Autoantibody Status Guides Treatment in Myasthenia Gravis

Currently, the gold standard for detection of anti-AChR and MuSK antibodies is radioimmunoprecipitation assay (RIPA) although it comes with a disadvantage of the need for radioactive reagents. Cell-based indirect immunofluorescence assays (CBAs) offer a viable alternative that is easier to implement. EUROIMMUN (Lübeck, Germany) has developed CBAs based on transfected human cell lines expressing the corresponding target antigens AChR (adult: AChR-E and fetal: AChR-G) and MuSK. In an evaluation study published in the Journal of the Neurological Sciences, the EUROIMMUN Anti-AChR CBA demonstrated similarly excellent specificity and a significantly higher sensitivity for MG compared to RIPA, detecting anti-AChR in 21% of patients otherwise considered to be seronegative.

In a further analysis, the Anti-AChR and Anti-MuSK CBAs demonstrated high positive and 100% negative agreement with RIPA in patients with clinically confirmed MG. CBAs thus provide equivalent or superior performance to RIPA without the use of radioactive materials. Moreover, anti-AChR and anti-MuSK antibodies can be analyzed simultaneously using the EUROIMMUN Myasthenia gravis Mosaic 2, which provides a composite of CBAs for adult/fetal AChR and MuSK together with a control substrate. This test is currently the only commercially available multiparameter assay for anti-AChR and anti-MuSK. The CBAs are CE-marked. The CBA procedure is simple and can be performed in any laboratory familiar with indirect immunofluorescence. There are automation options available to aid the processing and evaluation, allowing for the assay’s smooth integration into laboratory routines.

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