The immune system is a double-edged sword. While its primary role is to fight infections, it can also become overactive, leading to problems like allergies and autoimmune diseases.
For example, the part of the immune system responsible for resisting parasites acts by releasing white blood cells called eosinophil granulocytes into the blood. But elevated eosinophil levels are also responsible for allergic reactions, including most forms of asthma, gastrointestinal diseases, blood disorders, and cancers.
Now a study, led by Dr. Ariel Munitz of the Department of Clinical Microbiology and Immunology at the Sackler School of Medicine at Tel Aviv University, and conducted by graduate students Netali Baruch Morgenstern and Dana Shik, has found a mechanism that pushes eosinophils to die before they get into the blood and wreak havoc. The discovery is a breakthrough in science's understanding of the immune system and suggests powerful new treatments for eosinophilic diseases such as asthma.
"We've discovered an important and powerful pathway that works to kill eosinophils," says Dr. Munitz. "The fundamental knowledge we have gained may one day yield even bigger results and therapies."
Published online in Nature Immunology in November, the research was funded in part by the United States-Israel Binational Science Foundation, the Israel Science Foundation, the Israel Cancer Research Fund, and the Fritz Thyssen Stiftung. The Division of Allergy and Immunology at the Cincinnati Children's Hospital Medical Center collaborated on it.
The body's tug-of-war
The level of eosinophils in the blood is relatively low in healthy people, accounting for just 2 to 5 percent of white blood cells in circulation. But in eosinophilic disorders, a signalling protein called interleukin 5, or IL-5, triggers a rush of eosinophils from the bone marrow, where they are produced, and into the blood, where they are transported to va
|Contact: George Hunka|
American Friends of Tel Aviv University