Assess two non-invasive markers of intestinal barrier integrity {Claudin-3 and intestinal Fatty acid-binding protein (I-FABP)} in patients with psoriasis and to evaluate the possible relation of these markers with the demographic and clinical data.

Psoriasis is a common non-infectious chronic immune-mediated skin disorder that is associated with the considerable physical and social burden .Its estimated prevalence varies globally and is highest in western countries, where it affects around 2-4% of the population The most common form is plaque psoriasis, accounting 90% of all cases and manifesting as sharply demarcated erythematous plaques covered by silvery scales The gut microbiota refers to the complex community of microorganisms, covering more than 1000 different species of bacteria, viruses, fungi, and protozoa.

The gut commensals predominantly aid in nutrient metabolism, drug metabolism, prevention of colonization of pathogenic microorganisms and in intestinal barrier function..

Dysbiosis or alterations in the composition and function of the microbiota has been implicated in the development and progression of various skin diseases. The concept of "gut-skin axis" links the effects of dysbiosis with many skin diseases.

Disruption of the intestinal barrier can cause translocation of bacteria and their endotoxins or metabolites, which further induces or aggravates systemic inflammation The intestinal barrier function is maintained by a lining of enterocytes and tight junctions, sealing the paracellular space between adjacent enterocytes. Intestinal barrier integrity loss can be assessed by evaluation of intestinal epithelial cell damage or tight junction loss Claudins are transmembrane proteins which participate in the formation of tight junctions by binding to the actin cytoskeleton. Blood Claudin- 3 is considered as a useful early non-invasive biomarker of intestinal permeability due to its small size Fatty acid-binding proteins (FABP) are small (14-15 kDa) cytosolic water-soluble proteins, present in mature enterocytes of the small and large intestine... It is also considered a reliable marker of intestinal barrier integrity Psoriasis is a systemic inflammatory disease with complex multifactorial pathogenesis. Recently, considerable interest has been focused on the interaction between the gut microbiome, intestinal barrier and immune system. The so-called 'gut-skin axis' has been suggested to be a key factor and an interesting area of research in the etiopathogenesis of psoriasis with potential attractive therapeutic implications

Inclusion Criteria:

• psoriatic patients and age and sex-matched healthy volunteers as a control group

Exclusion Criteria:

• - History of acute gastrointestinal infection or gastrointestinal surgery during the last 3 months prior to the study
• Intake of probiotics or prebiotics during the last one month.
• Systemic anti-psoriatic treatment in the previous 3 months
• Topical or phototherapy during the last month
• Dietary restrictions during the last 3 months
• Chronic gastrointestinal disorder (celiac disease, inflammatory bowel diseases, irritable bowel disease, food allergies)
• Liver cirrhosis
• Cardiac failure
• Any associated skin or systemic illness

psoriatic patients and age and sex-matched healthy volunteers as a control group