Serum levels of interleukin-8, tumor necrosis factor-α and γ-interferon in Egyptian psoriatic patients and correlation with disease severity

Psoriatic plaques have been shown to contain increased levels of pro-inflammatory cytokines. Also, serum levels of several cytokines have been reported elevated in psoriatic patients. It is postulated that changes in cytokine production both locally and systemically could be useful in monitoring disease activity. The aim of this study was to evaluate serum cytokine profile of interleukin (IL)-8, gamma-interferon (IFN-gamma) and tumor necrosis factor-alpha (TNF-alpha) in Egyptian psoriatic patients by enzyme-linked immunosorbent assay (ELISA) technique and to correlate these levels with disease severity. We analyzed serum samples from 60 Egyptian patients (31 females and 29 males) with a mean age of 40.2 +/- 17.4 years with active psoriasis, and 21 healthy volunteers for major T-helper type 1 cytokines using the ELISA technique. The disease severity, including erythema, induration and scales, was assessed by Psoriasis Area and Severity Index (PASI) score. TNF-alpha and IFN-gamma were markedly elevated in all sera from psoriatic patients. TNF-alpha was found a more efficient predictor for disease severity than IL-8 and IFN-gamma using three receiver-operator curves with accuracy. IL-8 was also moderately elevated and correlated with the age of patients (r = 0.28). We have obtained evidence that TNF-alpha in our study was found to be more useful than the other two tested cytokines, IL-8 and IFN-gamma as a follow-up marker for monitoring disease severity in Egyptian psoriatic patients. A positive correlation between lL-8 and the age of the patients was also noted.