IFNG and gastroesophageal reflux disease: By contrast, Clayton et al (10) found no differences in the levels of TNF-α receptor, IL-6, IFN-γ, IL-12, IL-17, IL-22 and IL-23 in the serum of patients with achalasia compared with those with gastroesophageal reflux disease, in addition to those amongst the three subtypes of achalasia.