The course of myasthenia gravis (MG) may get complicated by the development of other autoimmune diseases. Estimates of the frequency of autoimmune diseases will help inform patients and physicians, direct health policy discussion, provide etiologic clues, and optimize the management of MG. However, the frequency of autoimmune diseases in people with MG is still uncertain. A systematic search for English language studies was conducted by MEDLINE and EMBASE from 1960 through 2010. Incidence studies and case series of all MG subtypes with information about autoimmune diseases were included; 25 studies met the inclusion criteria. Although there was considerable heterogeneity, the pooled estimate of the coexisting autoimmune diseases in MG was 13% (95% confidence interval, 12%-14%). Autoimmune thyroid disease seems to occur more frequently than other autoimmune conditions in MG patients. Heterogeneity in study estimates could be explained by ascertainment bias and case mix. Furthermore, autoimmune diseases occurred significantly more often in females and anti-acetylcholine receptor seropositive MG patients. Patients with MG have an increased frequency of coexisting autoimmune diseases. Autoimmune diseases seem to occur more often in female and seropositive MG patients. Further research is needed to expand our understanding of these associations.

Immune checkpoint inhibitors (ICIs) are being used in patients with various advanced malignancies, and patient outcomes have improved considerably. Although ICIs can effectively treat tumors, 30–60% of patients experience immune-related adverse events (irAEs). Autoimmune encephalitis (AE) is a rare irAE that has become a novel topic in neuroimmunology and has received increasing attention in recent years. Herein, we report a rare case of GAD65-antibody–associated AE after metastatic small cell lung cancer treatment with pembrolizumab. The patient received IVIg therapy for AE and continuous pembrolizumab therapy without suspension of tumor treatment. At 1 year follow-up, both the patient’s AE symptoms and tumors were stable. We consider that the treatment of ICI-associated AE should be more individualized with prudent decision-making and should balance the tumor progression and AE treatment. In addition, we have also comprehensively reviewed the literature of ICI-associated AE, and summarized the clinical features, treatment, and prognosis of AE caused by ICI, thus broadening our understanding of the neurological complications caused by ICI.

Background: Anti-IgLON5 disease, a rare autoimmune neurological disorder, remains understudied in Eastern populations. This study aimed to characterize the clinical characteristics, treatment responses, and long-term outcomes of Chinese patients with anti-IgLON5 disease in a multicenter Chinese cohort. Methods: This retrospective multicenter study enrolled 24 patients with anti-IgLON5 disease confirmed by serum and/or cerebrospinal fluid antibody testing from 17 centers in China. Human leukocyte antigen (HLA) typing was performed on patient blood samples. Clinical characteristics, mRS/ICS outcomes, treatment response, relapse, and long-term outcomes were analyzed. Short-term response was defined as improvement in mRS from admission to discharge, and relapse was defined as recurrence or worsening of symptoms after initial clinical improvement. Results: The mean age at onset was 59.6 years. Among 18 patients who received immunotherapy, 10/18 (55.6%) met the definition of achieving a short-term response. Responders included more women (6/10 vs. 2/8), fewer patients with bulbar symptoms (4/10 vs. 5/8), and more frequently had HLA-DRB1*10:01 or HLA-DQB1*05:01 (8/10 vs. 4/8) compared with non-responders. Men aged ≥ 65 years had poorer outcomes, whereas younger men and most women responded well. Long-term follow-up was performed on 16 patients (median 18 months, range 3–60 months), and eight withdrew from follow-up. Relapse occurred in 4/16 patients (25.0%). It typically occurred about 6–12 months after discharge, often following abrupt treatment withdrawal, and was effectively controlled with re-treatment. Kaplan–Meier analysis indicated that relapse risk was the highest within the first 6 months post-discharge. Early treatment (≤ 6 months) tended to be associated with more favorable outcomes. Overall, 10/14 immunotherapy-treated patients with long-term follow-up (71.4%) showed improvement, and 7/14 (50.0%) became asymptomatic. In this cohort, HLA-DQA1*01:05 and HLA-DRB1*10:01/HLA-DQB1*05:01 were over-represented among the typed patients, and the response rate to immunotherapy was numerically higher than that in the Western population (55.6% vs. 40%). The misdiagnosis rate was 33.3%. The median diagnostic delay was 2 months (IQR, 1–12 months; range, 2 days–6 years). Conclusions: As the largest cohort of anti-IgLON5 disease in China to date, this multicenter series demonstrated that Chinese and Western patients with anti-IgLON5 disease have both shared and distinct clinical characteristics. Chinese patients exhibited relatively favorable responses to early immunotherapy, relapse susceptibility requiring prolonged treatment, and potential HLA associations, offering new insight into disease management.