Anti-chromatin and anti-C1q antibodies in systemic lupus erythematosus compared to other systemic autoimmune diseases.

Abstract

OBJECTIVE:

To evaluate the prevalence, sensitivity, and specificity of anti-chromatin and anti-C1q antibodies in systemic lupus erythematosus (SLE) and lupus nephritis compared to small vessel vasculitis and other connective tissue diseases. To provide long-term follow-up data for anti-chromatin antibodies in lupus nephritis.

METHODS:

We determined the significance of anti-nuclear antibodies (ANA), anti- double-stranded DNA (anti-dsDNA), anti-chromatin, and anti-C1q antibodies, as well as complement factors C3 and C4, in relation to disease activity in SLE patients with (n = 47; long-term follow-up data for 33 patients) and without (n = 31) biopsy-confirmed lupus nephritis, microscopic polyangiitis (n = 37), Wegener's granulomatosis (n = 66), primary Sjögren's syndrome (n = 17), limited scleroderma (CREST syndrome) (n = 6), and progressive systemic scleroderma (PSS) (n = 11).

RESULTS:

Anti-chromatin antibodies were more specific and sensitive than anti-C1q antibodies in distinguishing SLE patients from those with other systemic autoimmune diseases [anti-chromatin: sensitivity 64.1%, specificity 99.2%, odds ratio (OR) 219.6; anti-C1q: sensitivity 50%, specificity 72.6%, OR 2.65]. Anti-C1q antibodies were present in 75% of patients with Sjögren's syndrome and 35.1% of patients with microscopic polyangiitis. Anti-chromatin antibodies could identify SLE in patients with positive ANA but negative anti-dsDNA antibodies. Persisting anti-chromatin antibodies indicated SLE disease activity, even if anti-dsDNA antibodies had become negative. In long-term follow-up, those SLE patients with negative anti-dsDNA antibodies but persisting ANA and anti-chromatin antibodies relapsed if immunosuppression had been tapered. Anti-chromatin antibodies correlated with the SLE disease activity index (SLEDAI) as a marker of disease activity.

CONCLUSIONS:

The measurement of anti-chromatin, but not anti-C1q, antibodies in patients with systemic autoimmune diseases increases diagnostic sensitivity and specificity for SLE and assists in treatment decisions in anti-dsDNA-negative patients.

• Authors: A Braun, J Sis, R Max, K Mueller, C Fiehn, M Zeier, K Andrassy
• Journal: Scandinavian journal of rheumatology (Scand J Rheumatol) 2007 Jul-Aug Vol. 36 Issue 4 Pg. 291-8 ISSN: 0300-9742 [Print] England
• PMID: 17763207 (Publication Type: Journal Article)

Chemical References

• Antibodies, Antinuclear
• Autoantibodies
• Chromatin
• Complement C1q

Topics

• Adolescent
• Adult
• Age of Onset
• Aged
• Antibodies, Antinuclear (blood)
• Autoantibodies (blood)
• Autoimmune Diseases (blood, complications, immunology)
• Chromatin (immunology)
• Complement C1q (immunology)
• Female
• Humans
• Lupus Erythematosus, Systemic (blood, complications, immunology)
• Male
• Middle Aged
• Nephritis (etiology, immunology)
• Time Factors