Given the key role of ICs in maintaining immune tolerance and inhibition of autoimmunity [22] the observed decrease in the expression of PD-1 and TIGIT on the surface of oesophageal epithelial cells across the normal-BO—OAC disease sequence in this study might reflect a loss of homoeostasis and immune tolerance with disease development and progression. The gene discussed is TIGIT; the disease is bronchiolitis obliterans syndrome.