Background.  Psoriasis is a chronic, systemic, inflammatory disease. Inflammatory markers are used in clinical practice to detect acute inflammation, and as markers of treatment response. Etanercept blocks tumour necrosis factor (TNF)-α, which plays a central role in the psoriatic inflammation process.

Aim.  To reveal any possible association between disease severity [measured by Psoriasis Area and Severity Index (PASI)] and the inflammatory burden (measured by a group of inflammatory markers), before and after etanercept treatment.

Methods.  In total, 41 patients with psoriasis vulgaris, eligible for biological treatment with etanercept, were enrolled in the study. A set of inflammatory markers was measured, including levels of white blood cells and neutrophils, fibrinogen, ferritin, high-sensitivity C-reactive protein (hs-CRP), erythrocyte sedimentation rate (ESR), haptoglobin, ceruloplasmin and α1-antitrypsin, before and after 12 weeks of etanercept 50 mg twice weekly.

Results.  All markers were reduced after treatment (< 0.001). PASI correlated with fibrinogen and hs-CRP. Of the 41 patients, 19 (46.3%) achieved reduction of 75% in PASI (PASI75). An increase in hs-CRP and ESR difference (values before minus values after treatment) was related to higher likelihood of achieving PASI75.

Conclusions.  Inflammatory markers, particularly hs-CRP and to a lesser extent, fibrinogen and ESR, can be used to assist in assessing disease severity and response to treatment in patients with psoriasis. A combination of selected inflammatory factors (which we term the Index of Psoriasis Inflammation) in combination with PASI might reflect inflammatory status in psoriasis more accurately than each one separately.