Soluble tumour necrosis factor-α receptor type 1 as a biomarker of response to phototherapy in patients with psoriasis

Abstract

The purpose of the study was to analyze the relationship between the serum concentration of soluble tumour necrosis factor-α type 1 (sTNF-R1), the severity of plaque-type psoriasis and therapeutic response. We compared sTNF-R1 in 25 patients treated with narrowband ultraviolet B (NB-UVB) radiation and 25 patients treated with systemic photochemotherapy (psoralen plus UVA – PUVA). The pretreatment Psoriasis Area and Severity Index (PASI) score and sTNF-R1 concentration were 16.32±5.26 and 1.99±0.40 ng ml⁻¹, respectively, in the group treated with NB-UVB, and 17.22±3.48 and 2.07±0.31 ng ml⁻¹, respectively, in the group treated with PUVA. The concentration of sTNF-R1 in healthy controls was 1.49±0.34 ng ml⁻¹ (p<0.05 compared with patients with psoriasis). The pretreatment PASI score correlated with sTNF-R1 in both treatment groups (r=0.46 and r=0.44, p<0.05). NB-UVB and PUVA gave similar therapeutic effects (the PASI score after 20 treatments was 4.42±1.67 in the NB-UVB-treated group and 5.55±2.10 in PUVA-treated patients); however, the sTNF-R1 concentration at the same time differed significantly: 1.52±0.37 ng ml⁻¹ and 1.98±0.39 ng ml⁻¹ (p<0.001), respectively. Moreover, the decline in sTNF-R1 in both treatment groups was significant only in patients in whom the duration of skin lesions was less than 3 months. The results suggest that the value of serum sTNF-R1 concentration as a marker of response to phototherapy may depend on duration of skin lesions and the treatment method.

Keywords: :

• Soluble tumour necrosis factor-α receptor type 1
• psoriasis
• narrowband ultraviolet B
• systemic photochemotherapy