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2022 ◽  
Vol 16 (1) ◽  
pp. e0010109
Author(s):  
Ana Hernández-González ◽  
Belén González-Bertolín ◽  
Laura Urrea ◽  
Agnes Fleury ◽  
Elizabeth Ferrer ◽  
...  

Background Neurocysticercosis (NCC), and cystic echinococcosis (CE) are two neglected diseases caused by cestodes, co-endemic in many areas of the world. Imaging studies and serological tests are used in the diagnosis of both parasitic diseases, but cross-reactions may confound the results of the latter. The novel multiplex bead-based assay with recombinant antigens has been reported to increases the diagnostic accuracy of serological techniques. Methodology We set-up an immunoassay based on the multiplex bead-based platform (MBA), using the rT24H (against Cysticercus cellulosae, causing cysticercosis) and r2B2t (against Echinococcus granulosus sensu lato, causing CE) recombinant antigens, for simultaneous and differential diagnosis of these infections. The antigens were tested on 356 sera from 151 patients with CE, 126 patients with NCC, and 79 individuals negative for both diseases. Specificity was calculated including sera from healthy donors, other neurological diseases and the respective NCC or CE sera counterpart. The diagnostic accuracy of this assay was compared with two commercial ELISA tests, Novalisa and Ridascreen, widely used in the routine diagnosis of cysticercosis and CE, respectively. Main findings For the diagnosis of NCC, sensitivity ranged from 57.94–63.49% for the rT24H-MBA, and 40.48–46.03% for Novalisa ELISA depending on exclusion or inclusion of sera having equivocal results on ELISA from the analysis; specificities ranged from 90.87–91.30% and 70.43–76.96%, respectively. AUC values of the ROC curve were 0.783 (rT24H) and 0.619 (Novalisa) (p-value < 0.001). For the diagnosis of CE, the sensitivity of the r2B2t-MBA ranged from 68.87–69.77% and of Ridascreen ELISA from 50.00–57.62%; specificities from 92.47–92.68% and from 74.15–80.98%, respectively. AUC values were 0.717 and 0.760, respectively. Conclusions/Significance Overall, the recombinant antigens tested with the bead-based technology showed better diagnostic accuracy than the commercial assays, particularly for the diagnosis of NCC. The possibility of testing the same serum sample simultaneously for the presence of antibodies against both antigens is an added value particularly in seroprevalence studies for cysticercosis linked to control programs in endemic areas where these two parasites coexist.


PLoS ONE ◽  
2021 ◽  
Vol 16 (12) ◽  
pp. e0260963
Author(s):  
Tatsu Okabe ◽  
Wataru Kobayashi ◽  
Takehiro Hariya ◽  
Shunji Yokokura ◽  
Toru Nakazawa

This study measured the intraoperative anterior aqueous humor concentrations of various cytokines during corneal endothelial transplantation and searched for relationships between these concentrations and postoperative corneal endothelial cell (CEC) depletion. We recruited 30 consecutive patients who underwent corneal endothelial transplantation with Descemet’s stripping automated endothelial keratoplasty (DSAEK) at Tohoku University Hospital between February 2014 and July 2017. During surgery, we obtained aqueous humor samples and later measured the concentrations of 27 cytokines with a Multiplex Bead Assay (Bio-Plex Pro). We counted CECs 1, 6 and 12 months after surgery, and used Spearman’s rank correlation coefficient to identify relationships between CEC depletion and the concentrations of detected cytokines. The loss of CECs 1–6 months after surgery was significantly correlated with IL-7, IP-10, MIP-1a and MIP-1b concentrations (-0.67, -0.48, -0.39, and -0.45, respectively, all P <0.01). CEC loss 1–12 months after surgery was significantly correlated with IL-1b, IL-7, IP-10 and RANTES concentrations (-0.46, -0.52, -0.48, and -0.43, respectively). Multiple regression analysis showed that IL-7 concentration was significantly associated with CEC loss 1–6 months after surgery (b = -0.65, P < 0.01) and IP-10 concentration was associated with CEC loss 1–12 months after surgery (β = -0.38, P < 0.05). These results suggest that not only inflammatory cytokines but also IL-7, a cytokine related to lymphocytes, may be involved in the depletion of CECs after DSAEK, particularly depletion that occurs relatively early.


