Nanoparticles Could Boost Effectiveness and Reduce Side Effects of Allergy Shots

25 Sep 2015 --- Whether triggered by cats, bees, pollen or mites, allergies are on the rise. And the bad news doesn't stop there. The only current therapy that treats their causes is allergen-specific immunotherapy -- or allergy shots -- which can cause severe side effects. Now, researchers report in Biomacromolecules the development of a potentially better allergy shot that uses nanocarriers to address these unwanted issues.

For many people, allergies are a seasonal annoyance. But for others, exposure to a particular allergen can cause adverse reactions such as itching, breathing problems or even death. Allergy shots can reduce sensitivity by slowly ramping up exposure to the offending substance. But because these shots expose the body to the very thing people are allergic to, the treatment itself can sometimes trigger reactions. In order to develop a safer, more direct, cause-based therapy, researchers have developed nanoparticles that envelop an allergen and deliver it to specific cells. But these carriers degrade too slowly, hampering the effectiveness of the treatment. Holger Frey and colleagues set out to overcome these limitations.

The researchers designed a new type of nanocarrier based on the biocompatible molecule poly(ethylene glycol), or PEG, that releases its cargo only in targeted immune cells. The nanocarrier degrades when it encounters the acidic part of these cells, simultaneously releasing the allergen and getting rid of the packaging. The researchers say this approach also could be used for vaccines or immunotherapies for other conditions such as cancer or AIDS.

There has been some health concerns over the use of nanoparticles, but the main ones are toxicity depending on their chemical composition. If the composition is harmless that lessens the risk; however there are also concerns about the composition of any chemicals absorbed onto their surfaces. Their surfaces can be modified to make them less harmful to health.

The other health concern is that of nanoparticles trapped in the liver, which may damage its function and also taht they are capable of crossing the blood brain barrier. This may be beneficial in some cases but on the other hand, nanoparticles used to carry drugs such as vaccines may contain elements which are toxic to the brain.