Circulating cell-free DNA levels in Portuguese patients with psoriasis vulgaris according to severity and therapy

Abstract

Background: Inflammation has a key role in the pathogenesis of psoriasis. Circulating cell-free DNA (CFD) is a marker of tissue cell damage closely associated with inflammation.

Objectives: We aimed to understand the relation of CFD levels with psoriasis severity, defined by the Psoriasis Area and Severity Index (PASI), with inflammation and with psoriasis therapy.

Methods: Forty-six patients with psoriasis vulgaris were evaluated before (T0) and after 12 weeks (T12) of treatment with narrowband ultraviolet light B (NB-UVB; n = 17), psoralen plus UVA (PUVA; n = 20) or topical therapy (n = 9). We evaluated interleukin (IL)-6 and circulating CFD levels.

Results: Compared with controls, at T0, patients presented significantly higher levels of circulating CFD. CFD presented a significant positive correlation with IL-6 and a trend towards a positive correlation with PASI. Multiple linear regression analysis identified IL-6 as an independent variable associated with CFD circulating levels. As shown by the PASI score, a trend towards higher values of CFD was observed in the severe psoriasis forms; moderate and severe psoriasis presented also significantly higher CFD values, compared with control. Both NB-UVB and PUVA treatments significantly decreased the levels of CFD.

Conclusions: Patients with psoriasis, at the active stage of the disease, presented an increased inflammation associated with raised circulating CFD levels, which seem to be linked to psoriasis severity. Both NB-UVB and PUVA, anti-inflammatory therapies, were effective in decreasing CFD values. We propose that the evaluation of circulating CFD may provide a new biomarker to monitor psoriasis, its severity and its treatment.