The Science Behind IgG4
At Allergy Test Australia, we offer a range of blood tests to help find the right test for you. Our Intolerance Screen kit offers an IgG4 ELISA blood test, but what does this mean?
The IgG4 antibodies can influence the inflammatory response but not activate it. We are using IgG4 in our intolerance tests because we are investigating delayed symptoms that could be associated with food and non-food intolerances. These do not cause an immediate immunological response, however, could still be causing you problems. For food intolerance, the presence of specific IgE and IgG antibodies can be observed. Some subclasses of IgG (mainly IgG4) inhibit the degranulation of basophils and mast cells and the activation of the complement cascade.
We are using IgG4 antibodies because, when we are testing intolerances, we are not looking at the immediate allergic reaction of Type I (or Type 1) allergy or inflammation related to chronic diseases (IgG1, IgG2, IgG3). IgG4 in fact is considered as preventative screening as they block access of IgE to the allergen, helping us to understand how your immune system is reacting to food antigens before an allergic reaction is developed.
The concentration of IgG4 is about 10,000 times higher than the IgE concentration. Therefore, IgG4 can bind faster and with greater frequency to the allergen than IgE mapping your immune response to food allergens. IgG4 antibodies result in only 1% of the histamine released by IgE, with few patients experiencing allergic symptoms. Therefore, IgG4 antibodies are mostly produced when the allergy is asymptomatic.
The primary function of IgG4 is to influence the immune inflammatory response without the release of histamine factors (the main cause of inflammatory reactions), having the possibility to explore how the amount of IgG4 antibodies could be related to some of your symptoms (bloating, abdominal cramps, headaches to mention some). This will be the first step on your journey to find a better version of yourself.
For food intolerance, the presence of specific IgG antibodies (IgG4) will inhibit the degranulation of mast cells and activation of allergic symptoms (this will not exclude you experiencing digestive imbalance, headaches and inflammatory reactions but not as serious as anaphylactic symptoms). Food items responsible for intolerance can be reintroduced in small quantities while monitoring how much you can eat without causing symptoms after following an elimination diet of six weeks.
1) Tsvetelina Velikova et al. Methods for detection of food Intolerance. Recent Advances in Food Science RAdvFoodScie 2018; 1(3): 106-119
2) Elif Ilgaz Aydinlar, MD; Pinar Yalinay Dikmen, MD; Arzu Tiftikci, MD; Murat Saruc, MD; Muge Aksu; Hulya G. Gunsoy; Nurdan Tozun, MD. IgG-Based Elimination Diet in Migraine Plus Irritable Bowel Syndrome. American Headache Society 2012
3) Hong Sub Lee and Kwang Jae Lee. Alterations of Food-specific Serum IgG4 Titers to Common Food Antigens in Patients with Irritable Bowel Syndrome. J Neurogastroenterology and Motility 2017; 23(4): 578-584