Neuropsychiatric Disease and Treatment (Mar 2024)

Clinical Features and Prognostic Analysis of MuSK-Antibody-Positive Myasthenia Gravis versus Double-Seropositive Myasthenia Gravis: A Single-Center Study from Central South China

  • He T,
  • Chen K,
  • Li Y,
  • Luo Z,
  • Luo M,
  • Yang H

Journal volume & issue
Vol. Volume 20
pp. 725 – 735

Abstract

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Ting He,1,* Kangzhi Chen,1,* Yi Li,1 Zhaohui Luo,1 Mengchuan Luo,2 Huan Yang1 1Department of Neurology, Xiangya Hospital, Central South University, Changsha, 410008, People’s Republic of China; 2Department of Geriatrics, Xiangya Hospital, Central South University, Changsha, 410008, People’s Republic of China*These authors contributed equally to this workCorrespondence: Huan Yang, Department of Neurology, Xiangya Hospital, Central South University, 87 Xiangya Road, Changsha, 410008, People’s Republic of China, Email [email protected]: To decipher the discrepancies between muscle-specific kinase antibody-positive myasthenia gravis (MuSK-MG) and double-seropositive myasthenia gravis (DSP-MG), and to determine prognostic factors for minimal manifestation status (MMS) achievement in MG patients with MuSK autoantibodies (MuSK-Ab).Patients and Methods: A total of 34 MG patients seropositive for MuSK-Ab were enrolled in this study. The demographic and clinical features were compared between MuSK-MG (n = 28) and DSP-MG (n = 6) patients, and factors affecting MMS induction in all patients with MuSK-Ab were identified using Cox regression analysis.Results: Compared to MuSK-MG patients, those with DSP-MG had similar clinical characteristics, except that they had a lower frequency of bulbar muscle involvement at nadir (50% vs 92.9%; P = 0.029) and higher proportions of comorbidities with diabetes mellitus (33.3% vs 0%; P = 0.027) and thymic abnormalities (33.3% vs 0%; P = 0.027). Higher MG Activities of Daily Living (MG-ADL) scores (HR = 0.16, 95% CI: 0.037– 0.7, P = 0.015) and axial muscle involvement at nadir (HR = 0.39, 95% CI: 0.16– 0.94, P = 0.035) were negative prognostic factors for MMS achievement in patients with MuSK-Ab regardless of acetylcholine receptor antibody (AChR-Ab) positivity. Multivariable Cox regression analysis further established higher MG-ADL scores at the nadir (HR = 0.19, 95% CI: 0.04– 0.94; P = 0.042) as an independent risk factor for MMS achievement.Conclusion: DSP-MG was comparable to MuSK-MG and could be considered a single entity in our cohort. In all MG patients with MuSK-Ab, a higher MG-ADL score at nadir may herald a lower chance of MMS achievement, with no observed potential effect of AChR-Ab presence.Keywords: double-seropositive myasthenia gravis, muscle-specific kinase antibody, acetylcholine receptor antibody, minimal manifestation status, myasthenia gravis activities of daily living

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