PIK3R1 and systemic lupus erythematosus: We chose the following six genes for their potential role in the innate response: TNFSF13, PIK3R1, NFATC1, FES, TCF7 and RORA. The TNF superfamily 13, or APRIL, protein is a surface or secreted ligand recognized by the transmembrane activator and calcium-modulating cyclophilin ligand interactor (TACI) and B-cell maturation antigen (BCMA) receptors and has been implicated in the pathogenesis of numerous pro-inflammatory conditions such as rheumatoid arthritis [56], atherosclerosis [57], lupus [58] and psioriasis [59].