Method For Detection Of Antibodies Research Articles

Development and application of a colloidal-gold dual immunochromatography strip for detecting African swine fever virus antibodies.

African swine fever (ASF) is an acute and highly contagious infectious disease caused by the African swine fever virus (ASFV). Currently, there is no vaccine against ASF worldwide, and no effective treatment measures are available. For this reason, developing a simple, rapid, specific, and sensitive serological detection method for ASFV antibodies is crucial for the prevention and control of ASF. In this study, a 1:1 mixture of gold-labeled p30 and p72 probes was used as the gold-labeled antigen. The p30 and p72 proteins and their monoclonal antibodies were coated on a nitrocellulose membrane (NC) as a test (T) line and control (C) line, respectively. A colloidal-gold dual immunochromatography strip (ICS) for ASFV p30 and p72 protein antibodies was established. The results showed that the colloidal-gold dual ICS could specifically detect ASFV antibodies within 5-10min. There was no cross-reaction after testing healthy pig serum; porcine reproductive and respiratory syndrome virus (PRRSV), foot-and-mouth disease type A virus (FMDV-A), foot-and-mouth disease type O virus (FMDV-O), porcine circovirus type 2 (PCV-2), and classical swine fever virus (CSFV) positive sera. A positive result was obtained only for the positive control P1. The sensitivity of the test strips was 1:256, which was equivalent to that of commercially ELISA kits. Their coincidence rate with the two commercial ASFV ELISA antibodies detection kits was higher than 98%. The test strips were stably stored at 18-25°C and 4°C for 4 and 6months, respectively. The colloidal-gold dual ICS prepared in this study had high sensitivity and specificity and were characterized by rapid detection, simple operation, and easy interpretation of results. Therefore, they are of great significance to diagnose, prevent, and control African swine fever. KEY POINTS: • We establish an antibody detection that is quick and can monitor an ASF infection. • We observe changes in two protein antibodies to dynamically monitor ASF infection. • We use diversified detection on a single test strip to detect both antibodies.

Highly Sensitive and Specific SARS-CoV-2 Serological Assay Using a Magnetic Modulation Biosensing System.

Sensitive serological assays are needed to provide valuable information about acute and past viral infections. For example, detection of anti-severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) IgG antibodies could serve as the basis for an “immunity passport” that would enable individuals to travel internationally. Here, utilizing a novel Magnetic Modulation Biosensing (MMB) system and the receptor-binding domain of the SARS-CoV-2 spike protein, we demonstrate a highly sensitive and specific anti-SARS-CoV-2 IgG serological assay. Using anti-SARS-CoV-2 IgG antibodies, RT-qPCR SARS-CoV-2-positive and healthy patients’ samples, and vaccinees’ samples, we compare the MMB-based SARS-CoV-2 IgG assay’s analytical and clinical sensitivities to those of the enzyme-linked immunosorbent assay (ELISA). Compared with ELISA, the MMB-based assay has an ~6-fold lower limit of detection (129 ng/L vs. 817 ng/L), and it detects an increase in the IgG concentration much earlier after vaccination. Using 85 RT-qPCR SARS-CoV-2-positive samples and 79 -negative samples, the MMB-based assay demonstrated similar clinical specificity (98% vs. 99%) and sensitivity (93% vs. 92%) to the ELISA test, but with a much faster turnaround time (45 min vs. 245 min). The high analytical and clinical sensitivity, short turnaround time, and simplicity of the MMB-based assay makes it a preferred method for antibody detection.

Bacterial coloration immunofluorescence strip for ultrasensitive rapid detection of bacterial antibodies and targeted antibody-secreting hybridomas

