Similar to what was observed in psoriasis and psoriatic arthritis patients, Fig. 5d shows that PASI 100 improvements at 12 weeks were preceded by IL-19 reductions to normal levels after 2 weeks that were sustained through 12 weeks (one-way ANOVA p < 0.0001 for IL-19 at 2 and 12 weeks versus PASI at 12 weeks). This evidence concerns the gene IL19 and psoriatic arthritis.