information criterion (DIC). Genetic and environmental correlations were estimated using a bivariate animal model.3. Direct heritability estimates for internal organs ranged from 0.06 (Lu) to 0.57 (G) and for immune system traits from 0.05 (IgM) to 0.17 (IgG). Negative genetic correlations were found between BW35 and internal organs (-0.22 to -0.80).4. Including one of the internal organs, such as the spleen, in the selection index improved the immune response in heavier birds. Additionally, because of the moderate heritability of IgG (0.17) and its effect on lasting immunity, selecting for higher IgG concentration may improve the resistance of Japanese quail against pathogens.

Tracking the evolution of serum antibody levels and influencing factors post-SARS-CoV-2 infection among community residents in Fuzhou City

Objective

To track the level of serum antibodies in Fuzhou residents and analyze the possible influencing factors of serum antibodies, so as to provide a scientific basis for the adjustment of population immunity and prevention and control strategies.

Methods

Residents in the Fuzhou community who had symptoms of covid-19 infection or who had tested positive for nucleic acid or antigen since December 2022 were selected for the questionnaire survey and their sera were collected to analyze the trend of antibody changes, the antibody level was divided into high antibody group and low antibody group according to the literature data. The possible influencing factors of serum antibody level was analyzed by multivariate logistic regression model.

Results

A total of 2,521 Fuzhou residents were adopted in the study, including 223 in the high antibody group and 194 in the low antibody group. A univariate analysis showed that, there were significant differences in age (Z=-4.028, P<0.00), occupation (χ2 = 18.591, P=0.005), typical symptoms after the first infection (χ2 = 9.784, P=0.002), history of surgery (χ2 = 29.542, P<0.001), symptoms lasting more than 2 weeks after the first infection (χ2 = 4.887, P=0.027), smoking (χ2 = 18.524, P<0.001) and drinking (χ2 = 19.578, P<0.001) between the high antibody group and the low antibody group. Multivariate regression models show that, age (OR= 1.011, 95%CI: 1.002~1.020, P=0.017), history of surgery (OR=4.956,95%CI: 2.606~9.423, P<0.001),smoking (OR=2.089, 95%CI: 1.002~4.355, P=0.049), drinking (OR=2.214, 95%CI: 1.066~4.600, P=0.033) were the risk factors affecting antibody level. Typical symptoms after the first infection (OR=0.224, 95%CI: 0.086~0.579, P=0.002) and symptoms lasting more than 2 weeks after the first infection (OR=0.432, 95%CI: 0.258~0.723, P=0.001) were protective factors. By observing the trend of antibody changes in 3, 6 and 9 months, we found that the level of IgG antibody showed a decreasing trend.

Conclusions

The high level of protection was more likely to occur in young adults, people without operation history, people without smoking history, people without drinking history, people with typical symptoms after the first infection and symptoms lasting more than 2 weeks after the first infection. The level of IgG antibody was decreased in general, so it is necessary to strengthen immunization.

Nanotechnology-Based Modern Biosensors for the Detection of SARS-CoV-2 Virus

The emergence of the COVID-19 pandemic has pointed out the urgent need for rapid and accurate diagnostic tools to detect the SARS-CoV-2 virus. Nanotechnology-based biosensors have emerged as a promising solution due to their high sensitivity, specificity, and speed in detecting biological molecules. This article focuses on the advancements in using nanotechnology for the development of modern biosensors tailored for the detection of the SARS-CoV-2 virus. Various nanomaterials, such as quantum dots, metallic nanoparticles, and nanowires, have been harnessed to enhance the performance of biosensors, offering improved detection limits and specificity. Besides this, innovative detection platforms, such as field-effect transistors, surface plasmon resonance, and electrochemical sensors, have revolutionized the landscape of SARS-CoV-2 diagnostics. These nanotechnology-based biosensors demonstrate the potential for point-of-care testing, enabling rapid and on-site detection with minimal sample preparation. The scalability, cost-effectiveness, and portability of these biosensors make them suitable for mass screening efforts in various healthcare settings, including hospitals, clinics, and community centers. The development of reliable biosensors for SARS-CoV-2 detection aligns with global efforts to curb the spread of the virus through early identification and containment strategies.

T-cell immunobiology and cytokine storm of COVID-19

The 2019 coronavirus illness (COVID 2019) first manifests as a newly identified pneumonia and may quickly escalate to acute respiratory distress syndrome, which has caused a global pandemic. Except for individualized supportive care, no curative therapy has been steadfastly advised for COVID-19 up until this point. T cells and virus-specific T lymphocytes are required to guard against viral infection, particularly COVID-19. Delayed immunological reconstitution (IR) and cytokine storm (CS) continue to be significant barriers to COVID-19 cure. While severe COVID-19 patients who survived the disease had considerable lymphopenia and increased neutrophils, especially in the elderly, their T cell numbers gradually recovered. Exhausted T lymphocytes and elevated levels of pro-inflammatory cytokines, including IL6, IL10, IL2, and IL17, are observed in peripheral blood and the lungs. It implies that while convalescent plasma, IL-6 blocking, mesenchymal stem cells, and corticosteroids might decrease CS, Thymosin α1 and adaptive COVID-19-specific T cells could enhance IR. There is an urgent need for more clinical research in this area throughout the world to open the door to COVID-19 treatment in the future.

Rapid and comprehensive detection of viral antibodies and nucleic acids via an acoustofluidic integrated molecular diagnostics chip: AIMDx

Precise and rapid disease detection is critical for controlling infectious diseases like COVID-19. Current technologies struggle to simultaneously identify viral RNAs and host immune antibodies due to limited integration of sample preparation and detection. Here, we present acoustofluidic integrated molecular diagnostics (AIMDx) on a chip, a platform enabling high-speed, sensitive detection of viral immunoglobulins [immunoglobulin A (IgA), IgG, and IgM] and nucleic acids. AIMDx uses acoustic vortexes and Gor'kov potential wells at a 1/10,000 subwavelength scale for concurrent isolation of viruses and antibodies while excluding cells, bacteria, and large (>200 nanometers) vesicles from saliva samples. The chip facilitates on-chip viral RNA enrichment, lysis in 2 minutes, and detection via transcription loop-mediated isothermal amplification, alongside electrochemical sensing of antibodies, including mucin-masked IgA. AIMDx achieved nearly 100% recovery of viruses and antibodies, a 32-fold RNA detection improvement, and an immunity marker sensitivity of 15.6 picograms per milliliter. This breakthrough provides a transformative tool for multiplex diagnostics, enhancing early infectious disease detection.

Serologic Evidence for Early SARS-CoV-2 Circulation in Lima, Peru, 2020

During early 2021, Peru had the highest COVID-19-associated per-capita mortality rate. Socioeconomic inequality, insufficiently prepared healthcare, and surveillance systems are factors explaining the mortality rate, which can be severely worsened by early undetected SARS-CoV-2 circulation. We tested 1,441 individuals with fever sampled during August 2019-May 2021, several months before the first SARS-CoV-2 seroprevalence study available so far in Lima, Peru, for SARS-CoV-2-specific antibodies. The testing algorithm included a chemiluminescence immunoassay and surrogate virus neutralization test. Early positive samples (N = 24) from January-March 2020 were further tested using a plaque-reduction neutralization test (PRNT) and avidity test against the SARS-CoV-2 spike and nucleoprotein. None of the early samples were PRNT-confirmed, in contrast to 81.8% (18/22) of a subsample from April 2020 onward (Fisher exact test; P <0.0001). Therefore, we excluded non-PRNT-confirmed samples from subsequent analyses. The SARS-CoV-2 antibody detection rate was 0.9% in mid-April 2020 (1/104; 95% CI: 0.1-5.8%), suggesting viral circulation in early-middle March 2020, consistent with the first molecular detection of SARS-CoV-2 in Peru on March 2020. Mean avidity increase of 62-77% to 81-94% from all PRNT-confirmed SARS-CoV-2-positive samples during early 2020 were consistent with onset of SARS-CoV-2 circulation during late February/March 2020. Early circulation was also confirmed in a susceptible, exposed, infected, and recovered mathematical model that calculated an effective reproduction number >1 during February-March 2020. Early introduction of SARS-CoV-2 thus contributed to the high COVID-19 mortality rate in Peru. Emphasizing the role of diagnostic confirmation in understanding the pandemic's trajectory, this study highlights the importance of early detection and accurate testing in managing infectious disease outbreaks.

Lab-in-a-Vial Rapid Test for Internet of Things-Embedded Point-of-Healthcare Protein Biomarker Detection in Bodily Fluids

Amateurs often struggle with detecting and quantifying protein biomarkers in body fluids due to the high expertise required. This study introduces a Lab-in-a-Vial (LV) rapid diagnostic platform, featuring hydrangea-like platinum nanozymes (PtNH), for rapid, accurate detection and quantification of protein biomarkers on-site within 15 min. This method significantly enhances detection sensitivity for various biomarkers in body fluids, surpassing traditional methods such as enzyme-linked immunosorbent assays (ELISA) and lateral flow assays (LFA) by ≈250 to 1300 times. The LV platform uses a glass vial coated with specific bioreceptors such as antigens or antibodies, enabling rapid in vitro evaluation of disease risk from small fluid samples, similar to a personal ELISA-like point-of-care test (POCT). It overcomes challenges in on-site biomarker detection, allowing both detection and quantification through a portable wireless spectrometer for healthcare internet of things (H-IoT). The platform's effectiveness and adaptability are confirmed using IgG/IgM antibodies from SARS-CoV-2 infected patients and nuclear matrix protein (NMP22) from urothelial carcinoma (UC) patients as biomarkers. These tests demonstrated its accuracy and flexibility. This approach offers vast potential for diverse disease applications, provided that the relevant protein biomarkers in bodily fluids are identified.

