For years now immunologists have been trying to understand auto-immune diseases, which occur when the immune system turns its weapons on the cells of its own body. This is no easy task because the immune system is extremely complex, consisting of many different types of immune cells and a host of complex chemicals. All of these interact and like the musicians in an orchestra they normally they produce a seamless performance. Orchestras need to play faster and more loudly at times but they also need to reverse this so as to play softly or slowly. In an autoimmune disease it’s as if one section of the orchestra is ignoring the conductor and just keeps playing louder and faster. The conductor’s job in the immune system is undertaken by regulatory T cells. These are a type of lymphocyte, also known as Tregs or CD8 cells, that calm things down after a period of inflammation.
One of the most common autoimmune diseases is rheumatoid arthritis. In arthritis immune cells start attacking joints and the inflammation this causes runs out of control. For some reason the Tregs can't calm things down.
In some recently reported work, researchers injected some of Tregs into mice with arthritis and they worked – reducing the unwanted inflammation in the joints. They also used a technique to increase the number of Tregs produced by the mice and this also worked.
It is no easy task to tweak the workings of the immune system. Conventional drugs such as steroids can blunt more than one aspect of the immune system and cause other serious side effects throughout the body.
Experiments like these are beginning to give hope that one day the mountain of research papers in immunology will pay some real dividends in terms of treatments.