Hypereosinophilic syndromes are a group of disorders characterized by excessive numbers of eosinophils, a type of white blood cell, which accumulate in the blood. An increase in eosinophils is most commonly caused by an allergic reaction, resulting in the use of steroids to decrease their over-production.
However, in hypereosinophilic syndromes, eosinophils multiply in an uncontrolled manner, attacking numerous parts of the body, including the heart, lungs, gastrointestinal tract, and skin. Treatment usually involves the use of potentially toxic medications to stop the overproduction of eosinophils. However, current treatments only provide limited control and quickly become ineffective.
A research team led by Marc E. Rothenberg, MD, PhD, Cincinnati Children's Hospital Medical Center, is the first to report on the safety and efficacy of a new anti-IL-5 therapy in patients with severe forms of hypereosinophilic syndromes. Originally developed for the treatment of asthma, anti-IL-5 therapy blocks the eosinophil growth factor interleukin-5 (IL-5). IL-5 is a cytokine critically involved in regulating several aspects of eosinophils including their production, activation and tissue recruitment.
Four patients, previously dependent on a variety of toxic medications to partially treat their hypereosinophilic syndrome, were given three intravenous doses of anti-IL-5 administered at four week intervals. Researchers found that anti-IL-5 was well tolerated in all four patients and lowered eosinophil counts despite on-going systemic steroid therapy. This decline in eosinophil counts was sustained for at least 12 weeks after the last dose of Anti-IL-5.
Anti-IL-5 therapy improved the quality of life in all four patients. One patient, who was unable to eat solid foods for several years due to the disease narrowing his esophagus, was able to begin swallowing solid foods after treatment with Anti-IL-5. The other patients reported improved respiratory symptoms and began assuming more normal lifestyles.
"While hypereosinophilic syndromes are relatively rare compared with typical allergic diseases, it is important that appropriate therapy be developed for these often debilitating diseases," Rothenberg said.
The AAAAI is the largest professional medical specialty organization in the United States representing allergists, asthma specialists, clinical immunologists, allied health professionals and others with a special interest in the research and treatment of allergic disease. Allergy/immunology specialists are pediatric or internal medicine physicians who have elected an additional two years of training to become specialized in the treatment of asthma, allergy and immunologic disease. Established in 1943, the AAAAI has nearly 6,000 members in the United States, Canada and 60 other countries. The AAAAI serves as an advocate to the public by providing educational information through its Web site at www.aaaai.org or the toll-free physician referral and information line at 1-800-822-2762.