P156 Evidence of Type I interferon activation during vascular manifestations of systemic sclerosis

Abstract

Background/Aims Vascular involvement in systemic sclerosis (SSc) is known to start even before clinical diagnosis, driving digital ulcer (DU) disease. Later in the disease natural history, it can cause pulmonary artery hypertension (PAH) among other manifestations. Despite the proven immune origin of scleroderma, vascular involvement is not currently targeted by immune driven interventions. Similarly, few data are available on immune or inflammatory biomarkers and outcome measures of vascular disease in SSc. Digital artery volume index (DAVIX) has been recently proposed as an imaging surrogate outcome measure of vascular disease activity in SSc. Methods 86 patients attending our scleroderma program were consecutively enrolled for the evaluation of serum IFN score as previously described [2]. Clinical features, including presence or history of DUs, presence of PAH and DLCO, were recorded. DAVIX of the dominant hand’s fingers was calculated using time of flight magnetic resonance imaging analysed through IAG proprietary algorithm, as previously described [1]. Medians were compared by Mann-Whitney-Wilcoxon test; correlation with clinical parameters was performed using Spearman’s or Pearson test, as appropriate (R). Results 62 patients fulfilled the 2013 ACR/EULAR classification criteria for SSc (diffuse cutaneous 24.6%, limited cutaneous 75.4%), whereas 23 were classified as very early diagnosis of scleroderma (criteria score between 6 and 8). 23 patients had DU disease (history of DUs in the previous 24 weeks, presence of DUs at baseline assessment, or onset of new DUs during the following 24 weeks). 18 patients had reduced DLCO (<70) with FVC/DLCO>1.8 (suspected PAH). DAVIX showed a negative correlation with disease duration (r=-0.33 and p = 0.003) and with FVC/DLCO ratio (r=-0.34 and p = 0.009). Patients with DU disease presented lower DAVIX than patients without (p = 0.018). DAVIX showed a significant correlation with serum IFN score (r=-0.24, p < 0.032). Accordingly, patients classified as IFN-HI had lower DAVIX than those within the IFN-LO group (p = 0.016). Conclusion DAVIX correlated both with presence of DU disease, DLCO and disease duration. The correlation of DAVIX and serum IFN score does support the notion of innate immune involvement in vascular disease manifestations of SSc. Prospective testing in the context of randomised controlled trials will determine the value of DAVIX as a surrogate outcome measure of vascular disease severity in SSc. S. Di Donato: None. M. Hughes: None. K. Geloshi: None. E. De Lorenzis: None. V. Kakkar: None. R. Ross: None. P. O'Connor: None. O. Kubassova: Consultancies; Image Analysis Group CEO. F. Del Galdo: Grants/research support; Abbvie, AstraZeneca, Boeringher-Ingelheim, Capella, Chemomab, Janssen, Kymab, Mitsubishi-Tanabe.