INOVATIVE

IgG Subclasses

IgG antibodies have various functions, such as neutralisation of antigens, activation of the complement cascade, flagging of antigens for destruction (oponisation) and phagocyte binding. However, the four different subclasses of IgG play different roles (Table 1). Due to their strong oponisation and complement activation properties, IgG₁ and IgG₃ and to a lesser extent IgG₂ are pro-inflammatory. IgG₄ on the other hand has protective, anti-inflammatory properties. IgG₄ plays a defensive role in type I allergy, acting as an antagonist of IgE. It induces the release of histamine, although to a much lesser extent than IgE. Therefore, IgG₄ antibodies may lead to allergy symptoms particularly in histamine-intolerant patients. However, in chronic inflammatory processes, only the subclasses IgG₁, IgG₂ and IgG₃ are relevant. Since IgG₄ antibodies make up only a small proportion of all IgG, testing for total IgG is sufcient to detect clinical relevant titers of proinflammatory IgG₁, IgG₂, and IgG₃ antibodies..

Headaches and Migraine

Migraines have a complex etiology, but it is known that food can play a role in inducing or aggravating attacks. Already in the 1930s the benefts of an elimination diet were demonstrated. In recent studies, elimination diets based on IgG levels have been shown to have signifcant positive effects, such as reduction of the number of headache days, attack count or duration and severity of migraines. A further study revealed signifcant differences in the number of positive results for IgG to foods between 56 migraine sufferers and 56 controls, and elimination diets successfully controlled the migraines of these patients without the need for medication.

Arthritis

Food intolerance has been known for many decades to be a causative factor for developing arthritis. In a study of 22 patients with rheumatoid arthritis undertaking an elimination diet, 91% experienced an improvement of symptoms. All but one of these patients suffered a deterioration of their health status when the reactive foods were reintroduced into their diet.

Irritable Bowel Syndrome

Irritable bowel syndrome (IBS) is the most common functional gastrointestinal disorder with a reported prevalence in the general population of 12 to 22%. The disease is poorly understood, but food intolerance is a major factor in its pathogenesis. Specifc foods can provoke symptoms of IBS, while patients treated with dietary exclusion frequently show symptomatic improvement. In a study on 150 IBS patients, an elimination diet based on raised IgG antibodies resulted in a 26% improvement in the symptom score compared to a sham diet, while relaxation of the diet led to a 24% deterioration. In a further study, 20 IBS patients showed signifcant improvement after food elimination and rotation diet based on serum IgG measurements.

Inflammatory Bowel Diseases

A retrospective study on 112 patients with inflammatory bowel diseases (IBD) (79 with Crohn’s disease and 33 with ulcerative colitis) and 266 healthy individuals showed that patients with inflammatory bowel diseases exhibit a high prevalence of antibodies of class IgG against certain foods and that qFIGURE 1: Examples of test parameters in EUROLINE food profles this can be used to establish an elimination diet. Further studies have similarly shown higher levels of food IgG antibodies (e.g. against yeast and processed cheese) in Crohn’s patients than in healthy controls, and demonstrated that nutritional intervention based on circulating IgG antibodies against food antigens can improve symptoms.

Asthma and Atopic Dermatitis

Increased levels of IgG antibodies against foods or food additives have also been observed in asthma and atopic dermatitis. For example, in 125 patients with beef allergy manifesting with asthma, dermatitis or gastrointestinal disorders, beef-specifc IgG and also IgA were signifcantly detected alongside and sometimes in the absence of specifc IgE. An elimination diet ameliorated the symptoms in all of the allergic patients. In another study, signifcantly elevated levels of IgE and IgG were found in a relatively high proportion of patients with atopic dermatitis compared to controls.

Autism

The etiology of autism is not well understood, but dietary restrictions are benefcial and a prerequisite to beneft from other interventions. The main foods for exclusion are milk and dairy products, wheat and other gluten sources, sugar, chocolate, preservatives and food colouring. Individualised IgG and IgE testing can identify other troublesome foods. In a study of 36 infantile autistic patients, high levels of antibodies including IgG against milk proteins were found compared to control children. Behavioural symptoms improved on an elimination diet, indicating a possible relationship between food allergy and autism.

Diagnostic Value of IgG Testing

The diagnostic value of IgG antibody detection for the diagnosis of food intolerance is controversially discussed. Nevertheless, different studies with up to several thousand patient samples have come to the conclusion that the determination of the antibody titer can be a useful tool for the identifcation of food intolerances and for targeted patient therapy. Generally, it could be shown that elimination of those foods against which strong antibody reactions were measured helped to improve symptoms or to promote complete recovery in a statistically signifcant number of patients. A large internet-based study on the diagnostic beneft and clinical relevance of IgG antibodies as a marker qTABLE 1: Properties and abundance of different IgG subclasses of food intolerance concluded that IgG determination provides a clinically useful basis for establishing an elimination diet.

