Fig. 7.

CXCL4 from SSc blood stimulates pDCs in a DNA-dependent manner. a PDCs were stimulated with SSc plasma alone (SSc, 1:50 dilution) pretreated with 10 µg ml⁻¹ of huDNA (SSc+DNA) or with plasma from HD (same dilution) also pretreated with huDNA (HD+DNA) or untreated (HD), or with huDNA alone (DNA). IFN-α was quantitated by ELISA after 24 h. Horizontal bars are the means, vertical bars are the s.e.m. P-values by Wilcoxon signed-rank test. b PDCs were treated with SSc plasma pretreated with huDNA as in a in the absence or in the presence of a neutralizing anti-CXCL4 antibody (aCXCL4; see Methods), neutralizing anti-CD32 antibody (aCD32)¹⁶, corresponding control (Iso ctr), or irrelevant antibodies (aS100A8), and IFN-α was analyzed after 24 h by ELISA. Data are expressed as percent of inhibition of IFN-α production (using as a reference the amounts of IFN-α obtained after stimulation with SSc plasma pretreated with huDNA). Significance was assessed by Wilcoxon signed-rank test