As ILC3s are enriched in spondyloarthritis synovial tissue (34, 35), production of IL-17A and IL-17F by these cells could offer an explanation as to why ustekinumab, which targets the p40 subunit common to both IL-12 and IL-23, was also not efficacious in axial spondyloarthritis (36). The gene discussed is IL17F; the disease is spondyloarthropathy.