Li Fengzhan, Zhang Zhouao, Ma Tianyu, Li Yuting, Su Luyao, Wang Zhouyi, Luo Tiancheng, Peng Deyou, Guo Xinyan, Yang Mingjin, Du Xue, Huang Xiaoyu, Zhang Yong
People's Hospital of Jiawang of Xuzhou, Jiawang Branch of Xuzhou Medical University Affiliated Hospital, Xuzhou, Jiangsu, China.
Department of Neurology, The Affiliated Hospital of Xuzhou Medical University, Xuzhou, Jiangsu, China.
Front Immunol. 2025 Jul 25;16:1624038. doi: 10.3389/fimmu.2025.1624038. eCollection 2025.
This study summarized the clinical and immunological characteristics of patients with muscle-specific kinase (MuSK) antibody-positive myasthenia gravis (MG), compared their difference with acetylcholine receptor (AChR) antibody-positive MG, and evaluated the therapeutic efficacy of rituximab (RTX) in MuSK-MG.
This study included 10 MuSK-MG patients and 10 new-onset AChR-MG patients. Clinical and immunological data were collected from medical records before RTX treatment. The efficacy of RTX in MuSK-MG was evaluated by MG-specific activities of daily living (MG-ADL) and quantitative MG (QMG) scores.
All 10 MuSK-MG patients were female with a mean onset age of 44.3 ± 12.0 years, predominantly presenting with bulbar muscle weakness (90%) and limb weakness (80%). Compared to AChR-MG, MuSK-MG showed higher MG-ADL and QMG scores (P < 0.05), along with more frequent bulbar involvement at disease onset (P = 0.036). Immunological analyses revealed elevated CD19B cells and memory B cells in MuSK-MG (P < 0.05). CD4T cells and CD19B cells showed positive correlations with QMG score (r = 0.766, P = 0.027; r = 0.767, P = 0.026), while natural killer (NK) cells were negatively correlated (r = -0.803, P = 0.005) in MuSK-MG. MuSK-MG patients had a mean MG-ADL score of 8.7 ± 2.5 at baseline. Following RTX treatment, MG-ADL score showed significant improvement, decreasing by -5.1 (95% CI: -7.6 to -2.6) at month 1 and -8.0 (95% CI: -11.0 to -5.0) at month 24. Nine patients took prednisone before RTX, with a median daily dosage of 40.0 mg, which decreased to 2.5 mg/day at month 6, and 8 of 9 (88.7%) patients discontinuing prednisone since month 12.
MuSK-MG showed distinct clinical and immunological features, including predominant bulbar/limb onset, elevated CD19B and memory B cells, and disease severity associated CD4T, CD19B and NK-cell alterations. In patients with MuSK-MG, low-dose RTX may be associated with long-term and sustained clinical improvement.
本研究总结了肌肉特异性激酶（MuSK）抗体阳性重症肌无力（MG）患者的临床和免疫学特征，比较其与乙酰胆碱受体（AChR）抗体阳性MG的差异，并评估利妥昔单抗（RTX）在MuSK-MG中的治疗效果。
本研究纳入10例MuSK-MG患者和10例新发AChR-MG患者。收集RTX治疗前病历中的临床和免疫学数据。通过MG日常生活特异性活动（MG-ADL）和定量MG（QMG）评分评估RTX在MuSK-MG中的疗效。
所有10例MuSK-MG患者均为女性，平均发病年龄为44.3±12.0岁，主要表现为延髓肌无力（90%）和肢体无力（80%）。与AChR-MG相比，MuSK-MG的MG-ADL和QMG评分更高（P<0.05），疾病发作时延髓受累更频繁（P=0.036）。免疫学分析显示MuSK-MG中CD19B细胞和记忆B细胞升高（P<0.05）。在MuSK-MG中，CD4T细胞和CD19B细胞与QMG评分呈正相关（r=0.766，P=0.027；r=0.767，P=0.026），而自然杀伤（NK）细胞呈负相关（r=-0.803，P=0.005）。MuSK-MG患者基线时的平均MG-ADL评分为8.7±2.5。RTX治疗后，MG-ADL评分显著改善，第1个月下降-5.1（95%CI：-7.6至-2.6），第24个月下降-8.0（95%CI：-11.0至-5.0）。9例患者在RTX治疗前服用泼尼松，中位日剂量为40.0mg，第6个月降至2.5mg/天，9例患者中有8例（88.7%）自第12个月起停用泼尼松。
MuSK-MG表现出独特的临床和免疫学特征，包括主要的延髓/肢体起病、CD19B和记忆B细胞升高以及与疾病严重程度相关的CD4T、CD19B和NK细胞改变。在MuSK-MG患者中，低剂量RTX可能与长期持续的临床改善相关。
