Clinical Application of Antibody Immunity Against SARS-CoV-2: Comprehensive Review on Immunoassay and Immunotherapy

The current COVID-19 global pandemic poses immense challenges to global health, largely due to the difficulty to detect infection in the early stages of the disease, as well as the current lack of effective antiviral therapy. Research and understanding of the human immune system can provide important theoretical and technical support for the clinical diagnosis and treatment of COVID-19, the clinical implementations of which include immunoassays and immunotherapy, which play a crucial role in the fight against the pandemic. This review consolidates the current scientific evidence for immunoassay, which includes multiple methods of detecting antigen and antibody against SARS-CoV-2. We compared the characteristics, advantages and disadvantages, and clinical applications of these three detection techniques. In addition to detecting viral infections, knowledge on the body's immunity against the virus is desirable; thus, the immunotherapy-based neutralizing antibody (nAb) detection methods were discussed. We also gave a brief introduction to the new immunoassay technology such as biosensing. This was followed by an in-depth and extensive review on a variety of immunotherapy methods. It includes convalescent plasma therapy, neutralizing antibody-based treatments targeting different regions of SARS-CoV-2, immunotherapy targeted on the host cell including inhibiting the host cell receptor and cytokine storm, as well as cocktail antibodies, cross-neutralizing antibodies, and immunotherapy based on cross-reactivity between viral epitopes and autoepitopes and autoantibody. Despite the development of various immunological testing methods and antibody therapies, the current global situation of COVID-19 is still tense. We need more efficient detection methods and more reliable antibody therapies. The up-to-date knowledge on therapeutic strategies will likely help clinicians worldwide to protect patients from life-threatening viral infections.

Global burden of rabies in 204 countries and territories, from 1990 to 2019: results from the Global Burden of Disease Study 2019

OBJECTIVES

Rabies is an acute lethal infectious disease caused by a lyssavirus infection. In 2018, the World Health Organization proposed a global strategic plan to end human rabies deaths by 2030. However, systematic studies on the global rabies disease burden and epidemiological trends are scarce.

METHODS

We extracted the disease burden and epidemiological data of rabies worldwide in the preceding 30 years from the Global Burden of Disease Study 2019 and performed a comprehensive analysis.

RESULTS

In 2019, the incident cases of rabies worldwide were 14,075.51 (95% uncertainty interval: 6124.33-21,618.11), and the number of deaths was 13,743.44 (95% uncertainty interval: 6019.13-17,938.53), both of which were lower than that in 1990. With the improvement of the sociodemographic index, the incident cases, the number of deaths, age-standardized incidence rate, age-standardized incidence death rate, and disability-adjusted life years of rabies all showed downward trends. Adolescents and adults aged <50 years represented the majority of rabies cases worldwide.

CONCLUSION

The global disease burden of rabies has declined over the past 30 years. Furthermore, the disease burden of rabies was closely related to the sociodemographic index level.

Association between Sarcopenia and Cognitive Trajectories among Middle-Aged and Older Adults in China: A Nationally Representative Cohort Study

OBJECTIVES

The relationship between sarcopenia and cognitive function has been extensively studied, but is usually explored at a single time point. We used repeatedly measured cognitive data to examine the relationship between sarcopenia and cognitive trajectories over time among middle-aged and older Chinese adults.

DESIGN

A nationally representative cohort study.

SETTING AND PARTICIPANTS

Data were from three waves (2011, 2013 and 2015) of the China Health and Retirement Longitudinal Study (CHARLS). A total of 8963 participants with complete baseline data (wave 1) and at least two cognitive function tests (waves 1-3) were enrolled in this study.

MEASUREMENTS

Sarcopenia was diagnosed at baseline (wave 1). The wave 1-3 data were used to analyze cognitive trajectories over time by constructing a latent class trajectory model (LCTM). Logistic regression model was used to analyze the association between sarcopenia and cognitive trajectories.

RESULTS

Among 8693 participants, we identified two trajectories of cognitive function development, including a persistent low trajectory (n= 4856, 55.86%) and a persistent high trajectory (n= 3837, 44.14%). Sarcopenia was associated with persistently low cognitive trajectory of global cognitive (OR: 1.248, 95%CI: 1.046-1.490) after adjustment for other covariates. This association was still observed when stratified by age, gender, educational level, marital status, social activity, smoking status and drinking status. Mediation analysis showed that body mass index (BMI) mediated efficacy accounting for 42.32% of the relationship.

