Gut tissue‐resident memory T cells in coeliac disease

This mini‐review describes observations of the 1990ies with culturing of gluten‐specific and astrovirus‐specific CD4 + T cells from duodenal biopsies from subjects who presumably had a long time between the exposure to gluten or astrovirus antigens and the sampling of the biopsy. In these studies, it was also observed that antigen‐specific CD4 + T cells migrated out of the gut biopsies during overnight culture. The findings are suggestive of memory T cells in tissue which are resident, but which also can be mobilised on antigen stimulation. Of note, these findings were made years before the term tissue‐resident memory T cells was invoked. Since that time, many observations have accumulated on these gut T cells, particularly the gluten‐specific T cells, and we have insight into the turnover of CD4 + T cells in the gut lamina propria. These data make it evident that human antigen‐specific CD4 + T cells that can be cultured from gut biopsies indeed are bone fide tissue‐resident memory T cells.