CCL26 and gastroesophageal reflux disease: With our findings that differences in acid exposure might underlie the different effects of PPIs on eotaxin-3 expression in the proximal and distal esophagus, it will be important for future studies to measure the pH, frequency, duration and proximal extent of gastroesophageal reflux to elucidate the role of acid exposure in modifying PPI-responsiveness.