Background: The prevalence of patients positive for muscle-specific kinase antibody (hereafter, MuSK-Ab) accounts for 5–8% of all myasthenia gravis (MG) cases. Currently, efgartigimod has shown good therapeutic effects in MUSK-Ab-positive MG patients in a phase III clinical trial. However, phase III clinical trials tend to exclude MG patients in exacerbation, and there are only few real-world studies on the efficacy of efgartigimod in MuSK-Ab-positive myasthenic crisis (MC) patients. This retrospective, real-world study aimed to explore the efficacy of efgartigimod in MuSK-Ab-positive MG with exacerbation.Methods: We reviewed the clinical data of four MuSK-Ab-positive patients with exacerbation of MG who received efgartigimod at the First Affiliated Hospital of Sun Yat-sen University, including two patients with MC. All patients were admitted between September 2023 and May 2024. Most patients are simultaneously undergoing rituximab treatment.Results: Each patient completed one cycle of efgartigimod. After the first administration, four patients showed a clinically meaningful decrease in the Myasthenia Gravis Activities of Daily Living (MG-ADL) score (a reduction of more than 4 points compared to baseline), and all patients showed a decrease in IgG levels after one cycle of efgartigimod. Regarding safety, none of the patients experienced any obvious adverse effects. At the final follow-up, all patients achieved the minimal symptom expression status (an MG-ADL score of 0 or 1) following the first administration of efgartigimod for 8.75 ± 5.56 weeks. This article presents a case involving a patient who exhibited prompt alleviation of symptoms following the administration of a high dose of efgartigimod (20 mg/kg, given on days 1 and 5), without the use of any other fast-acting treatment.Conclusion: This retrospective real-world study demonstrates the effectiveness and safety of efgartigimod in these four MuSK-Ab-positive, female Asian patients with exacerbation of MG, as well as in patients experiencing MC. It is important to note that efgartigimod should not be viewed as a substitute for foundational immunotherapy; rather, it is intended as a rescue treatment during exacerbations and as an adjunctive therapy in the context of long-term immunotherapy. This non-invasive approach has the potential to become another treatment option for MuSK-Ab-positive MG patients.

Myasthenic crisis (MC) refers to rapid deterioration of myasthenia gravis (MG), affecting lung and bulbar muscles and causing breathing difficulties. Currently, efgartigimod has shown good therapeutic effects in patients with generalized myasthenia gravis (GMG). This retrospective real-world study explored the effectiveness of efgartigimod in patients with MC. Reviewing the clinical data of five patients (including four patients with refractory MC) with MC who received efgartigimod at the First Affiliated Hospital of Sun Yat-sen University, all of these patients were admitted from September 2023 to December 2023. Each patient received 20 mg/kg of efgartigimod on the first and fifth day. After discharge, all patients showed a clinically meaningful decrease in Myasthenia Gravis Activities of Daily Living (MG-ADL) scale (a decrease of ≥ 2 points) and an improvement in their lung function. Additionally, all patients had a decrease in IgG levels (58.59 ± 18.48% after one cycle of efgartigimod). We also explored the ICU stay and mechanical ventilation (MV) duration for these five patients, and found no significant improvement compared to a large sample data. In terms of safety, four patients experienced adverse events (AEs), all of which were mild. At the last follow-up, four patients achieved the minimal symptom expression (MSE) status (an MG-ADL score of 0 or 1) after 6.25 ± 3.30 weeks. Only one patient experienced a worsening of symptoms in the second week after discharge, but she also achieved the MSE status after receiving a second cycle of efgartigimod treatment. Given the conclusion that intravenous efgartigimod is a non-invasive fast-acting treatment with fewer AEs, this may provide NICU workers with another option for managing patients with MC.

Background: In myasthenia crisis (MC), plasma exchange (PE) and intravenous immunoglobulin (IVIG) are confirmed effective treatment options, but PE may not be available in time, and the response rate to IVIG is not always satisfactory. This study aimed to investigate whether addition of efgartigimod confers benefits in patients with MC. Methods: This real-world retrospective pilot study examined MC patients admitted to the First Affiliated Hospital of Sun Yat-sen University between August 2023 and May 2024, who were categorized into two groups: the traditional immunotherapy group ( n = 14) and the add-on efgartigimod group ( n = 9). In the efgartigimod group, patients received 20 mg/kg efgartigimod ( n = 9), administered on the first and fifth days. Results: Totally 23 patients were recruited in the study. Total hospital stays, MV duration, and non-invasive ventilation time were shorter in the efgartigimod group compared with the traditional immunotherapy group; however, these differences were not statistically significant ( p > 0.05). We subsequently applied a generalized estimating equation (GEE) to the patients over an 8-week period and observed a reduction in Myasthenia Gravis Activities of Daily Living (MG-ADL) scores in both groups; however, no significant differences were found within the groups ( p > 0.05). Survival analysis was also conducted, revealing that the addition of efgrtigimod allowed patients to reach the MSE state more quickly, which is statistically significant ( p = 0.0499). Additionally, three patients with MC who only received high-dose efgartigimod treatment all achieved favorable treatment outcomes. Conclusion: This suggests that efgartigimod may serve as an alternative option for MC patients or as a rescue treatment option for refractory individuals.

Objectives. To investigate the presence of serum antinuclear antibody (ANA) and anti-double-stranded DNA antibody (anti-dsDNA) in patients with myasthenia gravis (MG) and analyze the clinical characteristics and prognostic factors associated with MG. Methods. We retrospectively enrolled 363 patients with MG and analyzed the clinical characteristics and follow-up data between patients positive and negative for ANA and anti-dsDNA. We defined a Myasthenia Gravis Activities of Daily Living (MG-ADL) reduction as a main prognosis predictor and used logistic regression to determine independent factors associated with prognosis. We built a nomogram to predict prognosis and evaluate the internal validity of the model. Results. Ninety-eight (27.0%) patients were positive for ANA, and 51 (14.0%) were positive for anti-dsDNA. Patients positive for ANA and anti-dsDNA antibodies tended to be female and positive for acetylcholine receptor antibody (AChR-Ab). The rate of thymoma was higher in anti-dsDNA-positive patients with MG (p-dsDNA-MG) than in patients negative for anti-dsDNA (49.0% vs. 26.0%, ), and p-dsDNA-MG was associated with reduced MG-ADL score. Regression analysis showed that except for age of onset ( , , ), anti-dsDNA ( , , ), ptosis ( , , ), and eye movement disorder ( ,