BAFF (B cell activating factor), also referred to TNFSF13B (Tumor necrosis factor superfamily, member 13B) or CD257 antigen, is a type II membrane protein with 285 amino acids, located at the human chromosome 13q33.3. It is a fundamental survival factor of 31.2 kDa for B cells and belongs to the tumor necrosis factor (TNF) family. This cytokine is expressed on T cells, dendritic cells, macrophages, and monocytes, but not by B cells. BAFF is a ligand and is required for peripheral B-cell mature, survival and homeostasis. It is also involved in the regulation of expression on certain B-cell-surface proteins, such as CD21 and CD35. BAFF deficiency reduces the amount of B cells and result in a diminished ability to build robust humoral immune responses. IL17A (Interleukin 17A), also referred to IL17 or CTLA8 (Cytotoxic T-lymphocyte-associated serine esterase 8), is a 17.5 kDa glycoprotein encoded in humans by the IL17A gene that is located at the chromosome 6p12.2. It is composed of 155 amino acids and belongs to the IL17 protein family (IL17A- IL17F), of which each monomer contains four highly conserved cysteine residues. IL17A is a proinflammatory cytokine released by CD4+ T cells (Th17 cells), CD8+ T cells (Tc17 cells), invariant natural killer T cells (iNKT cells), γδ T cells and innate lymphoid cells (ILCs). This cytokine functions in the regulation of activities of NF-kappaB and mitogen-activated protein kinases. Its high levels are associated with several chronic inflammatory diseases such as psoriasis, rheumatoid arthritis, and multiple sclerosis.