Autoantibodies to the dense fine speckled 70 (DFS70) antigen are common among antinuclear antibodies (ANA) positive healthy individuals (HI). We assessed the prevalence of anti-DFS70 antibodies in ...patients with and without ANA-associated rheumatic diseases (AARDs) by two methods: chemiluminescent immunoassay (CIA) and an indirect immunofluorescence (IIF) assay based on immunoadsorption for DFS70.
Fifty-one ANA-positive sera samples from patients with confirmed clinical diagnosis of AARD, 92 samples from HI and 85 samples submitted to a reference laboratory for routine ANA testing were evaluated for the presence of anti-DFS70 antibodies. The samples were evaluated by QUANTA Flash DFS70 CIA using BIO-FLASH instrument and by NOVA Lite selected HEp-2 kit on NOVA View - an automated IIF system. Sera with DFS positive pattern were pre-absorbed with highly purified human DFS70 antigen, and then tested again.
Twenty-four samples (10.5%) tested by QUANTA Flash DFS70 CIA were positive for anti-DFS70 antibodies. The prevalence of monospecific anti-DFS70 antibodies was significantly higher in healthy subjects than in patients with AARDs (10.9% vs. 1.9%, p=0.02). The frequency of anti-DFS70 antibodies in samples submitted for routine ANA testing was 15.2%. A very good agreement was found between CIA and the DFS pattern identified by the automated HEp-2 IIF (kappa=0.97). In 80% of the samples obtained from patients without AARDs, immunoadsorption effectively inhibited the anti-DFS70 antibodies.
The data confirm that mono-specific anti-DFS70 antibodies are a strong discriminator between ANA positive HI and AARD patients, and their evaluation should be included in ANA testing algorithms.
The accurate detection of phospholipase A2 receptor (PLA2R) autoantibody is crucial in the diagnosis and monitoring of primary membranous nephropathy (pMN). While enzyme-linked immunosorbent assay ...(ELISA) is the commonly used detection method, its complexity and time-consuming nature pose challenges, especially for small sample sizes. Chemiluminescence immunoassay (CLIA) has emerged as a rapid alternative for clinical immunoassays. This study aims to compare the sensitivity, specificity, and precision of CLIA and ELISA in detecting PLA2R autoantibody.
A total of 145 patients with biopsy-confirmed primary membranous nephropathy and 85 patients with non-membranous nephropathy were enrolled in this comparative study. CLIA and ELISA were employed to test all samples for the presence of PLA2R autoantibodies. Statistical analysis of sensitivity, specificity, accuracy, positive predictive value (PPV), and negative predictive value (NPV) was performed using SPSS 26.0. The diagnostic value of ELISA and CLIA for pMN was analyzed using the ROC curve, and Correlation analysis was performed using Spearman.
Serum levels of anti-PLA2R antibody in pMN group were significantly higher than those in nMN group(P < 0.05). The accuracy of CLIA for detecting anti-PLA2R antibody was 76.96%, while ELISA showed an accuracy of 74.78%. The sensitivity for CLIA was 64.83%, compared to 60% for ELISA. However, no statistically significant difference was observed between the two methods (P > 0.05). The overall qualitative agreement of anti-PLA2R detection was 93.35% (95% confidence intervalCI 89.47–96.3). ROC curve analysis showed that AUC of anti-PLA2R antibody detected by ELISA and CLIA were 0.8737 (95% confidence interval CI 0.8270–0.9204), 0.8914 (95% confidence interval CI0.8495–0.9332), respectively. The Spearman correlation analysis revealed a significant correlation between them(P < 0.05). Notably, CLIA demonstrated a significant time-saving advantage, particularly when the sample size was less than 200, and especially when it was less than 20.
CLIA and ELISA showed similar accuracy and consistency in detecting anti-PLA2R antibody for primary membranous nephropathy. However, CLIA exhibited a significant advantage in terms of automation and time-saving compared to ELISA, particularly for smaller sample sizes. This finding suggests that CLIA has the potential to become a preferred and widely adopted test in the future.
