By Anne Hartenhauer
More than 90% of patients with signs and symptoms of myasthenia gravis can be readily detected and treated with a range of effective therapies. The key to early diagnosis and treatment that can lead to remission is the selection of sensitive, specific, and proven assays to detect and quantify the autoantibodies that cause myasthenia gravis. Fortunately, there are high-quality assays on the market that can save you valuable time in diagnostic procedures*, eliminate the need to develop in-house solutions, and ensure accurate and early disease detection.
Reliable and sensitive detection of autoantibodies in myasthenia gravis patients is crucial for diagnosis and treatment monitoring.
Myasthenia gravis: reliably identifying ARAb-positive patients
The first step in diagnosing myasthenia gravis (MG) is to perform a radioreceptor assay (RRA) to detect acetylcholine receptor autoantibodies (ARAbs). About 85% of patients with clinical symptoms of myasthenia disease will express ARAbs detectable with a RRA.
“We originally trialed and validated the Tecan ARAb RRA on the recommendation of a clinical colleague specializing in MG,” says Dr. Jan Damoiseaux, a Laboratory Specialist in Medical Immunology at Maastricht UMC+ in the Netherlands (see Correct Identification of Autoimmune Diseases). “This assay uses receptors from human muscle in combination with a radiolabeled alpha-bungarotoxin snake venom marker. The venom binds very specifically to acetylcholine receptors without interfering with ARAb binding, so there’s no need to purify the receptor. This is a very clear system, and the assay works very well, with good reproducibility and sensitivity.”
Not only is IBL International / Tecan’s ARAb RRA assay highly sensitive, it is also quantitative, which is particularly important with regard to the treatment of myasthenia gravis. Therapeutic monitoring based on measurements of ARAb-RRA can be used to monitor treatment efficacy and give an early indication of remission..
“Our neurologists aim to achieve a 50% reduction in a patient’s ARAb levels after treatment with immunosuppressants,” says Dr. Damoiseaux. “These therapies take time to work, and so ongoing monitoring of ARAb allows the treatment to be increased or changed if it is not having the desired effect.”
Detecting MuSK autoantibodies in seronegative MG patients
About 15% of patients with clinical symptoms will have no detectable ARAbs. Of these patients with seronegative disease, myasthenia gravis can be diagnosed in approximately 40% of cases based on the detection of autoantibodies to muscle-specific kinase (MuSK). Making an early and definitive diagnosis for these patients is crucial because they tend to have a more severe form of myasthenia gravis that requires more intensive therapy.
A sensitive and quantitative MuSK assay is particularly important because of the role it can play in therapeutic disease monitoring. Unlike with ARAbs, in which the target reduction for remission is 50%, with MuSK autoantibody-positive disease, the target for remission is complete elimimination. Therefore, a sensitive assay is “vital,” says Dr. Damoiseaux, noting that “IBL International / Tecan makes the only commercially-available* quantitative anti-MuSK-Ab ELISA.” He adds, “Our previous experience with the company’s assays gave us confidence in its performance.”
Making diagnosis easier and more reliable
As well as ensuring reliable and consistent results, commercial kits for ARAb and MuSK-Ab detection are saving labs valuable time when implementing a two-assay strategy for myasthenia gravis detection and monitoring.
Like the group at LAB Maastricht UMC+, with Tecan’s kits you can benefit from:
- Fully validated kits that are application-specific for myasthenia gravis
- Time saved not having to purify antibodies or develop your own tests
- Proven robust and reliable performance
- High sensitivity and specificityDeveloped and manufactured to industry-leading standards for quality and compliance
Want to see for yourself? Don’t miss our special offer.
We’re offering new customers a 50% discount on ARAb RRA or MuSK-Ab* ELISA kit.
* MuSK-Ab ELISA CE/IVD marked for European countries. ARAb RRA CE/IVD marked for European countries and 510(k) for the USA.
Tecan product expert
Dr. Constanze Drechsel joined Tecan in 2019 as a product manager responsible for the autoimmunity and infectious disease portfolio. Constanze has a scientific background and completed her PhD research in protein and allergy chemistry and now supports the Global Reagent Marketing & Support department with immunoassay solutions at Tecan.
Dr. Constanze Drechsel
About the author
Anne Hartenhauer joined IBL International / Tecan in 2016 as product manager. She was responsible for Immunoassays in the clinical diagnostic fields infectious disease and autoimmunity.