The indirect enzyme-linked immunosorbent assay (ELISA) is the gold standard method for monoclonal antibody (McAb) detection and plays a unique role in the preparation of bacterial antibodies. To solve the laborious issues associated with indirect ELISA, a novel bacterial coloration immunofluorescence strip (BCIFS) for antibody detection using colored bacteria instead of a labeled antibody as the antigen and tracer simultaneously and goat anti-mouse IgG as the test line was developed. The affinity range survey of BCIFS indicated that hybridoma cell cultures of E. coli O157:H7 (D3, E7) and Vibrio parahemolyticus (H7, C9) were detected, which complied with the results of indirect ELISA. Compared with the traditional indirect ELISA, the BCIFS sensitivity for E7 cell cultures, ascites, and purified antibodies was at least 4-fold more sensitive, and the BCIFS cross-reactivity for E7 cell cultures was almost consistent with that of indirect ELISA. In addition, the BCIFS isotypes for E. coli O157:H7 cell cultures and Vibrio parahemolyticus were IgG2a and IgG1, respectively, which were identical to the indirect ELISA. Furthermore, the BCIFS method was confirmed by McAb preparation, effective antibody use, and targeted antibody-secreted hybridoma preparation and screening, which showed excellent performance and substitution of the indirect ELISA method. Combined with methylcellulose semisolid medium, BCIFS offers a novel, easy to operate, rapid preparation method for antigen-specific hybridomas. This is the first report using BCIFS instead of indirect ELISA for bacterial antibody detection and application in different samples, which demonstrates a rapid and powerful tool for antibody engineering.

Next-Generation Serology by Mass Spectrometry: Readout of the SARS-CoV-2 Antibody Repertoire.

Methods of antibody detection are used to assess exposure or immunity to a pathogen. Here, we present Ig-MS, a novel serological readout that captures the immunoglobulin (Ig) repertoire at molecular resolution, including entire variable regions in Ig light and heavy chains. Ig-MS uses recent advances in protein mass spectrometry (MS) for multiparametric readout of antibodies, with new metrics like Ion Titer (IT) and Degree of Clonality (DoC) capturing the heterogeneity and relative abundance of individual clones without sequencing of B cells. We applied Ig-MS to plasma from subjects with severe and mild COVID-19 and immunized subjects after two vaccine doses, using the receptor-binding domain (RBD) of the spike protein of SARS-CoV-2 as the bait for antibody capture. Importantly, we report a new data type for human serology, that could use other antigens of interest to gauge immune responses to vaccination, pathogens, or autoimmune disorders.

Recent Developments in SARS-CoV-2 Neutralizing Antibody Detection Methods.

The ongoing Coronavirus disease 19 pandemic has likely changed the world in ways not seen in the past. Neutralizing antibody (NAb) assays play an important role in the management of the severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) outbreak. Using these tools, we can assess the presence and duration of antibody-mediated protection in naturally infected individuals, screen convalescent plasma preparations for donation, test the efficacy of immunotherapy, and analyze NAb titers and persistence after vaccination to predict vaccine-induced protective effects. This review briefly summarizes the various methods used for the detection of SARS-CoV-2 NAbs and compares their advantages and disadvantages to facilitate their development and clinical application.

Anti-Spike (S) Antibody Production Post Covid-19 Vaccination after B Cell Depleting Therapy (BCDT) for Non-Hodgkin Lymphoma (NHL)

