Background/Purpose: In Systemic Sclerosis tight monitoring during the first years of disease is required in order to detect organ complications timely. Although a clear pathophysiologic role of disease specific auto-antibodies has never been confirmed, these antibodies are associated with distinct clinical futures, strongly indicating that their prevalence is of relevance. Therefore we aimed to evaluate to what extent disease specific auto-antibodies in Systemic Sclerosis improve clinical subsetting, identifying high-risk disease

Methods: Clinical clusters of patients were determined, using data from the Combined Care In Systemic Sclerosis cohort, Leiden University Medical Center. Hierarchical clustering based on Ward Method was performed on Principal Component Analysis scores of solely baseline clinical variables. To determine disease-risk, 5-year mortality rates since first non-Raynaud phenomenon were assessed. Prevalence of disease specific auto-antibodies in each cluster was studied. Second, the cluster process was repeated, taking auto-antibodies into account. Clinical and auto-antibody characteristics of obtained clusters were compared to clustering based on clinical variables alone.

Results: Of 407 patients, 91% (n=371) fulfilled ACR/EULAR 2013 criteria. Prevalence of auto-antibodies was: anti-centromere 37%, anti-topoisomerase 24%, anti-RNA polymerase III 5%, anti-fibrillarin 4% and anti-Pm/Scl 5%. Clinical cluster analysis identified 4 different clusters with two clusters showing higher than average mortality (resp. 17% and 7% vs. total group mortality of 4% (n=15)). Adding auto-antibody status to the cluster process resulted in 5 clusters, with an additional cluster 5 with frequent RNA polymerase III (18%, n=14; mortality rate 8%). The total number of patients clustered to a cluster with higher than average mortality-risk increased indicating the need of more intensive screening in a larger group of patients.

Conclusion: Auto-antibodies partially contribute to risk-stratification and clinical subsetting in Systemic Sclerosis. We hypothesize that additional characteristics of auto-antibodies like isotypes might reflect their pathophysiological role, and that the value of autoantibodies as biomarkers for severe disease might increase when adding these characteristics.

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ACR Meeting Abstracts - https://acrabstracts.org/abstract/to-what-extend-do-auto-antibodies-help-to-identify-high-risk-patients-in-systemic-sclerosis/