IgG Determination

IgG antibodies against different food and food additives can be easily determined by immunoassay. Immunoblots are particular useful for this application as they allow multiparameter analysis of hundreds of different parameters in parallel, providing an extremely wide-ranging screening (Figure 1). This is especially important in food intolerance, as symptoms tend to be delayed or chronic and may be difcult to link with consumption of a particular food.

Total IgG against 108 or 216 foods and food additives can be analysed simultaneously with a new range of immunoblot profles based on established EUROLINE technology. The foods represented on the strips are divided into categories, encompassing gluten-containing cereals, gluten-free cereals and alternative foods, meats, dairy and egg, fruits, herbs and spices, nuts and seeds, vegetables, legumes, salads, mushrooms, fsh and seafood, and other foodstuffs such as yeasts, honey, coffee and black tea. Only small volumes of patient serum are required for the analysis, just 40 µl for 108 results. By analysing 22 patient samples in one run, 2,376 single results can be obtained in just 4.5 hours. Results are evaluated semiquantitatively using four calibrators corresponding to the WHO reference serum 1st IRP 67/86. To increase productivity further the entire procedure, from sample identifcation and incubation to evaluation and archiving of results, can be fully automated e.g. on the EUROBlotOne device with EUROLineScan software.

Perspectives

The determination of IgG antibodies against food and food additives can contribute to the diagnostic workup for patients with chronic food-related health problems. Although the link between food-specifc IgG antibodies and chronic inflammatory processes has not yet been frmly established, many studies have demonstrated an association between food IgG antibodies and different diseases, and shown that elimination diets based on IgG reactions can help to relieve symptoms. Thus, patients with unspecifc gastrointestinal and other symptoms which cannot be attributed to any known cause may beneft from a comprehensive IgG analysis and a corresponding elimination diet. As with classic IgE allergy tests, IgG results should always be interpreted in the context of clinical observations. Further studies should help to clarify the role of food-specifc IgG antibodies in poor gut health.

