Monitoring changes to anti-acetylcholine receptor antibodies (anti-AChR-ab) was found to be a useful indicator in the diagnosis and monitoring of myasthenia graves (MG), according to study findings published in the European Journal of Neurology.

MG is a neuromuscular autoimmune disease associated with alterations to muscle strength and worsening muscular exhaustion with exertion. Although anti-AChR-ab is used in the diagnosis of MG, there is no consensus on whether monitoring anti-AChR-ab over the course of this chronic disease is beneficial. The objective of the current study was to analyze the potential association between anti-AChR-ab serum levels and the clinical improvement of MG.

This retrospective study analyzed pre-existing data from the Maastricht University Medical Center in the Netherlands. All blood samples (n=837) collected between 1997 and 2020 from patients (N=90) with MG were assessed for trends in anti-AChR-ab over time and associated changes with disease course and outcomes.


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Patients were 61.1% women, aged median 53.5 (range, 18-83) years at baseline, they had been diagnosed with MG 7 (range, 0-300) months previously, 18.9% had thymoma, and 54.4% underwent thymectomy.

During a median follow-up of 72 (range, 16-223) months, 84.4% went into MG remission after a median time of 19 (range, 2-139) months.

Among the cohort of patients who did not achieve remission, 64.3% were women, 64.3% received immunosuppressive therapy, and 46.7% had no improvement to their anti-AChR-ab levels.

In a logistic regression analysis, MG Foundation of America (MGFA) score improvement was associated with a 50% or greater decrease in anti-AChR-ab (adjusted odds ratio [aOR], 3.65; 95% CI, 1.40-9.54; P =.008) and a continuous 10% decrease in anti-AChR-ab (aOR, 1.19; 95% CI, 1.10-1.29; P <.001) concentrations.

Stratified by thymoma status, the decrease in anti-AChR-ab level (10% decrease) was more strongly associated with MGFA score improvement among the thymoma cohort (aOR, 1.37; 95% CI, 1.10-1.70; P =.005) than the cohort of patients without thymoma (aOR, 1.18; 95% CI, 1.09-1.28; P <.001). For thymectomy, the decrease in anti-AChR-ab concentration was more strongly associated with MGFA score improvement among the patients who did not undergo thymectomy (aOR, 1.45; 95% CI, 1.17-1.80; P =.001) than those who did (aOR, 1.14; 95% CI, 1.05-1.25; P =.003).

In a subgroup analysis, women, younger patients, and those with longer remission times were more likely to undergo thymectomy (all P £.028). No group differences were observed for thymoma instances.

This study was limited by having no standardization protocols for timing of anti-AChR-ab assessment. Additional study is needed to develop evidence-based guidelines for anti-AChR-ab follow-up timing.

“A change in anti-AChR-ab serum level is associated with clinical status in patients with MG,” the researchers concluded. They believe this may be useful for improving decision-making and clinical outcomes among patients with MG.

Reference

Marcuse F, Brandts L, Moens D, et al. The association between anti-acetylcholine receptor antibody level and clinical improvement in myasthenia gravis. Eur J Neurol. Published online December 30, 2021. doi:10.1111/ene.15238