Six (DPP4, ENTPD1, GNB4, PPAT, SLC29A2, SLX1A) of 9 genes regulated by the presence of 6MP and/or the combination therapy (6MP+AP) compared with 6MP alone interacted with 18 genes present at 17 IBD susceptibility loci associated with CD (n = 2), UC (n = 4) and IBD overall (n = 11) as judged by the STRING analysis (Fig 4 and Table 1). This evidence concerns the gene SLX1A and inflammatory bowel disease.