Abstract
Of sera of patients with myasthenia gravis (MG), 30% contains titin and ryanodine receptor (RyR) antibodies. In early-onset MG (i.e., before 50 years of age), the presence of titin antibodies strongly suggests a thymoma. Late-onset MG comprises one MG group, characterized by a broad antimuscle immune response, including both titin and the acetylcholine receptor (AChR). Another group is preferentially associated with the HLA-A3, B7 and DRw2 antigens, representing a delayed early-onset of the disease that has a selective AChR immune response. The presence of titin and RyR antibodies is associated with more severe disease. Titin antibodies may, in some patients with rippling muscle disease, affect the contractile machinery of myofibers, thereby affecting their mechanical sensitivity. It is not known whether this occurs in MG. RyR antibodies may impair excitation–contraction coupling and contribute to muscle weakness in MG patients. Titin antibodies may serve as tumor markers in early-onset MG patients.
Financial & competing interests disclosure
The authors have no relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript. This includes employment, consultancies, honoraria, stock ownership or options, expert testimony, grants or patents received or pending, or royalties.
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