Besides being pro-fibrotic and a biomarker for SSc, CXCL4 has been found to reduce the expression of UPR genes from the IRE1-XBP1 pathway in pDCs from SSc patients, while also promoting expression of type I IFN by activated pDCs, particularly in conditions of ER stress [13]. The gene discussed is PF4; the disease is systemic sclerosis.