New ultrasensitive blood test for peanut allergy

Researchers, including one of Indian-origin, are developing a blood test that can tell whether someone has peanut allergy and also determine how intense their allergic reaction will be.
Current peanut allergy tests are not very reliable when it comes to diagnosing the severity of an individual's allergic reaction, which can range from hives to life-threatening anaphylactic shock, researchers said.
Three researchers at the University of Connecticut (UConn) are developing a more advanced peanut allergy test that, based on initial results, is many times more sensitive than current procedures.
The new test is capable of determining the potential intensity of a patient's allergic reaction through just a few drops of blood.

When an allergic person eats peanuts, their immune system releases an antibody protein known as immunoglobulin E or IgE. These antibodies fight off peanut allergen molecules by binding to them and flushing them out of the body.
But the release of the antibodies causes tissue cells in the body to produce histamine, which in turn generates a variety of allergy symptoms such as itchy skin, runny nose, coughing, or wheezing.

The more antibodies that are released, the more histamine is generated, the stronger the person's allergic response.
"A patient who has a serious allergy and gets exposed to an allergen protein will form antibodies in their body that should stay there for awhile," said UConn Professor James Rusling, who specialises in detecting protein biomarkers and used a similar process to detect proteins linked to cancer.

"Our theory is that the level of those antibodies can be used to predict how severe a patient's allergy is at any one point in time," Rusling said.
While existing peanut allergy tests can generally measure IgE antibodies found in a blood sample, the presence of other biomolecules can distort the results and they are not always accurate.
The allergy test designed by Rusling, Mark Peczuh and Challa Vijaya Kumar screens out other biomolecules and measures the presence of antibodies that bind to very specific protein fragments, called peptides, and carbohydrate residues found in peanuts.
"The traditional method of measuring these antibodies uses a mixture of all the peanut proteins, not individual parts," said Peczuh, a specialist in carbohydrate synthesis.

"But some of the stuff in the mixture can lead to readings that a patient is allergic when she or he is not. And the converse can be true, where the results show someone is not allergic when they actually are," Peczuh said.
Although the initial results are promising, the time frame for any clinical use of the test is still years away, researchers said.