Allergy
Profile
General information
In recent decades, physicians have witnessed a worldwide increase
in the incidence of food and environmental allergies. Epidemiological
studies in the past 20 years indicate that there has been an increase
in diseases commonly associated with allergies, such as asthma,
atopic dermatitis, and allergic rhinitis.[1],[2],[3],[4] Public
awareness has increased, demanding better medical guidance and
identification of allergens (such as chemicals, additives and colorings)
used in the manufacture of prepared foods.[5] Peer-reviewed
medical literature reveals how little is known and how important
it is to increase awareness and education of patients regarding
the causes, symptoms and prevention of allergic reactions.[6],[7],[8]
Reactions to food and environmental influences may be due to
intolerance or to the specific and non-specific functions of the
immune system. The former involves complex interactions of immune,
gastrointestinal, nervous, and endocrine functions. The role of
the immune system includes the production of chemical mediators
that influence inflammation and release of antibodies both within
the affected tissue and into circulation. The antibodies most
involved are IgE, which is responsible for immediate type hypersensitivity
reactions, and IgG, which plays a role in delayed reactions to
food allergies.
US BioTek offers five allergy profile assays using the highly
sensitive ELISA (Enzyme Linked Immunosorbent Assay) method for
identifying and quantitating both serum IgE and IgG antibodies
in response to foods and inhalants. The Standard Food Allergy
Panel detects IgG and IgE responses to 88 specific foods, while
the Expanded Food Allergy Panel detects responses to 112
foods and 24 spices. The Vegetarian Food Allergy Panel detects
responses to 88 foods most commonly eaten by vegetarians. The Standard
Inhalant Panel detects IgE in response to 40 different inhalants
(including grass, tree, shrub and weed pollens, fungi and pet allergens),
while the Comprehensive Food Allergy and Inhalant Profile includes
testing of 88 foods (for IgG and IgE) and 48 inhalants (for IgE).
These tests allow the physician to confirm suspicions of food
or environmental sensitivities in patients who present with common
allergic symptoms, and to help reveal hidden allergies in those
patients who present with more complex medical conditions. US BioTeks ELISA, which has been totally redeveloped and refined,
is the most highly sensitive, accurate and consistent allergy test
available today. It provides physicians with reliable test results
that can be used for both establishing a diagnosis and managing
a therapeutic program.
The Impact of Allergies
The human body comes into contact with hundreds of different
environmental compounds. Defense mechanisms have been created to
deal with the potential harm of these foreign materials. These
wind-borne substances can create a problem when they are inhaled
and pass through the respiratory tract. Similarly, allergic symptoms
can result from the foods that we eat.
While keen observers throughout history have no doubt formed
that very hypothesis, it has taken a great deal of time for us
to recognize the mechanisms by which that might occur. In the
early 20th century several investigators began to piece
together the story behind reactions to our food. Scientists in
the late 1920s and the early 1930s demonstrated that undigested
food proteins are able to pass through the mucosal barrier of the
gastrointestinal tract and initiate an inflammatory response in
tissue elsewhere in the body.[9] And
in 1936, HJ Rinkel, writing in the Journal of the Kansas Medical
Society, first described reactions to food that, unlike the
well-known anaphylactic reactions, took hours or days to occur.[10]
Regardless of these findings, and many more which have been described
since 1936, the subject of food allergies remains controversial
today. There are several reasons why this is so: skin tests used
for detection of food allergies have not been reliable; symptoms
of some food allergies are commonly delayed in their appearance
(e.g. cows milk); the offending antigen may have been hidden in
a food preparation, and some symptoms may be the result of food
intolerance rather than food allergies.[11],[12] In
addition, foods may initiate complex and individual adverse reactions,
varying from minor irritation of the mucosal membranes to severe
emotional disturbances.[13]
As a result of these complicating factors, information raising
the possibility of food allergies is not conveyed easily from patient
to physician in the personal history. Also, since physicians do
not routinely discuss with patients the possibility that food allergies
might be causing their symptoms, or that certain lifestyle and
nutritional habits may lead to food allergies[14], their treatment may not completely address the underlying
problem, and their symptoms may persist. One case study sampled
postpartum women in a hospital setting and concluded that 87 percent
were not aware of the need to avoid risk factors that might lead
to allergies in their infants[15].
