Assessment and relevance of enzyme-linked immunosorbent assay for antibodies toSaccharomyces cerevisiaein Australian patients with inflammatory bowel disease

This prospective observational study including consecutive patients with inflammatory bowel disease treated with either infliximab or adalimumab showed that although the correlation between the ELISA and the homogeneous mobility shift assay was good for both drugs, the agreement was poor.

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P092 COMPARISON OF INFLIXIMAB AND ADALIMUMAB CONCENTRATIONS BETWEEN THE ENZYME-LINKED IMMUNOSORBENT ASSAY AND THE HOMOGENEOUS MOBILITY SHIFT ASSAY (HMSA) IN INFLAMMATORY BOWEL DISEASE: AN UPDATE FOLLOWING IMPLEMENTATION OF CORRECTIVE MEASURES FOR THE HMSA

Inflammatory Bowel Diseases ◽

10.1093/ibd/zaa010.176 ◽

2020 ◽

Vol 26 (Supplement_1) ◽

pp. S69-S69

Author(s):

Konstantinos Papamichail ◽

William Clarke ◽

Niels VandeCasteele ◽

Katharine Germansky ◽

Joseph Feuerstein ◽

...

Keyword(s):

Inflammatory Bowel Disease ◽

Immunosorbent Assay ◽

Drug Concentration ◽

Bowel Disease ◽

Enzyme Linked Immunosorbent Assay ◽

Therapeutic Drug ◽

Mobility Shift ◽

Drug Concentrations ◽

Inflammatory Bowel ◽

Mobility Shift Assay

Abstract Background and aims We previously showed a discrepancy between a commercially available enzyme-linked immunosorbent assay (ELISA) and the homogenous mobility shift assay (HMSA) for both infliximab and adalimumab concentrations in patients with inflammatory bowel disease (IBD).1 Based also on the results of this study, Prometheus Laboratories initiated a comprehensive review of their HMSA assays and found that there was an upward drift for both infliximab and adalimumab over a 2-year period, including when our study was being performed. Prometheus corrected the errant values and reported the revised drug concentrations to physicians. We aimed to compare these two assays following the implementation of these corrective measures. Methods Samples from patients with IBD either on infliximab or adalimumab maintenance therapy were prospectively evaluated using both ELISA (InformTx™, Inform Diagnostics) (for research purposes) and the HMSA (ANSER™, Prometheus Laboratories) (performed clinically). Comparison of drug concentrations between assays was performed as previously described.1 Results In total 74 samples were analysed (infliximab, n=45; adalimumab, n=29). Drug concentrations (median [interquartile range, IQR]) were still significantly higher when measured by the HMSA compared to ELISA for foth infliximab (9 [7.1–12.4] vs. 5.7 [4.8–9] μg/ml; p<0.001, respectively) and adalimumab (12.9 [10.3–16.9] vs. 10.6 [8.6–14] μg/ml; p=0.036, respectively). The correlation of infliximab and adalimumab concentrations between assays is depicted in Figure 1. Agreement between assays was moderate [ICC: 0.658; 95% confidence interval (CI): -0.080 to 0.892; p<0.001] for infliximab and strong (ICC = 0.826, 95%CI: -0.066 to 0.949, p<0.001) for adalimumab. A Bland–Altman plot of infliximab and adalimumab concentrations to compare the two assays is shown in Figure 2. Qualitative agreement in drug concentration status (therapeutic or sub-therapeutic) was only minimal between assays using >5 μg/ml (K = 0.299, p=0.005), >7 μg/ml (K = 0.303, p=0.005) or >10 μg/ml (K = 0.323, p=0.003) as therapeutic drug concentrations for infliximab, while for adalimumab was weak using >10 μg/ml as therapeutic drug concentrations (K = 0.437, p=0.004), although overall agreement using either >5 or >7 μg/ml as therapeutic drug concentrations was 97%. Conclusions These data suggest that although the correlation between the ELISA and the HMSA was very good for both infliximab and adalimumab it is difficult to compare absolute drug concentrations. Until commercial assays are properly cross-validated and standardized, assay-dependent drug concentration thresholds may need to be applied to better interpret therapeutic drug monitoring results and it is advisable that patients are monitored with the same assay. 1Inflamm Bowel Dis. 2019 Sep 27. https://doi.org/10.1093/ibd/izz202. [Epub ahead of print]

