Session Information
Session Type: Abstract Submissions (ACR)
Background/Purpose: a high number of antinuclear antibody specificities can be detected in Systemic Lupus Erythematosous (SLE). Some of them are related to a distinct clinical subset of disease, independently from their frequence. Aim of our study was investigate, in a cohort of SLE patients from a single Centre, the prevalence and the clinical relevance of autoantibodies to cellular antigens less frequently found in SLE.
Methods: antinuclear antibodies was detected by indirect immunofluorescence (IIF) on HEp-2 cells while counterimmunoelectrophoresis (CIE) was used to detect anti-ENA antibodies in 532 patients with SLE classified according to SLICC criteria1. Clinical and serological features about our cohort of SLE patients were collected from clinical charts. Categorical variables were analyzed with Chi-Squared test or Fisher’s exact test. Multivarite analysis was conducted with a logistical regression model (Statview), p<0.05 was considered as significant.
Results: 311 (58.5%) of 532 sera were positive for anti-ENA antibodies. Anti-SSA/Ro was the most prevalent antibody found in 232 out of the 311 positive sera (74.5%), 50 of whom (16%) also contains anti-SSB/La. Anti-U1RNP were detected in 69 (22%) and anti-Sm in 45 (14.5%) patients. In a multivariate analysis anti-U1UNP and anti-SSA/Ro resulted to be associated with malar rash (p= 0.010 and p=0.029 respectively) while anti-U1RNP was also associated with leukopenia (p=0.0065). Other anti-ENA antibodies were found in 49 out of the 311 anti-ENA positive sera (15.8%). Anti-Ki/SL antibodies represented the most frequent between these rare antibodies and were detected in 31 sera, anti-Ku in 8 sera, anti-centromere in 4, isolated anti-SSB/La, PCNA and anti-Scl70 in 3 sera each and anti-Jo-1 in 2 sera. About half of these antibodies (26 out of 49; 53%) were detected as the single anti-ENA specificity in serum. Anti-Ki/SL was significantly associated with male gender (p=0.0054), being detected in 7 males and in 24 females; anti-Ku was significantly associated with African ethnicity (0.00031) being detected in 3 out of 11 patients of African origin. No sign of muscular or pulmonary involvement were found in the anti-Jo-1 positive patients while features of systemic sclerosis were detectable in 2 out of 3 anti-Scl70 and in one of the 4 anti-centromere positive patients.
Conclusion: our study shows that antibodies to cellular antigens more rarely found in SLE are detectable in more than 15% of patients with anti-ENA antibodies. The majority of them are found as a single anti-ENA specificity. Anti-Ki and anti-Ku appears to characterize a subset of disease with a prevalence of male and of patients from African origin respectively. Clinical features of scleroderma and/or myositis was found only in a minority of patients with antibodies to topoisomerase-1, Jo-1 or centromere.
1 Petri M, Orbai A-M, Alarcon G, et al. Derivation and Validation of the Systemic Lupus International Collabarating Clinics Classification Criteria fo Systemic Lupus Erithematosous. Arthritis Rheum 2012; 64:2677-86.
Disclosure:
M. Fredi,
None;
I. Cavazzana,
None;
M. Quinzanini,
None;
M. Taraborelli,
None;
S. Cartella,
None;
A. Tincani,
None;
F. Franceschini,
None.
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ACR Meeting Abstracts - https://acrabstracts.org/abstract/rare-autoantibodies-to-cellular-antigens-in-systemic-lupus-erythematosous/