Group 2 ILCs (ILC2) & Interleukin-33 (IL-33)

The skin, lungs, and intestines are always in contact with the environment, which can lead to inflammation and damage. Group 2 ILCs (ILC2), which depend on Interleukin-33 (IL-33), are found in large numbers at these barrier surfaces. They are known to play a role in inflammation, but how they help protect tissues, especially in the intestines, is not well understood.
Monticelli et al. 2015 Proc Natl Acad Sci USA 112: 10762-10767

When Group 2 ILCs (ILC2) in the gut are activated by Interleukin-33 (IL-33), they produce a growth factor called amphiregulin (AREG). This is a key feature of these cells. In experiments with mice that had intestinal damage and inflammation, more Group 2 ILCs (ILC2) produced AREG after the intestines were injured. If the natural pathway involving AREG and its receptor (EGFR) was disrupted, the disease got worse. However, giving extra AREG reduced inflammation and made the disease less severe, even in mice without certain immune cells. This shows a new way that the immune system can protect intestinal tissues.
Monticelli et al. 2015 Proc Natl Acad Sci USA 112: 10762-10767

Additionally, treating with Interleukin-33 (IL-33) or transferring Group 2 ILCs (ILC2) helped reduce the severity of intestinal disease, and this effect depended on AREG. So, signals from damaged tissues activate immune cells to produce growth factors. These factors are crucial for repairing the epithelial barrier and keeping the tissue healthy.
Monticelli et al. 2015 Proc Natl Acad Sci USA 112: 10762-10767

see also:
Allergic reactions / Allergies