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The Clinical Accuracy of the BÜHLMANN fCAL ELISA in the Differentiation of Inflammatory Bowel Disease From Irritable Bowel Syndrome: A Multicenter Prospective Case–Control Study

Crohn's & Colitis 360 ◽

10.1093/crocol/otz037 ◽

2019 ◽

Vol 1 (3) ◽

Author(s):

Jeffrey A Berinstein ◽

Calen A Steiner ◽

Athos Bousvaros ◽

Felix P Tiongco ◽

Eugene Greenberg ◽

...

Keyword(s):

Inflammatory Bowel Disease ◽

Irritable Bowel Syndrome ◽

Bowel Disease ◽

Case Control Study ◽

Case Control ◽

Enzyme Linked Immunosorbent Assay ◽

Inflammatory Bowel ◽

Irritable Bowel ◽

Control Study ◽

Prospective Case Control Study

Abstract Background Fecal calprotectin (fCAL) is a noninvasive biomarker used to differentiate between inflammatory bowel disease (IBD) and irritable bowel syndrome (IBS). Methods A multicenter prospective case–control study evaluating the BÜHLMANN fCAL enzyme-linked immunosorbent assay (ELISA) was conducted in 478 subjects. Sensitivity, specificity, predictive values, and area under the receiver operator characteristic (AuROC) curve are reported and compared to another device. Results In differentiating IBD from IBS, the BÜHLMANN fCAL ELISA is very sensitive (93.3%) at a cutoff <80 μg/g and balanced sensitivity (84.4%) and specificity (85.4%) at a cutoff >160 μg/g (AuROC 0.933). Conclusions The BÜHLMANN fCAL ELISA demonstrates excellent discriminating between IBD and IBS.

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Anti-TNF-α Monoclonal Antibody Therapy Improves Anemia through Downregulating Hepatocyte Hepcidin Expression in Inflammatory Bowel Disease

Mediators of Inflammation ◽

10.1155/2019/4038619 ◽

2019 ◽

Vol 2019 ◽

pp. 1-13

Author(s):

Weigang Shu ◽

Zhi Pang ◽

Chunjin Xu ◽

Jian Lin ◽

Gengfeng Li ◽

...

Keyword(s):

Inflammatory Bowel Disease ◽

Iron Metabolism ◽

Bowel Disease ◽

Caspase 3 ◽

Enzyme Linked Immunosorbent Assay ◽

Anemia Of Chronic Disease ◽

Hepcidin Expression ◽

Serum Hepcidin ◽

Inflammatory Bowel

Anemia is one of the most common complications in patients with inflammatory bowel disease (IBD). Hepcidin as a key regulator of iron metabolism is pivotal in mediating the occurrence of anemia of chronic disease. Herein, we analyzed the levels of hepcidin in sera from IBD patients by enzyme-linked immunosorbent assay and investigated its potential role in regulating the anemia in IBD. We observed that the levels of serum hepcidin were increased in active IBD patients compared with those in remitted IBD patients and healthy controls and that serum hepcidin was associated with disease activity, CRP, and ESR, respectively. Importantly, we found that the increased levels of serum hepcidin were positively correlated with the severity of anemia and the imbalance of iron metabolism in anemic UC and CD patients. Proinflammatory factors (e.g., IL-6, IL-17, and TNF-α) were positively correlated with the concentrations of serum hepcidin in IBD patients. Interestingly, hepcidin was found to be decreased in patients with Crohn’s disease after successful therapy with anti-TNF-α mAb (i.e., infliximab), indicating the underlying association between TNF-α and hepcidin expression. To investigate the specific mechanisms involved, we cultured LO2 and HepG2 cell lines in vitro under stimulation with TNF-α and observed that the levels of hepcidin mRNA were markedly upregulated in caspase-3/8- and NF-κB-dependent manners. Therefore, our data suggest that TNF-α stimulates the expression of hepcidin in IBD patients, resulting in aggravated anemia and that blockage of TNF-α or the caspase-3/8 and NF-κB pathways could downregulate hepcidin expression. This study provides inspiration for the therapy and management of anemia in IBD.

