Severity Assessment and IL-5 Evaluation after Immunotherapy in Atopic Dermatitis Mice

Background: The effectiveness of immunotherapy in atopic dermatitis (AD) has been debated for many years. Immunotherapy suppresses Th2 cytokines, such as IL-5, which play a crucial role in the pathogenesis of AD. This study assessed the effect of immunotherapy on severity and IL-5 expression in AD mice. Methods: Male BALB/c mice were separated into three groups. The mice were sensitized with Dermatophagoides pteronyssinus allergen for seven days, except the mice in control group. The house dust mite (HDM) immunotherapy was injected subcutaneously every 3 days for 1.5 months with increasing doses (0.1, 1, 10, 100 μg in 100 μL PBS) every 4 injections. The mice in AD model and control group received placebo injections. Following immunotherapy, the mice were exposed to HDM allergen patch two times with 2 weeks interval in between. The mice were evaluated for severity score as the clinical marker and IL-5 expression with semiquantitative method as the histological marker. Results: The evaluation of severity score from two independent researchers showed a substantial agreement (Cohen’s kappa 0.613, p <0.001). The severity score of the immunotherapy group was significantly lower than the AD model group, while both immunotherapy and AD model group had significantly higher score than control group. IL-5 expression in the immunotherapy group was lower than the AD model group and slightly higher than control group. The mean difference between groups was not significant. Conclusion: The severity of skin lesion and IL-5 expression in AD mice receiving immunotherapy were lower than AD model group.