CONCLUSIONS

Our study showed two trajectory groups of global cognitive function. Sarcopenia was associated with a persistent low trajectory over time and BMI mediated the relationship between sarcopenia and cognitive trajectories among middle-aged and older Chinese adults.

[Efficacy of endoscopic treatment oncolorectal laterally spreading tumor and risk factors of delayed bleeding after operation]

Objective: To evaluate the endoscopic treatment efficacy of colorectal laterally spreading tumor (LST) and analyze the risk factors for delayed post-polypectomy bleeding (DPPB). Methods: Between January 2015 and December 2020, patients underwent colorectal endoscopic submucosal dissection (ESD) or hybrid ESD were recruited from the Second Affiliated Hospital of Zhejiang University. Complete resection rate, perforation rate, bleeding rate, operation time and lesion adhesion were compared between the ESD and hybrid ESD groups. Patients were divided into bleeding and non-bleeding groups based on the presence of DPPB. Multivariate logistic regression analysis was used to analyze the risk factors of DPPB. Results: A total of 665 patients with colorectal LST were enrolled, including 376 males and 289 females, with an average age of (57.4±0.4) years. There were 471 cases underwent ESD and 194 cases underwent hybridized ESD. There were no significant differences in gender, age, history of smoking and drinking, and prevalence of hypertension between the two groups (all P>0.05). Likewise, the rate of lesion adhesion (4.2% vs 7.7%, P=0.067), lesion complete resection (96.8% vs 93.8%, P=0.418), perforation (0.6% vs 1.0%, P=0.594), delayed bleeding (2.8% vs 2.1%, P=0.605) were not statistically significant between the two groups. Seventeen patients (2.6%) developed DPPB after endoscopic treatment. Multivariate logistic regression analysis showed that the lesion was in the rectum (OR=3.594, 95%CI: 1.237-10.443, P=0.019) and the diameter of the lesion>2 cm (OR=3.776, 95%CI: 1.411-10.106, P=0.008) were risk factors for DPPB. Conclusions: Both ESD and hybrid ESD are successful treatments for colorectal LST. Colorectal LST lesion site and lesion size>2 cm are risk factors of DPPB.

Step scheme nickel-aluminium layered double hydroxides/biochar heterostructure photocatalyst for synergistic adsorption and photodegradation of tetracycline

Improving the adsorption ability of layered double hydroxide (LDH) has been considered as a promising strategy to promote its photodegradation of aqueous pollutants. In this work, nickel-aluminium layered double hydroxides (NiAl-LDH)/biochar nanocomposites were prepared using a simple coprecipitation method, and then applied in synergistic adsorption-photodegradation of tetracycline (TC) in aqueous solutions. In addition, the governing TC removal mechanisms by the nanocomposites were revealed. All NiAl-LDH/BC samples showed strong adsorption and photodegradation of TC. The Langmuir maximum TC adsorption capacity of optimized NiAl-LDH/BC-0.5 reached 124.2 mg/g, which was much better than that of NiAl-LDH (56.1 mg/g) and biochar (11.1 mg/g). Besides, TC photodegradation rate constant of NiAl/BC-0.5 was 3.6 and 4.4 times of that of NiAl-LDH and BC, respectively. The NiAl/BC-0.5 exhibited the maximum TC adsorption-photodegradation efficiency 94.4% in 90 min compared to NiAl-LDH (73.7%) and BC (48.2%). The rate constant of modified Elovich kinetic model for synergistic adsorption and photodegradation on NiAl/BC-0.5 (9.477 min^-1) was the highest among the composites. The NiAl-LDH/BC had significantly larger BET surface areas than NiAl-LDH and BC. The step scheme (S-scheme) heterostructures were constructed on the interface of BC and NiAl-LDH in nanocomposites, which facilitated the transfer of photo-induced charges. This work demonstrates that combination of NiAl-LDH and biochar can create synergy for TC adsorption-photodegradation, which is a promising and green strategy.

