FIT 22

The FIT 22 food sensitivity test by KBMO Diagnostics offers a comprehensive assessment of 22 food sensitivities.  Using a patented multiple pathway approach that measures IgG1-4 and complement activation via the marker C3d, this test accurately indicates inflammation at the gut lining.  

This analysis allows KBMO to eliminate false positives commonly associated with IgG-only testing, enabling practitioners to pinpoint key food sensitivities more effectively. 

The FIT 22 test may be valuable for patients experiencing a range of symptoms or conditions including digestive/gut issues, struggles with weight loss, autoimmune disease, migraines, thyroid problems, arthritis or joint pain, brain fog, fatigue, and skin problems such as eczema, psoriasis, or acne.

It may be considered as initial testing of food sensitivity.  This test does not include the Gut Barrier Panel, which is available as a standalone test, and is included in the FIT 132 and FIT 176 food sensitivity tests.  This test also does not include the mobile phone app or meal plan, which are included in the FIT 132 and FIT 176 tests.

This is a blood spot test.

What is the Clinical Significance of IgA 1 + 2 Antibody Testing for Food Sensitivities?

IgA 1 and IgA 2 testing in food sensitivity tests holds clinical significance primarily in the context of assessing mucosal immunity and gut barrier function, and it may play a role in the development of immune tolerance.  [8., 12.]  

Immunoglobulin A (IgA) is the primary antibody found in mucosal secretions, including those of the gastrointestinal tract. IgA defends against pathogens and antigens present in the gut, as well as in maintaining the integrity of the gut epithelium and developing immune tolerance to beneficial gut microbes.  [8.]

Dysregulation of mucosal immunity, characterized by alterations in IgA production, has been implicated in various gastrointestinal disorders, including inflammatory bowel diseases, celiac disease, and irritable bowel syndrome. [18.]

By measuring IgA 1 and IgA 2 levels in the context of food sensitivity testing, healthcare providers can gain insights into the status of mucosal immunity, the integrity of the gut barrier, and immune activity in the GI tract. 

Abnormalities in IgA levels may indicate disruptions in gut barrier function, increased intestinal permeability (leaky gut), or heightened immune responses to dietary antigens, all of which can contribute to gastrointestinal symptoms and systemic inflammation.

What is the Clinical Significance of IgG 1-4 Antibody Testing for Food Sensitivities?

The FIT 132 by KBMO Diagnostics employs testing for all four IgG antibody subclasses: IgG 1-4.  IgG antibodies 1-3 activate a branch of the innate immune system called complement, which stimulates an inflammatory response.  In contrast, IgG 4 does not have this capability.  

IgG 1-4 food sensitivity testing is used to identify delayed immune responses to specific food antigens. [7.]  While IgE-mediated food allergies typically provoke immediate hypersensitivity reactions, IgG-mediated responses are associated with delayed onset reactions, making them challenging to diagnose clinically. 

However, accumulating evidence suggests that IgG antibody testing for food sensitivities may shed light for clinicians.  [6., 16., 19.]  Some studies indicate that IgG-mediated immune responses might contribute to the pathogenesis of gastrointestinal inflammation.  [7., 17..]  

By detecting IgG antibodies to specific food antigens, the FIT 132 by KBMO Diagnostics aims to identify potential triggers for immune-mediated reactions and provide insights into personalized dietary modifications to alleviate symptoms and improve overall health outcomes.

IgG4, a subtype of immunoglobulin G antibodies, plays a crucial role in modulating immune responses, particularly in the context of allergies. Research indicates that IgG4 antibodies can help neutralize allergic reactions orchestrated by IgE, thereby mitigating histamine responses and promoting immune tolerance to foods.  

It's essential to maintain a balanced level of IgG4, as excessive amounts can paradoxically lead to increased inflammation and immune sensitization.  Increased IgG4 levels have been associated with allergies and with autoimmune conditions.  For instance, elevated IgG4 levels have been implicated in conditions such as rheumatoid arthritis, myasthenia gravis, pemphigus vulgaris and thrombotic thrombocytopenic purpura. [11., 13., 15.]

What is the Clinical Significance of C3d Testing for Food Sensitivities? 

C3d (Complement Component 3) is a protein of the innate immune system that can promote an inflammatory response.  The inclusion of complement proteins C3d in the FIT 132 by KBMO Diagnostics provides a more comprehensive assessment of the immune response to dietary antigens. 

