IL19 and psoriatic arthritis: To determine if IL-19 levels in psoriasis and psoriatic arthritis patients were correlated with PASI scores, we measured IL-19 in baseline samples of 556 patients with psoriasis (from phase 2 and phase 3 ixekizumab studies and a phase 2 baricitinib study), 293 patients with psoriatic arthritis (from a phase 3 ixekizumab study), and 120 patients with genital psoriasis (from a phase 3b ixekizumab study), and compared IL-19 results to PASI scores.