Serum squamous cell carcinoma antigen (SCCA)-2 correlates with clinical severity of pediatric atopic dermatitis in Ishigaki cohort

Background: We sometimes encounter difficulties in assessing the severity of pediatric atopic dermatitis (AD) using currently available biomarkers such as thymus and activation-regulated chemokine (TARC) due to the higher baseline values in non-AD children. Recent case control studies have indicated the usefulness of squamous cell carcinoma antigens (SCCAs) in pediatric and adult AD. Notably, SCCAs are induced by IL-4 and IL-13, vital Th2 cytokines that play important roles in AD etiology. Objectives: Relatively low prevalence and mild disease severity of pediatric AD are observed in our Ishigaki cohort presumably due to the moisturising subtropical climate, which could conversely mean possible higher allergic potential of non-AD subjects towards AD. Thus, the purpose of this study was to further investigate the feasibility of using SCCAs together with TARC and periostin as biomarkers for pediatric AD even in the Ishigaki cohort. Methods: We enrolled 1459 nursery school children and identified 96 as having AD through 2009–2011. As statistical analyses, we performed Student's t-test, correlation analysis, and receiver and operating characteristic (ROC) analysis. Results: Serum SCCA1, SCCA2, periostin and TARC levels were all significantly increased in AD compared with those in non-AD, but only serum SCCA2 showed a significant increase in AD when assessed in each age group or in subgroup analysis. Among the biomarkers tested, serum SCCA2 also showed the best correlations with clinical AD severity and TARC and showed the best diagnosability for AD in ROC analysis. Conclusions: SCCA2 is a potent biomarker for pediatric AD in the Ishigaki cohort.