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•Aim to find a more convenient method for detecting phospholipase A2 receptor (PLA2R) autoantibody than enzyme-linked immunosorbent assay (ELISA).•Chemiluminescence immunoassay (CLIA) showed similar sensitivity and specificity with ELISA in our study. The overall qualitative agreement of anti-PLA2R detection was 93.35% (95% confidence interval CI 89.47–96.3).•CLIA has the potential to become a preferred and widely adopted test in the future for detecting PLA2R autoantibody.
Background: Coronavirus disease 2019 (COVID-19) was a recent global pandemic of the era which posed a great challenge for the health care in terms of preventive, diagnostic and treatment dimensions. ...The seroprevalence rate of COVID IgG antibodies is very crucial in estimating the susceptibility of a particular area to the viral disease. In our study, we estimated the seroprevalence of COVID-19 in a rural area.
Aims and Objectives: We aimed to estimate the seroprevalence of COVID-19 in a rural district of Tamil Nadu, 6 months after the index case.
Materials and Methods: We conducted a cross-sectional study of 509 adults aged more than 18 years. From all the seven Taluks, two gram panchayats (administrative cluster of 8–10 villages) were randomly selected followed by one village through convenience. The participants were invited for the study to the community-based study kiosk set up in all the eight villages through village health committees. We collected sociodemographic characteristics and symptoms using a mobile application-based questionnaire, and we tested samples for the presence of IgG antibodies for severe acute respiratory syndrome coronavirus 2 using an electro chemiluminescent immunoassay. We calculated age-gender adjusted and test performance adjusted seroprevalence.
Results: The age-and gender-adjusted seroprevalence was 8.5% (95% confidence interval CI 6.9–10.8%). The unadjusted seroprevalence among participants with hypertension and diabetes was 16.3% (95% CI: 9.2–25.8) and 10.7% (95% CI: 5.5–18.3), respectively. When we adjusted for the test performance, the seroprevalence was 6.1% (95% CI 4.02–8.17). The study estimated 7 (95% CI 1:4.5–1:9) undetected infected individuals for every reverse transcription polymerase chain reaction confirmed case. Infection fatality rate (IFR) was calculated as 12.38/10,000 infections as on October 22, 2020. History of self-reported symptoms and education were significantly associated with positive status (P<0.05).
Conclusion: A significant proportion of the rural population in a district of Tamil Nadu remains susceptible to COVID-19. A higher proportion of susceptible, relatively higher IFR, and a poor tertiary health-care network stress the importance of sustaining the public health measures and promoting early access to the vaccine are crucial to preserving the health of this population. Low population density, good housing, adequate ventilation, limited urbanization combined with public, private, and local health leadership are critical components of curbing future respiratory pandemics.
In August 2020, anew West Nile virus (WNV) outbreak affected 71 people with meningoencephalitis in Andalusia (Spain). Samples from these individuals were received in our laboratory, a regional Virus ...Referral Centre. The aim of this study was to compare the agreement, sensitivity and specificity of findings between the WNV VIRCLIA IgG and IgM assay (Vircell, Spain) and the WNV ELISA IgM and IgG assay (Euroimmun, Germany) and to compare the performance of WNV VIRCLIA IgM and Euroimmun ELISA for cerebrospinal fluid (CSF) diagnosis. The study included 24 CSF samples (paired with serum samples) and 247 serum samples from 217 patients with suspected WNV infection (1 or 2 per patient). The agreement between ELISA and CLIA tests for IgM and Ig G detection in serum was 93% (kappa index = 0.85) and 96% (kappa index = 0.89) respectively. Sensitivity values of ELISA and CLIA tests for IgM in serum samples were 96.7% and 98.9%, respectively, and specificity values were 96.4% and 95.4% respectively. Sensitivity values of ELISA and CLIA test for IgG in serum samples were 91.1% and 97%, respectively, and specificity values were 100% and 98.8% respectively. Results obtained with ELISA and CLIA tests in CSF samples showed 75% agreement between them (kappa index = 0.51). According to these findings, the WNV VIRCLIA IgM and IgG monotest offers an accurate qualitative detection of WNV in serum and CSF specimens.
