Altered immunoregulatory profile during anti-tumour necrosis factor treatment of patients with inflammatory bowel disease.

Inflammatory bowel disease (IBD) can be treated effectively by anti-tumour necrosis factor (TNF) therapy. We set out to investigate the unclear immunoregulatory mechanisms of the treatment. Thirty-four patients with IBD treated with anti-TNF were included. Lymphocytes from peripheral blood and intestinal biopsies were analysed by flow cytometry. Regulation of antigen-stimulated proliferation was analysed by blocking of interleukin (IL)-10, transforming growth factor (TGF)-β or depletion of CD25(+) cells in peripheral blood mononuclear cell cultures. No changes in CD4(+)CD25(+), CD25(+)TNF-RII(+) or CD4(+)CD25(+) forkhead box protein 3 (FoxP3(+)) T cells could be observed in peripheral blood after, in comparison to before, 6 weeks of treatment. The suppressive ability of CD4(+)CD25(+) cells did not change. There was an initial decrease of CD4(+)CD25(+) cells in intestinal mucosa after 2 weeks of treatment, followed by an increase of these cells from weeks 2 to 6 of treatment (P < 0·05). This was accompanied by an increased percentage of CD69(+) cells among these cells after 6 weeks of treatment compared to before treatment (P < 0·01). There was also an increase of mucosal T helper type1 cells from weeks 2 to 6 (P < 0·05). In addition, CD25(+)TNF-RII(+) cells in the mucosa were decreased after 6 weeks of treatment compared to before treatment (P < 0·05). Before treatment, peripheral blood mononuclear cell baseline proliferation was increased when IL-10 was blocked (P < 0·01), but not after. In CD25(+) cell-depleted cultures proliferation increased after treatment (P < 0·05). Our data indicate that anti-TNF treatment leads to an induction of effector T cells. Anti-TNF therapy has no significant impact on regulatory T cells in IBD, although the composition of regulatory T cell subsets may change during treatment.