Abstract
Background We recently reported that squamous cell carcinoma antigen 2 (SCCA2) is a reliable biomarker for atopic dermatitis (AD) in children. To further clarify its utility, we investigated for possible effects of comorbid allergies and AD treatment on serum SCCA levels in children and adolescents.Methods Volunteers aged less than 18 years were recruited through our website. Their allergic status was elucidated using the International Study of Asthma and Allergies in Childhood (ISAAC) questionnaire. We also recruited pediatric patients who needed to be hospitalized because of severe AD. The serum levels of SCCA1 and SCCA2 were measured by ELISAs. In the severe AD patients, the levels of thymus and activation-regulated chemokine (TARC), SCCA1 and SCCA2 were measured before and after hospitalization. The severity of AD was assessed using the severity scoring of atopic dermatitis (SCORAD) index.Results A total of 576 participants (547 volunteers and 29 patients) were enrolled in the study. The levels of SCCA1 and SCCA2 were significantly higher in volunteers with mild AD and patients with severe AD than in healthy volunteers without allergic diseases. In contrast, the levels were not elevated in those who had mild bronchial asthma or mild allergic rhinitis without AD. TARC, SCCA1 and SCCA2 were decreased in patients with severe AD, reflecting clinical improvement in response to treatment. Linear regression analysis for predicting a decrease in the SCORAD index showed R2 values of 0.16, 0.38 and 0.48 for TARC, SCCA1 and SCCA2, respectively..Conclusions SCCAs, especially SCCA2, are sensitive biomarkers for detecting AD in children and adolescents, even in the mild stage, and for assessing the severity and response to treatment of severe AD.