The following results are an example of an independent blood test and the differences between IgE and IgG. The bars in black are examples of IgE and those in grey IgG.

If i use the example of cabbage which has a low IgE but a high IgG, what does this mean in relation to food intake and its effect on the body?

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  • The test setting is not clear. Were the blood tests done after an individual was fed with different foods? Were all the tests done on one individual or on different individuals? If multiple individuals were involved, how many tests were done in each individual? These may affect the interpretation of the graph.
    – rnso
    Aug 9 '15 at 10:50
  • I've been wandering the same thing as @arkiaamu in the edit of their answer: is it IgG (as in the title of the question) or IgA (as in the body of the question) - there can be quite a difference. Or would you like all three discussed (but still it would be good to know which ones are compared in your picture).
    – Lucky
    Aug 9 '15 at 17:39
  • @Lucky - Apologies. I have updated the heading. The question pertains to IgG and IgE.
    – Motivated
    Aug 12 '15 at 6:23
  • @rnso - The test was conducted on an individual. Blood was drawn and tested with antigens.
    – Motivated
    Aug 12 '15 at 6:24

Immunoglobulin E (IgE) is an antibody which is important part of type 1 hypersensitivity, or allergy in common language. It is said that, ie. milk allergy is IgE-mediated. This means that exposure to milk protein causes the immune system to "sensitize" (= milk IgE is produced) to milk during the first exposure. During the subsequent exposures the milk protein activates the immune system due to the presence of these milk associated IgEs. The results of this activation is the allergic symptoms. Amount of each food-IgE level in the blood is quite good surrogate for presence of allergy. I recommend to read the Guidelines for the diagnosis and management of food allergy in the United States.

I find it strange that immunoglobulin A (IgA) levels are measured in association to IgE levels. For example, the guideline earlier has no mention of IgA with regard to food allergy. IgA may have a mediator role in type 1 hypersensivity but I have trouble finding any record that this would have any clinical significance. Moreover, there are IgA-related diseases, but these have nothing to do with food allergy.

Corresponding guideline from Europe by the European Academy of Allergy and Clinical Immunology does not mention anything about IgAs. Of course, there is the non-IgE-mediated food allergy but nevertheless that does not involve IgAs.

If these were your own test results, I would recommend you ask from the provider of the test about the clinical significance of IgAs. I would be very interest about their response.

EDIT: Are we talking about IgA or IgG here? IgA is mentioned in the text and IgG in the topic. In the case of IgG, my answer would be different.

  • Apologies. I have updated the heading as well as the body of the question. I am unsure as to why the provider has given a comparison of IgG and IgE. Is the higher IgG an indication of something? For example, if one looks at sweet potato, it has a reasonably high IgG reaction however a slightly lower IgG result. Does the correlation mean something?
    – Motivated
    Aug 12 '15 at 7:08

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