2021 ◽  
Vol 6 (10) ◽  
pp. 2735
Author(s):  
Ellen M. Cody ◽  
Michael R. Bennett ◽  
Gaurav Gulati ◽  
Qing Ma ◽  
Mekibib Altaye ◽  
...  

2021 ◽  
Vol 20 (1) ◽  
Author(s):  
Alice C. Sutcliffe ◽  
Seth R. Irish ◽  
Eric Rogier ◽  
Micaela Finney ◽  
Sarah Zohdy ◽  
...  

Abstract Background Plasmodium spp. sporozoite rates in mosquitoes are used to better understand malaria transmission intensity, the relative importance of vector species and the impact of interventions. These rates are typically estimated using an enzyme-linked immunosorbent assay (ELISA) utilizing antibodies against the circumsporozoite protein of Plasmodium falciparum, Plasmodium vivax VK210 (P. vivax210) or P. vivax VK247 (P. vivax247), employing assays that were developed over three decades ago. The ELISA method requires a separate assay plate for each analyte tested and can be time consuming as well as requiring sample volumes not always available. The bead-based multiplex platform allows simultaneous measurement of multiple analytes and may improve the lower limit of detection for sporozoites. Methods Recombinant positive controls for P. falciparum, P. vivax210 and P. vivax247 and previously developed circumsporozoite (cs) ELISA antibodies were used to optimize conditions for the circumsporozoite multiplex bead assay (csMBA) and to determine the detection range of the csMBA. After optimizing assay conditions, known amounts of sporozoites were used to determine the lower limit of detection for the csELISA and csMBA and alternate cut-off measures were applied to demonstrate how cut-off criteria can impact lower limits of detection. Sporozoite rates from 1275 mosquitoes collected in Madagascar and 255 mosquitoes collected in Guinea were estimated and compared using the established csELISA and newly optimized csMBA. All mosquitoes were tested (initial test), and those that were positive were retested (retest). When sufficient sample volume remained, an aliquot of homogenate was boiled and retested (boiled retest), to denature any heat-unstable cross-reactive proteins. Results Following optimization of the csMBA, the lower limit of detection was 25 sporozoites per mosquito equivalent for P. falciparum, P. vivax210 and P. vivax247 whereas the lower limits of detection for csELISA were found to be 1400 sporozoites for P. falciparum, 425 for P. vivax210 and 1650 for P. vivax247. Combined sporozoite rates after re-testing of samples that initially tested positive for Madagascar mosquitoes by csELISA and csMBA were 1.4 and 10.3%, respectively, and for Guinea mosquitoes 2% by both assays. Boiling of samples followed by csMBA resulted in a decrease in the Madagascar sporozoite rate to 2.8–4.4% while the Guinea csMBA sporozoite rate remained at 2.0%. Using an alternative csMBA cut-off value of median fluorescence intensity (MFI) of 100 yielded a sporozoite rate after confirmational testing of 3.7% for Madagascar samples and 2.0% for Guinea samples. Whether using csMBA or csELISA, the following steps may help minimize false positives: specimens are appropriately stored and bisected anterior to the thorax-abdomen junction, aliquots of homogenate are boiled and retested following initial testing, and an appropriate cut-off value is determined. Conclusions The csMBA is a cost-comparable and time saving alternative to the csELISA and may help eliminate false negatives due to a lower limit of detection, thus increasing sensitivity over the csELISA. The csMBA expands the potential analyses that can be done with a small volume of sample by allowing multiplex testing where analytes in addition to P. falciparum, P. vivax210 and P. vivax247 can be added following optimization.


Author(s):  
Yong Wang ◽  
TaLesa Aderohunmu ◽  
Henry Bishop ◽  
Isabel McAuliffe ◽  
Hilda N. Rivera ◽  
...  

