A recently published study in Frontiers in Neurology has found a significant iron deficiency in patients, specifically premenopausal females with myasthenia gravis (MG). The study showed that nonanemic immunotherapy-naive patients with MG had considerably lower serum iron (SI) and transferrin saturation (TS) levels than healthy individuals.

The study recruited 105 patients with MG (53 males and 52 females) from the Peking Union Medical College Hospital in Beijing, China, between July 2018 and March 2022. The inclusion criteria for patients were as follows: confirmed diagnosis of MG, a hemoglobin level of at least 120 g/L for male patients or at least 110 g/L for female patients, those who are not following supplementary iron therapy, the minimal manifestation status (MMS) not achieved and immunotherapy required to induce the target MMS, and no history of getting immunotherapy.

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Study results suggested significantly lower levels of SI and TS in the nonanemic immunotherapy-naive patients with MG compared with healthy patients. A larger proportion of the patients with MG reported SI and TS levels below the normal range. Moreover, the premenopausal female patients reported iron deficiency and SI level under 65 µg/dL, but not TS under 25% in those patients with MG. Furthermore, iron metabolism parameters reported no notable change after 12 ± 3 months of immunotherapy in the patients with MG.

“Our study is novel in its kind and is probably the first study to analyze the iron metabolism pattern and factors associated with it in patients with MG, and to compare the iron metabolism pattern between patients with MG and healthy individuals, and that in the same group of patients before and after immunotherapy,” the authors highlighted.

Myasthenia gravis (MG) is an autoimmune disease resulting from the disablement of the postsynaptic membrane at the neuromuscular junction and largely demonstrates skeletal muscle fatigue. Two of the most prevalent pathogenic autoantibodies in MG are the antiacetylcholine receptor antibody and the antimuscle-specific tyrosine kinase antibody.

Prior evidence has demonstrated that iron metabolism disorders might be notable in neuroimmune diseases, including dermatomyositis, multiple sclerosis, and polymyositis, the researchers noted. However, limited studies have investigated iron metabolism patterns and the associated factors in patients with MG, they added.

The authors reported several limitations in the study, including the relatively small sample size and no analysis of the soluble transferrin receptor (sTfR) and sTfR–ferritin index since they were only tested in a small number of included patients.

“Iron inadequacy in patients with MG, particularly premenopausal female patients, should be given more importance, given the essential role of iron in multiple physiological and pathophysiological processes,” the authors concluded.

Reference

Li K, Hou L, Tan Y, et al. Iron metabolism patterns in non-anemic patients with myasthenia gravis a cross-sectional and follow-up studyFront. Neurol. Published online November 22, 2022. doi: 10.3389/fneur.2022.1060204.