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Expression of interleukin 1β and interleukin 1β converting enzyme by intestinal macrophages in health and inflammatory bowel disease

Gut ◽

10.1136/gut.42.2.214 ◽

1998 ◽

Vol 42 (2) ◽

pp. 214-219 ◽

Cited By ~ 121

Author(s):

M E McAlindon ◽

C J Hawkey ◽

Y R Mahida

Keyword(s):

Inflammatory Bowel Disease ◽

Bowel Disease ◽

Colonic Mucosa ◽

Peripheral Blood Monocyte ◽

Interleukin 1Β ◽

Enzyme Linked Immunosorbent Assay ◽

Normal Colonic Mucosa ◽

Converting Enzyme ◽

Inflammatory Bowel ◽

Targeted Inhibition

Background—In the lipopolysaccharide (LPS) stimulated peripheral blood monocyte, the precursor form of interleukin 1β (IL-1β, 31 kD) is processed by IL-1β converting enzyme (ICE) to the mature, bioactive form (17 kD). IL-1β is a proinflammatory cytokine which is likely to have a role in the pathogenesis of inflammatory bowel disease (IBD).Aims—To investigate the expression and processing of IL-1β and ICE by tissue macrophages from normal and IBD colonic mucosa.Methods—Mucosal biopsy specimens and lamina propria cells from normal and IBD colons were studied by reverse transcription polymerase chain reaction (RT-PCR), western blot analysis, and ELISA (enzyme linked immunosorbent assay).Results—Normal colonic macrophages synthesised only the precursor form of IL-1β whereas in IBD the mature form was also produced. Similarly, cells from normal colonic mucosa synthesised ICE as the precursor (p45) only, whereas macrophages from IBD colons produced active (p20) ICE. Ac-Tyr-Val-Ala-Asp-CHO, a specific peptide aldehyde inhibitor of ICE, significantly reduced the amount of mature IL-1β released by isolated IBD macrophages (from a median of 1.2 (range 0.78–4.42) ng/ml to 0.43 (0.21–1.6) ng/ml; p<0.01).Conclusions—Exposure of normal colonic macrophages to LPS only induces the production of the precursor form of IL-1β, because the cells fail to activate ICE. In contrast, IBD colonic macrophages are able to activate ICE and hence release mature IL-1β in a manner similar to circulating monocytes. This is consistent with IBD macrophages being recently recruited from the circulating monocyte population. Targeted inhibition of ICE may represent a novel form of therapy in IBD.

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An Evaluation of the Correlation between Hepcidin Serum Levels and Disease Activity in Inflammatory Bowel Disease

Gastroenterology Research and Practice ◽

10.1155/2015/810942 ◽

2015 ◽

Vol 2015 ◽

pp. 1-4 ◽

Cited By ~ 11

Author(s):

Zehra Betül Paköz ◽

Cem Çekiç ◽

Mahmut Arabul ◽

Elif Sarıtaş Yüksel ◽

Serkan İpek ◽

...

Keyword(s):

