Serum and Tissue Leptin Levels in Relation to Psoriasis vulgaris Severity

Background: Psoriasis is a chronic inflammatory T-cell-mediated skin disease, with a preponderance of type 1 cytokines that contribute in the induction and persistence of the inflammatory process. Leptin, a peptide hormone secreted mainly from the adipocytes of white fat is known to regulate a wide range of biological responses. Recently, leptin has been considered a cytokine -like hormone that modulates T-helper cell activity, it promotes type 1 cytokine synthesis and suppresses type 2 cytokine production. Accordingly, leptin was suggested to have a role in the pathogenesis of several chronic inflammatory diseases including psoriasis. However, the relationship between leptin and the severity of the disease still needs further studies. Objective: This study aims at investigating the suggested relationship between leptin levels in both serum and tissue and the severity of psoriasis vulgaris. Patients and Methods: This study included forty patients with chronic psoriasis vulgaris and forty healthy volunteers as a control group. Psoriasis area and severity index (PASI) was scored for all patients. Serum leptin levels were estimated using an Enzyme Linked Immunosorbant Assay (ELISA) technique. Skin biopsies were taken from lesional and non lesional skin of psoriatic patients as well as from normal skin of the control group. Tissue leptin levels were studied by both ELISA and reverse transcription-polymerase chain reaction (RT-PCR) in all patients and controls. Results: Tissue leptin levels were found to be significantly higher in psoriatic lesions (p < 0.05) when compared to controls, as well as significantly higher when compared to the non lesional skin of the patients themselves (p<0.05) when studied by both ELISA and R-T PCR techniques. Moreover, tissue leptin levels were found to be significantly higher in the non lesional skin of psoriatic patients when compared to controls (p<0.05). Serum leptin levels, lesional and non lesional tissue leptin levels were found to be significantly higher in patients with severe psoriasis vulgaris than mild to moderate psoriasis than controls (p<0.05). A statistically significant correlation was found between serum leptin levels, lesional tissue leptin levels and PASI score in patients with severe psoriasis vulgaris (r=0.68, p=0.001, r=0.793, p=0.000). Conclusion: Serum and tissue leptin levels are elevated in patients with severe psoriasis vulgaris and leptin level might serve as a marker of severity. [Journal of American Science 2010;6(10):412-422]. (ISSN: 1545-1003).