Arthritis & Rheumatism, Volume 62,
November 2010 Abstract Supplement

Abstracts of the American College of
Rheumatology/Association of Rheumatology Health Professionals
Annual Scientific Meeting
Atlanta, Georgia November 6-11, 2010.


Longitudinally Followed Serum Levels of B-Cell Activating Factor of the TNF Family Correlate with Disease Activity in Anti-Jo-1 Positive Patients with Myositis.

Krystufkova1,  Olga, Mitterwald-Modra2,  Marta, Mann2,  Herman, Ekholm5,  Louise, Hulejova2,  Hana, Lundberg4,  Ingrid E., Vencovsky3,  Jiri

Institute of Rheumatology, Prague, Czech Republic
Institute of Rheumatology
Institute of Rheumatology and Dept of Rheumatology of the 1st Faculty of Medicine, Charles University, Prague, Prague, Czech Republic
Karolinska Institutet, Stockholm, Sweden
Karolinska Institutet, Sweden

Purpose:

A role of B cells in pathogenesis of myositis is supported by common occurrence of autoantibodies. Anti-histidyl-tRNA synthetase (anti-Jo-1) is the most frequent myositis specific autoantibody, associated with a distinct clinical phenotype. Its observation before onset of clinical symptoms suggests a role in the pathogenesis of this subset of myositis. B-cell activating factor of the TNF Family (BAFF) plays a role in autoantibody production. In a previous cross-sectional study we found elevated serum levels of BAFF in patients with anti-Jo-1 positive polymyositis (PM) and in dermatomyositis (DM) and there was a correlation with serum creatine kinase (CK) levels.

The aim of the study was to investigate if serum levels of BAFF change over time and if there is a relation to disease activity measures in anti-Jo-1 positive myositis.

Methods:

Sixty-seven anti-Jo-1 autoantibody positive patients from two centers were included. Paired serum samples from two time points (mean interval 28 months) in 50 patients (21 DM and 29 PM) were evaluated. Anti Jo-1 positivity was confirmed by line-blot and western blot assays. BAFF levels in serum were measured by ELISA. Serum levels of CK, myoglobin, aminotransferases (ALT, AST) and C-reactive protein (CRP) were retrieved from patients' records or measured in the same sera. Clinical disease activity was assessed by the score of the core set tool according to the IMACS Group, including both extramuscular, muscular and the physician's score of overall disease activity.

Results:

The baseline BAFF levels correlated positively with serum levels of CK (rs=0.49, p<0.0001), myoglobin, (rs=0.37, p=0.005), AST (rs=0.46, p=0.0001) and CRP (rs=0.42, p=0.0006) and with cutaneous disease activity (rs=0.26, p=0.04). Levels of BAFF and myoglobin had decreased significantly at the second visit (paired test p<0.05), while p value for CK was 0.09. A significant improvement of cutaneous, skeletal, pulmonary, muscle and global disease activities was also recorded (p<0.05 for all). A positive correlation between changes of serum BAFF levels and changes of CK (rs=0.7, p=0.0001), myoglobin (rs=0.6, p<0.0001), ALT (rs=0.52, p=0.0001), AST (rs=0.62, p<0.0001) and CRP (rs=0.29, p=0.049) levels in serum or skeletal (rs=0.45, p=0.003), muscle (rs=0.32, p=0.04) and global (rs=0.37, p=0.02) disease activities was also recorded.

Conclusions:

The correlation between serum levels of BAFF and markers of muscle involvement or clinical measures of disease activity as well as a correlation of their changes over time might indicate a role of BAFF in the pathogenesis of myositis with anti-Jo-1 autoantibodies. BAFF could thereby be a novel potential target of intervention in this subset of myositis.

Acknowledgement:

AutoCure LSHB CT-2006–018661 funding. Institutional support MEYS CR 0021620812

To cite this abstract, please use the following information:
Krystufkova, Olga, Mitterwald-Modra, Marta, Mann, Herman, Ekholm, Louise, Hulejova, Hana, Lundberg, Ingrid E., et al; Longitudinally Followed Serum Levels of B-Cell Activating Factor of the TNF Family Correlate with Disease Activity in Anti-Jo-1 Positive Patients with Myositis. [abstract]. Arthritis Rheum 2010;62 Suppl 10 :926
DOI: 10.1002/art.28694

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