Complement proteins play a crucial role in the immune cascade triggered by IgG-mediated reactions. Specifically, C3d is involved in the opsonization of immune complexes, facilitating their recognition and clearance by phagocytic cells; their role can increase the actions of IgG antibodies many times over. By measuring levels of C3d alongside IgG antibodies against common foods, this test offers valuable insights into the inflammatory response associated with food sensitivities.

Complement activation, particularly through the C3d pathway, may contribute to the pathogenesis of various immune-mediated disorders, including food sensitivities and allergic reactions.  [21.]

Who Can Benefit from the FIT 22 Test by KBMO Diagnostics?

Individuals Seeking to Optimize Health: even in the absence of symptoms, the FIT 22 Test can offer insights into gut health, providing an opportunity for preventative measures against potential health issues and supporting the body’s natural processes.

Patients with Chronic Digestive Dysfunction: for those who have suffered from chronic symptoms with or without a clear diagnosis, the FIT 22 Test can begin to identify underlying food sensitivities that may be contributing to their health issues.

Autoimmune Diseases: since gut health is closely linked to the immune system, identifying and addressing food allergies and sensitivities can provide additional treatment options and provide crucial support in managing autoimmune conditions. [2.]

Gastrointestinal Disorders: for patients struggling with Small Intestinal Bowel Overgrowth (SIBO), Irritable Bowel Syndrome (IBS) and Inflammatory Bowel Disease (IBD), the FIT 22 Test by KBMO Diagnostics can identify previously-silent food sensitivities that may be contributing to symptoms like gas, bloating, diarrhea, and constipation. [3., 14.]

Digestive Complaints: people experiencing unexplained digestive issues such as gas, bloating, heartburn, indigestion, diarrhea, or constipation can identify potential causes and receive targeted treatment recommendations.  [14.] 

Neurological and Cognitive Issues: the vagus nerve is the primary nerve that innervates the digestive tract, and is considered the “highway of the gut-brain axis”.  Insights into the gut-brain axis through the FIT 22 may reveal how gut health impacts an individual’s cognitive function and affects memory, concentration, and brain fog. [5.]

Skin Conditions: conditions like acne and psoriasis have been linked to gut health. Identifying and removing food sensitivities can be a part of a comprehensive treatment plan to improve and restore skin health. [10.]

Mood Disorders: the gut-brain connection means that digestive inflammation can impact mood and emotional well-being, making the FIT 22 by KBMO Diagnostics valuable for individuals with these conditions. [5.]

References:

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[2.] Brady DM. Molecular Mimicry, the Hygiene Hypothesis, Stealth Infections and Other Examples of Disconnect between Medical Research and the Practice of Clinical Medicine in Autoimmune Disease. Open Journal of Rheumatology and Autoimmune Diseases. 2013;03(01):33-39. doi:https://doi.org/10.4236/ojra.2013.31007 

[3.] Capobianco I, Di Vincenzo F, Puca P, Becherucci G, Mentella MC, Petito V, Scaldaferri F. Adverse Food Reactions in Inflammatory Bowel Disease: State of the Art and Future Perspectives. Nutrients. 2024 Jan 25;16(3):351. doi: 10.3390/nu16030351. PMID: 38337636; PMCID: PMC10857040. 

[4.] Fasano A. Zonulin and Its Regulation of Intestinal Barrier Function: The Biological Door to Inflammation, Autoimmunity, and Cancer. Physiological Reviews. 2011;91(1):151-175. doi:https://doi.org/10.1152/physrev.00003.2008

[5.] Fasano A. All disease begins in the (leaky) gut: role of zonulin-mediated gut permeability in the pathogenesis of some chronic inflammatory diseases. F1000Res. 2020 Jan 31;9:F1000 Faculty Rev-69. doi: 10.12688/f1000research.20510.1. PMID: 32051759; PMCID: PMC6996528. 

[6.] Geiselman JF. The Clinical Use of IgG Food Sensitivity Testing with Migraine Headache Patients: a Literature Review. Curr Pain Headache Rep. 2019 Aug 27;23(11):79. doi: 10.1007/s11916-019-0819-4. PMID: 31456119.

[7.] Gocki J, Bartuzi Z. Role of immunoglobulin G antibodies in diagnosis of food allergy. Postepy Dermatol Alergol. 2016 Aug;33(4):253-6. doi: 10.5114/ada.2016.61600. Epub 2016 Aug 16. PMID: 27605894; PMCID: PMC5004213.