Introduction:Patients with NHL have a longer duration of illness and higher mortality rate after infection with Covid-19 1-3. Vaccination is strongly recommended to mitigate these problems in the general population, however, patients with cancer were not eligible to enter the pivotal vaccine trials. Furthermore, patients with NHL as well as other hematologic malignancies are frequently treated with B cell depleting therapies (BCDT) such as Rituximab and other anti-CD20 antibodies which in theory affect antibody production after vaccination. There are no data in the literature regarding patients with NHL and scarce data on other tumors concerning the antibody response against the S protein of Sars-Cov-2. To investigate the production of antibodies against the spike protein following vaccination against Sars-Cov-2, we studied 180 patients with cancer. We also aimed to determine if factors such as timing of BCDT in relation to number of days elapsed between such treatment and vaccination, as well as other features such as peripheral blood absolute B cell count correlate with antibody production.Materials and Methods:Anti-spike protein antibody production was evaluated in 104 patients with NHL and 76 with other malignancies. Eligible participants were aged 21 years or older. Study inclusion criteria included diagnosis of lymphoma or other hematological malignancy as well as solid tumors.The Dimension Exel 200 method for qualitative detection of total antibodies was used to determine antibody production. The antibody test was performed > 14 days after the second Moderna or Pfizer vaccine dose or after the Johnson & Johnson single dose.We prospectively evaluated antibody production following administration of BCDT as well as cytotoxic chemotherapy in 104 patients with NHL, 27 hematologic malignancies and in 49 solid tumors. In addition, we explored the timing of such treatments in relation to the vaccination date as well as the type of vaccine administered.Results:Median age was 61 and 59% were females. Of 180 entered, 104 had NHL. Of these, 95 (91.3%) were treated with BCDT, including rituximab (89), obinutuzumab (5) or anti-CD19 CAR-T cell therapy (1). BCDT was usually given together with induction chemotherapy and followed by maintenance. Histologic types of NHL treated with these therapies were: aggressive NHLs (N=35), follicular low grade (N=33), marginal zone NHL (14) and others (N=13). There were 49 patients with solid tumors. We also included 10 patients with other hematologic tumors who received BCDT and were analyzed together with the 95 NHLs to determine if this treatment interfered with anti-spike antibody production.Conclusions:These results imply a deleterious effect of BCDT on the humoral immune response to the SARS-Cov-2 vaccine. The correlation between the administration of BCDT and poor production of anti-spike antibodies is very robust, particularly in those cases who were vaccinated 9 months or less after BCDT. However, administration of cytotoxic chemotherapy without BCDT was not associated with reduced production of antibodies. In fact, almost all patients (94%) who received cytotoxic chemotherapy without BCDT, produced antibodies against spike protein (table 2). However, when chemotherapy was combined with BCDT there was a significant reduction of antibody production. These results strongly suggest that the major problem with poor antibody production following vaccination against Sars-Cov-2 relates to the use of BCDT and not so much to cytotoxic chemotherapy. The same findings apply to the 104 cases of NHL where half of patients treated with BCDT did not produce antibodies while 88% who did not receive BCDT produced antibodies (table 2). Almost all patients with solid tumors in our study (95.9%) were able to produce antibodies, irrespective of whether they received chemotherapy or not.These data raise the question whether vaccinated patients treated with BCDT who failed to make antibodies against the spike protein, could also benefit from a third dose. [Display omitted] DisclosuresNo relevant conflicts of interest to declare.

A pilot study to assess the performance of a rapid ultrasound particle agglutination method for the detection of HIV antibodies

ABSTRACT Anti-HIV antibody screening and confirmatory tests include rapid diagnostics tests (RDT), which have limited sensitivity, and high-sensitivity ELISA and western blot tests, which are laborious and require technical proficiency. Thus, there is an unmet need for novel rapid, simple, and highly sensitive tests. A pilot study was conducted to assess the performance of a recently developed ultrasound particle agglutination (UPA) method for high-sensitivity HIV antibody detection using 51 confirmed positive and 310 presumably negative plasma samples, and 6 commercially available anti-HIV-1 seroconversion panels (total 56 members). Optimal cutoff value of the UPA method was determined by receiver operating characteristics (ROC) analysis, providing clinical sensitivity and specificity of 100% and 98.1%, respectively. The performance characteristics of UPA, compared with those of some established RDT’s and ELISA tests using HIV seroconversion panels, showed 2 days earlier HIV antibody detection than other RDT’s and 2nd-generation ELISA, and at approximately the same time as 3rd-generation ELISA. The preliminary analysis of the UPA method performance characteristics showed that it meets the minimum requirements of the WHO guidelines for RDTs as first-line assays. This pilot study paves the way for more detailed validation studies of the UPA method for HIV antibody detection in clinical practice.

Comparisons of Anti-dsDNA Antibody Detection Methods by Chemiluminescent Immunoassay and Enzyme-Linked Immunosorbent Assay in Systemic Lupus Erythematosus.