Integration of nanobiosensors into organ-on-chip systems for monitoring viral infections

The integration of nanobiosensors into organ-on-chip (OoC) models offers a promising advancement in the study of viral infections and therapeutic development. Conventional research methods for studying viral infection, such as two-dimensional cell cultures and animal models, face challenges in replicating the complex and dynamic nature of human tissues. In contrast, OoC systems provide more accurate, physiologically relevant models for investigating viral infections, disease mechanisms, and host responses. Nanobiosensors, with their miniaturized designs and enhanced sensitivity, enable real-time, continuous, in situ monitoring of key biomarkers, such as cytokines and proteins within these systems. This review highlights the need for integrating nanobiosensors into OoC systems to advance virological research and improve therapeutic outcomes. Although there is extensive literature on biosensors for viral infection detection and OoC models for replicating infections, real integration of biosensors into OoCs for continuous monitoring remains unachieved. We discuss the advantages of nanobiosensor integration for real-time tracking of critical biomarkers within OoC models, key biosensor technologies, and current OoC systems relevant to viral infection studies. Additionally, we address the main technical challenges and propose solutions for successful integration. This review aims to guide the development of biosensor-integrated OoCs, paving the way for precise diagnostics and personalized treatments in virological research.

Serological survey in a university community after the fourth wave of COVID-19 in Senegal

A cross-sectional survey was conducted at Polytechnic High School (PHS) to assess the spread of COVID-19 infection among students and staff. A random cluster sampling was conducted between May 19 and August 18, 2022, after the fourth wave of COVID-19 in Senegal. IgM and IgG SARS-CoV-2 antibodies were screened using WANTAI SARS-CoV-2 ELISA assays. Seroprevalence and descriptive statistics were calculated, and associations between seropositivity and different factors were determined using logistic regression. A total of 637 participants were recruited and the median age was 21 years [18-63]. 62.0% of the participants were female, and 36.89% were male, with a male-to-female ratio = 0.59. The overall IgG and IgM seroprevalence were 92% and 6.91% respectively. Among those who tested positive for IgM, 6.75% were also positive for IgG, and 0.15% were negative for IgG. Interestingly, 6.90% of participants tested negative for both IgM and IgG. We found a higher IgM seroprevalence in men than women (9.4% vs. 5.6%) and a lower IgM seroprevalence in (18-25) age group compared to (55-65) years. We revealed a significant difference according to IgG seroprevalence among participants who declared fatigue symptoms [92.06% (95% CI: 89.96-94.16)] compared to those who did not [80.39% (95% CI: 77.31-83.47)], p = 0.0027. IgM seropositivity was found to be associated with Body Mass Index (BMI) categories (O.R. 0.238, p = 0.043), ethnic group (O.R. 0.723, p = 0.046), and marital status (O.R. 2.399, p = 0.021). Additionally, IgG seropositivity was linked to vaccination status (O.R. 4.741, p < 0.001). Our study found that most students and staff at PHS were exposed to SARS-CoV-2, confirming the virus's circulation at the time of the survey. We also identified differences in individual susceptibility that need further clarification. Our results highlight the importance of seroepidemiological surveys to assess the true impact of the COVID-19 pandemic in a community and to monitor variations in antibody response.

TRP36-ELISA for E. canis detection: Concordance with TaqMan real-time PCR and point-of-care testing

Ehrlichia canis, a widely distributed tick-borne pathogen, requires prompt and accurate diagnosis for effective management. Real-time PCR serves as the reference standard for diagnosing E. canis infection, whereas serological tests are crucial for detecting antibody responses indicative of infection or post-exposure status. Early detection during the acute phase of the disease is essential for optimal treatment and recovery. E. canis Tandem Repeat Protein 36 (TRP36) elicits early acute phase responses. We developed an enzyme-linked immunosorbent assay (ELISA) using recombinant TRP36 to detect IgM and IgG antibodies against E. canis. We assessed the diagnostic agreement, sensitivity, and specificity of the rTRP36-ELISA and a commercial test kit (SNAP 4Dx Plus Test) with TaqMan Real-time PCR (qPCR) using the NCSS 2023 program version 23.0.1. Leftover serum samples from 32 dogs at the Veterinary Teaching Hospital were randomly selected and examined for E. canis infection using qPCR, rTRP36-ELISA, and SNAP 4Dx Plus Test. qPCR detected positive results in 12 (37.5 %), whereas ELISA and SNAP 4Dx Plus detected positive results in 10 (31.25 %) and 13 (40.62 %), respectively. Moderate agreement (κ = 0.545) was observed between rTRP36-ELISA and qPCR, and fair agreement (κ = 0.379) between SNAP 4Dx Plus and qPCR. Substantial agreement (κ = 0.79) was found between rTRP36-ELISA and SNAP 4Dx Plus. Compared to qPCR, the sensitivity and specificity of rTRP36-ELISA were 70 % and 77.27 %, respectively, compared to 53.85 % and 73.86 %, respectively, for SNAP 4Dx Plus. Our findings suggest that TRP36 is a promising antigen for E. canis serodiagnosis, potentially improving sensitivity and specificity.

COVID 19: Prevention and treatment through the Indian perspective

The most destructive period the world has experienced seems to be behind us. Not a single nation was spared by this disease, and many continue to struggle today. Even after recovering from COVID, patient may continue to experience some post-COVID effects, such as heart irregularities or a decline in lung vitality. In the past three years (2019-2022), the world has witnessed the power of a small entity, a single peculiar virus. Science initially appeared to be helpless in this regard, but due to the emergence of disease, pharmaceutics (the development of anti-covid drugs), immunology (the rapid antigen test), microbiology (the isolation of viruses from infected people), biotechnology (the development of recombinant vaccines), biochemistry (the blood profile, the D-dimer test), and biochemistry (blood profile, D-dimer test), biophysics (PCR, RT-PCR, CT Scan, MRI) had worked together to fight the disease. The results of these efforts are the development of new diagnostic techniques, possible treatment and finally the availability of vaccines against COVID-19. However, it is not proven that the treatment through the traditional medical system is directly active on SARS-CoV-2 but is instead indirectly acting on SARS-CoV-2 effects by improving symptoms derived from the viral disease. In India, the traditional system of medicine and tradition knowledge together worked in the pandemic and proved effective strategies in prevention and treatment of SARS-CoV-2. The use of effective masks, PPE kits, plasma therapy, yoga, lockdowns and social seclusion, use of modern antiviral drugs, monoclonal antibodies, herbal remedies, homoeopathy, hygienic practice, as well as the willpower of people, are all contributing to the fight against COVID. Which methods or practices will be effective against COVID nobody is aware since medical professionals who wear PPE kits do not live longer, and some people in India who remained unprotected and roamed freely were not susceptible to infection. The focus of this review is on the mode of transmission, diagnosis, preventive measures, vaccines currently under development, modern medicine developed against SARS-CoV-2, ayurvedic medicine used during pandemic, homoeopathic medicine used during pandemic, and specific yoga poses that can be used to lessen COVID-related symptoms.

A mathematical model simulating the adaptive immune response in various vaccines and vaccination strategies

Vaccination has been widely recognized as an effective measure for preventing infectious diseases. To facilitate quantitative research into the activation of adaptive immune responses in the human body by vaccines, it is important to develop an appropriate mathematical model, which can provide valuable guidance for vaccine development. In this study, we constructed a novel mathematical model to simulate the dynamics of antibody levels following vaccination, based on principles from immunology. Our model offers a concise and accurate representation of the kinetics of antibody response. We conducted a comparative analysis of antibody dynamics within the body after administering several common vaccines, including traditional inactivated vaccines, mRNA vaccines, and future attenuated vaccines based on defective interfering viral particles (DVG). Our findings suggest that booster shots play a crucial role in enhancing Immunoglobulin G (IgG) antibody levels, and we provide a detailed discussion on the advantages and disadvantages of different vaccine types. From a mathematical standpoint, our model proposes four essential approaches to guide vaccine design: enhancing antigenic T-cell immunogenicity, directing the production of high-affinity antibodies, reducing the rate of IgG decay, and lowering the peak level of vaccine antigen-antibody complexes. Our study contributes to the understanding of vaccine design and its application by explaining various phenomena and providing guidance in comprehending the interactions between antibodies and antigens during the immune process.

Immune and inflammation features of severe and critical Omicron infected patients during Omicron wave in China

OBJECTIVE

The current study aimed to investigate the baseline immune and inflammatory features and in-hospital outcomes of patients infected with the Omicron variant (PIWO) who presented with different disease severities during the first wave of mass Omicron infections in the Chinese population has occurred.

METHOD

A cross-sectional study was conducted on 140 hospitalized PIWO between December 11, 2022, and February 16, 2023. The clinical features, antibodies against SARS-CoV-2, immune cells, and inflammatory cytokines among mildly, severely, and critically ill PIWO at baseline and during follow-up period were compared.

