Date: Sunday, November 8, 2015
Session Type: ACR Poster Session A
Session Time: 9:00AM-11:00AM
Recently, the study of anti-nucleosome antibodies (ANUCs) has been suggested that they may be useful in the diagnosis of systemic lupus erythematosus (SLE) and in the monitoring of disease activity.
Our objective was to compare the diagnostic performance of ANUCs versus anti-nDNA in the diagnosis of SLE and analyze their correlation with markers of disease activity.
ANUCs and anti-nDNA were prospectively determined in 122 patients with SLE (SLICC 2012 criteria) and 136 patients without the disease (control population). ANUC determination was determined using a dot-blot + ELISA and anti-nDNA using FEIA + IFI. For each of the antibodies, sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), positive likelihood ratio (LR+), negative likelihood ratio (LR-) and diagnostic accuracy were calculated for the SLE diagnosis. Diagnostic accuracy was calculated according to the following formula: (true positives + true negatives) / (true positives + true negatives + false positives + false negatives).
The correlation of the ANUC titer with different markers of SLE activity (SLEDAI 2K, anti-nDNA antibody titer, lymphocyte count, C3 and C4 complement fractions, ESR and C reactive protein) was analyzed using a Pearson product-moment correlation coefficient.
In the 122 patients with SLE, 80 (66%) were ANUC positive and 83 (68%) were anti-nDNA positive: 62 (51%) patients were ANUC and anti-nDNA positive, 18 (15%) were ANUC positive/anti-nDNA negative, 21 (17%) were ANUC negative/anti-nDNA positive, and 21 (17%) were ANUC and anti-nDNA negative.
Eleven (8%) patients in the control population were anti-nDNA positive, and 39 (29%) control patients were ANUC positive. Patients from the control population with positive ANUC had psoriasis (many of them were treated with anti-TNF therapy), infections (pneumonia, HCV, or HIV infection), or an autoimmune disease (pemphigus, Crohn’s disease, glomerulonephritis associated with ANCA, primary anti-phospholipid syndrome, rheumatoid arthritis, or autoimmune hepatitis).
The following table shows the diagnostic value of both antibodies:
The ANUC titer was significantly correlated with the SLEDAI-2K score (r = 0.425, p = 0.031), anti-nDNA titer (r = 0.603, p = 0.001), the number of lymphocytes (r = -0.410; p = 0.038), and ESR (r = 0.414, p = 0.036). No statistically significant correlation was observed with levels of complement or CRP.
ANUCs exhibit similar sensitivity as anti-nDNA for SLE diagnosis but a lower specificity. Therefore, the presence of ANUCs does not appear to increase diagnostic accuracy.
A simultaneous determination of ANUCs and nDNA increases the diagnostic yield, whereas ANUCs are useful in diagnosing disease in anti-nDNA negative patients.
The ANUC titer was positively correlated with disease activity and can therefore be considered a complementary marker in monitoring these patients
To cite this abstract in AMA style:Borrell Paños H, Narváez J, Bas J, Armengol E, Aparicio M, Pascual M, López de Recalde M, Nolla JM. Anti-Nucleosome Antibodies Versus Anti-DNA Antibodies in the Diagnosis and Monitoring of Activity of Systemic Lupus Erytematosus [abstract]. Arthritis Rheumatol. 2015; 67 (suppl 10). http://acrabstracts.org/abstract/anti-nucleosome-antibodies-versus-anti-dna-antibodies-in-the-diagnosis-and-monitoring-of-activity-of-systemic-lupus-erytematosus/. Accessed December 16, 2017.
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