Asthma drugs cause immune cell build-up

NEW YORK, Nov 28 (Reuters) The use of beta-agonist inhalers, which include drugs such as Proventil (albuterol), for asthma appears to promote the accumulation of immune cells called type 2 T cells, according to a report in the Journal of Allergy and Clinical Immunology. The results reinforce the importance of including anti-inflammatory steroids, note the authors.

''Our findings that suggest beta-agonists promote preferential type 2 T-cell accumulation are consistent with clinical findings that continuous beta-agonist therapy leads to deterioration of control in some asthmatics,'' Dr Raymond B Penn from Wake Forest University School of Medicine, Winston-Salem, North Carolina told Reuters Health. ''Why this deterioration occurs is not clear, but the fact that deterioration is less likely to occur when...steroids are used in conjunction suggests a failure to control inflammation.'' Penn and colleagues investigated the effects of beta-agonists on accumulation of type 2 T cells in blood from adult subjects.

The authors found that under certain circumstances treatment with the beta-agonist isoproterenol led to accumulation of type 2 T cells. The drug achieved this effect by not only increasing the production of these cells, but also by increasing their survival.

''These studies add to the body of data that question the ability of beta-agonists to function as anti-inflammatory agents in the treatment of asthma,'' Penn said. ''Dual therapies that include both beta-agonist and inhaled...steroids are therefore probably preferable to just'' beta-agonists alone.

Penn cautioned against using these findings to justify interrupting effective therapy. ''It is important that physicians and lay people not reject beta-agonists as an asthma therapy, as beta-agonist inhalers save thousands of lives each year by preventing or rescuing people from fatal asthma attacks,'' Penn said. ''They are important and often critical forms of asthma therapy, and for the mild asthmatic, an occasional beta-agonist inhaler treatment is usually sufficient to manage the disease.'' REUTERS SP PM0955