Figure 4: Intrinsic immune cells coordinate the initiation of SPEM.
Severe damage in the corpus mucosa leads to the release of IL-33 from surface mucous cells and IL-25 from tuft cells, both of which stimulate the release of IL-13 from ILC2s. IL-13 in turn is required for initiation of the reprogramming of chief cells into SPEM cells and the development of pyloric metaplasia.