Solid Phase Plates Are Crucial to Accurate ELISA Tests

Celiac.com 02/05/2020 - The enzyme-linked immunosorbent assay (ELISA) is a critical diagnostic tool for spotting or differentiating diseases, such as celiac disease, and other autoimmune conditions, and also to monitor disease progression or drug efficacy. However, accuracy is a crucial factor in such tests. 

Chitinase-3-like protein 1, aka CHI3L1, is a potential new culprit in inflammatory bowel disease (IBD). A team of researchers recently set out to develop an ELISA that can identify IgA and IgG autoantibodies against chitinase-3-like protein 1 (CHI3L1), in the serum of both control and disease groups.

Celiac.com Sponsor (A12):
The research team included Claudia Deutschmann, Dirk Roggenbuck, Peter Schierack, and Stefan Rödigera. They are variously affiliated with the Institute of Biotechnology, Faculty Environment and Natural Sciences, Brandenburg University of Technology Cottbus-Senftenberg, Universitätsplatz 1, 01968 Senftenberg, Germany; and the Faculty of Health Sciences, Joint Faculty of the Brandenburg University of Technology Cottbus - Senftenberg, The Brandenburg Medical School Theodor Fontane, The University of Potsdam, Senftenberg, Germany.

While ELISA is often used to spot the difference between diseased or healthy states, it can also be used for quantitative assessment of biomarkers, like autoantibodies. In this way, ELISA technology can help to discover and confirm new autoantibodies. 

Researchers have been keen to develop immunoassays that can detect diseases, such as celiac disease in the early stages. 

To produce an ELISA, researchers must work extra hard, and they can be forced to deal with numerous factors, including buffer systems or antigen-autoantibody interactions. This often means lots of testing to dial-in several blocking substances to yield highly accurate results. In this case, the research team developed an ELISA to detect IgA and IgG autoantibodies against chitinase-3-like protein 1 (CHI3L1), a newly identified autoantigen in inflammatory bowel disease (IBD), in the serum of 23 control subjects and 23 disease patients.

The spot any issues with reproducibility, the team tested microwell plates with both PolySorp and MaxiSorp surface coatings. Among the important issues they discovered with the surface properties of the microwell plates: IgA antibody reactivity was markedly lower, since it was in the range of background noise, when measured on MaxiSorp coated plates (p < 0.0001). 

The IgG antibody reactivity did not change between plates, but the plate surface significantly influenced test results (p = 0.0005). The team's report, published in Heliyon highlights the properties of solid phases and their effects on the detection of autoantibodies by ELISA. 

They advise that using the wrong plate can cause false negative readings, which can impair the discovery of autoantibodies, such as Chitinase-3-like protein 1, aka CHI3L1. Poor accuracy can impair the ability of doctors to accurately diagnose celiac and other diseases.

Read more in Heliyon. 2020 Jan; 6(1): e03270.