RESULT

Patients with severe (n = 49) and critical (n = 35) disease were primarily male, needed invasive mechanical ventilation treatment, and exhibited higher mortality than those with mild disease (n = 56). During acute infection, SARS-CoV-2-specific antibody levels fluctuated with disease severity, serum antibodies increased and the incidence of severe cases decreased in critically ill PIWO over time. Antibody titers in severe or critical PIWO with no antibody responses at baseline did not increase significantly over time. Meanwhile, CD4+T cell, CD8+T cell, and natural killer cell counts were negatively correlated with disease severity, whereas interleukin (IL)-6 and IL-10 levels were positively correlated. In addition, combined diabetes, immunosuppressive therapy before infection, serum amyloid A, IL-10 and neutrophil counts were independently associated with severe and critical illness in PIWO. Among the 11 nonsurvivors, 8, 2, 1 died of respiratory failure, sudden cardiac death, and renal failure, respectively. Compared with survivors, nonsurvivors exhibited lower seropositivity of SARS-CoV-2-specific antibody, reduced CD3+T and CD4+T cell counts, and higher IL-2R, IL-6, IL-8, and IL-10 levels. Of note, lactate dehydrogenase was a significant risk factor of death in severe or critically ill PIWO.

CONCLUSION

This present study assessed the dynamic changes of SARS-CoV-2-specific antibodies, immune cells and inflammatory indexes between severely and critically ill PIWO. Critical and dead PIWO featured compromised humoral immune response and excessive inflammation, which broadened the understanding of the pathophysiology of Omicron infection and provides warning markers for severe disease and poor prognosis.

Performance of protein N linear epitopes in serodiagnosis of COVID-19 infection

Introduction

Despite the efforts to contain the spread of COVID-19, the virus remains in circulation, posing a considerable risk to populations across the globe. Hence, rapid and early detection of this infection is essential for effective disease control. The nucleocapsid (N) protein of the virus serves as a primary target for antibody response during CoV2 infections, making it a potential candidate for COVID-19 detection. This study aims to prepare and evaluate the linear epitopes of the N protein for serodiagnosis of COVID-19 infection.

Methods

The linear epitope of the N protein gene was identified using ABCpred, BCpred, and IEDB. These epitopes were subsequently amplified by RT-PCR, cloned, and expressed in soluble form in the E. coli BL21 strain. The recombinant protein was purified using the Ni-NTA column. The reactivity of purified N protein with sera from SARS-CoV-2 patients was analyzed using an ELISA assay.

Results

Sequencing analysis demonstrated the successful cloning of the linear epitopes of the N protein into the PET-28a vector, along with an n-terminal His-tag fusion. The recombinant protein was produced in E. coli BL21 and purified with a Ni-NTA column. The analysis demonstrated that the N protein linear epitopes were expressed in a soluble form and appeared as a 50 kDa band in the SDS-PAGE. Examination for the reactivity of the purified N protein with the COVID-19 patient's sera by ELISA revealed that the N protein recognizes the infection with high sensitivity and specificity.

Conclusion

The results of this study indicated that linear epitopes of the SARS-CoV-2 N protein are highly immunogenic and could be exploited for serodiagnosis of infection in patients suspected of COVID-19 infection.

Potential Usefulness of IgA for the Early Detection of SARS-CoV-2 Infection: Comparison With IgM

Serological testing can be a powerful complementary approach to achieve timely diagnosis of severe acute respiratory coronavirus 2 (SARS-CoV-2) infection, along with nucleic acid detection. Immunoglobulin (Ig) A antibodies are less frequently utilized to detect SARS-CoV-2 infection than IgM and IgG antibodies, even though IgA antibodies play an important role in protective immunity against SARS-CoV-2. This review discusses the differences in kinetics and assay performance between IgA and IgM antibodies and the factors influencing antibody responses. It highlights the potential usefulness of analyzing IgA antibodies for the early detection of SARS-CoV-2 infection. The early appearance of IgA and the high sensitivity of IgA-based immunoassays can aid in diagnosing coronavirus disease 2019. However, because of cross-reactivity, it is important to recognize the only moderate specificity of the early detection of SARS-CoV-2 IgA antibodies against spike antigens. Either the analysis of antibodies targeting the nucleocapsid antigen or a combination of antibodies against the nucleocapsid and spike antigens may strengthen the accuracy of serological evaluation.

Does coronavirus disease 2019 history alone increase the risk of postoperative pulmonary complications after surgery? Prospective observational study using serology assessment

BACKGROUND

Concern exists about the increasing risk of postoperative pulmonary complications in patients with a history of coronavirus disease 2019 (COVID-19).

OBJECTIVE

We conducted a prospective observational study that compared the incidence of postoperative pulmonary complications in patients with and without a history of COVID-19.

METHODS

From August 2022 to November 2022, 244 adult patients undergoing major non-cardiac surgery were enrolled and allocated either to history or no history of COVID-19 groups. For patients without a history of confirming COVID-19 diagnosis, we tested immunoglobulin G to nucleocapsid antigen of SARS-CoV-2 for serology assessment to identify undetected infection. We compared the incidence of postoperative pulmonary complications, defined as a composite of atelectasis, pleural effusion, pulmonary edema, pneumonia, aspiration pneumonitis, and the need for additional oxygen therapy according to a COVID-19 history.

RESULTS

After excluding 44 patients without a COVID-19 history who were detected as seropositive, 200 patients were finally enrolled in this study, 100 in each group. All subjects with a COVID-19 history experienced no or mild symptoms during infection. The risk of postoperative pulmonary complications was not significantly different between the groups according to the history of COVID-19 (24.0% vs. 26.0%; odds ratio, 0.99; 95% confidence interval, 0.71-1.37; P-value, 0.92). The incidence of postoperative pulmonary complications was also similar (27.3%) in excluded patients owing to being seropositive.

CONCLUSION

Our study showed patients with a history of no or mild symptomatic COVID-19 did not show an increased risk of PPCs compared to those without a COVID-19 history. Additional precautions may not be needed to prevent PPCs in those patients.

An Unconventional Immunosensor for Biomolecule Detection via Nonspecific Gold Nanoparticle-Antibody Interactions

Immunogold, that is, gold nanoparticles (AuNPs) conjugated with biomolecules such as antibodies and peptides, have been widely used to construct sandwiched immunosensors for biodetection. Two main challenges in these immunoassays are difficulties in finding and validating a suitable antibody, and the nonspecific interaction between the substrate and immunogold, which lowers the detection sensitivity and even causes false results. To avoid these issues, we took advantage of the nonspecific interaction between AuNPs and capture antibodies and proposed a new sensing mechanism. That is, after the capture of analyte targets by the capture antibodies on the substrate, AuNPs of certain chemical functionality would preferably bind to the free capture antibodies. Consequently, the amount of deposited AuNPs will inversely depend on the concentration of the analytes. As a proof-of-concept, we designed a mass-based sensor where anti-IgG antibodies were coated on a quartz crystal microbalance substrate. After IgG was introduced, tannic acid-capped AuNPs were applied to bind with the free anti-IgG antibody molecules. A frequency change (Δf) of the quartz substrate was induced by the increased mass loading. To further amplify the loading mass, an Ag enhancer solution was added, and Ag growth was catalyzed by the bound AuNPs. The Δf response showed a concentration-dependent decrease when increasing IgG concentration with a detection limit of 2.6 ng/mL. This method relies on the nonspecific interaction between AuNPs and anti-IgG antibodies to realize sensitive detection of IgG and eliminates the use of detection antibodies. The concept is an alternative to many existing immunoassay technologies.

Molecular Interactions Leading to Advancements in the Techniques for COVID-19 Detection: A Review

Since 2019 the world has been in a combat with the highly contagious disease COVID-19 which is caused by the rapid transmission of the SARS-CoV-2 virus (severe acute respiratory syndrome coronavirus 2). Detection of this disease in an early stage helps to control its spread and management. To combat this epidemic with one-time effective medication, improved quick analytical procedures must be developed and validated. The requirement for accurate and precise analytical methods for the diagnosis of the virus and antibodies in infected patients has been a matter of concern. The global impact of this virus has motivated scientists and researchers to investigate and develop various analytical diagnostic techniques. This review includes the study of standard methods which are reliable and accredited for the analytical recognition of the said virus. For early detection of SARS-CoV-2 RNA, RT-PCR (Real-time reverse transcriptase-polymerase chain reaction) is an accurate method among other methods and, thus, considered as the "gold standard" technique. Here, we outline the most extensively used analytical methods for diagnosing COVID-19, along with a brief description of each technique and its analytical aspects/perspective.

Validation of a plasmonic-based serology biosensor for veterinary diagnosis of COVID-19 in domestic animals

The coronavirus disease 2019 (COVID-19) pandemic recently demonstrated the devastating impact on public health, economy, and social development of zoonotic infectious diseases, whereby viruses jump from animals to infect humans. Due to this potential of viruses to cross the species barrier, the surveillance of infectious pathogens circulation in domestic and close-to-human animals is indispensable, as they could be potential reservoirs. Optical biosensors, mainly those based on Surface Plasmon Resonance (SPR), have widely demonstrated its ability for providing direct, label-free, and quantitative bioanalysis with excellent sensitivity and reliability. This biosensor technology can provide a powerful tool to the veterinary field, potentially being helpful for the monitoring of the infection spread. We have implemented a multi-target COVID-19 serology plasmonic biosensor for the rapid testing and screening of common European domestic animals. The multi-target serological biosensor assay enables the detection of total SARS-CoV-2 antibodies (IgG + IgM) generated towards both S and N viral antigens. The analysis is performed in less than 15 min with a low-volume serum sample (<20 μL, 1:10 dilution), reaching a limit of detection of 49.6 ng mL-1. A complete validation has been carried out with hamster, dog, and cat sera samples (N = 75, including 37 COVID-19-positive and 38 negative samples). The biosensor exhibits an excellent diagnostic sensitivity (100 %) and good specificity (71.4 %) for future application in veterinary settings. Furthermore, the biosensor technology is integrated into a compact, portable, and user-friendly device, well-suited for point-of-care testing. This study positions our plasmonic biosensor as an alternative and reliable diagnostic tool for COVID-19 serology in animal samples, expanding the applicability of plasmonic technologies for decentralized analysis in veterinary healthcare and animal research.

