IL17A and autoimmune disease: Extracellular NaCl concentration through the activation of IL-23 receptor and its binding by IL-23 influences the activity of SGK1 and NFAT5 which drives the expression of transcription factor RORγt, IL-23R, IL-17A, and IL-17F resulting in the phenotype switch from naïve CD4+ T cells to pathogenic Th17 cells in MS, psoriasis, and other autoimmune disorders (Figure 12).