Original Research Article Antigen Specific IgG4 in Patients with Gastrointestinal Complaints

Antigen Specific IgG4 in Patients with Gastrointestinal Complaints 

Viktorija Priedite, Jevgenij Nikiforenko, Natalja Kurjane and Juta Kroica

Abstracts

Aims: To find the antigen specific IgG4 in patients with gastrointestinal complaints and in control group, to demonstrate suitability of detection of IgG4 by using antigen panel.
Place and Duration of Study: Laboratory Management and Consultancy, Riga, Latvia, October 2012 – February 2013.
Methodology: The study included 147 patients (46 men, 101 women, aged from 1 to 76) with different complaints regarding gastrointestinal habitus. Antigen specific IgG4 analysis by using regional adopted antigen panel was executed.
Results: Almost all patients with gastrointestinal complaints -141 out of 147-have at least 2nd level antibodies, while in control group 15 out of 24 have 2nd level of antibodies.
Conclusion: IgG4 antigen specific antibody tests by panels could be used as a screening tool for food intolerance detection.

Keywords :
Antigen specific IgG4; food intolerance.

Full article
Food hypersensitivity is a wide-spread and common problem, however, at the same time this
issue has not been widely reflected in literature, except IgE class antibody and “true” allergy
studies.
It is known that IgE class of antibodies sign the allergy in human body and antigen specific
IgE as an allergy marker is determined worldwide. Since allergic reactions could be life
threatening, allergist try to reverse IgE class response to IgG4 class response. As a result,
IgG4 class antigen specific tests are developed for detection of successful immunological
answer switch. When IgG4 class antibodies are detected against particular “dangerous”
antigen, allergists lost their interest in patients because their patients seem to be safe from
anaphylaxis. IgG4 has been postulated to have a role in developing tolerance against
allergens and in responses to certain infectious agents, but its physiologic role is poorly
understood. In terms of tolerance it is always suggested as absence of IgE mediated allergic
reactions and it is not taken into account less prominent, less visible IgG4 accompanied
manifestations which in long term could also be harmful.
True prevalence of food intolerance is still unknown, but it has been estimated to be 5-7%
and even reach up to 20% in general population. It is clear that IgG4 is not a cause of food
intolerance but rather a result or mediator of adverse reactions to some food ingredients.
For a long time IgG4 has been considered as something normal or at least harmless. During
the past few years we could find a lot of publications regarding IgG4 as a marker of Type 1
autoimmune pancreatitis (IgG4-related pancreatitis) and IgG4-related sclerosing cholangitis
in medical literature and a lot of other serious conditions related to IgG4 class antibody
presence in serum and tissues as well. However, it is still little known about IgG4
formation or function in human body. Mainly for antigen-specific IgG4 investigations an IBS
(Irritable Bowel Syndrome) patients probably were chosen due to the absence of any other
explanations for such condition. Sameer Zar et al. described the correlations of antigenspecific
IgG4 presence and food intolerance in IBS patients. As authors mentioned, in case
of IBS – IgE class antibodies do not play pathophysiological role.
A very little information exist in scientific papers about IgG4 antigen specific antibodies and
their relationships with food intolerance. The authors of study identify IgG4 antigen specific
antibodies against most widely used products and compare the existence of such antibodies
in healthy individuals and in individuals suffering from different gastrointestinal problems with
the aim to find suitable laboratory test for detection of food intolerance against particular
product. There is a high probability that food intolerance could be one of triggering factors for
many pathologies. Improvement of physical conditions after exclusion diets show that some
screening analysis should be helpful in selection of appropriate diet to avoid unnecessary
dietary restrictions.

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