Abstract
Objectives. To determine the longitudinal trends in serum levels of four myositis-associated autoantibodies: anti-Jo-1, -transcription intermediary factor 1 α (TIF1-α), -signal recognition particle (SRP) and -Mi-2, after B cell depletion with rituximab, and to determine the longitudinal association of these autoantibody levels with disease activity as measured by myositis core-set measures (CSMs). Methods. Treatment-resistant adult and pediatric myositis subjects (n = 200) received rituximab in the 44- week Rituximab in Myositis Trial. CSMs [muscle enzymes, manual muscle testing (MMT), physician and patient global disease activity, HAQ, and extramuscular disease activity] were evaluated monthly and anti- Jo-1 (n = 28), -TIF1-α (n = 23), -SRP (n = 25) and -Mi-2 (n = 26) serum levels were measured using validated quantitative ELISAs. Temporal trends and the longitudinal relationship between myositis-associated autoantibodies levels and CSM were estimated using linear mixed models. Results. Following rituximab, anti-Jo-1 levels decreased over time (P<0.001) and strongly correlated with all CSMs (P<0.008). Anti-TIF1-α levels also decreased over time (P<0.001) and were only associated with HAQ, MMT and physician and patient global disease activity. Anti-SRP levels did not change significantly over time, but were significantly associated with serum muscle enzymes. Anti-Mi-2 levels significantly decreased over time and were associated with muscle enzymes, MMT and the physician global score. Conclusion. Anti-Jo-1, anti-TIF1-α and anti-Mi-2 levels in myositis subjects decreased after B cell depletion and were correlated with changes in disease activity, whereas anti-SRP levels were only associated with longitudinal muscle enzyme levels. The strong association of anti-Jo-1 levels with clinical outcomes suggests that anti-Jo-1 autoantibodies may be a good biomarker for disease activity.
Original language | English (US) |
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Article number | kev444 |
Pages (from-to) | 991-999 |
Number of pages | 9 |
Journal | Rheumatology (United Kingdom) |
Volume | 55 |
Issue number | 6 |
DOIs | |
State | Published - Jun 1 2016 |
Keywords
- Anti-Jo-1
- Anti-SRP
- Anti-TIF1-α and anti-Mi-2 autoantibodies
- Autoantibody levels
- Disease activity
- Myositis
- Rituximab
ASJC Scopus subject areas
- Rheumatology
- Pharmacology (medical)