Anti-Ro52 antibodies positivity in antisynthetase syndrome: a single centre cohort study

Objective. Although antisynthetase antibodies (ARS) are the established markers of the so-called antisynthetase syndrome (ASSD), in these patients the concomitant positivity of anti-Ro52 antibodies, reported in up to the 50% of cases, is not rare. Several studies focused on the effect of different ARS specificities on the evolution of ASSD, the most recent showing no effects. On the contrary, the role of co-occurring anti-Ro52 antibodies in ASSD is still debated. We investigated the potential of anti-Ro52 antibodies in identifying a clinical phenotype of ASSD or influencing prognosis, irrespectively to the underlying ARS specificity.Methods. Retrospective analysis of clinical, imaging and laboratory characteristics, therapeutic approaches and outcome at baseline and at last followup, of 60 ASSD patients progressively enrolled at our Hospital.Results. We identified 34 anti-Ro+ and 26 anti-Ro-ASSD patients. Classic triad prevalence at baseline was similar between the two groups, whereas interstitial lung disease (ILD) (p-value=0.01) and myositis (p-value=0.03) were significantly more prevalent in anti-Ro52+ and in anti-Ro52-patients at last follow up, respectively. No differences in therapeutic approaches, oxygen need and ILD patterns were observed. Overall mortality was 25% (15 subjects). No differences in mortality, overall and disease related, between anti-Ro52+ and anti-Ro52- patients were observed (p-value=0.764), despite the more frequent ILD occurrence in anti-Ro52+ patients. Survival curves were not different at any time point (Log-rank test, p-value 0.98).Conclusion. Anti-Ro52 antibodies affect time course and clinical characteristics of ASSD. Although ILD is significantly more associated to anti-Ro52 antibodies, no difference in mortality was observed compared to anti-Ro52 negative patients.