This study aimed to compare the test results of anti-double-stranded DNA (anti-dsDNA) antibodies obtained using chemiluminescent immunoassay (CIA) and enzyme-linked immunosorbent assay (ELISA), and investigate predictors of inconsistent results. This retrospective study included 502 patients who underwent CIA and ELISA to determine their anti-dsDNA antibody values within a year. We compared the diagnostic power for SLE, disease activity, and predictive power for lupus nephritis (LN). A multivariate analysis was performed to determine the predictors of inconsistencies. CIA and ELISA were moderately correlated in terms of their consistency (Cronbach’s α = 0.571), and yielded comparably favorable results in terms of SLE diagnostic power and SLE disease activity. However, if the patient had LN, CIA displayed higher predictive power than ELISA (0.620 vs. 0.555, p = 0.026). Compared with the CIA/ELISA double-positive group, the inconsistent group had lower anti-C1q circulating immune complexes (CIC) antibody values (OR: 0.42, 95% CI: 0.18–0.94, p = 0.036), and lower SLEDAI scores (≥4) (OR: 0.33, 95% CI: 0.14–0.79, p = 0.013). Anti-dsDNA antibody detection with CIA exhibited higher predictability for diagnosing LN than did ELISA. In the event of inconsistencies between anti-dsDNA methods, SLE disease activity and CIC test values should be considered simultaneously.

Multi-functional magnetic molecular imprinting probe for visual detection of IgY antibodies.

Egg yolk antibodies (IgY)are analternative to mammalian antibodies, which have been successfully applied in treatment ofdisease, asimmunochemical reagents and asfood additives. A fast, accurate, and easy-to-operate detection method for IgY antibodies is needed. Herein, we developed a rapid and cost-effective colorimetric assay for the ultrasensitive detection of anti-S. aureus IgY antibodies using multi-functional magnetic molecularly imprinted polymers (MMIPs). The prepared MMIPs can recognize, adsorb, and separate the analyte from the matrix efficiently, and oxidize TMB to generate a colorimetric signal within ~ 60min. As low as 0.013mg·mL-1 was able to be detected by using this method. The visual detection limit reached 0.02mg·mL-1. By testing the IgY in milk samples, the feasibility was verified.

Development of ELISA Using Recombinant Proteins for the Diagnosis of Mycoplasma hyopneumoniae Infection.

In order to develop a more sensitive and reliable method for detection of serum antibodies against Mycoplasma hyopneumoniae infection in pigs, six recombinant proteins of M. hyopneumoniae (P102, P95, P46, P97 like, Lppt, and hypothetical P987) were used for the standardization of an indirect enzyme-linked immunosorbent assay (ELISA). The proteins were evaluated against 50 sera of the specific pathogen-free and 50 sera of pigs with lesions suggestive of infection. The sensitivity was 88%, 86%, 78%, 74%, 66%, and 60% for the proteins P102, P95, P46, P97 like, Lppt, and hypothetical protein P987, respectively. Moreover, the proteins were used to establish the seroprevalence in two different commercial herds (254 sera pigs from farm considered free of M. hyopneumoniae and 246 from farm with clinical signs of enzootic pneumonia and positive serology for M. hyopneumoniae) and the positive rate was 65.2% for P95, 54.6% for P102, 40.2% for P46, 37.2% for P97 like, 17.4% for the hypothetical P987, and 14% for Lppt protein. In addition, the ELISA with six recombinant proteins was compared to commercial HerdCheck kit using 118 random pig sera samples and the results showed that ELISA with recombinant proteins were more sensitive than the commercial test. These data show that the recombinant proteins P95 and P102 are potential targets to be used in diagnostic tests to detect antibodies against M. hyopneumoniae. Although more studies are necessary, this study provides insights that these recombinant proteins can be useful in epidemiological investigations and as potential biomarkers in differentiating infected animals from those vaccinated.

Aspects of “antigen–antibody” interaction of chicken infectious bronchitis virus determined by surface plasmon resonance

Authors performed investigation on “antigen–antibody” interaction of chicken infectious bronchitis coronavirus (IBV) by a method based on the surface plasmon resonance (SPR). Presence of space-size effect related to a difference between antigen and antibody particle sizes has been theoretically grounded and experimentally proven. Herewith, the difference between responses of the SPR-sensor to specific and non-specific interactions is considerably less (up to 6.3 times) than the expected one (8 – 11 times). An impact of functionalization of sensor’s sensitive element surface, as well as acidity of buffer solution on the activity of antigen–antibody interaction was studied here. The difference between sensor’s responses to specific and non-specific interactions increased two-fold from 200 to 432ang sec due to this treatment. When changing the acidity of analyzed solution from pH7.3 to pH6.8, the corresponding difference between sensor’s responses increased by 6.3 times from 194 up to 1235ang.sec. Thus, an impact of space-size effect on interaction between IBV antigen and specific antibody can be considerably (almost in 3 times) decreased by reducing the acidity of used buffer solution. The results of our investigation can be successfully applied to develop new methods for detection of pathogens and specific antibodies using SPR.

