Increased levels of serum neurofilament heavy chain in patients with myasthenia gravis are consistent with muscle denervation, a new study published in Muscle & Nerve reported. “We suggest that there is ongoing remodeling of the neuromuscular junction in myasthenia gravis,” the authors of the study wrote. “Longitudinal quantification of neurofilament isoform levels will be needed to investigate the prognostic value and potentially guide treatment decisions.”
To test whether the levels of serum neurofilament heavy chain, a biomarker for axonal degeneration, are elevated in patients with myasthenia gravis, researchers from University College London Institute of Neurology, Department of Neuroimmunology & The National Hospital for Neurology and Neurosurgery in the United Kingdom analyzed 70 patients with ocular myasthenia gravis and 74 healthy controls.
Read more about the diagnosis of myasthenia gravis
They found that the serum levels of neurofilament heavy chain were significantly higher in patients with myasthenia gravis than in healthy controls (0.19 ng/mL vs 0.07 ng/mL).
Statistical analysis revealed that a cutoff level of 0.06 ng/mL yielded a diagnostic sensitivity of 82% and a diagnostic specificity of 76%. It also gave a positive predictive value of 0.77 and a negative predictive value of 0.81.
“The increase of serum neurofilament heavy chain levels in myasthenia gravis is consistent with observations of muscle denervation,” the researchers said.
Myasthenia gravis is a rare neuromuscular disease affecting the neuromuscular junction that is characterized by the presence of autoantibodies that attack the nicotinic acetylcholine receptors found in the postsynaptic membranes of muscle cells, in most cases. Muscle denervation in myasthenia gravis is associated with muscle atrophy and symptoms such as droopy eyelids, impaired walking, and difficulties speaking, swallowing, and breathing.
There are several tests available to diagnose myasthenia gravis, but the disease remains difficult to diagnose due to the symptoms overlapping with those of many other diseases.
Wong SH, Petzold A. Remodeling of the neuromuscular junction in myasthenia gravis increases serum neurofilament heavy chain levels. Muscle Nerve. Published online May 5, 2023. doi:10.1002/mus.27838