There have been several false-positive results in the antibody detection of COVID-19. This study aimed to analyze the distribution characteristics of severe acute respiratory syndrome coronavirus 2 ...(SARS-CoV-2) immunoglobulin M (IgM) and immunoglobulin G (IgG) in false-positive results using chemiluminescent immunoassay. The characteristics of false-positive results in SARS-CoV-2 IgM and IgG tests were analyzed. The false-positive proportion of single SARS-CoV-2 IgM-positive results was 95.88%, which was higher than those of single SARS-CoV-2 IgG-positive results (71.05%;
< 0.001) and SARS-CoV-2 IgM- and IgG-positive results (39.39%;
< 0.001). The S/CO ratios of SARS-CoV-2 IgM and IgG in false-positive results ranged from 1.0 to 50.0. The false-positive probability of SARS-CoV-2 IgM in the ratios of specimen signals to the cutoff value (S/CO) range (1.0–3.0) was 95.06% (77/81), and the probability of false-positive results of SARS-CoV-2 IgG in the S/CO range (1.0–2.0) was 85.71% (24/28). Dynamic monitoring showed that the S/CO values of IgM in false-positive results decreased or remained unchanged, whereas the S/CO values of IgG in false-positive results decreased. The possibility of false-positive single SARS-CoV-2 IgM-positive and single SARS-CoV-2 IgG-positive results was high. As the value of S/CO ratios decreased, the probability of false-positives consequently increased, especially among the single SARS-CoV-2 IgM-positive results.
LPS plays an important role in the establishment of inflammation. LPS binds to LPS binding protein（LBP）, and CD14 further binds to LPS/LBP complex to induce inflammatory signals into the cell. This ...study examined the relationship between serum LBP levels and ACPA antibodies in long-term（> 5 years）patients with rheumatoid arthritis. To evaluate the clinical significance of LBP as a biomarker, CRP and IL-6, which are indicators of inflammation, were simultaneously measured.In this study, the LBP（Mean±SD）of healthy subjects, the OA group, and the RA group was measured. The measurement results of LBP were 3.7±1.3μg/mL for healthy subjects, 6.1±2.4μg/mL in the OA group, and 11.1±5.2μg/mL in the RA group, which were the highest values in the RA group with statistical significance.Furthermore, LBP tended to increase as the stage and class progressed. In addition, a correlation（r=0.410）was observed with ACPA, and the ACPA positive cases demonstrated significantly（p < 0.002）higher LBP concentration in comparison with the ACPA negative cases.Therefore, the measurement of high-sensitivity LBP may be one of the indicators for new pathological analysis of RA.
Abstract
Heparin-induced thrombocytopenia (HIT) is an antibody-mediated hypercoagulable state featuring high thrombosis risk and distinct pathogenesis involving immunoglobulin G-mediated platelet ...activation. The target of the immune response is a cationic “self” protein, platelet factor 4 (PF4), rendered antigenic by heparin. A key problem is that only a minority of anti-PF4/polyanion antibodies induced by heparin are pathogenic, i.e., capable of causing platelet activation and thereby clinical HIT. Since thrombocytopenia occurs frequently in hospitalized, heparin-treated patients, testing for “HIT antibodies” is common; thus, the problem of distinguishing between pathogenic and nonpathogenic antibodies is important. The central concept is that those antibodies that have platelet-activating properties demonstrable in vitro correlate well with pathogenicity, as shown by platelet activation tests such as the serotonin-release assay (SRA) and heparin-induced platelet activation assay. However, in most circumstances, immunoassays are used for first-line testing, and so it is important for clinicians to appreciate which immunoassay result profiles—in the appropriate clinical context—predict the presence of platelet-activating antibodies (Bayesian analysis). Clinicians with access to rapid, on-demand HIT immunoassays (e.g., particle gel immunoassay, latex immunoturbidimetric assay, chemiluminescent immunoassay) can look beyond simple dichotomous result interpretation (“negative”/“positive”) and incorporate semiquantitative interpretation, where, for example, a strong-positive immunoassay result (or even combination of two immunoassays) points to a greater probability of detecting platelet-activating antibodies, and hence supporting a diagnosis of HIT. Recent recognition of “SRA-negative HIT” has increased the importance of semiquantitative interpretation of immunoassays, given that strong immunoassay reactivity is a potential clue indicating possible HIT despite a (false) negative platelet activation assay.