Investigation of IL-6 serum level in COVID-19 patients with positive COVID-19 IgG/IgM antibody titers to check inflammation and disease progression

OBJECTIVE

The SARS-CoV-2, the cause of coronavirus disease 2019 (COVID-19), leads to severe pathogenicity and high mortality among different communities around the world. Therefore, it is important to understand the mechanisms of virus pathogenesis and the immune system's response to prevent the further spread of this virus. This study was aimed to evaluate the relationship between the serum level of interleukin 6 and positive IgG and IgM antibody levels in patients with COVID-19 to investigate inflammation and disease progression.

METHODS & MATERIALS

In this study, 10 ml of EDTA blood samples were taken from 414 COVID-19 patients. Then, the plasma was separated and the levels of IgM and IgG antibodies and interleukin 6 cytokine were evaluated by ELISA and chemiluminescence methods, respectively. All data were analyzed by SPSS 22 and GraphPad prism 9 software at the significance level of P < 0.05.

RESULTS

The results of this study showed that there was no significant difference in the expression of IgM and IgG antibodies between men and women. Also, a significant increase in the mean expression of IL-6 was observed only in the high concentration range (100-〉1000 pg/ml) in men compared to women (P < 0.001). In addition, in the female population, all three concentration ranges (negative, medium, and high) of IL-6 have the highest correlation with high titers (>10 U/ml) of IgM and IgG antibodies. While, in men, all three concentration ranges of IL-6 had the highest correlation with > 10 U/ml IgM antibody titers, but in the case of IgG, the highest correlation between different concentrations of IL-6 was observed with the negative or moderate titers of this antibody and there was an inverse relationship with the high titers of IgG (>10 U/ml).

CONCLUSION

As a result, the relationship between different serum levels of cytokine IL-6 with different titers of IgM and IgG antibodies was observed in both male and female populations. In general, it can be concluded that the correlation between different concentrations of IL-6 with different IgM titers was similar in both men and women, but in the case of different IgG titers, this correlation was higher in women than men.

Investigating the diagnostic and prognostic value of anti-SARS-CoV-2 Spike IgG/IgM ELISA tests in patients infected with coronavirus Delta variant

Aim

This study aimed to investigate the diagnostic and prognostic value of anti-severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) Spike IgG/IgM antibodies in patients infected with coronavirus Delta variant.

Methods

This analytical observational study included 270 unvaccinated patients (aged ≥18 years) diagnosed with coronavirus disease 2019 (COVID-19) Delta variant who referred to Emergency Department of our hospital. The serum levels of anti-SARS-CoV-2 Spike IgG and IgM were measured by indirect ELISA. Main measured outcomes included anti-SARS-CoV-2 Spike IgG and IgM, chest computed tomography (CT) severity score, clinical and laboratory findings which were prospectively evaluated throughout the study period.

Results

The IgM levels in critical patients were significantly higher than non-critical patients (p<0.05). But the mean level of IgG in critical patients was not significantly different from its level in non-critical patients (p>0.05). However, a significant positive correlation was observed between the levels of both antibodies and chest CT severity score (p<0.0001); this implies that their levels may reflect the degree of lung involvement. The IgM level on 15th-16th days after symptoms onset was significantly associated with the hazard of death even after adjusting for all other factors (adjusted HR (95%CI):1.28(1.014_1.63), p=0.03), whereas IgG was not (p>0.05). The survival probability among patients with IgM level ≥8.67 RU/ml (34.2%) was significantly lower than those with IgM level <8.67 RU/ml (99.5%, p=0.0001).

Conclusions

Anti-SARS-CoV-2 Spike IgM antibody was significantly associated with the disease severity and risk of death in unvaccinated patients infected with coronavirus Delta variant. However, further large-scale investigations on diverse infected populations are required to precisely determine the diagnostic/prognostic value of these antibodies.

Advances and Challenges in SARS-CoV-2 Detection: A Review of Molecular and Serological Technologies

The urgent need for accurate COVID-19 diagnostics has led to the development of various SARS-CoV-2 detection technologies. Real-time reverse transcriptase polymerase chain reaction (RT-qPCR) remains a reliable viral gene detection technique, while other molecular methods, including nucleic acid amplification techniques (NAATs) and isothermal amplification techniques, provide diverse and effective approaches. Serological assays, detecting antibodies in response to viral infection, are crucial for disease surveillance. Saliva-based immunoassays show promise for surveillance purposes. The efficiency of SARS-CoV-2 antibody detection varies, with IgM indicating recent exposure and IgG offering prolonged detectability. Various rapid tests, including lateral-flow immunoassays, present opportunities for quick diagnosis, but their clinical significance requires validation through further studies. Challenges include variations in specificity and sensitivity among testing platforms and evolving assay sensitivities over time. SARS-CoV-2 antigens, particularly the N and S proteins, play a crucial role in diagnostic methods. Innovative approaches, such as nanozyme-based assays and specific nucleotide aptamers, offer enhanced sensitivity and flexibility. In conclusion, ongoing advancements in SARS-CoV-2 detection methods contribute to the global effort in combating the COVID-19 pandemic.

A Comprehensive Study of Cellular and Humoral Immunity in Dogs Naturally Exposed to SARS-CoV-2

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) was identified as the causal agent behind coronavirus disease 2019 (COVID-19), a disease declared pandemic in 2020. Because of the zoonotic origin of SARS-CoV-2 and the close contact kept by domestic dogs with their owners, it became imperative to understand the role of dogs in the epidemiology of the disease and in the virus transmission. In the present study, we determined the presence of virus and described the long-term immune effects of SARS-CoV-2 in 24 dogs exposed to SARS-CoV-2 in the domestic environment. Our findings highlight that only a subset of dogs, naturally exposed to SARS-CoV-2, exhibit a humoral response to the new virus (close to 17% had IgM antibodies and close to 33% has IgG antibodies). We identified for the first time SARS-CoV-2-specific IFN-γ-secreting cells in dogs (approximately in half of our dogs). While 56% of dogs maintained humoral response 8 months, only 22% of dogs maintained cellular response after 4 and 8 months. Although some alterations in blood parameters and proinflammatory cytokines were described, there was no evidence indicating an exacerbated cytokine release process. Considering that none of the animals enrolled in this study showed viral shedding and presented specific immune responses, it is reasonable to propose that the canine immune system in certain companion dogs is effective at blocking the negative effects of viral replication, thereby suggesting that dogs would not be potential transmitters of this pathogen to the other dogs or other species and could aid in promoting collective immunity.

Detection methods and dynamic characteristics of specific antibodies in patients with COVID-19: A review of the early literature

Coronavirus disease 2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has caused a global pandemic. Early and accurate diagnosis and quarantine remain the most effective mitigation strategy. Although reverse transcriptase polymerase chain reaction (RT-qPCR) is the gold standard for COVID-19 diagnosis, recent studies suggest that nucleic acids were undetectable in a significant number of cases with clinical features of COVID-19.Serological assays for SARS-CoV-2 play a role in diagnosis of COVID-19, in understanding viral epidemiology and screening convalescent sera for therapeutic and prophylactic purposes, to better understand the immune response to the virus, and to assess the degree and duration of the response of specific antibodies. In this article, we retrieved PubMed, Embase, China National Knowledge Infrastructure (CNKI) and WEB OF SCI databases for articles and reviews published before December 1, 2022. Using "IgM, IgG,IgA, neutralizing antibody, specific antibody,COVID-19, dynamic characteristics" as keywords, and comprehensively reviewed on their basis.According to the authors' criteria, only articles deemed relevant were included, covering original articles, case series, experimental studies, reviews, and case reports. Articles on performance evaluation, opinion pieces, and technical issues were excluded. From the onset of COVID-19 symptoms, the median time of seroconversion was 11 days for immunoglobulin A (IgA), the median time of peak antibody titer was 23 (16-30 days) for IgA.Immunoglobulin M (IgM) is detected prior to immunoglobulin G (IgG), peaking 2-5 weeks post symptom onset and detectable for a minimum of 8 weeks in the immunocompetent.Neutralizing antibodies were earliest detectable within 6-7 days following disease onset, with levels increasing until days 14-22 before levelling and then decreasing, but titres were lower in clinically mild disease. Different clinical types of patients showed different antibody responses to SARS-CoV-2, with severe COVID-19 patients > non-severe COVID-19 patients > asymptomatic infected persons, but no difference in the early stage of the disease. Usually, IgM and IgA antibodies are detectable earlier than IgG antibodies.IgA antibodys plays an important role in local mucosal immunity.Detection of IgM antibodies tends to indicate recent exposure to SARS-CoV-2, whereas the detection of COVID-19 IgG antibodies indicates virus exposure some time ago. The detection of potent neutralizing antibodies in convalescent plasma is important in the context of development of therapeutics and vaccines.With the emergence of immune escape variants of SARS-CoV-2, humoral immunity is being challenged, and a detailed understanding of Specific antibodies is critical to guide vaccine design strategies and antibody-mediated therapies.

