CXCR1 and systemic lupus erythematosus: The CLINVAR database for genes involved in human disease19,20 indicated that SLE haematopoietic circulating progenitors differentially expressed key genes being involved in pro-inflammatory and immune-regulatory functions, including cell mobilisation [IFN-γ, IL-8R (CXCR1), CCL3L1-CCL3], as well as in SLE-specific immune regulation (CTLA4, STAT4, PCD1), when compared to Healthy PB circulating progenitors (Supplementary Fig. 2A).