Prevalence and Disability-Adjusted Life Year Rates of Asthma in China: Findings from the GBD Study 2019 of the G20

BACKGROUND

The credible materials about the burden of asthma in China when compared to other countries in the group of twenty (G20) remain unavailable.

OBJECTIVES AND DESIGN

Following the popular analysis strategy used in the Global Burden of Disease Study, the age-, sex-, country-specific prevalence, and disability-adjusted life years (DALYs) of asthma in China were analyzed. Meanwhile, the comparison in trends between China and other countries in the G20 was also evaluated.

RESULTS

In 2019, asthma was the 8th leading cause of the DALYs' burden of 369 diseases in China. From 1990 to 2019, the age-standardized prevalence and DALY rates of asthma in China decreased by 14% and 51%, respectively; further, the decline rate of DALYs was much higher than the global average (-51%: -43%). It is worth noting that the overall population age-standardized DALYs rate of asthma in China was the lowest in the G20 during 2019 (102.81, 95% UI: (72.30,147.42)/100,000). Moreover, the age-standardized asthma prevalence rate peaks in both childhood (178.14, 95% UI: (90.50, 329.01)/100,000) and the elderly (541.80, 95% UI: (397.79, 679.92)/100,000). Moreover, throughout the study, subjects in the 5 to 9 years old interval were a constant focus of our attention.

CONCLUSIONS

The disease burden of asthma has varied greatly by gender and age over the past 30 years. In contrast to the increasing burden in most other G20 countries, the age-standardized prevalence rate of asthma shows a significant decreasing trend in China, however, the age-standardized DALYs rate shows a fluctuating change, and has even shown a rebound trend in recent years.

Immunoassay and mass cytometry revealed immunological profiles induced by inactivated BBIBP COVID-19 vaccine

With the global prevalence of COVID-19 and the constant emergence of viral variants, boosters for COVID-19 vaccines to enhance antibody titers in human bodies will become an inevitable trend. However, there is a lack of data on antibody levels and the protective effects of booster injections. This study monitored and analyzed the antibody potency and the antibody responses induced by the booster injection in the subjects who received three vaccine doses. The study was conducted in a multicenter collaboration and recruited 360 healthy adults aged 20-74. Participants received the first, second, and booster doses of inactivated Sinopharm/BBIBP COVID-19 vaccine at 0, 1, and 7 months. Vaccine-induced virus-specific antibody levels (SARS-COV-2-IgA/IgM/IgG) were monitored at multiple time points, surrogate virus neutralization test (sVNT), and the spatial distribution and proportion of immune cells and markers were analyzed using the CyTOF method before vaccination and a month after the second dose. The titers of SARS-CoV-2-IgA/IgM/IgG and neutralizing antibodies increased to a high level in the first month after receiving the second dose of vaccine and declined slowly after that. The antibody levels of SARS-CoV-2-IgG and sVNT were significantly increased at 0.5 months after the induction of the booster (p < 0.05). Despite a downward trend, the antibody levels were still high in the following 6 months. The B cell concentration (in humoral sample) a month after the second injection was significantly reduced compared to that before the vaccine injection (p < 0.05). The proportion of the C01 cell cluster was significantly decreased compared with that before vaccine injection (p < 0.05). Individual cell surface markers showed distinctions in spatial distribution but were not significantly different. This study has shown that serum antibody titer levels will decrease with time by monitoring and analyzing the antibody efficacy and the antibody reaction caused by the booster injection of healthy people who received the whole vaccination (completed three injections). Still, the significant peak of the antibody titer levels after booster highlights the recall immune response. It can maintain a high concentration of antibody levels for a long time, which signifies that the protection ability has been enhanced following the injection of booster immunization. Additionally, CyTOF data shows the active production of antibodies and the change in the immunity environment.

Detection of interstitial pneumonia with autoimmune features and idiopathic pulmonary fibrosis are enhanced by involvement of matrix metalloproteinases levels and clinical diagnosis

BACKGROUND

Higher detection of interstitial pneumonia with autoimmune features (IPAF), and idiopathic pulmonary fibrosis (IPF), has significant diagnostic and therapeutic implications. Some matrix metalloproteinases (MMPs) have become reliable diagnostic biomarkers in IPAF and IPF in previous studies, yet relevant reliability remains to be recognized.

