Possible Noninvasive Biomarker of Eosinophilic Esophagitis: Clinical and Experimental Evidence.

Eosinophilic esophagitis (EoE) diagnosis and follow-up response to therapy is based on repeated endoscopies and histological examination for eosinophils/HPF. The procedure is invasive and risky in particular for the pediatric population. Presently, there is no highly sensitive and specific noninvasive blood test available to monitor the disease pathogenesis. Reports indicate the expression of PDL1 (CD274) on the eosinophils in allergic patients. Herein, we report that CD274-expressing and -nonexpressing eosinophils were detected in both examined pediatric and adult EoE patients. We show that CD274 expression on blood eosinophils and blood mRNA expression levels increase in the blood of EoE patients and decrease following treatment. These observations are consistent with the esophageal eosinophilia of before and after treatment in both examined patients. These two clinical and experimental analysis reports provide the possibility that the CD274 mRNA and CD274-expressing esinophil levels may be novel possible noninvasive biomarkers for EoE.