ABSTRACT
Psoriasis is a chronic inflammatory autoimmune skin disease, with a prevalence varying between 0.6% to 4.8% of the population worldwide. Psoriatic arthritis [PsA] is an inflammatory arthritis which can involve the musculoskeletal system and is characterized by negative rheumatoid factor. To evaluate the serum level of TNF-alpha, IL23 and oxidative stress [OS] markers in various stages of psoriasis including PsA. The psoriatic patients [N=30] were chosen with different clinical types of psoriasis including PsA, They were subdivided into four subgroups according to Schmitt and Wozel [2005] model of PASI score; mild[N = 8], moderate[N = 8], severe [N = 8] and PsA[N = 6]. The serum levels of TNF-alpha, IL23, NO, MDA, SOD and CAT were determined in all groups. The levels of TNF-alpha, IL23, MDA and NO were significantly higher in both Psoriatic and PsA patients respectively acc. to increase in PASI score in comparison to the control. On the other hand, the levels of SOD and CAT were significantly lower in both Psoriatic and PsA patients, respectively according to increase in PASI score than the control. The finding suggested that both Th1 and Th17 may play an important rule in the pathogenesis of psoriasis in addition to the rule of Oxidative Stress . Moreover, these markers can be used as biomarkers for various stages of psoriasis severity