Inflammatory Bowel Disease ◽

Disease Activity ◽

Bowel Disease ◽

Active Phase ◽

Serum Levels ◽

Enzyme Linked Immunosorbent Assay ◽

C Reactive Protein ◽

Reactive Protein ◽

Inflammatory Bowel ◽

The Mean

Aim. While there are many well-defined serological markers for inflammatory bowel disease (IBD), there is limited evidence that they positively affect clinical outcomes. This study aimed to evaluate the correlation between hepcidin serum levels and disease activity in IBD.Materials and Methods. Eighty-five consecutive IBD patients were enrolled in the study. Hepcidin serum levels were assessed using an enzyme-linked immunosorbent assay (ELISA) and were compared with disease activity as well as the interleukin-6 (IL-6) and C-reactive protein (CRP) levels.Results. The mean hepcidin serum levels in Crohn’s disease (CD) patients in remission and in the active phase were3837±1436and3752±1274 pg/mL, respectivelyP=0.613. The mean hepcidin serum levels in ulcerative colitis (UC) patients in remission and in the active phase were4285±8623and3727±1176 pg/mL, respectivelyP=0.241. Correlation analysis between inflammatory markers and hepcidin serum levels indicated that there was no correlation between hepcidin levels and IL-6P=0.582or CRPP=0.783.Conclusion. As an acute-phase protein, hepcidin seems to have a lower efficacy than other parameters in the detection of activation in IBD.

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P295 Comparative Assessment of Infliximab Trough Levels between Point-of-Care Testing and current Standard of Care (enzyme linked immunosorbent assay) in patients with Inflammatory Bowel Disease

Journal of Crohn s and Colitis ◽

10.1093/ecco-jcc/jjab076.419 ◽

2021 ◽

Vol 15 (Supplement_1) ◽

pp. S325-S325

Author(s):

D Maniero ◽

G Lorenzon ◽

I Marsilio ◽

A Rigo ◽

R Cardin ◽

...

Keyword(s):

Inflammatory Bowel Disease ◽

Bowel Disease ◽

Whole Blood ◽

Point Of Care ◽

Enzyme Linked Immunosorbent Assay ◽

Blood Collection ◽

Point Of Care Testing ◽

Deming Regression ◽

Inflammatory Bowel ◽

Trough Levels

Abstract Background Infliximab (IFX) is a monoclonal antibody that targets cytokine tumor necrosis factor; it is used for the treatment of patients with active inflammatory bowel disease (IBD), including Crohn’s disease (CD) and ulcerative colitis (UC). IFX induces and maintains remission and mucosal healing in patients with IBD. Measurement of trough levels (TL) of IFX is important to assess if the drug is within its therapeutic concentrationand to explain lack/loss of response. Standard laboratory tests to assess IFX trough levels (enzyme linked immunosorbent assays, ELISA) present some downsides, related to the long turnaround (about 3 hours), and the need of specialized equipment and laboratory personnel. For this reason, point-of care testing (POCT) was developed to provide results within a few minutes from blood collection, leading to a decision-making approach. Aim To determine the degree of analytical correlation between a recently developed POCT (ProciseDx) IFX assay which analyze capillary whole blood and the comparative ELISA from serum. Methods From October 2020 to January 2021, patients (aged≥18 years) taking IFX were recruited at Gastroenterology Unit, Padua University Hospital. In each patient, IFX levels from capillary whole blood collected by finger stick were performed using the ProciseDx IFX assay with reportable range between 1.7-77.2 µg/mL; at the same time, a serum sample from venous blood was collected to carry out Grifols’ Promonitor ELISA test (range 0.035–14.4 µg/mL). A Deming regression test was used to identify the correlation between the two methods. Results Eighty-seven patients were enrolled (63% males; mean age of 44±16), with 52% of them having CD, 45% UC and 3% an undetermined-Inflammatory Bowel Disease. The assessment with ProciseDx POCT was feasible in each patient and only in three cases blood collection from finger prick was repeated. Moreover, from blood collection to results we needed about 3±0.5 minutes, while serum ELISA analysis required the collection of at least 40 samples (around three weeks at our centre) and 3 hours to be performed. 39 patients (59% males; mean age of 44±16) had TL as assessed by ProciseDx IFX assay lower than 1.7 or greater than 14.4 µg/mL, in accordance with ELISA assessment. Among the remaining 48 patients (67% males with mean age of 45±17), The correlation between the two tests was high (the total results showed an R squared of 0.691 (95% CI 0.717-0.902). Conclusion The ProciseDx POCT has good accuracy but was more rapid and easy to be performed in providing the results of Therapeutic Drug Monitoring in outpatients taking IFX. This could lead to a more effective optimization of the biological drug, thus avoiding treatment failure.

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