Immunoglobulin A response to SARS-CoV-2 infection and immunity

The novel coronavirus disease (COVID-19) and its infamous "Variants" of the etiological agent termed Severe Acute Respiratory Syndrome Corona Virus 2 (SARS-CoV-2) has proven to be a global health concern. The three antibodies, IgA, IgM, and IgG, perform their dedicated role as main workhorses of the host adaptive immune system in virus neutralization. Immunoglobulin-A (IgA), also known as "Mucosal Immunoglobulin", has been under keen interest throughout the viral infection cycle. Its importance lies because IgA is predominant mucosal antibody and SARS family viruses primarily infect the mucosal surfaces of human respiratory tract. Therefore, IgA can be considered a diagnostic and prognostic marker and an active infection biomarker for SARS CoV-2 infection. Along with molecular analyses, serological tests, including IgA detection tests, are gaining ground in application as an early detectable marker and as a minimally invasive detection strategy. In the current review, it was emphasized the role of IgA response in diagnosis, host defense strategies, treatment, and prevention of SARS-CoV-2 infection. The data analysis was performed through almost 100 published peer-reviewed research reports and comprehended the importance of IgA in antiviral immunity against SARS-CoV-2 and other related respiratory viruses. Taken together, it is concluded that secretory IgA- Abs can serve as a promising detection tool for respiratory viral diagnosis and treatment parallel to IgG-based therapeutics and diagnostics. Vaccine candidates that target and trigger mucosal immune response may also be employed in future dimensions of research against other respiratory viruses.

Advances in nanobiosensors during the COVID-19 pandemic and future perspectives for the post-COVID era

The unprecedented threat of the highly contagious virus, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), which causes exponentially increased infections of coronavirus disease 2019 (COVID-19), highlights the weak spots of the current diagnostic toolbox. In the midst of catastrophe, nanobiosensors offer a new opportunity as an alternative tool to fill a gap among molecular tests, rapid antigen tests, and serological tests. Nanobiosensors surpass the potential of antigen tests because of their enhanced sensitivity, thus enabling us to see antigens as stable and easy-to-access targets. During the first three years of the COVID-19 pandemic, a substantial number of studies have reported nanobiosensors for the detection of SARS-CoV-2 antigens. The number of articles on nanobiosensors and SARS-CoV-2 exceeds the amount of nanobiosensor research on detecting previous infectious diseases, from influenza to SARS-CoV and MERS-CoV. This unprecedented publishing pace also implies the significance of SARS-CoV-2 and the present pandemic. In this review, 158 studies reporting nanobiosensors for detecting SARS-CoV-2 antigens are collected to discuss the current challenges of nanobiosensors using the criteria of point-of-care (POC) diagnostics along with COVID-specific issues. These advances and lessons during the pandemic pave the way for preparing for the post-COVID era and potential upcoming infectious diseases.

A Correlation Study to Comprehend the SAR-CoV-2 Viral Load, Antiviral Antibody Titer, and Severity of COVID-19 Symptoms Post-infection Amongst the Vaccinated Population in Kamrup District of As sam, Northeast India

BACKGROUND

As per the recommendation of the United States Food and Drug Administration, more research is needed to determine the antibody titer against COVID-19 vaccination.

OBJECTIVE

The study aimed to understand the relationship between the antibody titer to the demographics, infection severity, and cycle threshold (CT) values of confirmed COVID-19 patients.

METHODS

Initially, we obtained consent from 185 populations and included sixty RT-PCRpositive COVID-19 patients from Kamrup District in the Northeast State of Assam, India. The vaccination status was recorded and tested for the level of serum immunoglobulin (IgG). The CT values, gender, and clinical symptoms-based scoring (CSBS) correlated with their IgG value.

RESULTS

Around 48% of participants gained an antibody titer more than the threshold value and showed CT values between 18-25. Moreover, the maximum distributed score above the average was found between the CT values 18-25.

CONCLUSION

The IgG titer value differs significantly amongst the vaccinated population, which may depend upon their genetic and demographic variability.

Behavior of Coronavirus pandemic in Yemen: practical experience review

COVID-19 is caused by a coronavirus called SARS-CoV-2, which spread, all over the world. The virus is spreading very easily and sustainably between people. Information from the ongoing pandemic disease suggests that this virus is spreading more efficiently than influenza. Older adults and people who have severe underlying medical conditions like heart or lung disease or diabetes seem to be at higher risk for developing more serious complications from COVID-19 illness. Coronavirus constantly changes through mutation. When a virus has one or more new mutation, it has called a variant of concern. There is no data from Yemen to show what type of coronavirus variant is spread in Yemen. We believe it is a unique situation where almost all people have been affected by the coronavirus. We tested the cardiac center workers and we found all of them have positive results. No severe symptoms among our staff were reported and many of them suffered from mild to moderate symptoms, which does not need admission to the hospital. Young age among this worker sample may explain the mild severity of COVID-19 infection detected; another explanation is the frequent exposure to viral infection in Yemen and the type of coronavirus variant in Yemen. We conducted this review to describe the current situation and our experience during the pandemic and further studies are needed to identify the exact variant in Yemen and the immunity response for this coronavirus variant in the Yemeni Society.

Hematological, inflammatory, and novel biomarkers assessment as an eminent strategy for clinical management of COVID-19

BACKGROUND

Different biomarkers have been suggested as novel biomarkers of coronavirus disease 2019 (COVID-19) theragnosis. With the aim of having a better clinical management of COVID-19, we decided to determine the relationship between hematological, inflammatory, and novel biomarkers with severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) immunoglobulin (Ig)M and IgG antibodies.

METHODS

Blood samples from 127 confirmed COVID-19 patients aged 11-84 years old were collected and tested for SARS-CoV-2 IgM and IgG antibodies alongside with hematological, inflammatory, and novel biomarkers. The Spearman correlation test was utilized to analyze the correlation between these biomarkers with SARS-CoV-2 IgM and IgG antibodies.

RESULTS

The SARS-CoV-2 IgM antibody significantly correlated with erythrocyte sedimentation rate (ESR) (r = 0.329, p = 0.000), C-reactive protein (CRP) (r = 0.459, p = 0.000), interleukin (IL)-6 (r = 0.345, p = 0.000), IL-8 (r = 0.263, p = 0.003), neutrophil to lymphocyte ratio (NLR) (r = 0.182, p = 0.040), derived NLR (dNLR) (r = 0.197, p = 0.026), neutrophil to monocyte ratio (NMR) (r = 0.184, p = 0.038), and CRP to lymphocyte ratio (CLR) (r = 0.495, p = 0.000). Also, we find significant correlation between SARS-CoV-2 IgG antibody with hemoglobin (Hb) (r = -0.257, p = 0.004), hematocrit (Hct) (r = -0.227, p = 0.010), mean corpuscular Hb concentration (MCHC) (r = -0.212, p = 0.017), lymphocyte count (r = -0.211, p = 0.017), platelet count (r = 0.179, p = 0.044), ESR (r = 0.461, p = 0.000), CRP (r = 0.344, p = 0.000), IL-6 (r = 0.178, p = 0.046), IL-8 (r = 0.237, p = 0.007), platelet to lymphocyte ratio (PLR) (r = 0.295, p = 0.001), and CLR (r = 0.376, p = 0.000).

CONCLUSION

Hematological biomarkers (Hb, Hct, MCHC, lymphocyte count, and platelet count), inflammatory biomarkers (ESR, CRP, IL-6, and IL-8), and novel biomarkers (dNLR, NLR, NMR, PLR, and CLR) are valuable indicators for clinical management of COVID-19.

Significance of Anti-COVID-IgA antibody response in COVID-19 breakthrough infection in vaccinated patients - a single-centered study from Pakistan

An increasing number of breakthrough-COVID-19-vaccinated individuals are being reported across the world. Humoral immunity has a crucial role in combating infection. In this study, we aimed to assess the importance of anti-COVID-S1-IgA and anti-COVID-NP-IgA in confirmed COVID-19 after vaccination (breakthrough infection group). Blood samples were collected from the breakthrough infection group within one week of breakthrough infections (n = 34). A second sample was also collected after 4 to 8 weeks (n = 27). Blood samples of healthy individuals (n = 29) were collected 4-8 weeks after the completion of vaccination. Anti-COVID-S1-IgA and anti-COVID-NP-IgA were detected by ELISA. Statistical analysis was performed using IBM SPSS version 24. In this study, we found a higher positivity rate for anti-COVID-S1-IgA in the breakthrough infection group (70% vs. 28% in healthy individuals). Anti-COVID-NP-IgA was not found in the control group (11% in the breakthrough infection group vs. 0 in healthy individuals). In the breakthrough-infected group, the positivity rate of anti-COVID-NP-IgA decreased significantly (median titers 16.9 IU/ml decreased to 4.2 IU/ml) p = 0.001), while anti-COVID-S1-IgA increased over a period of 4-8 weeks (9.35-16.35 IU/ml). Importantly, IgA response to both COVID-19 NP and S1 antigens was not found in 13 patients at initial testing. The findings of this study show that serum IgA may have a role both in breakthrough infections and also in the prevention of severe infection. Sluggish anti-COVID-19-IgA antibody response may be responsible for the occurrence of COVID-19 infection in breakthrough infection. On the other hand, more sustained anti-COVID-19-S1-IgA over a longer period of time may have a role in preventing these patients from severe infections and hospitalization. However, a study on a larger sample size including patients with severe disease after vaccination is required to prove this hypothesis. To the best of our knowledge, this is the first study reporting the importance of serum IgA in breakthrough-infected patients from our region.

The Serum ACE2, CTSL, AngII, and TNFα Levels after COVID-19 and mRNA Vaccines: The Molecular Basis

BACKGROUND

The SARS-CoV-2 virus as well as the COVID-19 mRNA vaccines cause an increased production of proinflammatory cytokines.

AIM

We investigated the relationship between ACE2, CTSL, AngII, TNFα and the serum levels of IL-6, IL-10, IL-33, IL-28A, CD40L, total IgM, IgG, IgA and absolute count of T- and B-lymphocytes in COVID-19 patients, vaccinees and healthy individuals.

