Novel method to reduce cat allergic reactions

Scientists have discovered a novel method to reduce cat allergic reactions by topping up the immune cells responsible for controlling them.

According to research published in the Public Library of Science (PLoS) Medicine, the team from Imperial College London and Royal Brompton Hospital have discovered a way to decrease allergic reactions by increasing numbers of CD4+ regulatory T-cells.

Dr Mark Larché from Imperial College London and Royal Brompton Hospital, and senior author comments: "This discovery is a hugely important step in our understanding of how immunity and inflammation play a role in allergic reactions. Although we have known about the role of these regulatory immune cells for a number of years, this is the first time we have found a way to manipulate them to help control allergic reactions."

There are a number of types of T-cells in the body including T-helper 1, which are important in autoimmune diseases, T-helper 2, which are important in allergies, and T-regulatory cells. In allergic diseases, the body produces too many T-helper 2 cells, and not enough T-regulatory cells. This can result in asthma, hayfever and allergic eczema.

The researchers discovered that by increasing the levels of CD4+ T-regulatory cells they were able to control the extent of the allergic inflammation. They injected cat allergen synthetic peptides into volunteers to stimulate the growth of the regulatory cells, and found the extent of the allergic reaction was reduced.

At the same time, this discovery could also have implications for autoimmune diseases such as type 1 diabetes and multiple sclerosis. Autoimmune diseases arise when too many T-helper 1 cells are produced against one's own body. With this approach, it may be possible to stop or limit these diseases.

Professor Barry Kay from Imperial College London and Royal Brompton Hospital, and author on the paper, adds: "This is an important step in our understanding of how to treat allergic disease. Allergies are becoming increasingly common, and in may cases, progressively more difficult to manage. This discovery could be crucial in helping to alleviate the worst effects."

To date the team have carried out these studies in small groups of volunteers, but over the summer they are looking to organise a much larger clinical trial in conjunction with Circassia, a company spun out from Imperial.