List of references

1. Alpay K, Ertas M, Orhan EK, Ustay DK, Lieners C, Baykan B. Diet restriction in migraine, based on IgG against foods: a clinical double-blind, randomised, cross-over trial. Cephalalgia. 2010 Jul;30(7):829-37. doi: 10.1177/0333102410361404. Epub 2010 Mar 10.
2. Arroyave Hernández CM, Echavarría Pinto M, Hernández Montiel HL. Food allergy mediated by IgG antibodies associated with migraine in adults. Rev Alerg Mex. 2007 Sep-Oct;54(5):162-8. Erratum in: Rev Alerg Mex. 2010 Mar-Apr;57(2):49. Echevarría Pinto, Mauro.
3. Awazuhara H, Kawai H, Maruchi N. Major allergens in soybean and clinical significance of IgG4 antibodies investigated by IgE- and IgG4-immunoblotting with sera from soybean-sensitive patients. Clin Exp Allergy. 1997 Mar;27(3):325-32.
4. Aydinlar EI, Dikmen PY, Tiftikci A, Saruc M, Aksu M, Gunsoy HG, Tozun N. IgG-based elimination diet in migraine plus irritable bowel syndrome. Headache. 2013 Mar;53(3):514-25. doi: 10.1111/j.1526-4610.2012.02296.x. Epub 2012 Dec 6.
5. Bentz S, Hausmann M, Piberger H, Kellermeier S, Paul S, Held L, Falk W, Obermeier F, Fried M, Schölmerich J, Rogler G. Digestion. Clinical relevance of IgG antibodies against food antigens in Crohn's disease: a double-blind cross-over diet intervention study. 2010;81(4):252-64. doi: 10.1159/000264649. Epub 2010 Jan 30.
6. Bernardi D, Borghesan F, Faggian D, Bianchi FC, Favero E, Billeri L, Plebani M. Time to reconsider the clinical value of immunoglobulin G4 to foods? Clin Chem Lab Med. 2008;46(5):687-90.
7. Bischoff SC, Herrmann A, Manns MP. Prevalence of adverse reactions to food in patients with gastrointestinal disease. Allergy. 1996 Nov;51(11):811-8.
8. Cai C, Shen J, Zhao D, Qiao Y, Xu A, Jin S, Ran Z, Zheng Q. Serological investigation of food specific immunoglobulin G antibodies in patients with inflammatory bowel diseases. PLoS One. 2014 Nov 13;9(11):e112154. doi: 10.1371/journal.pone.0112154. eCollection 2014.
9. Calderon TE, Ferrero M, Marino GM, Cordoba A, Beltramo D, Muino JC, Rabinovich GA, Romero MD. Meat-specific IgG and IgA antibodies coexist with IgE antibodies in sera from allergic patients: clinical association and modulation by exclusion diet. J Biol Regul Homeost Agents. 2010 Jul-Sep;24(3):261-71.
10. Codina RM, Calderón E, Lockey RF, Fernández-Caldas E, Rama R. Specific immunoglobulins to soybean hull allergens in soybean asthma. Chest. 1997 Jan;111(1):75-80.
11. Drisko J, Bischoff B, Hall M, McCallum R. Treating irritable bowel syndrome with a food elimination diet followed by food challenge and probiotics. J Am Coll Nutr. 2006 Dec;25(6):514-22.
12. Duchateau J, Michils A, Lambert J, Gossart B, Casimir G. Anti-betalactoglobulin IgG antibodies bind to a specific profile of epitopes when patients are allergic to cow's milk proteins. Clin Exp Allergy. 1998 Jul;28(7):824-33.
13. el Rafei A, Peters SM, Harris N, Bellanti JA. Diagnostic value of IgG4 measurements in patients with food allergy. Ann Allergy. 1989 Feb;62(2):94-9.
14. Gaby AR. The role of hidden food allergy/intolerance in chronic disease. Altern Med Rev. 1998 Apr;3(2):90-100.
15. Germano P, Pezzini A, Boccagni P, Zanoni G, Tridente G. Specific humoral response to cows' milk proteins and ovalbumin in children with atopic dermatitis. Int J Clin Lab Res. 1993;23(4):206-11.
16. Haddad ZH, Vetter M, Friedmann J, Sainz C, Brunner E. Detection and kinetics of antigenspecific IgE and IgG immune complexes in food allergy. Ann Allergy. 1983 Aug;51(2 Pt 2):255.
17. Halpern GM, Scott JR. Non-IgE antibody mediated mechanisms in food allergy. Ann Allergy. 1987 Jan;58(1):14-27. Review.
18. Arroyave Hernández CM, Echavarría Pinto M, Hernández Montiel HL. Food allergy mediated by IgG antibodies associated with migraine in adults. Rev Alerg Mex. 2007 Sep-Oct;54(5):162-8. Erratum in: Rev Alerg Mex. 2010 Mar-Apr;57(2):49. Echevarría Pinto, Mauro.
19. Jones VA, McLaughlan P, Shorthouse M, Workman E, Hunter JO. Food intolerance: a major factor in the pathogenesis of irritable bowel syndrome. Lancet. 1982 Nov 20;2(8308):1115-7.
20. Kawaguchi T, Mori M, Saito K, Suga Y, Hashimoto M, Sako M, Yoshimura N, Uo M, Danjo K, Ikenoue Y, Oomura K, Shinozaki J, Mitsui A, Kajiura T, Suzuki M, Takazoe M. Food antigeninduced immune responses in Crohn's disease patients and experimental colitis mice. J Gastroenterol. 2015 Apr;50(4):394-405. doi: 10.1007/s00535-014-0981-8. Epub 2014 Aug 7.
21. Kidd PM. Autism, an extreme challenge to integrative medicine. Part 2: medical management. Altern Med Rev. 2002 Dec;7(6):472-99.
22. Lindberg E, Magnusson KE, Tysk C, Järnerot G. Antibody (IgG, IgA, and IgM) to baker's yeast (Saccharomyces cerevisiae), yeast mannan, gliadin, ovalbumin and betalactoglobulin in monozygotic twins with inflammatory bowel disease. Gut. 1992 Jul;33(7):909-13.
23. Lucarelli S, Frediani T, Zingoni AM, Ferruzzi F, Giardini O, Quintieri F, Barbato M, D'Eufemia P, Cardi E. Food allergy and infantile autism. Panminerva Med. 1995 Sep;37(3):137-41.
24. Mitchell N, Hewitt CE, Jayakody S, Islam M, Adamson J, Watt I, Torgerson DJ. Randomised controlled trial of food elimination diet based on IgG antibodies for the prevention of migraine like headaches. Nutr J. 2011 Aug 11;10:85. doi: 10.1186/1475-2891-10-85.
25. Mullin GE, Swift KM, Lipski L, Turnbull LK, Rampertab SD. Testing for food reactions: the good, the bad, and the ugly. Nutr Clin Pract. 2010 Apr;25(2):192-8. doi: 10.1177/0884533610362696.
26. Nanda R, James R, Smith H, Dudley CR, Jewell DP. Food intolerance and the irritable bowel syndrome. Gut. 1989 Aug;30(8):1099-104.
27. Shakib F, Brown HM, Phelps A, Redhead R. Study of IgG sub-class antibodies in patients with milk intolerance. Clin Allergy. 1986 Sep;16(5):451-8.
28. Shakib F, McLaughlan P, Stanworth DR, Smith E, Fairburn E. Elevated serum IgE and IgG4 in patients with atopic dermatitis. Br J Dermatol. 1977 Jul;97(1):59-63.
29. Volpi N, Maccari F. Serum IgG responses to food antigens in the italian population evaluated by highly sensitive and specific ELISA test. J Immunoassay Immunochem. 2009;30(1):51-69. doi: 10.1080/15321810802571903.
30. Zar S, Benson MJ, Kumar D. Food-specific serum IgG4 and IgE titers to common food antigens in irritable bowel syndrome. Am J Gastroenterol. 2005 Jul;100(7):1550-7.

Dr. Thomas Pfeiffer, Luebeck, Germany
www.medlabmagazine.com • DIAGNOSTICS / FOOD-SPECIFIC IgG TITERS