METHODS

We measured the serum levels ACE2, AngII, CTSL, TNFα and humoral biomarkers (CD40L, IL-28A, IL-10, IL-33) by the ELISA method. Immunophenotyping of lymphocyte subpopulations was performed by flow cytometry. Total serum immunoglobulins were analyzed by the turbidimetry method.

RESULTS

The results established an increase in the total serum levels for ACE2, CTSL, AngII and TNFα by severely ill patients and vaccinated persons. The correlation analysis described a positive relationship between ACE2 and proinflammatory cytokines IL-33 (r = 0.539) and CD40L (r = 0.520), a positive relationship between AngII and CD40L (r = 0.504), as well as between AngII and IL-33 (r = 0.416), and a positive relationship between CTSL, total IgA (r = 0.437) and IL-28A (r = 0.592). Correlation analysis confirmed only two of the positive relationships between TNFα and IL-28A (r = 0.491) and CD40L (r = 0.458).

CONCLUSIONS

In summary, the findings presented in this study unveil a complex web of interactions within the immune system in response to SARS-CoV-2 infection and vaccination.

The burden of the coronavirus disease 2019 virus infection in Burkina Faso: Results from a World Health Organization UNITY population-based, age-stratified sero-epidemiological investigation

BACKGROUND

This study aimed to estimate the anti-SARS-CoV-2 antibody seroprevalence in the general population of Bobo-Dioulasso and Ouagadougou (Burkina Faso).

METHODS

We collected from March to April 2021 blood samples from randomly selected residents in both main cities based on the World Health Organization (WHO) sero-epidemiological investigations protocols and tested them with WANTAI SARS-CoV-2 total antibodies enzyme-linked immunosorbent assay (ELISA) kits intended for qualitative assessment. We also recorded participants' socio-demographic and clinical characteristics and information on exposure to SARS-CoV-2. Data were analysed with descriptive and comparative statistics.

RESULTS

We tested 5240 blood samples collected between 03 March and 16 April 2021. The overall test-adjusted seroprevalence for SARS-CoV-2 antibodies was (67.8% [95% CI 65.9-70.2]) (N = 3553/3982). Seroprevalence was highest among participants aged 15-18 years old (74.2% [95% CI 70.5-77.5]) (N = 465/627), compared with those aged 10-14 years old (62.6% [95% CI 58.7-66.4]) (N = 395/631), or those over 18 (67.6% [95% CI 66.2-69.1]) (N = 2693/3982). Approximately 71.0% (601/860) of participants aged 10-18 years old who tested positive for SARS-CoV-2 antibodies experienced no clinical COVID-19 symptoms in the weeks before the survey, compared with 39.3% (1059/2693) among those aged over 18 years old.

CONCLUSION

This study reports the results of the first known large serological survey in the general population of Burkina Faso. It shows high circulation of SARS-CoV-2 in the two cities and a high proportion of asymptomatic adolescents. Further studies are needed to identify the SARS-CoV-2 variants and to elucidate the factors protecting some infected individuals from developing clinical COVID-19.

Distinct anti-NP, anti-RBD and anti-Spike antibody profiles discriminate death from survival in COVID-19

Introduction

Infection by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) induces rapid production of IgM, IgA, and IgG antibodies directed to multiple viral antigens that may have impact diverse clinical outcomes.

Methods

We evaluated IgM, IgA, and IgG antibodies directed to the nucleocapsid (NP), IgA and IgG to the Spike protein and to the receptor-binding domain (RBD), and the presence of neutralizing antibodies (nAb), in a cohort of unvaccinated SARS-CoV-2 infected individuals, in the first 30 days of post-symptom onset (PSO) (T1).

Results

This study included 193 coronavirus disease 2019 (COVID-19) participants classified as mild, moderate, severe, critical, and fatal and 27 uninfected controls. In T1, we identified differential antibody profiles associated with distinct clinical presentation. The mild group presented lower levels of anti-NP IgG, and IgA (vs moderate and severe), anti-NP IgM (vs severe, critical and fatal), anti-Spike IgA (vs severe and fatal), and anti-RBD IgG (vs severe). The moderate group presented higher levels of anti-RBD IgA, comparing with severe group. The severe group presented higher levels of anti-NP IgA (vs mild and fatal) and anti-RBD IgG (vs mild and moderate). The fatal group presented higher levels of anti-NP IgM and anti-Spike IgA (vs mild), but lower levels of anti-NP IgA (vs severe). The levels of nAb was lower just in mild group compared to severe, critical, and fatal groups, moreover, no difference was observed among the more severe groups. In addition, we studied 82 convalescent individuals, between 31 days to 6 months (T2) or more than 6 months (T3), PSO, those: 12 mild, 26 moderate, and 46 severe plus critical. The longitudinal analyzes, for the severe plus critical group showed lower levels of anti-NP IgG, IgA and IgM, anti-Spike IgA in relation T3. The follow-up in the fatal group, reveals that the levels of anti-spike IgG increased, while anti-NP IgM levels was decreased along the time in severe/critical and fatal as well as anti-NP IgG and IgA in several/critical groups.

Discussion

In summary, the anti-NP IgA and IgG lower levels and the higher levels of anti-RBD and anti-Spike IgA in fatal compared to survival group of individuals admitted to the intensive care unit (ICU). Collectively, our data discriminate death from survival, suggesting that anti-RBD IgA and anti-Spike IgA may play some deleterious effect, in contrast with the potentially protective effect of anti-NP IgA and IgG in the survival group.

The combination of circulating IgM and geriatric nutritional risk index predicts the prognostic of hepatocellular carcinoma patients who underwent immune checkpoint inhibitors

OBJECTIVE

Immune checkpoint inhibitors (ICIs) have shown promise in hepatocellular carcinoma (HCC) treatment. With the increasing use of ICIs in cancer treatment, identifying biomarkers that can predict the prognosis of patients receiving ICIs is of great importance. We aimed to investigate the potential of circulating immunoglobulins and the combination of Geriatric Nutritional Risk Index (GNRI) with IgM to predict prognosis in patients with HCC who received ICIs.

METHODS

Clinical and pathological data were collected from 101 patients with HCC who were administered ICIs and underwent circulating immunoglobulin testing between January 2018 and December 2021. Survival analysis, Cox regression analysis, and nomogram construction were performed to evaluate the prognostic value of the indicators.

RESULTS

In the preliminary survival analysis, we observed a significant correlation between patient prognosis and IgM levels. Patients with low IgM had shorter survival times. Upon combining the GNRI with IgM, patients with low GNRI and IgM levels had shorter progression-free survival (PFS) and overall survival (OS) (P < 0.001). Additionally, GNRI-IgM had the highest area under the curve (AUC) and was identified as an independent prognostic marker in this study. The C-indices of the nomograms for PFS and OS were 0.797 (0.734-0.860) and 0.827 (0.778-0.876), respectively.

CONCLUSIONS

IgM was significantly associated with the prognosis of patients with HCC receiving ICIs. The combination of the GNRI with IgM provided superior prognostic value and served as an independent prognostic marker. The GNRI-IgM can be used to effectively identify patients with HCC who are responsive to ICIs.

Immunological changes in a cohort of COVID-19 survivors: Mansoura University experience

Background: COVID-19 is a global pandemic that has affected millions of people all over the world since 2019. Infection with COVID-19 initiates a humoral immune response that produces antibodies against specific viral antigens, which in turn is supposed to provide immunity against reinfection for a period of time. The aim of this research was to study the kinetics of IgM and IgG antibodies against SARS-CoV-2. Methods: One hundred and seventeen post-COVID-19 participants were enrolled in the study.  Qualitative assessment of IgM and IgG antibodies over six months (three visits) post recovery was conducted. Results: The current study revealed a significant reduction in IgM and IgG titers between the first and second visits (p <0.001). After six months, the antibody titer had declined by 78.8% from the first visit for IgM and by 49.2% for IgG antibodies. Regarding younger age and male sex, statistically significant persistence of IgM antibodies was noticed at the six months follow up. Also, statistically significant persistent IgG immunity was found in male patients and diabetics by the end of the six months follow up. Conclusions: We observed a significant waning of IgM and IgG titers over a period of six months follow up.. The persistence of positive IgM and IgG antibodies by the end of six months was variable due to differences in age, gender and presence of diabetes mellitus.

