Purpose: The aim of the study was to examine the tumour necrosis factor alpha (TNF-alpha)-converting enzyme (TACE) concentration in peripheral blood mononuclear cells (PBMC) and its relationship with plasma concentration of soluble TNF-alpha receptor type 1 (sTNF-R1) and with the disease severity in psoriasis patients treated with narrowband ultraviolet B (NB-UVB).
Methods: The study has been conducted among 40 patients with plaque-type psoriasis vulgaris: 23 had only skin lesions (PV) and 17 had co-existing, inactive, psoriatic arthritis (PsA). Control blood samples were obtained from 20 healthy subjects. The assessment of the severity of skin lesions (using Psoriasis Area and Severity Index - PASI), TACE and sTNF-R1 concentrations (using quantitative sandwich enzyme immunoassays) have been performed at baseline (T 0) and after 20 NB-UVB irradiations (T 20).
Results: The baseline sTNF-R1 and TACE concentrations in all patients was higher than that in controls (2.55 +/- 1.67 vs. 1.70 +/- 0.15 ng/ml, P<0.001, respectively, and 2.62 +/- 0.32 vs. 1.31 +/- 0.30 ng/ml, P<0.001, respectively). The sTNF-R1 and TACE concentrations were lower in PV than in PsA patients (2.47 +/- 0.16 vs. 2.65 +/- 0.13 ng/ml, and 2.52 +/- 0.22 vs. 2.76 +/- 0.39 ng/ml, P<0.05, respectively). The baseline PASI correlated with sTNF-R1 and to TACE concentrations (R=0.48 and 0.39, P<0.05, respectively). The sTNF-R1 correlated to TACE concentration (R=0.52, P<0.05). The significant decline in sTNF-R1 and TACE concentrations at T 20 was noticed, TACE reached control values (1.20 +/- 0.44 ng/ml in PV patients and 1.16 +/- 0.48 ng/ml in PsA patients, respectively).
Conclusion: TACE from PBMC can contribute to up-regulation of sTNF-R1 in patients with active psoriasis vulgaris and with psoriatic arthritis. It also can serve as a sensitive marker of the disease severity.