MRT Labs, Allergen Specific IgG4

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MRT Laboratories, Inc.

50 Johnson Ave.
Hackensack, NJ 07601
201-342-5400
800-631-1379
FAX 201-342-1123
Email

Update on the Value of Allergen Specific IgG4 Testing in Patients with
Adverse Reactions to Foods

Reactions can vary from mild food intolerance to a severe anaphylactic
response often of the type found in patients with elevated levels of
allergen specific IgE antibody.

Case in point: A 62 year old woman with swelling of the lips and tongue
after ingestion of banana. This patient's reaction was so severe that
the treating physician initially ordered testing for IgE antibody to
banana, expecting to confirm that her reaction must be due to an
elevated measurement of IgE similar to scores seen in his peanut
sensitive patients. To his amazement, the patient had no detectable
levels of IgE reactivity to banana!

MRT Laboratories, Inc. then performed an allergen specific IgG4
assay for banana. The result was surprising. She had extremely high
levels of banana IgG4. The result was well above the 10 ug/ml that has
been reported by others with adverse reactions to milk and other food
intolerances. Our lab has observed similar antibody responses in food
sensitive patients; i.e. low allergen specific IgE and high allergen
specific IgG4.

Laboratory data suggests that levels above 10 ug/ml represent an
extraordinary immune response to the specific food antigen.

Specimen requirement: 1 ml serum is sufficient for 90 tests.

General information about IgG4 use:
  Many studies have been carried out to establish the clinical role and
usefulness of IgG4 testing.
  It is well known that the IgG4 measurement has been a useful indicator for the effect of hyposensitization therapy.
  IgG4 seems to play the role of blocking antibody in allergen immunotherapy.
  In contrast, in food induced allergy reactions IgG4 may have a provocative
role.
  High levels of IgG4 antibodies to foods have been observed in atopic
eczema patients as well as in patients with asthma, celiac disease,
chronic rhinitis, irritable bowel syndrome.

Since IgG4 antibodies may be associated with delayed reaction to
foods, it has been suggested that IgG4 testing may assist in confirming
food sensitivity in IgE negative patients.

MRT Laboratories Inc. has identified that the rate of positive results is
highest for dairy foods, eggs and high fiber foods, such as legumes,
grains, banana, and pineapple. The allergen specific IgG4 assay may
be ordered for individual allergens as well as suggested and/or custom
panels.

Suggested Food Panel (20)

Almond	Milk
Banana	Oat
Beef	Orange
Bean, kidney	Peanut
Bean, kidney	Pork
Casein	Potato
Cheese, cheddar	Soybean
Corn	Tomato
Egg, whole	Walnut
Gluten	Wheat

Depending on exposure, fish and shellfish may be added to the
suggested panel. Custom Panel requests are dependent on the individual
patient's diet.

The interpretation of a positive test result by the practitioner should
always be correlated with the history, physical and clinical symptoms
of the patient.