Babesia duncani is the causative agent of babesiosis in the western United States. The indirect fluorescent antibody (IFA) assay is the diagnostic test of choice for detection of B. duncani specific antibodies. However, this test requires parasitized red blood cells harvested from infected hamsters and test results are often difficult to interpret. To simplify serological testing for B. duncani , a proteomics approach was employed to identify candidate immunodiagnostic antigens. Several proteins were identified by electrospray ionization (ESI) mass spectrometric analysis and four recombinant protein constructs were expressed and used in a multiplex bead assay (MBA) to detect B. duncani -specific antibodies. Two antigens, AAY83295.1 and AAY83296.1, performed well with high sensitivities and specificities. AAY83295.1 had a higher sensitivity (100%) but lower specificity (89%) in comparison to AAY83296.1, which had a sensitivity of 90% and a specificity of 96%. Combining these two antigens did not improve the performance of the assay. This MBA could be useful for diagnosis, serosurveillance, and blood donor screening for B. duncani infection.


Author(s):  
Sarah Gwyn ◽  
Andrew W. Nute ◽  
Eshetu Sata ◽  
Zerihun Tadesse ◽  
Ambahun Chernet ◽  
...  

Programs to eliminate trachoma as a public health problem use prevalence of the clinical sign trachomatous inflammation—follicular (TF) in 1- to 9-year-olds in endemic districts to make decisions to begin or end mass drug administration with azithromycin. Trachomatous inflammation—follicular is used as a proxy for transmission of ocular Chlamydia trachomatis infection. Long-term monitoring of previously endemic districts for recrudescence of ocular C. trachomatis infection would benefit from a simple blood test that could be integrated with other public health programs. In this study, we evaluated multiple tests to measure antibodies against the C. trachomatis antigen Pgp3—a multiplex bead assay (MBA), an ELISA, and two versions of a lateral flow assay (LFA)—in four districts of the Amhara region of Ethiopia with varying levels of TF. Seroprevalence and seroconversion rate (SCR) results were proportional to TF prevalence by district for most tests, with the notable exception of the LFA using colloidal gold as the developing reagent. Changing the test developing reagent to black latex improved agreement between serological measures and TF prevalence and in inter-rater agreement. Seroconversion rate estimates using data derived from the LFA-gold assay were inconsistent with the shape of the age-seroprevalence curve, which did not increase in older ages. These data revealed potential complications with using SCR that will need further evaluation. Data from MBA, ELISA, and LFA with the black test line showed good agreement with each other and proportionality to TF estimates, providing further data that serology has potential utility for trachoma surveillance.


Author(s):  
Jeffrey W. Priest ◽  
Sukwan Handali

The recent introduction of large-scale, population-based serologic surveys in several nations where human African trypanosomiasis (HAT) remains endemic could provide an opportunity to better map the remaining disease foci and to identify asymptomatic, seropositive individuals who are infected with the more chronic form of the parasite, Trypanosoma brucei gambiense (gHAT). We have incorporated a soluble form of variant surface glycoprotein 117 and a recombinant invariant surface glycoprotein 65.1 into a multiplex bead assay (MBA) method that is commonly used for the detection of IgG antibody responses to other neglected tropical diseases. A positive result was defined as reactivity to both antigens. MBA sensitivity and specificity for gHAT infection were 92% and 96%, respectively. Assay specificity for the acute form of disease caused by T.b. rhodesiense (rHAT) was 94%, but the sensitivity was only 63.6%. In the future, additional antigens could be incorporated into the multiplex assay to improve rHAT sensitivity.


2021 ◽  
Vol 11 (14) ◽  
pp. 6430
Author(s):  
Mepur H. Ravindranath ◽  
Narendranath M. Ravindranath ◽  
Carly J. Amato-Menker

The number and the binding affinity, measured as the mean fluorescent intensity (MFI) of HLA-specific IgG antibodies, formed in the sera of end-stage organ disease patients and allograft recipients, referred to as sensitization, may restrict the availability of a donor organ and/or lead to graft failure after transplantation. The MFI of HLA Abs in sera is monitored with the Luminex-based single-antigen bead (SAB) immunoassay. The following two factors may impact the reliable measurement of MFI: one, the HLA structural variants on the SAB, namely, trimeric HLA (closed conformers, CC) and monomeric heavy chains (open conformers, OC); and two, the nature of the detection Abs, namely, IgG heavy-chain binding polyclonal-Fab (IgHPolyFab) or Fc-binding monoclonal-IgG (FcMonoIgG). Anti-CC Abs correlate with positive flow cross-matches, and are considered to be pathogenic and damaging to the graft, whereas anti-OC Abs appear to have little relevance to graft attrition. The presence of both CC and OC on beads may impair the reliability of monitoring the nature and MFI of pathogenic Abs. Our objective is to compare the MFI of the HLA Abs in the sera of 20 sensitized patients in two different SAB assays, with the two detection Abs. Our data reveal that the admixture of OC with CC on beads will affect the reliability of the measurement of the pathogenic Abs, and that FcMonoIgG is the more sensitive and specific detection Ab for the accurate assessment of HLA sensitization.


