Cytokine-induced IL-17A production was different in both RA and PsA patients when compared to healthy donors (<i>p</i> = 0.0000026 and <i>p</i> = 0.0001047, respectively).
Altogether, we demonstrate that CXCL4 boosts pro-inflammatory cytokine production especially IL-17 by human CD4<sup>+</sup> T cells, either by acting directly or indirectly via myeloid antigen presenting cells, implicating a role for CXCL4 in PsA pathology.