A Quantitative ELISA Protocol for Detection of Specific Human IgG against the SARS-CoV-2 Spike Protein.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has caused a worldwide pandemic with at least 3.8 million deaths to date. For that reason, finding an efficient vaccine for this virus quickly became a global priority. The majority of vaccines now marketed are based on the SARS-CoV-2 spike protein that has been described as the keystone for optimal immunization. In order to monitor SARS-CoV-2 spike-specific humoral responses generated by immunization or infection, we have developed a robust and reproducible enzyme-linked immunosorbent assay (ELISA) protocol. This protocol describes a method for quantitative detection of IgG antibodies against the SARS-CoV-2 spike protein using antigen-coated microtiter plates. Results showed that antibodies could be quantified between the range of 1.953 ng/mL to 500 ng/mL with limited inter- and intra-assay variability.

IMMUNOHISTOCHEMICAL EXPRESSION OF P16 IN CERVICAL AND URINARY BLADDER SQUAMOUS CELL CARCINOMA

Background: p16 is a tumor suppressor protein important in regulating cell cycle. In bladder cancer, p16 mutations are widespread and tend to be more prevalent in low-grade superficial tumors than in higher-grade invasive tumors. Objective: To evaluate expression of p16 in 25 cases of cervical squamous cell carcinoma and 25 cases of urinary bladder squamous cell carcinoma. Patients and methods: This study was carried out in the Histopathology Department of Al-Azhar University Hospitals and from some private laboratories during the period from August 2019 up to January 2020. H & E stained sections were prepared from paraffin blocks for revision of diagnosis. Immunohistochemical analysis was done on 4 micron sections of formalin-fixed paraffin-embedded tissue using the labeled streptavidin-biotin method after antigen retrieval. Antibodies against P16 were utilized on sections from paraffin blocks. CINtec Histology kit includes a two-step antibody method for detection of human p16 antibody. Results: Expression of P16 was positive in 92% of cases of squamous cell carcinoma of the uterine cervix and 60% of cases squamous cell carcinoma of the urinary bladder. In patients with cervical squamous cell carcinoma, there was statistically significant relation between intensity of P16 staining and tumor grading. In patients with squamous cell carcinoma of the urinary bladder, there was a statistically significant relation between intensity of P16 staining and tumor grading and staging. Moderate/strong staining intensity can predict staging 2B among patients with squamous cell carcinoma of the uterine cervix, and negative/weak staining intensity can predict staging 1A, 1B, 2A with sensitivity 52.9% and specificity 37.5% among patients with squamous cell carcinoma of the urinary bladder. Conclusion: p16 immunohistochemical expression alone should not be used as a marker for differentiation between cervical and urinary squamous cell carcinoma.

Monitoring Coronavirus Disease 2019: A Review of Available Diagnostic Tools.

Coronavirus disease 2019 (COVID-19) pneumonia is caused by the virus severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and has rapidly become a global public health concern. As the new type of betacoronavirus, SARS-CoV-2 can spread across species and between populations and has a greater risk of transmission than other coronaviruses. To control the spread of SARS-CoV-2, it is vital to have a rapid and effective means of diagnosing asymptomatic SARS-CoV-2-positive individuals and patients with COVID-19, an early isolation protocol for infected individuals, and effective treatments for patients with COVID-19 pneumonia. In this review, we will summarize the novel diagnostic tools that are currently available for coronavirus, including imaging examinations and laboratory medicine by next-generation sequencing (NGS), real-time reverse transcriptase–polymerase chain reaction (rRT-PCR) analysis, immunoassay for COVID-19, cytokine and T cell immunoassays, biochemistry and microbiology laboratory parameters in the blood of the patients with COVID-19, and a field-effect transistor-based biosensor of COVID-19. Specifically, we will discuss the effective detection rate and assay time for the rRT-PCR analysis of SARS-CoV-2 and the sensitivity and specificity of different antibody detection methods, such as colloidal gold and ELISA using specimen sources obtained from the respiratory tract, peripheral serum or plasma, and other bodily fluids. Such diagnostics will help scientists and clinicians develop appropriate strategies to combat COVID-19.

