Altered expression of innate immunity genes in different intestinal sites of children with ulcerative colitis.

Background: Innate immunity has been very rarely investigated in ulcerative colitis and never in paediatrics. The present study was aimed at describing expression of innate immunity genes (NOD2, RIP2, α-defensins HD5 and HD6) in inflamed colon and in ileum of children with ulcerative colitis. Expression of TNFα and IL-1β was also analyzed.

Methods: 15 children with ulcerative colitis (9 pancolitis, 6 left-sided colitis) and 10 control children were enrolled. mRNA and protein expressions were detected by real time PCR and western blot assays.

Results: NOD2, RIP2, IL-1β, TNFα expression levels were significantly increased in colonic mucosa of patients compared to controls (p<0.01). These genes were also upregulated (p<0.01) in the ileum of both pancolitis and left-sided colitis children. HD5 and HD6 were significantly upregulated (p<0.01) in the inflamed colon of patients as well as in the ileum of those with pancolitis.

Conclusions: An increased mucosal expression of innate immunity genes was found in the inflamed colon of children with ulcerative colitis, outlining the role of the innate immune response in disease pathogenesis. Involvement of the ileum in ulcerative colitis suggests that an immune activation can also be established in intestinal sites classically uninvolved by the inflammation, carrying implications for the treatment and course of the disease.