Fig. 1.

CXCL4 is overexpressed in SSc and correlates with IFN-I. CXCL4 was measured by ELISA in the plasma of SSc (N = 38) (discovery cohort), HD (N = 34), and SLE (N = 34) (a), and in the sera of SSc patients (N = 88), HD (N = 60), and SLE patients (N = 85) (b). Horizontal bars are the means and vertical bars are the standard errors of the mean (s.e.m.). P-values are calculated with Student’s t test for unpaired samples (two-tailed). c Confocal images of SSc skin stained with DAPI (blue) to color nuclei, anti-BDCA2 (green), anti-Mx1 (magenta), and anti-CXCL4 (red). White arrows indicate co-localization of BDCA2, CXCL4, and Mx1. Upper images show a dermal compartment (objective ×60; bar, 10 µm). Lower images show a detail (inset) of the dermal compartment. One representative experiment of 10 performed with different SSc donors. Amounts of CXCL4 measured in SSc plasma (d, f) or serum (e, g) were correlated to IFN-α level measured by ELISA in the same sera/plasma. Correlation was measured by Pearson’s correlations test. Coefficient of correlation “r”, significance “P”, and sample size “N” are indicated