Facile and rapid detection of SARS-CoV-2 antibody based on a noncompetitive fluorescence polarization immunoassay in human serum samples

Antibody detection methods for viral infections have received broad attention due to the COVID-19 pandemic. In addition, there remains an ever-increasing need to quantitatively evaluate the immune response to develop vaccines and treatments for COVID-19. Here, we report an analytical method for the rapid and quantitative detection of SARS-CoV-2 antibody in human serum by fluorescence polarization immunoassay (FPIA). A recombinant SARS-CoV-2 receptor binding domain (RBD) protein labeled with HiLyte Fluor 647 (F-RBD) was prepared and used for FPIA. When the anti-RBD antibody in human serum binds to F-RBD, the degree of polarization (P) increases by suppressing the rotational diffusion of F-RBD. The measurement procedure required only mixing a reagent containing F-RBD with serum sample and measuring the P value with a portable fluorescence polarization analyzer after 15 min incubation. We evaluated analytical performance of the developed FPIA system using 30 samples: 20 COVID-19 positive sera and 10 negative sera. The receiver operating characteristic curve drawn with the obtained results showed that this FPIA system had high accuracy for discriminating COVID-19 positive or negative serum (AUC = 0.965). The total measurement time was about 20 min, and the serum volume required for measurement was 0.25 μL. Therefore, we successfully developed the FPIA system that enables rapid and easy quantification of SARS-CoV-2 antibody. It is believed that our FPIA system will facilitate rapid on-site identification of infected persons and deepen understanding of the immune response to COVID-19.

Expression and purification of recombinant SARS-CoV-2 nucleocapsid protein in inclusion bodies and its application in serological detection

The current standard for the diagnosis of COVID-19 is the nucleic acid test of SARS-CoV-2 RNA, however, virus antibody detection has the advantages of convenient sample collection, high throughout, and low cost. When combining detection with nucleic acid detection, antibody detection can effectively compensate for nucleic acid detection. Virus infection always induce high antibody titer against SARS-CoV-2 nucleocapsid protein (N protein), which can be used to detect COVID-19 at both infected and convalescent patients. In this study we reported the expression and purification of N protein in E.coli from inclusion bodies by a combination of two cation exchange chromatography, and the yield of N protein was around 50 mg/L fermentation broth with more than 90% purity. A corresponding colloidal gold detection kit prepared with our purified N protein was used to verify the efficiency and accuracy our N protein in antibody detection method. Of the 58 COVID-19 PCR positive patients' inactivated serum samples, 40 samples were IgM positive (69.0%), and 42 samples were IgG positive (72.4%), and all 95 COVID-19 negative patients’ inactivated serum samples were both IgM and IgG negative. Our results indicates that the refolded soluble N protein could be used for the preliminary detection of IgG and IgM antibodies against SARS-CoV- 2.

Anti-Cytosolic 5'-Nucleotidase 1A Autoantibodies Are Absent in Juvenile Dermatomyositis.

ObjectiveTo assess anti–cytosolic 5′‐nucleotidase 1A (anti–cN‐1A) autoantibodies in children with juvenile dermatomyositis (DM) and healthy controls, using 3 different methods of antibody detection, as well as verification of the results in an independent cohort.MethodsAnti–cN‐1A reactivity was assessed in 34 Dutch juvenile DM patients and 20 healthy juvenile controls using the following methods: a commercially available full‐length cN‐1A enzyme‐linked immunosorbent assay (ELISA), a synthetic peptide ELISA, and immunoblotting with a lysate from cN‐1A–expressing HEK 293 cells. Sera from juvenile DM patients with active disease and those with disease in remission were analyzed. An independent British cohort of 110 juvenile DM patients and 43 healthy juvenile controls was assessed using an in‐house full‐length cN‐1A ELISA.ResultsAnti–cN‐1A reactivity was not present in sera from juvenile DM patients or healthy controls when tested with the commercially available full‐length cN‐1A ELISA or by immunoblotting, in either active disease or disease in remission. Additionally, in the British juvenile DM cohort, anti–cN‐1A reactivity was not detected. Three Dutch juvenile DM patients had weakly positive results for 1 of 3 synthetic cN‐1A peptides measured by ELISA.ConclusionJuvenile DM patients and young healthy individuals did not show anti–cN‐1A reactivity as assessed by different antibody detection techniques.