MATERIALS AND METHODS

In this study, 36 ILDs patients, including 31 IPAF patients (Mean ± SD, 50.20 ± 5.10 years; 16 [51.6%] females) and five IPF patients (Mean ± SD, 61.20 ± 6.73 years; one [20.0%] females) were retrospectively enrolled. Serial serum samples were collected from patients with IPAF and IPF between January 2019 and December 2020. Notably, Serum MMPs levels were measured by U-PLEX Biomarker Group 1(Human) Multiplex Assays (MSD, USA).

RESULTS

A combination of MMPs and combinatorial biomarkers was strongly associated with clinical subjects in this study (AUC, 0.597 for Stability vs. Improvement and 0.756 for Stability vs. Exacerbation). Importantly, the AUC of MMP-12 reaches 0.730 (p < 0.05, Stability AUC vs. Improvement AUC) while MMP-13 reaches 0.741 (p < 0.05, Stability AUC vs. Exacerbation AUC) showed better performance than other MMPs in two comparisons.

CONCLUSIONS

Clinical risk factors and MMPs are strongly associated with either stratification of the disease of progression of IPAF or in two IPAF and IPF independent cohorts. To our knowledge, this is the first to illustrate that MMP-12 and MMP-13 may be expected to become typical promising biomarkers in Improvement - IPAF and Exacerbation - IPAF, respectively.

Incorporation of Suppression of Tumorigenicity 2 into Random Survival Forests for Enhancing Prediction of Short-Term Prognosis in Community-ACQUIRED Pneumonia

(1) Background: Biomarker and model development can help physicians adjust the management of patients with community-acquired pneumonia (CAP) by screening for inpatients with a low probability of cure early in their admission; (2) Methods: We conducted a 30-day cohort study of newly admitted adult CAP patients over 20 years of age. Prognosis models to predict the short-term prognosis were developed using random survival forest (RSF) method; (3) Results: A total of 247 adult CAP patients were studied and 208 (84.21%) of them reached clinical stability within 30 days. The soluble form of suppression of tumorigenicity-2 (sST2) was an independent predictor of clinical stability and the addition of sST2 to the prognosis model could improve the performance of the prognosis model. The C-index of the RSF model for predicting clinical stability was 0.8342 (95% CI, 0.8086–0.8598), which is higher than 0.7181 (95% CI, 0.6933–0.7429) of CURB 65 score, 0.8025 (95% CI, 0.7776–8274) of PSI score, and 0.8214 (95% CI, 0.8080–0.8348) of cox regression. In addition, the RSF model was associated with adverse clinical events during hospitalization, ICU admissions, and short-term mortality; (4) Conclusions: The RSF model by incorporating sST2 was more accurate than traditional methods in assessing the short-term prognosis of CAP patients.

Effect of a Functional Phospholipid Metabolome-Protein Association Pathway on the Mechanism of COVID-19 Disease Progression

This study aimed to explore the clinical practice of phospholipid metabolic pathways in COVID-19. In this study, 48 COVID-19 patients and 17 healthy controls were included. Patients were divided into mild (n=40) and severe (n=8) according to their severity. Phospholipid metabolites, TCA circulating metabolites, eicosanoid metabolites, and closely associated enzymes and transfer proteins were detected in the plasma of all individuals using metabolomics and proteomics assays, respectively. 30 of the 33 metabolites found differed significantly (P<0.05) between patients and healthy controls (P<0.05), with D-dimmer significantly correlated with all of the lysophospholipid metabolites (LysoPE, LysoPC, LysoPI and LPA). In particular, we found that phosphatidylinositol (PI) and phosphatidylcholine (PC) could identify patients from healthy controls (AUC 0.771 and 0.745, respectively) and that the severity of the patients could be determined (AUC 0.663 and 0.809, respectively). The last measurement before discharge also revealed significant changes in both PI and PC. For the first time, our study explores the significance of the phospholipid metabolic system in COVID-19 patients. Based on molecular pathway mechanisms, three important phospholipid pathways related to Ceramide-Malate acid (Cer-SM), Lysophospholipid (LPs), and membrane function were established. Clinical values discovered included the role of Cer in maintaining the inflammatory internal environment, the modulation of procoagulant LPA by upstream fibrinolytic metabolites, and the role of PI and PC in predicting disease aggravation.

