Background: Narrow-band UVB (NB-UVB) phototherapy is widely used worldwide for moderate and severe psoriasis, which is a chronic autoimmune inflammatory disease characterized by skin infiltrates of Th1-, Th17- and Th22-cells releasing locally pro-inflammatory cytokines. We investigate serum levels of tumor necrosis factor-α (TNF-α) in psoriatic patients before and after NB-UVB phototherapy.
Methods: Twenty-eight subjects with moderate/severe plaque type psoriasis were enrolled. The severity of skin involvement was rated according to the Psoriasis Area and Severity Index (PASI) score at baseline (T0) and after 4 (T1) and 12 (T2) weeks of NB-UVB treatment. At the same time points, blood samples were taken for evaluation of TNF-α levels. NB-UVB phototherapy was administered twice weekly on non-consecutive days until 12 weeks.
Results: The median PASI score significantly decreased from 12.0 at baseline (T0), to 6.9 after 4 weeks (T1, P<0.001) and to 0 after 12 weeks (T2, P<0.001). TNF-a serum levels significantly increased in respect to the baseline after 12 weeks of therapy.
Conclusions: NB-UVB phototherapy is highly effective against psoriasis but, as it increases the TNF-α serum level, it seems unlikely that it can decrease the chronic inflammatory state that is thought to be responsible of the systemic co-morbidities of psoriasis.