Background and Objectives
Voluntary non‐remunerated blood donors (VNRBDs) are recognized as being crucial for the safety and sustainability of national blood supplies. Systems based on replacement ...donors (RDs) pose high risks of transfusion transmissible infections (TTIs). Currently, only 10%–13% of blood donations are voluntary in Pakistan. No large‐scale studies have been conducted to objectively evaluate the impact of the mode of donation on the frequency of TTIs, a gap this study aimed to fill.
Materials and Methods
The study was conducted at the Indus Hospital, Karachi. Data from a total of 591,820 blood donations were included from 1 October 2017 to 30 May 2021 and evaluated for type of donations and results of TTI testing, primarily performed on Architect i2000SR (Abbott). The TTIs tested include hepatitis B virus, hepatitis C virus, human immunodeficiency virus, syphilis and malaria.
Results
A total of 477,938 (80.7%) RDs and 113,882 (19.3%) VNRBDs were screened. Among these, 53,590 (9.06%) were positive for TTIs. There were 10.2% positive RDs (10.08–10.25 95% confidence interval CI) while 4.4% in VNRBDs (4.29–4.53 95% CI). Co‐infections were observed in 2367 (0.4%) RDs, while 159 (0.02%) in VNRBDs. Geographically, the highest frequency of TTIs was observed in semi‐urban areas of Sindh (11.2%) and Punjab (9.6%). A site‐wise comparison of TTIs in RD versus VNRBD showed significant differences (p‐value 0.00).
Conclusion
RDs are associated with higher frequencies of TTIs, compared with VNRBD. However, the study was unable to assess whether the significant difference was related to individual risk or repeat/first time status of the donors. Other important variables affecting frequency are the catchment area of the blood donors in Pakistan. Urban areas have less prevalence than semi‐urban areas.
The worldwide pandemic of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has continued to date. Given that some of the patients with coronavirus disease 2019 (COVID-19) are ...asymptomatic, antibody tests are useful to determine whether there is a previous infection with SARS-CoV-2. In this study, we measured IgM and IgG antibody titers against SARS-CoV-2 in the serum of asymptomatic healthy subjects in The University of Tokyo, Japan.
From June 2020, we recruited participants, who were students, staff, and faculty members of The University of Tokyo in the project named The University of Tokyo COVID-19 Antibody Titer Survey (UT-CATS). Following blood sample collection, participants were required to answer an online questionnaire about their social and health information. We measured IgG and IgM titers against SARS-CoV-2 using iFlash-SARS-CoV-2 IgM and IgG detection kit which applies a chemiluminescent immunoassay (CLIA) for the qualitative detection.
There were 6609 volunteers in this study. After setting the cutoff value at 10 AU/mL, 32 (0.48%) were positive for IgG and 16 (0.24%) for IgM. Of six participants with a history of COVID-19, five were positive for IgG, whereas all were negative for IgM. The median titer of IgG was 0.40 AU/mL and 0.39 AU/mL for IgM. Both IgG and IgM titers were affected by gender, age, smoking status, and comorbidities.
Positive rates of IgG and IgM titers were relatively low in our university. Serum levels of these antibodies were affected by several factors, which might affect the clinical course of COVID-19.
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