Serum Thymus and Activation Regulated Chemokine (TARC), IL- 18 and IL-18 Gene Polymorphism as Associative Factors with Atopic Dermatitis.

Atopic dermatitis (AD) is a worldwide chronic inflammation of skin.Many factors and chemokines play role in pathogenesis of AD. Identifying the reliable biomarkers to diagnose and assess severity of AD is important. In this study we aimed to find a reliable biomarker to determine the severity of AD and monitor treatment as well as, examining the possible association between IL-18 gene [rs 187238] promoter polymorphism and AD disease. The study included 30 Egyptian patients with AD and 30 healthy controls. Patients were clinically evaluated according to SCORAD scoring system. For each subject levels of Thymus and activation regulated chemokine (TARC), IL-18, total IgE and Lactate dehydrogenase enzyme (LDH) in serum were measured and Polymorphism in IL-18 gene was analyzed using restriction fragment length polymorphism (RFLP). Patients were reevaluated after treatment. Serum levels of TARC, IL-18, IgE and LDH were significantly higher in patients than controls, and were associated with high SCORAD score. G allele was risk factor with OR 2.31 (1.10- 4.85) and significant p-value < 0.05 for AD. GG genotype was significantly associated with elevated serum levels of TARC, IL-18 and IgE. After treatment serum level of TARC showed significant decrease and was associated with low SCORAD score. We concluded that TARC, IL-18, total IgE and LDH are potential markers of severity in AD. G allele in IL-18 gene [rs 187238] is risk factor for AD while C allele is considered protective. TARC is also a reliable marker formonitoring treatment.