Author(s):  
Sarah Gwyn ◽  
Solomon Aragie ◽  
Dionna M. Wittberg ◽  
Jason S. Melo ◽  
Adane Dagnew ◽  
...  

Multiplex bead assays (MBAs) for serologic testing have become more prevalent in public health surveys, but few studies have assessed their test performance. As part of a trachoma study conducted in a rural part of Ethiopia in 2016, dried blood spots (DBS) were collected from a random sample of 393 children aged 0 to 9 years, with at least two separate 6-mm DBS collected on a filter card. Samples eluted from DBS were processed using an MBA on the Luminex platform for antibodies against 13 antigens of nine infectious organisms: Chlamydia trachomatis, Vibrio cholera, enterotoxigenic Escherichia coli, Cryptosporidium parvum, Entamoeba histolytica, Camplyobacter jejuni, Salmonella typhimurium Group B, Salmonella enteritidis Group D, and Giardia lamblia. Two separate DBS from each child were processed. The first DBS was run a single time, with the MBA set to read 100 beads per well. The second DBS was run twice, first at 100 beads per well and then at 50 beads per well. Results were expressed as the median fluorescence intensity minus background (MFI–BG), and classified as seropositive or seronegative according to external standards. Agreement between the three runs was high, with intraclass correlation coefficients of > 0.85 for the two Salmonella antibody responses and > 0.95 for the other 11 antibody responses. Agreement was also high for the dichotomous seropositivity indicators, with Cohen’s kappa statistics exceeding 0.87 for each antibody assay. These results suggest that serologic testing on the Luminex platform had strong test performance characteristics for analyzing antibodies using DBS.


2021 ◽  
Vol 10 (13) ◽  
pp. 2986
Author(s):  
Laura Martinez Valenzuela ◽  
Juliana Draibe ◽  
Oriol Bestard ◽  
Xavier Fulladosa ◽  
Francisco Gómez-Preciado ◽  
...  

Background: Acute tubulointerstitial nephritis (ATIN) diagnosis lays on histological assessment through a kidney biopsy, given the absence of accurate non-invasive biomarkers. The aim of this study was to evaluate the accuracy of different urinary inflammation-related cytokines for the diagnostic of ATIN and its distinction from acute tubular necrosis (ATN). Methods: We included 33 patients (ATIN (n = 21), ATN (n = 12)), and 6 healthy controls (HC). We determined the urinary levels of 10 inflammation-related cytokines using a multiplex bead-based Luminex assay at the time of biopsy and after therapy, and registered main clinical, analytical and histological data. Results: At the time of biopsy, urinary levels of I-TAC/CXCL11, CXCL10, IL-6, TNFα and MCP-1 were significantly higher in ATIN compared to HC. A positive correlation between the extent of the tubulointerstitial cellular infiltrates in kidney biopsies and the urinary concentration of I-TAC/CXCL11, MIG/CXCL9, CXCL10, IL17, IFNα, MCP1 and EGF was observed. Notably, I-TAC/CXCL11, IL-6 and MCP-1 were significantly higher in ATIN than in ATN, with I-TAC/CXCL11 as the best discriminative classifier AUC (0.77, 95% CI 0.57–0.95, p = 0.02). A combinatory model of these three urinary cytokines increased the accuracy in the distinction of ATIN/ATN compared to the individual biomarkers. The best model resulted when combining the three cytokines with blood eosinophil and urinary leukocyte counts (LR = 9.76). Follow-up samples from 11ATIN patients showed a significant decrease in I-TAC/CXCL11, MIG/CXCL9 and CXCL10 levels. Conclusions: Urinary I-TAC/CXCL11, CXCL10, IL6 and MCP-1 levels accurately distinguish patients developing ATIN from ATN and healthy individuals and may serve as novel non-invasive biomarkers in this disease.


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