IL17A and psoriasis: Highlighting an evolving understanding of the immunological basis of psoriasis, the third generation of biologic medications approved by the FDA was the IL-17 inhibitors: secukinumab (a fully human monoclonal IgG1 antibody against IL-17A) in 2015; ixekizumab (a humanized monoclonal IgG4 antibody against IL-17A) in 2016; brodalumab (a human monoclonal IgG2 antibody against IL-17RA) in 2017 [187].