Background Anti-Ro antibodies (Ab) are especially directed against two antigens, Ro52 and Ro60, with different structure and function. Studies in systemic lupus erythematosus (SLE) have been described a relationship between the presence of anti-Ro Ab and dry syndrome, subacute cutaneous lupus, myocardial involvement or minor renal involvement. However, studies about the clinical usefulness of determining the 2 specificities of anti-Ro Ab in SLE are not conclusive. It seems that anti-Ro52 could be associated with joint involvement and lung disease, while anti-Ro60 could be related to late-onset SLE. In this paper we evaluate the clinical usefullness of anti-Ro52 and Ro60 Ab chemiluminescence quantification in patients with SLE.

Objectives To analyze the presence of anti-Ro52 and Ro60 Ab in a cohort of patients with SLE and evaluate its correlation with clinical, analytical and immunological parameters.

Methods 152 patients with SLE (according to the SLICC criteria 2013) attended in an university hospital were included. Qualitative immunoblot analysis of anti-Ro Ab was performed on all of them; those with positive values were also assessed by a chemiluminescence quantification of anti-Ro52 and Ro60 Ac (normality <19.9 CU). Other LES specific Ab were also analyzed by immunoblot, indirect immunofluorescence and ELISA. Clinical variables (age, oral ulcers, alopecia, synovitis, serositis, antiphospholipid syndrome (APS), Sjögren's syndrome, cutaneous, neurological and renal involvement), analytical (complement, cytopenia and coombs test) and activity and damage index of SLE (SLEDAI and SLICC) were also evaluated. The study was approved by the Clinical Research Ethics Committee of the center, and all patients signed informed consent.

Results 91% (138) were women with a mean age of 46±12 years (range, 20–75) and an average SLE evolution of 12±7 years (range, 1–40). 32% (49/138) of the patients had anti-Ro positive determination by immunoblot: 36 were anti-Ro52 positive (mean value 696±726 CU) and 48 anti-Ro60 positive (mean value 504±696 CU) by chemiluminescence. Only one anti-Ro52 positive patient was anti-Ro60 negative. 10.5% had late-onset SLE. The mean SLEDAI was 1.84±2.48 while the SLICC was 0.32±0.7, with a mean anti(ds)DNA Ac values about 207.87±357.15 IU/ml. 37.5% had hypocomplementemia. Anti-Ro positive patients by immunoblot had a higher value of anti(ds)DNA compared to the patients without Ro positive values and patients with both positivity by chemiluminescence had lower prevalence of APS, however the quantitative values of anti-Ro52 and anti-Ro60 were not related with clinical, analytical or immunological parameters.

Conclusions 32% of patients in the cohort were anti-Ro positive being mostly anti-Ro60 positive. The presence of anti-Ro Ab was associated with higher value of antiDNAds and lower prevalence of APS. However, the quantitative values of anti-Ro52 and anti-Ro60 Ab by chemiluminescence were not related to the different parameters analyzed in the study. These results indicate the need to assess the quantification of anti-Ro Ab in a larger cohort of patients with SLE.

Disclosure of Interest None declared