Conceivably, based on recent insights described above, inhibitors of IL-23, p40 (the common subunit of IL-23 and IL-12) and IL-17A, may be more rationally deployed in seropositive individuals before clinically overt arthritis develops – in which context the role of Th17 cells could be more pivotal [17▪▪]. Here, IL9 is linked to arthritic joint disease.