SUNDAY, Sept. 28 (HealthDay News) -- A vaccine that protects against the miserable symptoms of ragweed allergy for a longer period of time -- and with fewer injections -- could be available in the coming years.
Unlike traditional allergy vaccines that are given weekly for several months, new formulations would require only a few injections and would offer longer-lasting relief.
"What you would hope is that you would get fewer injections less often, less likelihood of an allergic reaction and the same or better improvement in your symptoms," said Dr. William C. Howland III, an allergist and medical director of Lovelace Scientific Resources in Austin, Texas.
Howland has presented research at an American College of Allergy, Asthma & Immunology meeting showing that just four injections of an investigational ragweed vaccine, called Pollinex Quattro, were safe and effective.
Separately, a research team led by Dr. Peter Creticos, clinical director of the Johns Hopkins Asthma and Allergy Center in Baltimore, has led pilot testing of another ragweed vaccine, called Tolamba, developed by Berkeley, Calif.-based Dynavax Technologies Corp. Those results were published recently in the New England Journal of Medicine.
"Our study was able to demonstrate that after a concise six-week, six-injection regimen, we were able to shut off seasonal symptoms for at least the two seasons we followed the patients in the study," Creticos said.
Ragweed is a type of weed that grows throughout the United States but is most common in the eastern states and in the Midwest. Among Americans who are allergic to pollen-producing plants, 75 percent are allergic to this particular weed, according to the Asthma and Allergy Foundation of America.
Ragweed season typically runs from mid-August to October and is a significant cause of fall allergy symptoms, says the American Academy of Allergy, Asthma & Immunology.
Antihistamines help some people achieve relief from their symptoms, including runny or stuffy noses, sneezing, and itchy eyes, nose and throat. But when these medications don't work, allergy shots are the next line of treatment.
Allergy vaccines are highly effective but have certain drawbacks, allergists say, including the number of shots required to build up an immune response.
"It takes between six and 18 months of weekly injections to reach the maximum effect, so people are coming in every week, and they get an injection," Howland explained.
In addition, it's recommended that patients wait in their doctor's office 30 minutes after each injection to be monitored for any adverse reactions that may occur.
The new wave of investigational vaccines have been tweaked to be more effective in fewer doses and to reduce the incidence of immediate side effects.
Early results look promising.
Howland and his colleagues, for example, studied different doses of a ragweed extract and their effect on antibodies in the bloodstream. People with allergies produce an antibody called immunoglobulin E, which sets off a cascade of chemicals to fend off a perceived allergen, such as ragweed. This chemical response triggers the allergic symptoms that people experience. Another antibody in blood, called immunoglobulin G, fights infection.
"What the study showed was that the G antibodies increased proportionate to the strength of the injections given," he said. "So, the weaker injection had less of an effect, and then the medium had more, and the highest dose had the highest effect on the G antibodies."
However, don't expect new-and-improved vaccines to pop up in your doctor's office this ragweed season. Vaccine makers have to clear several hurdles first.
Allergy Therapeutics PLC, the U.K.-based maker of the Pollinex Quattro vaccine, reported that the U.S. Food and Drug Administration had placed a "hold" on its clinical studies while the agency reviewed a report of a rare adverse event. The company noted that a physician involved said the event was "possibly related" to the study drug. Last November, the company said it had met with the FDA, submitted information, and would continue to work with the agency to lift the hold.
Meanwhile, Creticos said a large, multi-center trial replicated findings of the Tolamba pilot study that his team led. Additional studies are continuing.
Dr. Thomas B. Casale, chief of the Division of Allergy and Immunology at Creighton University School of Medicine in Omaha, Neb., expects it will take another couple of years for these vaccines to become available, assuming, he added, that the next wave of clinical trials show that these approaches are safe and effective.
Until there are better treatments, people with ragweed allergy can minimize their exposure by keeping windows in their cars and homes closed to prevent pollen from drifting in, according to the American Academy of Allergy, Asthma & Immunology. And take a shower after spending time outdoors, because pollen can collect on your hair and skin.
More information
The Asthma and Allergy Foundation of America can tell you more about outdoor allergies 
.
THURSDAY, Oct. 2 (HealthDay News) -- The inhaled steroids that are often used to treat asthma don't work as well in the overweight or obese, new research shows.
In fact, the treatments are 40 percent less effective in these patients than in those of a healthy weight, said study author Dr. E. Rand Sutherland, an associate professor of medicine at National Jewish Health in Denver.
"The combination of obesity and asthma appears to do something to limit the pathways by which steroids reduce inflammation," he said.
"We had seen these preliminary reports that inhaled steroids might not work as well [in overweight patients]," he said. So, his team decided to try to see if that was so, and to find out why.
About 20 million Americans have asthma, said Sutherland, and nearly half are overweight or obese, having a body-mass index (BMI) of 25 or higher.
His team looked at 33 adults with asthma and 12 without. "We took blood cells and airway cells" from all, he said, and measured the response of the cells to the glucocorticoid called dexamethasone.
The steroid works by interfering with inflammatory signaling pathways by raising the level of a molecule called MAP kinase phosphatase-1 (MKP-1).
When the cells were exposed to the steroid, the levels of MKP-1 increased by 5.27 times in the lean asthma patients but increased by 3.11 times -- 41 percent less -- in those who were overweight or obese.
Why the difference occurs is not known, Sutherland said. "We can speculate. Obesity has been associated with increasing inflammation in the body. It may be that the same processes that increase inflammation leading to diabetes and cardiovascular disease may also be implicated in modifying steroid effects."
The study is well-done, said Dr. John E. Heffner, past president of the American Thoracic Society and chair of medical education at the Providence Portland Medical Center, in Oregon.
It shows that the more obese a person with asthma is, the less the expression of MKP-1 -- and the more inflammation.
The practical advice, Heffner said, is to suggest overweight patients with asthma lose weight. However, he said, "We don't know if you can regain your responsiveness to glucocorticoids if you lose weight."
Sutherland cautions those with asthma not to stop taking medications. "This [study ] doesn't mean the drug won't work, it just means the drugs might not work as well" in overweight patients with asthma. Physicians may want to increase the dose, however.
The study was published in the first October issue of the American Journal of Respiratory and Critical Care Medicine.
More information
To learn more about asthma medications, visit the American Academy of Allergy, Asthma & Immunology .