– CLEC9A expression was significantly higher in psoriatic skin compared with healthy donor. In psoriatic skin and PsA ST, CLEC9A() cells were in close proximity to TUNEL() cells. SF CLEC9A levels were significantly lower compared with paired PsA serum. Adalimumab treatment did not affect CLEC9A serum level and skin expression. The downregulation of synovial CLEC9A might be associated with a novel mechanism by which anti-TNF therapy might reduce CD8-mediated inflammation in PsA patients.