No correlation between acetylcholine receptor antibody concentration and individual clinical symptoms of myasthenia gravis: A systematic retrospective study involving 67 patients

OBJECTIVE: To investigate the correlation between acetylcholine receptor antibodies (AChR‐Ab) concentration levels and individualized clinical symptoms in patients with AChR myasthenia gravis (AChR‐MG) in China. METHODS: ELISA was used to determine the concentration of AChR‐Ab in patients with MG. The Myasthenia Gravis Foundation of America (MGFA) Clinical Classification, Quantitative Myasthenia Gravis (QMG) score, and MG‐specific activities of daily living (MG‐ADL) scoring systems were used to evaluate the clinical status of patients. Spearman correlation analysis was used to determine the correlation between the AChR‐Ab concentration and clinical score. The changes in the antibody concentration and clinical score are shown in MGFA‐antibody concentration–treatment plots. RESULTS: Autoantibody detection tests were performed in 67 patients, and their clinical scores were recorded. Forty‐nine patients received immunosuppressive therapy, 17 patients received pyridostigmine only, and 1 patient under thymectomy without any medication. The AChR‐Ab concentration correlated with the MGFA Classification in 5 (29.4%) patients in the pyridostigmine‐only group and 15 (30.6%) patients in the immunosuppressive drug group. The changes in the MGFA Classification preceded the changes in the AChR‐Ab concentration in 4 (23.5%) patients treated with pyridostigmine and 10 (20.4%) patients on immunosuppressive drugs. In patients on oral non‐steroidal immunosuppressants, the AChR‐Ab concentration changed by more than 50%, whereas the MGFA Classification did not increase. The AChR‐Ab concentration decreased in 17/32 (53.1%) patients after thymectomy, and then increased, whereas the AChR‐Ab concentration increased in 15/32 (46.9%) patients and the MGFA Classification decreased in 27/32 (81.8%) patients after thymectomy. The AChR‐Ab concentration presented a slight correlation with the corresponding MGFA, QMG, and MG‐ADL in patients with thymoma. DISCUSSION: In the Chinese AChR‐MG population, the Changes in the AChR‐Ab concentration in individuals with AChR‐MG did not consistently correlate with the severity of clinical symptoms.