CD4 and systemic lupus erythematosus: Many patients with SLE present with increased expression of type I interferon (IFN)-regulated genes in blood cells and in tissue, an IFN signature [2, 3], and a single cell RNA sequencing analysis of PBMC showed that increased expression of type I IFN regulated genes in monocytes correlate with low naïve CD4 + T cells in SLE [21].