Allergy Shots May Ease Some Asthma Symptoms

     In carefully selected patients, allergy shots can safely and
effectively ease the suffocating symptoms of ragweed asthma and,
in some cases, may be even better than conventional asthma
treatment, according to a new study by researchers at Hopkins and
the Mayo Clinic.

     Doctors have recognized the value of allergy shots for
treating sneezing, runny noses and the other symptoms caused   
by ragweed allergic rhinitis, or "hayfever."  But they have long
debated the potential benefits of allergy shots for patients
whose allergies trigger asthma attacks.

     "Immunotherapy involves more time and trouble than typical
asthma treatments, and there is a risk in allergic asthma
patients of a more serious reaction to the treatment, which can
shut down a patient's ability to breathe,"says Peter Creticos, a
Hopkins associate professor of medicine and lead author of the
new study.

     But in a three-year double-blind study funded by the
National Institute of Allergy and Infectious Diseases, Creticos
and colleagues learned that ragweed immunotherapy safely improved
all of the many indicators that they studied--ranging from the
patients' descriptions of their breathing difficulties to
objective laboratory measurements of their responses to ragweed.

     Results were published in last week's issue of the New
England Journal of Medicine.

     For the study, researchers recruited 77 patients in whom
ragweed allergy was the primary cause of asthma. The patients
were divided into two groups; both groups were observed for a
year, and then entered a two-year treatment phase. 

     During this phase, one group received injections of ragweed
allergen--the proteins that trigger allergic reactions. The other
group received a placebo injection and standard asthma
treatments--such as inhaled steroids to control inflammation and
bronchodilator drugs to relieve acute symptoms.  

     Regular injections of allergen, given in increasing doses,
stimulate changes in the immune system that decrease the chance
of future allergic reactions, Creticos explains. Because the
injections can also cause allergic reactions, Creticos and
colleagues used ragweed allergen doses already found to be safest
and most effective for treating hayfever.

     "Both the group getting ragweed injections and the placebo
group, who also saw doctors regularly and received standard
asthma treatments, improved," says Creticos. 

     "But the group receiving the active ragweed shots used
significantly less medication during the peaks of the ragweed
season. They demonstrated improvements in their daily peak flow
rates, meaning they could expel more air from their lungs more
rapidly; they were also less sensitive to ragweed when exposed to
it in the laboratory.  That's consistent with what you'd expect
if you were really turning off the underlying disease process."

     Because of the regular, required visits to the doctor's
office, allergy shots still might not be the best treatment for
some patients, Creticos notes. Additional studies are also needed
to learn if allergy shots are effective for patients with asthma
caused by other allergens, or multiple allergens.