Good News for Pet Allergy Sufferers

Research on allergies is focused on understanding what happens to the human body during the allergic process – the sequence of events leading to the allergic response and the factors responsible for allergic diseases.

Scientists supported by NIAID (National Institute of Allergy and Infectious Diseases) found that, during the first years of their lives, children raised in a house with two or more dogs or cats may be less likely to develop allergic diseases as compared with children raised without pets. The striking finding here is that high pet exposure early in life appears to protect some children from not only pet allergy but also other types of common allergies, such as allergy to house dust mites, ragweed, and grass. This new finding is changing the way scientists think about pet exposure. Scientists must now figure out how pet exposure causes a general shift of the immune system away from an allergic response.

The results of this and a number of other studies suggest that bacteria carried by pets may be responsible for holding back the immune system’s allergic response. These bacteria release molecules called endotoxin. Some researchers think endotoxin is the molecule responsible for shifting the developing immune system away from responding to allergens through a class of lymphocytes called Th-2 cells. (These cells are associated with allergic reactions.) Instead, endotoxin may stimulate the immune system to block allergic reactions.

If scientists can find out exactly what it is about pets or the bacteria they carry that prevents the allergic response, they might be able to develop a new allergy treatment.