CD40 and systemic lupus erythematosus: Interacting with CD154 on T-lymphocytes (52), CD40 itself triggers B-lymphocyte activation, proliferation, cytokine secretion, and antibody production (52), acts as a co-stimulatory molecule for the B cell receptor (BCR) (53, 54), and amplifies innate signals driven by toll like receptors (TLRs) (55), including TLR7 (56, 57), implicated in SLE pathogenesis (58–60).