Another study demonstrated that college students who lost time
from work and school due to asthma and allergy symptoms did not
have patient education or awareness of asthma and allergy management
skills.[16]
Prevalence of Allergies
As stated earlier, the incidence of diseases associated with
allergies is on the rise in most parts of the world. Evidence
continues to mount indicating associations of both food and inhalant
allergies with common allergic symptoms, such as rhinitis,
sinusitis, eczema, and asthma. Food allergies mediated by IgE
have been implicated in approximately one third of children with
refractory atopic dermatitis presenting to the dermatologists
office.[17] Infants
are particularly susceptible to some foods and develop intolerance
easily. There is speculation that this is a normal developmental
activity of the immune system as it is exposed to new foods. Approximately
18 percent of infants do develop IgE mediated atopic dermatitis
from exposure to cows milk, eggs, or peanuts. Colic is a
problem in about 15 to 40 percent of the infant population, and
studies indicate that changes in the nursing mothers diet
can alleviate those symptoms. Colic associated with vomiting has
been associated with gastroesophageal reflux, in some cases due
to food intolerance. Even low allergenic protein formulas may induce
symptoms in some of these children.[18] In
contrast to these early reactions to foods, allergies to inhalants
do not usually manifest themselves until after the third birthday.[19]
The prevalence of cows milk allergy is currently between
2 and 5 percent.[20] Peanut allergy is increasing
dramatically and represents a more serious threat to health than
other food allergies. The number of food allergens continues to
grow, and the clinical indications are evolving into more complex
symptom pictures.[21] Adverse
reactions to foods and food additives represent a common problem
in the United States. About 10 percent of the US population are
affected by immune-modulated food sensitivities.[22] One reason for the increased
prevalence of food allergies may be the early introduction of highly
allergenic foods, such as peanuts and other nuts. [23]
Exposure to chemical toxins may also correlate with food allergies. Studies
illustrate that a number of individuals who report feeling ill
when repeatedly exposed to low levels of environmental chemical
odors may also be experiencing food sensitivities.[24] Foods that are consumed excessively
may trigger an immune response in time. On the other hand, some
patients who experience an adverse reaction or find that they are
IgG positive for a particular food may indicate in their diet history
that they rarely eat the food. Careful questioning, however, about
meals may reveal that this food is included in many prepared foods
the patient consumes.[25]
Unusual situations may also increase the individuals risk
for development of food allergies. An interesting study from Bangladesh
reported that acute, watery diarrhea in children correlated with
an increase in IgG antibodies to lactoglobulin. IgE antibodies
to lactoglobulin developed after the diarrheal episode in approximately
12 percent of these children.[26]
Family Patterns
Common Allergens
Symptoms and Diseases Associated with
Allergies
Types of Reactions Initiated
by the Immune System
Type I immune responses (also known as Immediate
Hypersensitivity Reactions) occur within seconds to minutes
following exposure to t-he offending antigens. IgE antibodies,
bound non-specifically on the surface of mast cells and basophils
(via their Fc receptors), come into contact with the offending
antigen. Attachment of antigen results in the release of
the contents of cytoplasmic granules (e.g., histamine), as
well as in synthesis and secretion of biologically active
products of arachidonic acid (e.g., leukotrienes) and other
chemotactic and proinflammatory agents. Mast cell products
increase vascular permeability and constrict bronchial smooth
muscle. Type I responses are responsible for such allergic
phenomena as urticaria, seasonal rhinitis, asthma, and in
settings where large amounts of allergens enter the host
circulation, systemic anaphylaxis.
Type II immune responses (also known as Acute Inflammation
Mediated by Cytotoxic Antibodies) occur in hours to one day,
and result in severe tissue destruction following the binding
of complement-fixing antibodies (IgG or IgM) to erythrocytes,
platelets or leukocytes. Once bound with the antigens, the
complement cascade is initiated resulting in the deposition
of complement fragments (e.g., the opsonin C3b) on the surface
of these cells. Fixed or free phagocytes (containing receptors
for the complement fragments or immunoglobulins) then eliminate
the cells from circulation. Type II responses are associated
with autoimmune hemolytic anemia, thrombocytopenia and systemic
lupus erythematosus.
Type III immune responses (also known as Immune
Complex-mediated Reactions) occur within hours to 1 day following
exposure to antigen. Type III responses involve the formation
of both IgG and IgM mediated antibody-antigen complexes. Once
complexes are formed, they circulate throughout the body. This
often leads to the accumulation of neutrophils, eosinophils
and macrophages in local tissues with resultant inflammation. Type
III responses are responsible for such conditions as Rheumatoid
arthritis, glomerulitis and systemic lupus erythematosus.
Type IV immune responses (also known as Chronic
Inflammatory Reactions or Delayed-Type Hypersensitivity Reactions)
involve the interaction of antigen withT lymphocytes on mucosal
surfaces and in the skin. Type IV responses do not involve
antibodies. Whereas allergic reactions occur within seconds
and minutes, and immune complex reactions occur within several
hours to one day, delayed-type reactions peak at 2 to 3 days. Delayed-type
hypersensitivity reactions are probably important for host
defense against intracellular parasites such as Mycobacterium
tuberculosis and against certain viruses, and are prevalent
in certain diseases such as sarcoidosis and polymyositis.
IgE and IgG Antibodies and Their
Roles
IgE antibodies act by forming crosslinks on the surface
of mast cells within the gastrointestinal system. The chemical
mediators that are released as a result of this binding initiate
physiological changes that result in inflammation and allows
the passage of food antigens into systemic circulation. In
contrast, IgG antibodies are most likely responsible for
delayed reactions from food allergens, as they generally
circulae longer in the blood.
