We first compared differential gene expression of two class Ib MHC molecules (HLA-E and CD1d) and one class Ia MHC molecule (HLA-A) between non-inflamed and inflamed colon from descending and ascending colon in refractory Crohn’s disease (CD) using the CERTIFI cohort (GSE100833) (60). The gene discussed is HLA-A; the disease is Cowden disease.