The scientific team led by Raymond Penn, Ph.D., and Matthew Loza, Ph.D, found that beta-agonists, such as those used in the treatment of asthma, increase the accumulation of type 2 T cells, a type of white blood cell that participates in immune system defense mechanisms. In certain diseases such as asthma and lupus, an over-reactive type 2 T cell response occurs and is believed to contribute to the disease.
"Inhaled beta-agonists are very effective in opening up airways and allowing asthmatics to breathe, but their ability to address the underlying inflammation that causes most asthma has been debated for years," said Penn, an associate professor in the Department of Internal Medicine and the Center for Human Genomics.
The research is reported on-line in the Journal of Allergy and Clinical Immunology and will be published in an upcoming print issue.
In fact, numerous clinical studies have reported that asthma symptoms tend to worsen over time in patients on continuous beta-agonist therapy. Although the reasons for this deterioration of asthma control are not clear, the Food and Drug Administration now recommends that the treatment of asthma with long-acting beta-agonists be supplemented with inhaled anti-inflammatory medications.
Using blood samples from human participants, the scientists measured the effect of beta-agonists on white blood cells that were grown in the laboratory. They were surprised to find that the drugs promoted a preferential accumulation of type 2 T cells.
Beta-agonists belong to a class of chemicals that include the hormone adrenaline produced by the body. Consequently, conditions that elevate blood adrenaline, such as emotion
Source:Wake Forest University Baptist Medical Center