IL17RA and ankylosing spondylitis: Monoclonal antibodies targeting IL-17A (i.e., secukinumab and ixekizumab) or the IL-17 receptor subunit IL-17RA (i.e., brodalumab) have already demonstrated dramatic therapeutic results in patients with psoriasis, psoriatic arthritis, and ankylosing spondylitis, thus confirming the pathogenic relevance of IL-17 family members in mediating inflammation in psoriasis, psoriatic arthritis, and ankylosing spondylitis [13–16].