Autoantibodies in acquired myasthenia gravis: Clinical phenotype and immunological correlation

Abstract

Background: Data on antibody profile in myasthenia gravis (MG) from India are limited. Objectives: To investigate antibody profile in patients with MG and their clinical correlates. Patients and Methods: Patients of MG (n = 85, M:F::1.1:1, mean age: 39.29 ± 17.3 years, mean symptom duration: 72.94 ± 91.8 months) were evaluated for clinical features, MG foundation of America (MGFA) score, response to treatment, and outcome at last follow-up. Antibodies to acetylcholine receptor (AChR), muscle-specific kinase (MUSK), titin and ryanodine receptor (RYR) were analysed using ELISA.Results: Based on the regional distribution of weakness, the cohort could be categorized as: generalized: 60, ocular: 16 and oculo-bulbar: 9. Sixty patients were followed up for a mean duration of 26.74 ± 13.8 months. Outcome at last follow-up was as follows: remission-22, no remission-33 and dead-5. AChR and MUSK antibodies were detected in 58 and 8 patients, respectively. Frequency of generalized MG, worse MGFA score during the disease course and thymomatous histology significantly correlated with presence of AChR-antibodies, though outcome at last followup was comparable between AChR-antibody positive and negative groups. Patients with MUSK antibodies had oculo-bulbar or generalized MG and frequent respiratory crisis, but majority improved or remitted with treatment. Titin antibodies were detected in 31.8% and RYR antibodies in 32.9%. Their presence did not correlate with age at onset of MG, severity or presence of thymoma. Conclusion: This report highlights the spectrum of antibodies in MG in an Indian cohort. AChR-antibody positivity correlated with clinical severity. Outcome was good in majority of MUSK antibody-positive MG. The role of other antibodies, complementary vs epiphenomenon, remains open. K E Y W O R D S acetylcholine receptor, muscle-specific kinase, myasthenia gravis, ryanodine receptor, titin | 429 NAGAPPA et Al.

Case Report: Orbital Myositis and Myasthenia Gravis as Symptoms of Immune Reconstitution Inflammatory Syndrome in a Patient With Human Immunodeficiency Virus Infection

“…RyR is one of the antigens that activate Ca 2+ release channel of the sarcoplasmic reticulum, its RyR antibody is prevalent in thymoma-MG patients who show a good response to tacrolimus ( 26 ). Individuals with titin and RyR antibodies might need more active immunosuppressive therapy, while those with RyR antibodies have lower mean daily dosage requirements of pyridostigmine ( 27 ). Most RyR antibody-positive patients also have positive AChR antibodies ( 28 ).…”

Вплив Оксидативного Стресу На Клінічні Прояви Та Якість Життя Пацієнтів Із Генералізованою Формою Міастенії

“…(Ed. ), 2012; Nagappa M. et al, 2019). Поширеність міастенії зростає протягом останніх десятиліть і варіює у різних країнах у межах 17-300 випадків на 1 млн населення на рік (Carr A.S. et al, 2010;Andersen A.J.…”

“…У деяких наукових роботах зазначають роль ОС у патогенезі міастенії, проте цей зв'язок вивчено недостатньо (Yang D. et al, 2016). Існують дані про роль підвищення концентрації реактивного кисню, що може призводити до інактивації рецепторів ацетилхоліну та пошкодження їх структури (Venkatesham A. et al, 2005;Krishnaswamy A.et al, 2011).…”

Myasthenia gravis: Historical achievements and the “golden age” of clinical trials

“…Other associated auto-antibodies of potential pathological significance are those against titin, ryanodine receptors (RyRs), cortactin, agrin, collagen Q, and voltage-gated potassium channel 1.4 (K V 1.4). We will not describe the molecular pathology of MG in detail here, as others have done this extensively elsewhere thymomatous and late-onset MG [11,[17][18][19][20]. Anti-RyR antibodies are also found in late-onset MG and in up to 70% of patients with MG and thymoma [19,20].…”

“…We will not describe the molecular pathology of MG in detail here, as others have done this extensively elsewhere thymomatous and late-onset MG [11,[17][18][19][20]. Anti-RyR antibodies are also found in late-onset MG and in up to 70% of patients with MG and thymoma [19,20]. The presence of titin and RyR auto-antibodies in a young patient with MG suggests possible involvement of a thymoma, and patients with these striational antibodies tend to have more severe disease and worse prognosis [19,[21][22][23].…”