T helper type-2 cells induce ileal villus atrophy, goblet cell metaplasia, and wasting disease in T cell–deficient mice

Background & Aims: T helper (Th) 1 and Th2 cell subsets significantly influence the pathological features of inflammation in the gastrointestinal tract in a distinct manner. It is now established that the transfer of CD4+CD45RBHi (RBHi) T cells to either severe combined immunodeficient (SCID) or recombinase activation gene 2–deficient (RAG−/−) mice results in a severe granulomatous hypertrophic colitis mediated by Th1 cells. We have modified this approach to address the role of Th2 cells. Methods: RBHi T cells from wild-type (Wt) mice or mice genetically predisposed to Th2 responses (interferon-γ–defective [IFN-γ−/−]) with or without B cells were transferred to T cell receptor (TCR)-β and δ-chain–defective (TCR−/−) or SCID mice. Results: Transfer of Wt RBHi T cells induced wasting disease with severe colitis in the TCR−/− mice. In contrast, IFN-γ−/− RBHi T cells induced severe weight loss and hypoalbuminemia without significant inflammation in the colon. The small intestine of these mice exhibited villus atrophy, a decrease in brush-border enzymes, reduced enterocyte proliferation, and an increased number of goblet cells. The presence of B cells was necessary for these changes, because SCID recipients required cotransfer of B cells, together with IFN-γ−/− RBHi T cells for ileal lesions to develop. Treatment of TCR−/− recipients of IFN-γ−/− RBHi T cells with anti–IL-4 mAb abrogated both the wasting disease and the villus atrophy. Conclusions: Dysregulated Th2 cells cause atrophic changes and goblet cell transformation in the small intestinal epithelium and wasting disease mediated by excess interleukin-4 and B cells. GASTROENTEROLOGY 2003;124:672-682