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Autoantibodies in acquired myasthenia gravis: Clinical phenotype and immunological correlation
Author(s) -
Nagappa Madhu,
Mahadevan Anita,
Gangadhar Yashwanth,
Patil Shripad A.,
Bokolia Suresh,
Bindu Parayil S.,
Sinha Sanjib,
Taly Arun B.
Publication year - 2019
Publication title -
acta neurologica scandinavica
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.967
H-Index - 95
eISSN - 1600-0404
pISSN - 0001-6314
DOI - 10.1111/ane.13071
Subject(s) - myasthenia gravis , medicine , thymoma , antibody , autoantibody , gastroenterology , cohort , muscle weakness , immunology
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 follow‐up 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.