IL17A and ankylosing spondylitis: The aim of the present study was to: (i) Understand the balance changes in the secretion of T lymphocyte subtypes in ankylosing spondylitis patients; and (ii) illustrate the expression level changes of inflammation mediators, including IFN-γ, IL-17A, IL-4 and TGF-β, in ankylosing spondylitis patients.