Given that the pathophysiology of EoE remains unclear and the differential diagnosis between EOE and GERD is still challenging due to the overlap of these two diseases, in this study, blood CD4+, CD25+, FOXP3+ gated lymphocytes (Tregs) were studied in two groups of age and sex matched children with GERD and EoE as compared to healthy controls. The gene discussed is CD4; the disease is gastroesophageal reflux disease.