Antititin antibody in early- and late-onset myasthenia gravis
Version of Record online: 20 JUN 2014
© 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd
Acta Neurologica Scandinavica
Volume 130, Issue 4, pages 229–233, October 2014
How to Cite
Antititin antibody in Early- and Late-Onset Myasthenia Gravis. Acta Neurol Scand 2014: 130: 229–233. © 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd., , , , , , , .
- Issue online: 24 SEP 2014
- Version of Record online: 20 JUN 2014
- Manuscript Accepted: 20 MAY 2014
- Polish-Norwegian Research. Grant Number: PNRF-204-AI-1/07
- antititin antibody;
- course of myasthenia early onset;
- late onset;
- myasthenia gravis;
Myasthenia gravis (MG) is an autoimmune disease caused by antibodies against neuromuscular junction proteins, 85% of patients have antibodies against acetylcholine receptor (AChR-MG). Antititin antibodies are present in a subset of patients with MG. We aimed to determine the value of antititin antibodies as severity markers and thymoma predictors in early- and late-onset MG.
Materials & methods
Two-hundred and ninety-five consecutive MG patients (188 F and 107 M) aged 12-89 years (mean 50y) were included. 164 patients had early-onset (EOMG, ≤50 years of age), 131 had late-onset MG (LOMG). Twenty-six patients had thymoma. symptoms, severity graded with MGFA scale, thymus histology, medications, and treatment results were analyzed.
Antititin antibodies were present in 81 (27%) of all patients: 54% of thymoma MG, 0.6% of non-thymomatous EOMG, and 55% of LOMG, with proportion of titin-positive patients increasing linearly from 40% in the 6th to 88% in the 9th decade of life. Titin-positive patients had more bulbar symptoms (P = 0.003). Severity of MG, need for immunosuppression, myasthenic crisis risk or treatment results were not related to its presence. Antititin antibodies had 56% sensitivity, 99% specificity, 90% positive predictive value (PPV), and 95% negative predictive value (NPV) for thymoma diagnosis in EOMG, and 50% sensitivity, 75% specificity, 71% PPV and 55% NPV in LOMG.
Antititin antibodies have high PPV and NPV for thymoma in EOMG. In MG without thymoma, antititin antibodies can be considered as markers of LOMG, but not of a severe course in our MG cohort.