The Johns Hopkins University School of Medicine study, conducted during two fall ragweed (“hay fever” ) seasons in Baltimore, Md., enrolled 25 volunteers, ages 23 to 60, with a demonstrated history of ragweed allergy. Fourteen people received the vaccine, administered as six weekly shots, while 11 others received placebo injections.
During the test period, allergic symptoms were monitored and recorded, right down to how often volunteers’ noses ran and how many times they sneezed. Compared to the placebo group, those who received the vaccine exhibited a 60 percent reduction in all of their allergy symptoms, including sneezing, runny nose, watery eyes and itching.
Relief from allergic symptoms was as pronounced in the second year as in the first, even though no more vaccine was administered. Lead investigator Peter Creticos, M.D., medical director of the Johns Hopkins Asthma and Allergy Center in Baltimore, explained that such prolonged relief is an important part of his team’s findings because it appears that the vaccine’s efficacy doesn’t wear off quickly. A new study, currently under way, will further examine the drug’s lasting effects in a larger group of participants.
It is thought that the vaccine lessens the immune system's excessive reactions to inhaled allergens by stimulating protective cells that turn off the T-helper cell (Th2) involved in the body’s inflammatory response. The TH2 helper cells send out signals for the body to create more IgE, the protein largely responsible for making allergy sufferers miserable throughout the entire ragweed season.
“This therapeutic intervention heralds a major advance in the treatment of allergic rhinitis,” says Creticos. “Long-lasting relief can be achieved with a concise, six-week injection regimen, as opposed to the current, tedious, four- to five-year course of treatment with allergen immunotherapy.”
MEDICA.de; Source: Johns Hopkins Medical Institutions