Kalium channelrhodopsins are natural light-gated potassium channels that mediate optogenetic inhibition

Channelrhodopsins are used widely for optical control of neurons, in which they generate photoinduced proton, sodium or chloride influx. Potassium (K+) is central to neuron electrophysiology, yet no natural K+-selective light-gated channel has been identified. Here, we report kalium channelrhodopsins (KCRs) from Hyphochytrium catenoides. Previously known gated potassium channels are mainly ligand- or voltage-gated and share a conserved K+-selectivity filter. KCRs differ in that they are light-gated and have independently evolved an alternative K+ selectivity mechanism. The KCRs are potent, highly selective of K+ over Na+, and open in less than 1 ms following photoactivation. The permeability ratio PK/PNa of 23 makes H. catenoides KCR1 (HcKCR1) a powerful hyperpolarizing tool to suppress excitable cell firing upon illumination, demonstrated here in mouse cortical neurons. HcKCR1 enables optogenetic control of K+ gradients, which is promising for the study and potential treatment of potassium channelopathies such as epilepsy, Parkinson's disease and long-QT syndrome and other cardiac arrhythmias.

Investigation of Antibody Levels During Three Doses of Sinopharm/BBIBP Vaccine Inoculation

Levels of neutralizing antibodies (NAb) after vaccine against coronavirus disease 2019 (COVID-19) can be detected using a variety of methods. A critical challenge is how to apply simple and accurate methods to assess vaccine effect. In a population inoculated with three doses of the inactivated Sinopharm/BBIBP vaccine, we assessed the performance of chemiluminescent immunoassay (CLIA) in its implementation to detect severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) specific antibodies, as well as the antibody kinetics of healthcare workers throughout the course of vaccination. The antibody levels of NAb, the receptor-binding-domain (RBD) antibodies and IgG peaked one month after the second and remained at a relatively high level for over three months after the booster injection, while IgM and IgA levels remained consistently low throughout the course of vaccination. The production of high-level neutralizing antibodies is more likely when the inoculation interval between the first two doses is within the range of one to two months, and that between the first and booster dose is within 230 days. CLIA showed excellent consistency and correlation between NAb, RBD, and IgG antibodies with the cytopathic effect (CPE) conventional virus neutralization test (VNT). Receiver operating characteristic (ROC) analysis revealed that the optimal cut-off levels of NAb, RBD and IgG were 61.77 AU/ml, 37.86 AU/ml and 4.64 AU/ml, with sensitivity of 0.833, 0.796 and 0.944, and specificity of 0.768, 0.750 and 0.625, respectively, which can be utilized as reliable indicators of COVID-19 vaccination immunity detection.

[Clinical effect and influencing factors of focused ultrasound ablation surgery combined with suction curettage for the treatment of mass-type cesarean scar pregnancy]

Objective: To investigate the clinical effect of focused ultrasound ablation surgery (FUAS) combined with suction curettage for mass-type cesarean scar pregnancy (CSP) and to analyze the influencing factors of vaginal bleeding and readmission. Methods: From January 2014 to December 2020, 88 patients with mass-type CSP were treated by FUAS combined with suction curettage in the Third Xiangya Hospital of Central South University. The clinical results and the influencing factors of bleeding and readmission for mass-type CSP were analyzed. Results: All the patients underwent one time FUAS treatment successfully. Immediately after FUAS treatment, color Doppler ultrasound showed obvious necrosis and no perfusion area in all lesions, and the blood flow in the mass-type CSP tissue significantly decreased. The median volume of blood loss in the procedure was 20 ml (range: 5-950 ml). Thirteen patients (15%, 13/88) had vaginal bleeding≥200 ml, and 15 patients (17%, 15/88) were hospitalized again. The average time for menstruation recovery was (28±8) days (range: 18-66 days). The average time needed for serum human chorionic gonadotropin-beta subunit to return to normal levels was (22±6) days (range: 7-59 days). The risk of large vaginal bleeding of patients were related to the blood supply of the mass (OR=5.280, 95%CI: 1.335-20.858, P=0.018) and the largest diameter of the mass (OR=1.060, 95%CI: 1.010-1.120, P=0.030). The risk of readmission were related to the largest diameter of the mass (OR=1.055, 95%CI: 1.005-1.108, P=0.030) and the depth of the uterus cavity (OR=1.583, 95%CI: 1.015-2.471, P=0.043). No serious complications such as intestinal and nerve injury occurred during and after FUAS treatment. Conclusions: FUAS combined with suction curettage is safe and effective in treating patients with mass-type CSP through this preliminary study. The volume of vaginal bleeding are associated with the blood supply of the mass and the largest diameter of the mass, the risk of readmission are related to the largest diameter of the mass and the depth of the uterus cavity.

