P131 High type 1 interferon associates with subclinical myocardial involvement in systemic sclerosis

Background/Aims SSc is associated with up to 4-fold higher risk of cardiovascular involvement. Cardiovascular magnetic resonance (CMR) multiparametric testing enables detection of subclinical myocardial abnormalities. Type I interferon (IFN) is implicated in vascular and fibrotic processes and higher levels correlate with markers of disease activity; however, its relationship with cardiovascular involvement has not been established. We therefore aimed to evaluate whether IFN activity and/or its chemokine correlates associate with myocardial involvement. Methods We previously reported on SSc patients without known SSc/non-SSc heart disease, diabetes, or > 1 traditional cardiovascular risk factor who underwent CMR (3 Tesla Philips Achieva MR system)(1). Myocardial perfusion reserve (MPR) was recorded. For this study, abnormal myocardial tissue (MT) was defined by one/more: non-ischaemic late gadolinium enhancement (LGE) scar, native T1 >1050 ms (diffuse interstitial changes), and/or ECV >30% (diffuse fibrosis). Serum IFN score was derived from serum concentrations of CCL2, CCL8, CCL19, CXCL9, CXCL10, and CXCL11, with “high IFN” defined as ≥ 2 SD above healthy control mean1. χ² or Fisher’s exact test, Pearson or Spearman correlation coefficients, and logistic regression were applied for independent associations (p < 0.05 significant). Results 36 SSc patients were included, 13 with normal MT and 23 with abnormal MT. Baseline characteristics were comparable between groups except for high hs-TnI (>37 ng/L), significantly more frequent in the abnormal MT group (43.5% vs 15.4%, p = 0.02). Median NT-proBNP and hs-TnI were also numerically higher. Mean Luminex IFN scores were comparable (Table 1), but a high IFN signature was more frequent in abnormal MT (52.1% vs 23.1%, p = 0.03). IFN activity was not associated with individual quantitative CMR parameters. Among chemokines, CCL19 was higher in abnormal MT (192.2 ± 133.1 vs 169.0 ± 122.3 pg/mL, p = 0.03). IFN signature showed a moderate positive correlation with MPR (r = 0.36, p = 0.17), not statistically significant. Conclusion Myocardial tissue changes and injury are associated with a high IFN signature, specifically, increased CCL19 levels, suggesting a link between immune dysregulation and myocardial involvement. These exploratory findings warrant validation in larger cohorts to establish IFN as a biomarker of SSc-myocardial involvement and investigation to determine whether a therapeutic target in SSc-related cardiac disease.