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. This evidence concerns the gene IL6 and gastroesophageal reflux disease.