Smoking: a leading factor for the death of chronic respiratory diseases derived from Global Burden of Disease Study 2019

Background

Smoking is believed as one of the major risk factors resulting in a variety of non-communicable diseases, such as lung cancer and chronic respiratory diseases (CRDs). However, the global burden of CRDs attributed to smoking has not been systematically studied, particularly across different temporal and spatial scales.

Methods

We conducted a systematic analysis of the Global Burden of CRDs and related risk factors using data from the Global Burden of Disease Study 2019. Incidence, death, risk factors, and other parameters such as estimated annual percentage change have been analyzed. We also compared various risk factors across regions, countries, and genders.

Results

Globally, the incidence of CRDs and deaths cases have increased in the last 30 years, while the corresponding age-standardized incidence rate (ASIR) and death rate (ASDR) have declined. Smoking was the leading risk factor for the death of CRDs all over the world. However, in low and low-middle Socio-demographic Index (SDI) areas, particulate matter pollution was the main risk factor leading to death from CRDs, while smoking was ranked first among the major risk factors in areas with middle, middle-high, or high SDI. Globally, gender differences in morbidity and mortality from CRDs were observed. Males had slightly more cases and ASIR of chronic respiratory diseases than females over the last 30 years. However, the mortality cases and ASDR in males were significantly higher than that of females. Furthermore, the ASDR of all major risk factors, specially smoking, was higher in men than in women.

Conclusions

CRDs were still major threats human health. The current study highlights the dominating roles of smoking for death risks resulting from CRDs, followed by PM pollution. Therefore, tobacco control and improving air quality are key to reducing deaths from CRDs.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12890-022-01944-w.

Ball-milled bismuth oxybromide/biochar composites with enhanced removal of reactive red owing to the synergy between adsorption and photodegradation

In this paper, bismuth oxybromide (BiOBr)/biochar composites were synthesized by a facile ball milling method for synergistic adsorption and photodegradation of Reactive red 120 (RR120). The characterizations show that ball milling changed the degree of crystallization, increased the surface area, and promoted the charge transfer ability of biochar. The 70% BiOBr/BC composite showed the best removal efficiency for RR120 removal with or without light illumination, which proves its enhanced removal ability by adsorption and photodegradation. The biochar is served as a support of BiOBr for preventing its aggregation and a transporter of charges for promoting the separation of photo-induced carriers in composites. BiOBr can release the adsorption sites on the surface of composites by degradation, which facilitated the RR120 removal and regenerated the photocatalyst for reusing. The strong interactions between BiOBr and biochar in composites resulted from ball milling were beneficial for the charge transfer and synergistic removal of adsorption and degradation. Findings of this work indicate that ball milling method is an effective method to prepare highly efficient biochar-based composites for RR120 removal through synergistic adsorption and photodegradation.

Humoral immune response of BBIBP COVID-19 vaccination before and after the booster immunization

Background

The inactivated Sinopharm/BBIBP COVID‐19 vaccine has been widely used in the world and has joined the COVAX vaccine supply program for developing countries. It is also well adapted for usage in low‐ and middle‐income nations due to their low storage requirements.

Objective

This study aims to report on the kinetics, durability, and neutralizing ability of the induced immunity of the BBIBP vaccine, and the intensified antibody response elicited by the booster.

Methods

A total of 353 healthy adult participants, aged 20–74 years, were recruited in this multicenter study. A standard dose of the BBIBP vaccine was administered (Month 0), followed by a second standard dose (Month 1), and a booster dose (after Month 7). Vaccine‐induced virus‐specific antibody levels (SARS‐CoV‐2‐IgA/IgM/IgG), conventional virus neutralization test (cVNT), pseudovirus neutralization test (pVNT), and surrogate virus neutralization test (sVNT) were monitored over multiple time points.

