Histamines are an important chemical in the body. what is their purpose in the immune system

Histamine is a protein produced by mast cells in the body. It plays a very important role in the immune system of the body. Histamine is released in the body when affected by an allergen, e. g, pollen or animal dander. The immune system of the body will respond to such allergen by making more mucus in the nose by releasing histamine. There will be sneezing, itching, coughing and runny nose in response. This is a basic defense of the body's immune system to not enter any particle inside the body.