[8.] Gutzeit C, Magri G, Cerutti A. Intestinal IgA production and its role in host-microbe interaction. Immunol Rev. 2014 Jul;260(1):76-85. doi: 10.1111/imr.12189. PMID: 24942683; PMCID: PMC4174397.

[9.] Heidt C, Kämmerer U, Fobker M, Rüffer A, Marquardt T, Reuss-Borst M. Assessment of Intestinal Permeability and Inflammation Bio-Markers in Patients with Rheumatoid Arthritis. Nutrients. 2023 May 19;15(10):2386. doi: 10.3390/nu15102386. PMID: 37242269; PMCID: PMC10221762. 

[10.] Katta R, Schlichte M. Diet and dermatitis: food triggers. J Clin Aesthet Dermatol. 2014 Mar;7(3):30-6. PMID: 24688624; PMCID: PMC3970830. 

[11.] Koneczny I. Update on IgG4-mediated autoimmune diseases: New insights and new family members. Autoimmunity Reviews. 2020;19(10):102646. doi:https://doi.org/10.1016/j.autrev.2020.102646

[12.] Konstantinou GN, Nowak-Węgrzyn A, Bencharitiwong R, Bardina L, Sicherer SH, Sampson HA. Egg-white-specific IgA and IgA2 antibodies in egg-allergic children: is there a role in tolerance induction? Pediatr Allergy Immunol. 2014 Feb;25(1):64-70. doi: 10.1111/pai.12143. Epub 2013 Oct 7. PMID: 24118158; PMCID: PMC4134474.

[13.] Maslinska M, Dmowska-Chalaba J, Jakubaszek M. The Role of IgG4 in Autoimmunity and Rheumatic Diseases. Front Immunol. 2022 Jan 25;12:787422. doi: 10.3389/fimmu.2021.787422. PMID: 35145508; PMCID: PMC8821096. 

[14.] Pasta A, Formisano E, Calabrese F, Plaz Torres MC, Bodini G, Marabotto E, Pisciotta L, Giannini EG, Furnari M. Food Intolerances, Food Allergies and IBS: Lights and Shadows. Nutrients. 2024 Jan 16;16(2):265. doi: 10.3390/nu16020265. PMID: 38257158; PMCID: PMC10821155. 

[15.] Qin L, Tang LF, Cheng L, Wang HY. The clinical significance of allergen-specific IgG4 in allergic diseases. Front Immunol. 2022 Oct 25;13:1032909. doi: 10.3389/fimmu.2022.1032909. PMID: 36389804; PMCID: PMC9648126. 

[16.] Shakoor Z, AlFaifi A, AlAmro B, AlTawil LN, AlOhaly RY. Prevalence of IgG-mediated food intolerance among patients with allergic symptoms. Ann Saudi Med. 2016 Nov-Dec;36(6):386-390. doi: 10.5144/0256-4947.2016.386. PMID: 27920409; PMCID: PMC6074204.

[17.] Simeonova D, Ivanovska M, Murdjeva M, Carvalho AF, Maes M. Recognizing the Leaky Gut as a Trans-diagnostic Target for Neuroimmune Disorders Using Clinical Chemistry and Molecular Immunology Assays. Curr Top Med Chem. 2018;18(19):1641-1655. doi: 10.2174/1568026618666181115100610. PMID: 30430944.

[18.] Song DJ, Shen J, Chen MH, et al. Association of Serum Immunoglobulins Levels With Specific Disease Phenotypes of Crohn’s Disease: A Multicenter Analysis in China. Frontiers in Medicine. 2021;8. doi:https://doi.org/10.3389/fmed.2021.621337

[19.] Vita AA, Zwickey H, Bradley R. Associations between food-specific IgG antibodies and intestinal permeability biomarkers. Front Nutr. 2022 Sep 6;9:962093. doi: 10.3389/fnut.2022.962093. PMID: 36147305; PMCID: PMC9485556.

[20.] Vojdani A, Vojdani E, Herbert M, Kharrazian D. Correlation between Antibodies to Bacterial Lipopolysaccharides and Barrier Proteins in Sera Positive for ASCA and ANCA. Int J Mol Sci. 2020 Feb 18;21(4):1381. doi: 10.3390/ijms21041381. PMID: 32085663; PMCID: PMC7073094. 

[21.] Yves Laumonnier, Rabia Ülkü Korkmaz, Nowacka AA, Jörg Köhl. Complement‐mediated immune mechanisms in allergy. European Journal of Immunology. 2023;53(10). doi:https://doi.org/10.1002/eji.202249979