Results

Neutralizing titers induced by the two doses of inactivated vaccine for COVID‐19 peaked at Month 2 and declined to 33.89% at Month 6. Following the booster dose, elevated levels of antibodies were induced for IgA, IgG, and neutralizing antibodies, with neutralizing titer reaching 13.2 times that of before the booster.

Conclusion

By monitoring the antibody titer levels postvaccination, this study has shown that serum antibody levels will decrease over time, but a notable spike in antibody levels postbooster highlights the anamnestic immune response. This signifies that the protection capability has increased following the injection of booster immunization.

[An area under curve-based nomogram to predicts vancomycin-associated nephrotoxicity in critically ill patients: a retrospective cohort study]

Objective: To develop an area under curve (AUC)-based nomogram to predict vancomycin-associated nephrotoxicity in critically ill patients. Methods: This retrospective cohort study included adult patients treated with vancomycin in the intensive care unit at a tertiary teaching hospital from January 2015 to December 2017. Baseline clinical characteristics before vancomycin treatment and pharmacokinetic parameters were collected to establish a prediction model of nephrotoxicity. Univariate analysis was used to screen variables, and multivariate logistic regression analysis was used to establish the prediction model and nomogram. Results: A total of 159 patients met the inclusion criteria, sixty-four were included in the final analysis. Sixteen patients (25%, 16/64) developed vancomycin-associated nephrotoxicity. The following variables were incorporated into the prediction model: vancomycin AUC, estimated glomerular filtration rate (GFR), and combined nephrotoxic drugs. The following equation was established to calculate the probability of nephrotoxicity: logit (P)=-4.83+0.009×AUC-2.87×1 (if GFR>60 ml/min)+2.53×1 (if number of combined nephrotoxic drugs≥2). A nomogram was generated based on the equation. The receiver-operating characteristic curve demonstrated that the AUC of the prediction model was 0.927 (95%CI 0.851-1.000). The cut-off value of the probability of nephrotoxicity was 26.48%. The sensitivity and specificity were 87.5% and 87.5% respectively. Conclusion: The incidence of vancomycin-associated nephrotoxicity is high. The AUC-based nomogram can effectively predict vancomycin-associated nephrotoxicity in critically ill patients.

A238 ALTERED GUT MICROBIOME COMPOSITION AND FUNCTION ARE ASSOCIATED WITH GUT BARRIER DYSFUNCTION IN HEALTHY RELATIVES OF CROHN’S DISEASE PATIENTS

Background

The gut microbiome may play a role in gut barrier homeostasis including epithelial barrier function, but data are scarce and limited to animal studies

Aims

To assess if alterations in gut microbiome are associated with gut barrier function

Methods

We utilized the Genetic Environmental Microbial (CCC GEM) cohort of healthy first-degree relatives (FDRs) of Crohn’s disease (CD) patients. Gut barrier function was assessed using the ratio of urinary fractional excretion of lactulose to mannitol (LMR). Stool bacterial DNA was extracted and sequenced for the V4 hypervariable region of the 16S rRNA gene using MiSeq and processed using QIIME2. Microbial functions were imputed using PICRUSt2. The cohort was divided into a North American discovery cohort (n=2,472) and non-North American external validation cohort (n=655). LMR>0.025 was defined as abnormal. LMR-microbiome associations were assessed using multivariable regression model and Random Forest (RF) classifier algorithm. q<0.05 was considered significant when multiple tests were performed