Unveiling a New Perspective on Distinguishing Omicron Breakthrough Cases and Postimmune COVID-19-Naive Individuals: Insights from Antibody Profiles

In the situation of mass vaccination against COVID-19, few studies have reported on the early kinetics of specific antibodies (IgG/IgM/IgA) of vaccine breakthrough cases. There is still a lack of epidemiological evidence about the value of serological indicators in the auxiliary diagnosis of COVID-19 infection, especially when the nucleic acid results were undetectable. Omicron breakthrough cases post-inactivated vaccination (n = 456) and COVID-19-naive individuals with two doses of inactivated vaccination (n = 693) were enrolled. Blood samples were collected and tested for SARS-CoV-2 antibody levels based on the magnetic chemiluminescence enzyme immunoassay. Among Omicron breakthrough cases, the serum IgG antibody level was 36.34 Sample/CutOff (S/CO) (95% confidence interval [CI], 31.89 to 40.79) in the acute phase and 88.45 S/CO (95% CI, 82.79 to 94.12) in the recovery phase. Serum IgA can be detected in the first week post-symptom onset (PSO) and showed an almost linear increase within 5 weeks PSO. Compared with those of breakthrough cases, IgG and IgA titers of the postimmune group were much lower (4.70 S/CO and 0.46 S/CO, respectively). Multivariate regression showed that serum IgG and IgA levels in Omicron breakthrough cases were mainly affected by the weeks PSO (P < 0.001). Receiver operating characteristic ROC0 curve analysis showed that the area under the curve (AUC) was 0.744 and 0.806 when the cutoff values of IgA and IgG were 1 S/CO and 15 S/CO, respectively. Omicron breakthrough infection can lead to a further increase in IgG and IgA levels relative to those of the immunized population. When nucleic acid real-time PCR was negative, we would use the kinetics of IgG and IgA levels to distinguish the breakthrough cases from the immunized population. IMPORTANCE This study fills a gap in the epidemiological evidence by investigating the value of serological indicators, particularly IgG and IgA levels, in the auxiliary diagnosis of COVID-19 infections when nucleic acid results are undetectable. The findings reveal that among Omicron breakthrough cases, both IgG and IgA antibody levels exhibit significant changes. Serum IgG levels increase during the acute phase and rise further in the recovery phase. Serum IgA can be detected as early as the first week post-symptom onset (PSO), showing a consistent linear increase within 5 weeks PSO. Furthermore, receiver operating characteristic (ROC) curve analysis demonstrates the potential of IgG and IgA cutoff values as diagnostic markers. The study's conclusion underscores the importance of monitoring IgG and IgA kinetics in distinguishing Omicron breakthrough cases from vaccinated individuals. These findings contribute to the development of more accurate diagnostic approaches and help inform public health strategies during the ongoing COVID-19 pandemic.

Casirivimab + imdevimab accelerates symptom resolution linked to improved COVID-19 outcomes across susceptible antibody and risk profiles

Severe, protracted symptoms are associated with poor outcomes in severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. In a placebo-controlled study of casirivimab and imdevimab (CAS + IMD) in persons at high risk of severe coronavirus disease 2019 (COVID-19; n = 3816), evolution of individual symptoms was assessed for resolution patterns across risk factors, and baseline SARS-CoV-2-specific antibody responses against S1 and N domains. CAS + IMD versus placebo provided statistically significant resolution for 17/23 symptoms, with greater response linked to absence of endogenous anti-SARS-CoV-2 immunoglobulin (Ig)G, IgA, or specific neutralizing antibodies at baseline, or high baseline viral load. Resolution of five key symptoms (onset days 3-5)-dyspnea, cough, feeling feverish, fatigue, and loss of appetite-independently correlated with reduced hospitalization and death (hazard ratio range: 0.31-0.56; P < 0.001-0.043), and was more rapid in CAS + IMD-treated patients lacking robust early antibody responses. Those who seroconverted late still benefited from treatment. Thus, highly neutralizing COVID-19-specific antibodies provided by CAS + IMD treatment accelerated key symptom resolution associated with hospitalization and death in those at high risk for severe disease as well as in those lacking early, endogenous neutralizing antibody responses.

Carbon-based biosensors: Next-generation diagnostic tool for target-specific detection of SARS-CoV-2 (COVID-19)

Severe acute respiratory syndrome-coronavirus-2 (SARS-CoV-2) was declared a global pandemic in 2020. Having rapidly spread around the globe, with the emergence of new variants, there is a crucial need to develop diagnostic kits for its rapid detection. Since it validated accuracy and reliability, the reverse transcription polymerase chain reaction (RT-PCR) test has been declared the gold standard for disease detection. However, despite its reliability, the requirement of specialized facilities, reagents, and duration of a PCR run limits its usage for rapid detection. There is thus a continuous increase in the design and development of rapid, point-of-care (PoC), and cost-effective diagnostic kits. In this review, we discuss the potential of carbon-based biosensors for target-specific detection of coronavirus disease 19 (COVID-19) and present an overview of investigation within the timeframe of the last four years (2019-2022), which have developed novel platforms using carbon nanomaterial-based approaches for viral detection. The approaches discussed offer rapid, accurate, and cost-effective strategies for COVID-19 detection for healthcare personnel and research workers.

Dynamics of SARS-CoV-2 seroprevalence during the first year of the COVID-19 pandemic in the Northeast region of Brazil

In this household-based seroepidemiological survey, we analyzed the dynamics of SARS-CoV-2 seroprevalence during the first year of the COVID-19 pandemic in Sergipe State, Northeast Brazil, the poorest region of the country. A total of 16,547 individuals were tested using a rapid IgM-IgG antibody test and fluorescence immunoassay (FIA). Seroprevalence rates were presented according to age, sex, and geographic region. A comparative analysis was performed between the results obtained in July 2020 (peak of the first wave), August - November 2020 (end of the first wave), and February - March 2021 (beginning of the second wave). Seroprevalence rates in the three phases were estimated at 9.3% (95% CI 8.5-10.1), 12.0% (95% CI 11.2-12.9) and 15.4% (95% CI 14.5-16.4). At the end of the first wave, there was a rise in seroprevalence in the countryside (p < 0.001). At the beginning of the second wave, we found an increase in seroprevalence among women (p < 0.001), adults aged 20 to 59 years (p < 0.001), and the elderly (p < 0.001). In this phase, we found an increase in estimates both in metropolitan areas and in the countryside (p < 0.001). This study showed an increase in SARS-CoV-2 seroprevalence over the first year of the pandemic, with approximately one in six people having anti-SARS-CoV-2 antibodies at the beginning of the second wave of COVID-19. Furthermore, our results suggest a rapid spread of COVID-19 from metropolitan areas to the countryside during the first months of the pandemic.

Case report: A case of epidermolysis bullosa acquisita with IgG and IgM anti-basement membrane zone antibodies relapsed after COVID-19 mRNA vaccination

We report a case of autoimmune bullous disease (AIBD) with IgG and IgM autoantibodies against epidermal basement membrane zone (BMZ), which showed recurrence of mucocutaneous lesions after coronavirus disease 2019 (COVID-19) mRNA vaccination. A 20-year-old Japanese woman with a 4-year history of epidermolysis bullosa acquisita (EBA) presented to our clinic. She noticed fever and rash on the same day and visited at our hospital 2 days later. Physical examination revealed blisters, erosions and erythema on the face, shoulder, back, upper arms, and lower lip. A skin biopsy from the forehead showed subepidermal blister. Direct immunofluorescence showed linear depositions of IgG, IgM, and C3c in the epidermal BMZ. By indirect immunofluorescence of 1M NaCl-split normal human skin, circulating IgG autoantibodies were bound to the dermal side of the split at 1:40 serum dilution, and circulating IgM antibodies were bound to the epidermal side of the spilt. After the increase of prednisolone dose to 15 mg/day, the mucocutaneous lesions resolved in a week. The present case is the first case of possible EBA with IgG and IgM anti-BMZ antibodies, in which the mucocutaneous lesions were recurred after COVID-19 mRNA vaccination. Clinicians should be aware that bullous pemphigoid-like AIBDs, including EBA and IgM pemphigoid, might be developed after COVID-19 mRNA vaccination.

Immunoglobulin G follow-up and immune response longevity analysis in SARS-CoV-2 convalescent patients and vaccinated individuals: A longitudinal analysis

BACKGROUND

Although the detection of immunoglobulin G (IgG) molecules has long been considered to be crucial for successful humoral immune defence against infections and harmful metabolites, it has become increasingly important in relation to SARS-CoV-2 research.

OBJECTIVE

To compare longitudinal changes in IgG titres in post-infection and post-vaccination Iraqi participants, and to estimate the protective benefits of the two principal vaccines used in Iraq.

METHODS

This quantitative study used samples from SARS-CoV-2 recovered patients (n= 75), those vaccinated with two doses of Pfizer or Sinopharm vaccine (n= 75), and healthy unvaccinated individuals (n= 50) who formed a control group. Participant ages (range 20-80 years) and sex (52.7% men, 47.3% females). An enzyme-linked immunosorbent assay was used to measure IgG.

RESULTS

IgG antibody levels peaked in the first month and tapered off in the following three months in both convalescent and vaccinated groups. The latter showed a significant decrease in IgG titres than in the convalescent group. Samples from the group given the mRNA vaccination that targeted spike (S) proteins might have a cross-reactivity between nucleocapsid (N) and spike (S) proteins.

CONCLUSIONS

Participants who had recovered from or who were vaccinated against SARS-CoV-2 exhibited a protective, persistent and durable humoral immune response for at least a month. This was more potent in the SARS-CoV-2 convalescent group compared to the vaccinated cohort. The IgG titres decayed faster after vaccination with Sinopharm than following the Pfizer-BioNTech vaccine.

Detection of Virus SARS-CoV-2 Using a Surface Plasmon Resonance Device Based on BiFeO3-Graphene Layers

Coronavirus disease (COVID-19) pandemic outbreak is being investigated by severe respirational syndrome coronavirus-2 (SARS-CoV-2) as a global health issue. It is crucial to propose sensitive and rapid coronavirus detectors. Herein, we propose a biosensor based on surface plasmon resonance (SPRE) for the detection of SARS-CoV-2 virus. To achieve improved sensitivity, a BiFeO3 layer is inserted between a metal (Ag) thin film and a graphene layer in the proposed SPRE device so that it has the structure BK7 prism/ Ag/ BiFeO3/ graphene/ analyte. It has been demonstrated that a small variation in the refractive index of the analyte can cause a considerable shift in the resonance angle caused by the remarkable dielectric properties of the BiFeO3 layer, which include a high index of refraction and low loss. The proposed device has shown an extremely high sensitivity of 293 deg/RIU by optimizing the thicknesses of Ag, BiFeO3, and the number of graphene sheets. The proposed SPRE-based sensor is encouraging for use in various sectors of biosensing because of its high sensitivity.

