IgE (Immunoglobulin E)
IgE (Immunoglobulin E) allergies are the immediate responses to a foreign substance that has
entered the body via food or inhalation. IgE allergies can cause very serious symptoms like
difficulty in breathing, swelling, and hives. In more serious cases, IgE reactions can lead to
anaphylactic shock. Our test measures the blood level of IgE, one of the five subclasses of
antibodies. Antibodies are proteins made by the immune system that attack antigens such as
bacteria, viruses, and allergens.
They can become confused or cross-reactive and begin attacking foods instead. High titers of IgE
are associated with allergic reactions, which is when the immune system overreacts to
environmental antigens such as pollen, pet dander, and/or parasitic infections.
IgG (Immunoglobulin G, total)
IgG (Immunoglobulin G, total) are antibodies that provide long-term resistance to infections
and have a much longer half-life than an IgE allergy. This food sensitivity can be more subtle, and
many people live with it for years, if not their entire lives. Sensitivity symptoms range from
fatigue, headache/nausea, seizures, hyperactivity, bloating, mood changes, or dark circles under
the eyes. IgG symptoms typically occur within 3-72 hours after the offending food was ingested
and they will create ongoing inflammation that can make most conditions worse. Because they
can present at such varied times, it is hard to isolate from a diet history alone, and testing
becomes particularly useful.
The degree and severity of symptoms vary greatly from person to person because of genetic
makeup. The complete elimination of IgG positive foods may bring about important
improvements in symptoms of irritable bowel syndrome, autism, ADHD, cystic fibrosis,
rheumatoid arthritis, and epilepsy, as demonstrated in numerous clinical studies. It is important
to get tested for food sensitivities to know what foods work for the patient’s body and what foods
don’t. If you are only looking at allergies, or IgE, then you would miss the IgG mediated symptoms,
creating an incomplete patient picture.
C3 (Complement Component 3)
C3 (Complement Component 3) is a protein of the innate immune system that is activated by
microorganisms in the absence of an antibody. When C3d is activated in response to an antigen,
the C3 portion attaches to the antigen. This activation, even though it is independent, will amplify
the reaction that occurs with total IgG greatly increasing inflammation and symptoms of
sensitivity. This same reaction that was designed to amplify inflammation to microorganisms, can
be triggered in response to foods. If complement is present, it will amplify an IgG reaction as
much as 1000 to 10,000-fold. Therefore, tests that only measure IgG may miss the reactions to
foods that are most clinically relevant. C3 will be cleaved into multiple C3 breakdown products,
and all of these play a role in increasing inflammatory response to foods.
If complement is known to have a high level of reactivity in the condition you are treating, then
foods that confuse and irritate this part of the immune system should be given special attention.
See below table for conditions
Other Conditions Associated with Complement
| Lupus | Crohn’s Disease | Rheumatoid Arthritis | Ulcerative Colitis |
| Psoriasis | Cystic Fibrosis | Epilepsy | Gout |
| Scleroderma | Thyroiditis | Reiter Syndrome | Dermatomyositis |
| Depression | Food Reactions | Increased CRP | Acute Rheumatic Fever |
| Typhoid Fever | Sarcoidosis | Traumatic Spinal Cord Injuries | Periarteritis Nodosum |
| Acute Myocardial Infarction | Ankylosing Spondylitis |
IgG4 (Immunoglobulin G Subtype 4)
IgG4 (Immunoglobulin G Subtype 4) is another antibody produced in the body to fight infection.
Desensitization injections, or allergy therapies, increase IgG4 to help neutralize the reaction of
IgE. This is because of its potential to decrease histamine responses by blocking IgE from
attaching to receptors, causing degranulation. Levels of IgG4 are beneficial up to a point, as they
block IgE or allergic reactions and result in immune tolerance to
foods.
Too much IgG4 causes immune-mediated conditions, known as IgG4-RD that typically affects
multiple organ systems in the body. For these reasons, it’s important to know the levels of IgG4 in
the body to be able to maintain a correct balance. An example of a tissue that is susceptible to
higher levels of IgG4 is the esophagus, resulting in Eosinophilic Esophagitis. IgG4 also interferes
with the thyroid, contributing to autoimmune thyroiditis, and can also cause IgG4- Related
Diseases (IgG4-RD) of the ovaries and prostate.
Conditions Associated with IgG4
| Autoimmune pancreatitis | Salivary gland disease | Orbital disease, often complicated by proptosis | Retroperitoneal fibrosis |
| Increased number of eosinophils | Peripheral Eosinophilia | Atopy | Lymphadenopathy |
| Sclerosing cholangitis | Mikulicz disease | Sclerosing sialadenitis | IgG4-related submandibular gland disease |
| Lacrimal gland enlargement | “Idiopathic” retroperitoneal fibrosis | IgG4-related thyroid disease | IgG4-related thyroid disease |
| IgG4-related kidney disease | Mimics sarcoidosis in the lung | Hypopituitarism associated with IgG4-related hypophysitis | Prostatitis |
| IgG4-related disease of the ovary | Constrictive pericarditis | Nasopharyngeal disease | Midline-destructive lesion |
| Eosinophilic Esophagitis |
