IL17A and systemic lupus erythematosus: Interferon (IFN)-α is regarded an important cytokine in SLE pathogenesis but several additional cytokines have been put forward in this context, including interleukin (IL)-6, IL-1, tumour necrosis factor (TNF)-α, IFN-γ, IL-12, IL-10, transforming growth factor (TGF)-β, IL-2 and more recently the IL-23/IL-17 axis [5-7].