Effect of psoriasis activity on epidermal growth factor (EGF) and the concentration of soluble EGF receptor in serum and plaque scales.

BACKGROUND Epidermal growth factor receptors (EGFRs) are overexpressed in psoriatic keratinocytes, and regulate cell growth, proliferation and differentiation through binding to epidermal growth factor (EGF). The role of EGF and EGFRs in the pathogenesis of psoriasis and the contribution of their measurement to psoriasis management are still unknown. AIM To evaluate serum concentrations of EGF, soluble (s)EGFRs and EGF content in psoriatic scales of patients with severe psoriasis, and to analyse their association with the clinical activity of the disease. METHODS Serum samples and plaque scales were collected from 51 patients with plaque-type psoriasis. Concentrations of EGF and sEGFR in serum and of EGF in scales were measured using enzyme immunoassay. Data were analysed with respect to baseline Psoriasis Area and Severity Index (PASI). RESULTS Mean serum EGF concentration in patients was higher than in controls (701 ± 72 vs. 586 ± 63 pg/mL), but the difference was not significant. Mean serum concentration of sEGFR was significantly lower than controls (40.8 ± 1.4 vs. 86.4 ± 11.3 ng/mL, P < 0.001). Serum levels of EGF showed a significant positive correlation and EGFR showed a significant negative correlation with PASI (P < 0.05). No correlation was seen between PASI and EGF content in scales or between EGF and sEGFR levels. Serum EGF concentrations reached the highest mean level (914 ± 138 pg/mL) in patients with PASI > 20, and this was significantly higher than the mean of 414 ± 82 pg/mL in the group with PASI < 10. Mean sEGFR serum concentrations remained significantly lower than those of controls, irrespective of disease severity. CONCLUSIONS Compared with controls, patients with psoriasis had increased EGF and decreased sEGFR levels in serum. EGF and sEGFR levels correlated with disease severity.