A false positive serology test of SARS‑CoV‑2 in a patient with Waldenström's macroglobulinemia: A case report

The serology test of SARS-CoV-2 is one of the critical assays to make a diagnosis of SARS-CoV-2 infection. The gold immunochromatography assay (GICA) is a common measure to test SARS-CoV-2 specific IgG and IgM. The sensitivity and specificity of the assay are ~>80%. It has been reported that the result of GICA could be compromised in various situations, such as auto-immune diseases, Kawasaki disease, pregnancy or other conditions. However, following the European Hematology Association's consensus statement on the management of Waldenström's Macroglobulinemia (WM) patients, serological tests for SARS-CoV-2 specific IgM should not be affected by the total IgM or paraprotein levels. The present study reports a patient with duplicate positive serology tests of SARS-CoV-2 which is hypothesized to be due to monoclonal IgM caused by WM.

Memory SARS-CoV-2 T-cell response in convalescent COVID-19 patients with undetectable specific IgG antibodies: a comparative study

Background

During the COVID-19 pandemic, a variable percentage of patients with SARS-CoV-2 infection failed to elicit humoral response. This study investigates whether patients with undetectable SARS-CoV-2 IgG are able to generate SARS-CoV-2 memory T cells with proliferative capacity upon stimulation.

Methods

This cross-sectional study was conducted with convalescent COVID-19 patients, diagnosed with a positive real-time PCR (RT-PCR) from nasal and pharyngeal swab specimens. COVID-19 patients were enrolled ≥3 months after the last PCR positive. Proliferative T-cell response after whole blood stimulation was assessed using the FASCIA assay.

Results

A total of 119 participants (86 PCR-confirmed COVID-19 patients and 33 healthy controls) were randomly filtered from an initial cohort. Of these 86 patients, 59 had detectable (seropositive) and 27 had undetectable (seronegative) SARS-CoV-2 IgG. Seropositive patients were subclassified as asymptomatic/mild or severe according to the oxygen supplementation requirement. SARS-CoV-2 CD3+ and CD4+ T cells showed significantly lower proliferative response in seronegative than in seropositive patients. The ROC curve analysis indicated that ≥ 5 CD4+ blasts/μL of blood defined a "positive SARS-CoV-2 T cell response". According to this cut-off, 93.2% of seropositive patients had a positive T-cell response compared to 50% of seronegative patients and 20% of negative controls (chi-square; p < 0.001).

Conclusions

This proliferative assay is useful not only to discriminate convalescent patients from negative controls, but also to distinguish seropositive patients from those with undetectable SARS-CoV-2 IgG antibodies. Memory T cells in seronegative patients are able to respond to SARSCoV-2 peptides, although at a lower magnitude than seropositive patients.

COVID-19 in early 2023: Structure, replication mechanism, variants of SARS-CoV-2, diagnostic tests, and vaccine & drug development studies

Coronavirus Disease-19 (COVID-19) is an infectious disease caused by severe acute respiratory syndrome-coronaviruses-2 (SARS-CoV-2), a highly pathogenic and transmissible coronavirus. Most cases of COVID-19 have mild to moderate symptoms, including cough, fever, myalgias, and headache. On the other hand, this coronavirus can lead to severe complications and death in some cases. Therefore, vaccination is the most effective tool to prevent and eradicate COVID-19 disease. Also, rapid and effective diagnostic tests are critical in identifying cases of COVID-19. The COVID-19 pandemic has a dynamic structure on the agenda and contains up-to-date developments. This article has comprehensively discussed the most up-to-date pandemic situation since it first appeared. For the first time, not only the structure, replication mechanism, and variants of SARS-CoV-2 (Alpha, Beta, Gamma, Omicron, Delta, Epsilon, Kappa, Mu, Eta, Zeta, Theta, lota, Lambda) but also all the details of the pandemic, such as how it came out, how it spread, current cases, what precautions should be taken, prevention strategies, the vaccines produced, the tests developed, and the drugs used are reviewed in every aspect. Herein, the comparison of diagnostic tests for SARS-CoV-2 in terms of procedure, accuracy, cost, and time has been presented. The mechanism, safety, efficacy, and effectiveness of COVID-19 vaccines against SARS-CoV-2 variants have been evaluated. Drug studies, therapeutic targets, various immunomodulators, and antiviral molecules applied to patients with COVID-19 have been reviewed.

Simple prediction of COVID-19 convalescent plasma units with high levels of neutralization antibodies

BACKGROUND

Hyperimmune convalescent COVID-19 plasma (CCP) containing anti-SARS-CoV-2 neutralizing antibodies (NAbs) was proposed as a therapeutic option for patients early in the new coronavirus disease pandemic. The efficacy of this therapy depends on the quantity of neutralizing antibodies (NAbs) in the CCP units, with titers ≥ 1:160 being recommended. The standard neutralizing tests (NTs) used for determining appropriate CCP donors are technically demanding and expensive and take several days. We explored whether they could be replaced by high-throughput serology tests and a set of available clinical data.

METHODS

Our study included 1302 CCP donors after PCR-confirmed COVID-19 infection. To predict donors with high NAb titers, we built four (4) multiple logistic regression models evaluating the relationships of demographic data, COVID-19 symptoms, results of various serological testing, the period between disease and donation, and COVID-19 vaccination status.

RESULTS

The analysis of the four models showed that the chemiluminescent microparticle assay (CMIA) for the quantitative determination of IgG Abs to the RBD of the S1 subunit of the SARS-CoV-2 spike protein was enough to predict the CCP units with a high NAb titer. CCP donors with respective results > 850 BAU/ml SARS-CoV-2 IgG had a high probability of attaining sufficient NAb titers. Including additional variables such as donor demographics, clinical symptoms, or time of donation into a particular predictive model did not significantly increase its sensitivity and specificity.

CONCLUSION

A simple quantitative serological determination of anti-SARS-CoV-2 antibodies alone is satisfactory for recruiting CCP donors with high titer NAbs.

A colorimetric lateral flow immunoassay based on oriented antibody immobilization for sensitive detection of SARS-CoV-2

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) causes coronavirus disease 2019 (COVID-19). The high human-to-human transmission and rapid evolution of SARS-CoV-2 have resulted in a worldwide pandemic. To contain SARS-CoV-2, it is essential to efficiently control the transmission of the virus through the early diagnosis of infected individuals, including asymptomatic people. Therefore, a rapid and accurate assay is vital for the early diagnosis of SARS-CoV-2 in suspected individuals. In this study, we developed a colorimetric lateral flow immunoassay (LFIA) in which a CBP31-BC linker was used to immobilize antibodies on a cellulose membrane in an oriented manner. The developed LFIA enabled sensitive detection of cultured SARS-CoV-2 in 15 min with a detection limit of 5 × 10⁴ copies/mL. The clinical performance of the LFIA for detecting SARS-CoV-2 was evaluated using 19 clinical samples validated by reverse transcription-polymerase chain reaction (RT-PCR). The LFIA detected all the positive and negative samples accurately, corresponding to 100% accuracy. Importantly, patient samples with low viral loads were accurately identified. Thus, the proposed method can provide a useful platform for rapid and accurate point-of-care testing of SARS-CoV-2 in infected individuals to efficiently control the COVID-19 pandemic.

Recent development of microfluidics-based platforms for respiratory virus detection

With the global outbreak of SARS-CoV-2, the inadequacies of current detection technology for respiratory viruses have been recognized. Rapid, portable, accurate, and sensitive assays are needed to expedite diagnosis and early intervention. Conventional methods for detection of respiratory viruses include cell culture-based assays, serological tests, nucleic acid detection (e.g., RT-PCR), and direct immunoassays. However, these traditional methods are often time-consuming, labor-intensive, and require laboratory facilities, which cannot meet the testing needs, especially during pandemics of respiratory diseases, such as COVID-19. Microfluidics-based techniques can overcome these demerits and provide simple, rapid, accurate, and cost-effective analysis of intact virus, viral antigen/antibody, and viral nucleic acids. This review aims to summarize the recent development of microfluidics-based techniques for detection of respiratory viruses. Recent advances in different types of microfluidic devices for respiratory virus diagnostics are highlighted, including paper-based microfluidics, continuous-flow microfluidics, and droplet-based microfluidics. Finally, the future development of microfluidic technologies for respiratory virus diagnostics is discussed.

Study of some immunological signatures and their association with COVID-19 in a sample of recovered Iraqi patients

Since its emergence about two years ago, the novel coronavirus has continued to be a challenge and threat to public health, struck most parts of the world, leaving more than half a billion cases of infection and more than five million deaths. Immune response abnormalities post-infection with SARS-CoV-2 have been reported, and the mechanisms that lead to them are still ambiguous. This study was conducted to evaluate some immunological markers in the serum samples of COVID-19 convalescent patients and investigate the association of these immunological signatures with their age and sex. The serum levels of immunoglobulin G, interleukin-1 beta, and interferon lambda-1 of 75 patients and 50 healthy control group members were measured, with 55 % males and 45 % females participating and ages ranging from 20 to 80 years. The measurement of the immunological signatures was performed using the enzyme-linked immunosorbent assay (ELISA). The result revealed highly significant elevated levels of the serum immunological signatures of the convalescent group in comparison to the control group, with P-values of 0.00001 for each signature. Moreover, age was observed to have an association with an elevated level of the immunological signatures as it increased in the elderly, whereas no association with sex was detected. The findings strongly suggest that COVID-19 infection results in a persistent inflammatory response, which leads to prolonged post-recovery symptoms. Post-COVID-19 syndrome necessitates additional research to clarify its pathophysiology, pathogenesis, and long-term implications.