Evaluating an In-House Cell-Based Assay for Detecting Antibodies Against Muscle-Specific Tyrosine Kinase in Myasthenia Gravis
Min Ju Kim, Seung Woo Kim, Mingi Kim, Young‐Chul Choi, Seung Min Kim, Ha Young Shin
Abstract
BACKGROUND AND PURPOSE: Detecting antibodies against muscle-specific tyrosine kinase (MuSK Abs) is essential for diagnosing myasthenia gravis (MG). We applied an in-house cell-based assay (CBA) to detect MuSK Abs. METHODS: A stable cell line was generated using a lentiviral vector, which allowed the expression of MuSK tagged with green fluorescent protein in human embryonic kidney 293 (HEK293) cells. Serum and anti-human IgG antibody conjugated with red fluorescence were added. The presence of MuSK Abs was determined based on the fluorescence intensity and their colocalization in fluorescence microscopy. Totals of 218 serum samples collected from 177 patients with MG, 31 with other neuromuscular diseases, and 10 healthy controls were analyzed. The CBA results were compared with those of a radioimmunoprecipitation assay (RIPA) and an enzyme-linked immunosorbent assay (ELISA). RESULTS: <0.001). CONCLUSIONS: The results of the in-house CBA showed excellent agreement with both the RIPA and ELISA. Our in-house CBA can be considered a reliable method for detecting MuSK Abs.