In order to develop a single composite densitometric index for SSc-ILD quantification integrating MLA, skewness and kurtosis, we investigated a prospective series of SSc patients by low-dose thin section volumetric lung CT and searched for associations of this index with cardiopulmonary function parameters, and circulating markers of immune system activation (e.g. soluble interleukin-2 receptor alpha - sIL-2Rα - and chemokine CCL18) previously implicated in SSc and in SSc-ILD progression19–22. The gene discussed is CCL18; the disease is interstitial lung disease.