Skin Gene Expression Is Prognostic for the Trajectory of Skin Disease in Patients With Diffuse Cutaneous Systemic Sclerosis.

Objective. At present, there are no clinical or laboratory measures that accurately forecast the progression of skin fibrosis and organ involvement in patients with systemic sclerosis (SSc). The goal of this study was to identify skin biomarkers that could be prognostic for the progression of skin fibrosis in patients with early diffuse cutaneous SSc (dcSSc). Methods. We analyzed clinical data and gene expression in skin biopsy samples from 38 placebo-treated patients, part of the Roche Safety and Efficacy of Subcutaneous Tocilizumab in Adults with Systemic Sclerosis (FASSCINATE) phase II study of tocilizumab in SSc. RNA samples were analyzed using nCounter. Atrajectory model based on a modified Rodnan skin thickness score was used to describe 3 skin disease trajectories over time. We examined the association of skin gene expression with skin score trajectory groups, by chi-square test. Logistic regression was used to examine the prognostic power of each gene identified. Results. We found that placebo-treated patients with high expression of messenger RNA for CD14, SERPINE1, IL13RA1, CTGF, and OSMR at baseline were more likely to have progressive skin score trajectories. We also found that those genes were prognostic for the risk ofskin progression and that IL13RA1, OSMR, and SERPINE1 performed the best. Conclusion. Skin gene expression of biomarkers associated with macrophages (CD14, IL13RA1) and transforming growth factor activation (SERPINE1, CTGF, OSMR) are prognostic for progressive skin disease in patients with dcSSc. These biomarkers may provide guidance in decision-making about which patients should be considered for aggressive therapies and/or for clinical trials.