Eight (GMPS, IMPDH2, MGST2, NME6, NT5C2, RAC2, SLC29A2, TPMT) out of the 11 genes regulated by the combination therapy (6MP+AP) interacted with 35 genes present at 32 susceptibility loci associated with CD (n = 9), UC (n = 4) and IBD overall (n = 19), as judged by the STRING analysis (Fig 5 and Table 2). This evidence concerns the gene TPMT and inflammatory bowel disease.