Arthritis & Rheumatism, Volume 63,
November 2011 Abstract Supplement

Abstracts of the American College of
Rheumatology/Association of Rheumatology Health Professionals
Annual Scientific Meeting
Chicago, Illinois November 4-9, 2011.


Nitrated Nucleosome Levels in Patients with Systemic Lupus ErythematosusAssociations with Disease Activity.

Croca1,  Sara, Pericleous1,  Charis, Alber1,  Karim, Yong1,  Harry, Giles1,  Ian, Isenberg2,  David A., Rahman1,  Anisur

University College London, London, United Kingdom
University College London, London WC1E 6JF, United Kingdom

Background/Purpose:

Many different autoantibodies such as anti-nucleosome antibodies have been described in patients with SLE and serological assays have concentrated mainly on measuring autoantibody levels. Measuring levels of modified autoantigens may also be valuable. Since levels of reactive nitrogen species that promote nitration may rise with levels of systemic inflammation, we hypothesised that nitrated nucleosome (NN) levels may vary in parallel with disease activity. This abstract describes the result of longitudinal studies of NN levels and measures of disease activity in patients with SLE.

Methods:

Longitudinal serum samples (n= 398) were selected retrospectively from a cohort of 49 patients with SLE with a mean of 8 samples per patient (SD 2.16; min 3; max 14) and a mean follow-up of 89 months (SD 46; min 14; max 180). NN levels were measured using a capture ELISA. For all samples where data were available, we obtained anti-dsDNA and complement C3 levels and disease activity from a matching date and from the previous 3 assessments if these had occurred in the preceding 12 months. Using the British Isles Lupus Assessment Group (BILAG) index, we categorized the samples by disease activity as follows.

Current activity (on the date of the sample) was defined as high if global BILAG score was >=5 and low if it was <5). Disease activity over the most recent 4 assessments was characterized as persistently low activity (all systems BILAG C, D or E) or persistently moderate-high activity (A or >=1 B in any BILAG system on at least 2/4 occasions). 90% of all samples fell into one of those two categories and the rest were excluded.

Anti-dsDNA was defined as high or normal based on a cut-off of 50IU/ml. C3 was defined as low or normal based on a cut-off of 0.9g/l.

Results:

 Number of samples (n)Mean (SD) NN levelp-value (high vs. low)
Persistently moderate-high activity18840.50 (51.7)0.038
Persistently low activity15424.8 (72.3) 
BILAG< 520425.6 (57.3)0.045
BILAG>= 517137.9 (69.3) 
Anti-dsDNA   
High (>50IU/ml)17129,0 (48.1)0.035
Normal(<=50IU/ml)17721.9 (38.6) 
C3   
Normal (>=0.9g/l)20720.8 (40.6)<0.0001
Low (<0.9g/l)13831.6 (47.0) 

Conclusion:

High NN levels were associated with high disease activity, high anti-dsDNA and low complement. In addition, flares in different organ systems may be associated with different levels of NN.

To cite this abstract, please use the following information:
Croca, Sara, Pericleous, Charis, Alber, Karim, Yong, Harry, Giles, Ian, Isenberg, David A., et al; Nitrated Nucleosome Levels in Patients with Systemic Lupus ErythematosusAssociations with Disease Activity. [abstract]. Arthritis Rheum 2011;63 Suppl 10 :2288
DOI:

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