Solving any good mystery is a bit like a pulling a string. You begin to pull and more and more string follows, but the goal is always the same, to find the beginning. Allergy research is a lot like this. We study allergies in adults and children, continually looking for where it all starts. In an article published this week in Science Transitional Medicine, researchers looked further back, examining the umbilical cord blood of nearly 1000 newborns in an effort to find the end of the proverbial food allergy string. What was revealed was that even from birth, differences in the cord blood of infants who later developed allergies and those who did not, could be observed. This early detection of allergies revealed new details as to when allergies begin.

By examining and testing blood samples taken at birth then again at one year of age, researchers were able to notice a few distinct differences in the children who developed allergies and those who did not. These differences in white blood cells begin with monocytes.

Monocytes are like a “jack-of-all-trades” when it comes to the immune system. In different situations, they can play different roles and actually divide or differentiate into a different type of white blood cell, like a microphage. These cells are also important in that once they reach the site of infection the messages they send out can have a big impact on how other white blood cells react. In this study, researchers found that monoctyes were not only more numerous in the samples taken from children who would go on to later develop allergies, but that the monocytes were also more active. It’s somewhat fitting considering allergies is most easily thought of as an over or hyperreaction by the immune system to a normally harmless substance.

In follow up lab experiments, researchers found that the chemical signals (cytokines) monocytes in allergic children were sending was driving the immune response. Their effect on T helper cells, the white blood cells that essentially regulate the immune response, pushed the response, spurring inflammation.

While researchers still haven’t found the starting point of the food allergy string, this early detection of allergies sheds some light on a couple things. First, it would appear that individuals are effectively “primed” for allergies at birth. Second, this study leans towards a cause in the prenatal environment. That could mean that by reducing inflammation or sources of inflammation in an expecting mother, there’s the potential to normalize the immune system of the developing fetus. For many that means changing in diet as some foods can fight inflammation while others work to increase it.

To read the abstract of the new study.