MG with anti-MuSK antibodies (MuSK+) is often characterized with muscle atrophy and excellent response to plasma exchanges. To elucidate some MuSK+ MG features, we analyzed the functional effects of anti-MuSK Abs in human TE 671 muscle cells. We found that some MuSK+ sera induced a striking inhibition of proliferation, accompanied by: 1) cell cycle arrest, 2) atrogin-1 overexpression, 3) AChR subunits, rapsyn, Rho A and cdc42 downregulation. These effects correlated to disease severity and to anti-MuSK Abs titer and vanished following PE. Altogether, these results indicate that anti-MuSK Abs could be pathogenic by contributing to the muscle atrophy in MuSK+ MG patients.
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http://dx.doi.org/10.1016/j.jneuroim.2006.05.017 | DOI Listing |
Front Neurol
January 2023
Department of Neurology, Charité-Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin, Germany.
Background: This study aimed to evaluate the association of neurofilament light chain (Nfl) with neuromuscular destruction and disease severity in the serum of patients with myasthenia gravis (MG).
Materials And Methods: Sera from 134 patients with MG with varying degrees of disease severity and autoantibody (Abs) status were analyzed and compared to controls in a cross-sectional design. Prospectively, we additionally measured serum NfL (sNfl) levels in patients with MG longitudinally for up to 3 years.
Int J Mol Sci
August 2021
Dipartimento di Medicina e Chirurgia Traslazionale, Sezione di Patologia Generale, Fondazione Policlinico Universitario "A. Gemelli" IRCCS, Università Cattolica del Sacro Cuore, 00168 Rome, Italy.
Myasthenia gravis with antibodies (Abs) against the muscle-specific tyrosine kinase (MuSK) is a rare autoimmune disorder (AD) of the neuromuscular junction (NMJ) and represents a prototype of AD with proven IgG4-mediated pathogenicity. Thanks to the mechanism of Fab-arm exchange (FAE) occurring in vivo, resulting MuSK IgG4 k/λ Abs increase their interference on NMJ and pathogenicity. The characterization of hybrid MuSK IgG4 as a biomarker for MG management is poorly investigated.
View Article and Find Full Text PDFZhonghua Yi Xue Za Zhi
August 2021
Department of Neurology, Peking Union Medical College (PUMC)Hospital,Chinese Academy of Medical Science,Beijing 100730,China.
To determine the correlation between the titer of anti-muscle-specific tyrosine kinase (anti-MuSK) antibodies (Abs) and the severity and prognosis of Musk-associated myasthenia gravis (Musk-MG). A total of 33 MuSK-MG patients diagnosed at Department of Neurology, Peking Union Medical College Hospital from May 2018 to June 2020 were prospectively included. Patients were divided into different groups according to immune state, and the immune naive patients were further divided by the Myasthenia Gravis Foundation of America (MGFA) classification.
View Article and Find Full Text PDFFront Immunol
March 2021
Istituto di Neurologia, Università Cattolica del Sacro Cuore, Rome, Italy.
The use of rituximab (RTX), an anti-CD20 monoclonal antibody (Ab), in refractory myasthenia gravis (MG) is associated with a better response in patients with Abs to the muscle-specific tyrosine kinase (MuSK) than in other MG subgroups. Anti-MuSK Abs are mostly IgG4 with proven pathogenicity and positive correlation with clinical severity. The rapid and sustained response to RTX may be related to MuSK Ab production by short-lived Ab-secreting cells derived from specific CD20 B cells.
View Article and Find Full Text PDFActa Neurol Belg
September 2018
Department of Biomedical, Metabolic and Neural Sciences, University Hospital, Modena, Italy.
An unsolved issue remains whether there are clinical and immunological features to predict in a single patient the risk of conversion from ocular Myasthenia Gravis (OMG) to generalized disease (GMG) as 50-60% of patients may progress within 1-2 years since onset. Anti-acetylcholine receptor antibodies (AChR Abs) are found in up to 50% of OMG patients; muscle-specific tyrosine kinase antibodies (MuSK-Abs) are present in about 70% of the whole seronegative (SN), who usually develop a severe disease with bulbar involvement. We surveyed a cohort of 175 OMG patients with purely ocular symptoms and we compare the outcome of patients with antibodies to AChR or to MuSK with those seronegative for both Abs (DSN).
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