Agents used to treat psoriasis target commonly the underlying inflammation. C-reactive protein (CRP) is a sensitive, systemic marker of inflammation. In people with type 2 diabetes (T2DM) DPP-4 inhibitor therapy decreases CRP concentrations. Serum CRP concentrations correlate with psoriasis severity and interventions that decrease the CRP concentration may decrease also psoriasis severity. Medications that improve insulin resistance may decrease also systemic inflammation and improve psoriasis. We have shown previously, in psoriasis patients without T2DM (both lean and obese), that the fasting insulin concentration and the homeostatic model of insulin resistance (measures of insulin resistance) correlate strongly with the psoriasis area and severity index (PASI, a measure of psoriasis severity: r=0.48, p<0.001; r=0.49, p<0.001).