I think that protein substances could be possible. 

You can read these articles, I'll be back after more information  about this point

Best regards

Article Quantitation of antigen-specific immunoglobulin G in human s...

Article Cytotoxic T lymphocyte antigen 4-immunoglobulin G is a poten...

In the clinical setting, IgG sensitization can be only a marker of a previous contact with one antigen, but not necessarily a marker of an IgG-mediated disease. We often observe specific IgG antibody against multiple antigens which do not induce any adverse clinical consequence in patients. In fact, normal people usually show low titters of  IgG  against many foods if we measure them. In my experience, results of food-specific immunoglobulin G (IgG) testing do not correlate with symptoms and only cause difficult situations to patients, who face to impossible diets non alleviating their abdominal symptoms. I believe there are only one or two well-done controlled trials showing a minimal beneficial effects from these tests and always in patients suffering irritable bowel disease.

Best regards.

I think these food spesific IgG antibodies linked to autoiimunity.  I want to search the linkage these antibodies with systemic lupus or diabetes.

In my experience, I could agree with colleague Juan Manuel Igea, results of food-specific immunoglobulin G (IgG) testing do not correlate with symptoms and only cause difficult situations to patients, who face to impossible diets non alleviating their abdominal symptoms. I believe there are only one or two well-done controlled trials showing a minimal beneficial effects from these tests and always in patients suffering irritable bowel disease.

I appreciate your answers. It is known that food IgG isn't in correlation with food IgE (although it sometimes is). It is also known that IgG testing can't tell us anything about acute immune reaction to specific food antigens. These findings are in correlation with the use of IgG testing for acute food allergy reactions that doesn't exist in practice. However, I am interested what doest it mean to have food IgG's from molecular immunology point of view. What can food IgG tell me about patient's immune system. Is his gut barrier disrupted. Does it mean that chronic ingestion of foods he/she has IgG to will drive chronic inflammation that is now pretty popular topic in endocrinology, neurology, neuroscience,...? Binnur, can You please tell us more about Your work?

Thank You all for supporting discussion :)

Best,

Jan