Changing jejunal γδ T cell receptor (TCR)-bearing intraepithelial lymphocyte density in coeliac disease

Abstract

SUMMARY The function of jejunal intraepithelial γδ+ T cells is obscure, but they are commonly implicated as playing a role in inflammatory and autoimmune conditions. In coeliac disease (CoD), there are controversial reports as to gluten dependency of these cells. We have now studied the small bowel mucosal intraepithelial T cell densities, and the ratios of γδ+ to CD3+ T cells and γδ+ to αβ+ T cells during early disease development and on a gluten-free diet. Nine children initially excluded for CoD were followed up and rebiopsy after 0.8–4.5 years showed mucosal deterioration. Further, 21 biopsy specimens from newly diagnosed CoD patients were studied, together with 20 specimens taken from children on a gluten-free diet. During CoD development the density of γδ+ and αβ+ T cells as well as the ratios of γδ+ to CD3+ T cells and γδ+ to αβ+ T cells increased. In the latent stage of CoD when the small bowel mucosal architecture was still normal, two children had clearly normal densities of γδ+ (< 2.5 cells/100 epithelial cells) and αβ+ (< 25.0 cells/100 epithelial cells) T cells, and low ratios as well. In patients with newly diagnosed CoD the densities decreased significantly on a long-term gluten-free diet. We conclude that the density of intraepithelial γδ+ T cells as well as αβ+ T cells in CoD is gluten-dependent. CoD can develop in a child ingesting normal amounts of gluten and having normal jejunal mucosal morphology on biopsy and a normal density of γδ+ T cells.