Results

The median age of the entire cohort was 17.0 years [IQR 12.0; 24.0], 52.6% were females and 25.4% had LMR>0.025. In the discovery cohort, subjects with LMR>0.025 had markedly reduced alpha diversity (Chao1 index, estimate= -0.0037, p=4.0e-04) and altered beta diversity (Bray-Curtis dissimilarity index, PERMANOVA: pseudo-F statistic = 2.99, p=1.0e-03). We identified eight bacterial genera and 52 microbial pathways associated with LMR>0.025 (q<0.05). Four genera (decreased Adlercreutzia [odds ratio(OR)=0.74, 95% confidence interval (CI) 0.6–0.91], Clostridia-UCG-014 [OR=0.71, 95%CI 0.59–0.86], and Clostridium-sensu-stricto-1 [OR=0.75, 95%CI 0.61–0.92] and increased Colidextribacter [OR=1.65, 95%CI 1.2–2.26]) and eight pathways (including decreased biosynthesis of glutamate [OR=0.4, 95%CI 0.21–0.74], tryptophan [OR=0.06, 95%CI 0.01–0.27] and threonine [OR=0.038, 95%CI 0.003–0.41]) were replicated. Bacterial community composition was associated with gut barrier homeostasis as defined by the RF analysis (p= 1.4e-6)

Conclusions

Gut microbiome community and pathways are associated with gut barrier function. These findings may identify potential microbial targets to modulate barrier function

Submitted on behalf of the CCC-GEM Consortium

Funding Agencies

CCC, CIHRCrohn’s and Colitis Canada Genetics Environment Microbial (CCC-GEM) III; The Leona M. and Harry B. Helmsley Charitable Trust; Kenneth Croitoru is the recipient of the Canada Research Chair in Inflammatory Bowel Diseases

A157 DEFINITIONS OF MEDITERRANEAN DIET INCONSISTENTLY ASSOCIATE WITH MARKERS OF GUT BARRIER FUNCTION OR SUBCLINICAL INFLAMMATION IN A POPULATION-BASED COHORT

Background

The Mediterranean Diet (MD) is proposed to reduce the risk of Crohn’s disease (CD) onset in cohort studies, with inconsistent results. This inconsistency may be due to heterogeneity in defining MD scores. Additionally, relationships between MD compliance and intestinal permeability or sub-clinical inflammation are not defined.

Aims

We examined correlations between different MD scores, and determined associations between MD compliance and intestinal permeability or subclinical inflammation in a cohort of first degree relatives of CD patients.

Methods

We used food frequency questionnaire data from 2,112 subjects of the Crohn’s Colitis Canada- Genes, Environment, Microbial (CCC-GEM) project. We obtained 12 MD definitions from the literature and calculated daily percent compliance, we further compared MD scores via pairwise correlations (Kendall’s Tau). We measured intestinal permeability via urinary fractional excretion ratio of lactulose to mannitol (LMR) (LMR≥0.03 defined abnormal), and subclinical inflammation via fecal calprotectin (FCP) measured with BÜHLMANN fCAL® ELISA (FCP≥250 defined abnormal). We fit multivariable regression models between MD compliance and abnormal LMR and FCP, respectively. Two-sided p&lt;0.05 defined significance.

Results

There was large variation in cross-correlations among MD scores, from nil (t=0.0, p=0.54) to highly significant (t=0.97, p&lt;2.2e-16). Associations of MD compliance and abnormal LMR or FCP were in both directions of effect, largely non-significant. Of the 12 MD scores, none associated with abnormal LMR, while 4 associated with abnormal FCP-Odds Ratios =1.22, 1.23, 1.24, and 1.30; p=0.02, 0.02, 0.01, and 0.009, and 95% Confidence Intervals = [1.03,1.45], [1.04,1.45], [1.05,1.47], and [1.07,1.59] respectively. No diet remained significant after correcting for multiple testing.

Conclusions

Currently MD definitions vary widely. Despite discrepancies, we expected consistent directions of effect for MD compliance on LMR or FCP. The largely non-significant associations between MDs suggest limitations in definition, interpretation, and relation to biological outcomes.

Submitted on behalf of the CCC-GEM consortium.

Funding Agencies

CIHRCrohn’s and Colitis Canada Genetics Environment Microbial (CCC-GEM) III;The Leona M. and Harry B. Helmsley Charitable Trust; Justine Timpano is a recipient of a fellowship award from Mount Sinai Hospital; Kenneth Croitoru is the recipient of the Canada Research Chair in Inflammatory Bowel Diseases

Identifying COVID-19 Infections From a Vaccinated Population Using Specific IgA Antibody Test

We analyzed the serum from COVID-19 patients and vaccinated subjects, and found that the specific IgA titer level could be used to assist COVID-19 diagnosis, especially in China.