"Antibody of Unknown Significance" (AUS): The Issue of Interpreting Antibody Test Results.

"Antibody of Unknown Significance" (AUS): The Issue of Interpreting Antibody Test Results.

The worldwide seroprevalence of DENV, CHIKV and ZIKV infection: A systematic review and meta-analysis.

BackgroundAs the three major arthropod-borne viruses, dengue virus (DENV), chikungunya virus (CHIKV), and zika virus (ZIKV) are posing a growing threat to global public health and socioeconomic development. Our study aimed to systematically review the global seroprevalences of these arboviruses from existing publications.MethodsArticles published between Jan 01, 2000 and Dec 31, 2019 in the databases of Embase, Pubmed and Web of Science were searched and collected. Countries or areas with known local presence of Aedes vector mosquitoes were included. Random effects model was utilized to estimate the pooled seroprevalences and the proportion of inapparent infection.ResultsOut of 1375, a total of 133 articles involving 176,001 subjects were included for our analysis. The pooled seroprevalences of DENV, CHIKV and ZIKV were 38%, 25% and 18%, respectively; and their corresponding proportions of inapparent infections were 80%, 40% and 50%. The South-East Asia Region had the highest seroprevalences of DENV and CHIKV, while the Region of the Americas had the highest seroprevalence of ZIKV. The seroprevalences of DENV and CHIKV were similar when comparing developed and developing countries, urban and rural areas, or among different populations. In addition, we observed a decreased global seroprevalences in the new decade (2010–2019) comparing to the decade before (2000–2009) for CHIKV. For ZIKV, the positive rates tested with the nucleic acid detection method were lower than those tested with the antibody detection method. Lastly, numerous cases of dual seropositivity for CHIKV and DENV were reported.ConclusionsOur results revealed a varied prevalence of arbovirus infections in different geographical regions and countries, and the inapparent infection accounted an unneglected portion of infections that requires more attention. This study will shed lights on our understanding of the true burden of arbovirus infections and promote appropriate vaccination in the future.

A North American Cohort of Anti-SAE Dermatomyositis: Clinical Phenotype, Testing, and Review of Cases.

ObjectiveAntibodies against the small ubiquitin‐like modifier (SUMO) activating enzyme (SAE) are one of the rarer specificities associated with dermatomyositis (DM). The purpose of this study is to describe the clinical characteristics of patients with anti‐SAE autoantibodies in a North American cohort and to ascertain cancer prevalence. We also describe the performance characteristics of the line blotting (Euroimmun) method for antibody detection compared with an immunoprecipitation‐based assay.MethodsSera from 2127 patients suspected of having myositis were assayed for myositis‐specific autoantibodies using the Euroimmun platform. Those positive for SAE autoantibodies were assayed by a second method (immunoprecipitation) for confirmation. Only those cases positive by both methods were taken as definite cases of anti‐SAE–positive DM. Chart reviews of these patients were completed to obtain information on clinical characteristics, cancer history, and treatment.ResultsForty‐three of 2127 sera were anti‐SAE autoantibody positive by Euroimmun (≥15 units, +); of these, only 19 were confirmed positive by immunoprecipitation. All 19 cases had skin involvement and varying presentations of muscle, lung, and joint disease. Cancer occurred coincident with DM in two patients, and cancers were detected more than 5 years from symptom onset in three patients. In a population of suspected inflammatory myositis, a higher cutoff on line blot testing (≥36 units, ++) yielded better agreement with immunoprecipitation methods.ConclusionSAE autoantibodies associate with a clinical phenotype of DM, which most commonly presents with a rash first, followed by muscle involvement and varying extramuscular involvement. As coincident cancer was seen in anti‐SAE–positive DM, judicious malignancy screening may be warranted.