Because most food allergies, identified in the past, have
been immediate food reactions, most testing has been done
on IgE, both total circulating serum levels and specific
antiantigen IgE. Testing with the RAST test can identifies
only IgE antibodies. Likewise skin testing can only measure
those immediate reactions that occur as a result of IgE activity.
Research has identified that many allergic responses to
foods do not occur until hours or days after the exposure
to the offending allergen. IgG, once exposed to antigens,
initiates the release of chemical mediators which activate
the physiological changes associated with food allergies.
Frequency of exposure to the antigens influences a delayed
immune response as a result of IgG activity.[50]
Inflammation of the intestinal tract as a result of the
release of the chemical mediators in IgE and IgG reactions,
causes damage to the mucosal barrier and allows for the passage
of more allergenic food molecules.[51] Intestinal inflammation has
been measured using markers such as fecal eosinophil cationic
protein, tumor necrosis factor-alpha, and alpha-1
antitrypsin in patients with atopic eczema. The patients
were challenged with cows milk, and these indicators
of inflammation all rose. In those patients who exhibited
delayed type reactions to the milk, the rise in TNF-alpha concentration
was particularly noteworthy.[52]
Increased levels of IgG to various foods, including egg
white, orange, and wheat, may indicate an increased risk
to the development of IgE reactions to those food allergens,
as well as to animals and mites.[53] It is therefore helpful to identify both
the IgE and the IgG antibodies to the suspected foods.
Testing for Allergies
Elimination of all potential food allergens followed by
an oral challenge of those foods one by one is still considered
by some to be the most reliable test to identify food allergies. There
are some major problems associated with conducting these
tests, however, including compliance of the patient with
the rigorous dietary schedule. Not only is the test difficult
to do from the standpoint of avoidance and the slow challenge,
but it is also very difficult to identify delayed food reactions
through this method. Symptoms often appear in parts of the
body in which the patients have no suspicion of problems
and no direct exposure to the antigens. Thus it is difficult
for them to see the cause and effect relationships.
In addition, skin testing, which has been used for a number
of years to detect airborne allergens, has been found to
be unreliable for detecting food allergies. Skin tests have
only been shown to be useful only for measuring immediate
reactions to allergens. Differences in interpretation (which
has also been a problem with RAST in the past) has limited
the usefulness of the skin test for studying food allergies.[54]
US BioTek Allergy Profile
US BioTek offers testing for both IgE and IgG antibodies
to 88 foods on the Standard or Vegetarian Food Allergy Panels,
and over 135 foods and spices on the Extended Food Allergy
Panel. In addition, an inhalant panel identifies IgE antibodies
to common airborne substances and pet allergens.
US BioTeks ELISA is considered state-of-the
art for the following reasons: US BioTek currently
has two distinguised scientists on staff (with over 29 combined
years of ELISA experience including the development of over
60 unique immunoassays). To start with, close attention is
paid to working with quality materials. The use of robotics
avoids day-to-day variability and technical (human) pipetting
error. In the assay itself, all samples are run in duplicate
(this alone validates both the assay and the test results). The
ELISA is highly sensitive (it can detect less than 1 µg/ml
of IgE in serum, and less than 500 picogram/ml of IgG). The
ELISA, as we have developed it, is accurate, consistent and
reproducible. It provides physicians with reliable test
results that can enhance the diagnosis of allergies and improve
the clinical outcomes (by allowing the physician and patient
to review changes as they occur during the treatment protocol).
The results are returned to the physician in a very timely
manner (within 3-5 days after the blood sample is drawn)
and are presented in a very user-friendly report. Foods
are identified within their food group for ease of finding
specific results. Color bar graphing offers an immediate
visual representation of the findings. Total serum IgG and
IgE levels are furnished in the report as well as the specific
amount of antibody produced against each food. In addition,
the data are provided in such a way that absolute measurements
of each individual test sample (against a panel of antigens)
are evaluated based on a standard bell curve of normal individuals. This
allows the physician to see how their individual patients
values relate to a large known population.
[1] Hill DJ, Hosking CS, Heine RG. Clinical spectrum
of food allergy in children in Australia and South-East Asia:
identification and targets for treatment. Ann Med.
1999;31(4):272-281.
[2] Eseverri JL, Cozzo M, Marin AM, Botey J. Epidemiology
and chronology of allergic diseases and their risk factors. Allergol
Immunopathol (Madr). 1998;26(3):90-97.
[3] Hofer MF. The child, his mother, and allergies. Rev
Med Suisse Romande. 1999;119(8):623-627.
[4] King WP. Food hypersensitivity in otolaryngology.
Manifestations, diagnosis, and treatment. Otolaryngol
Clin North Am. 1992;25(1):163-179.
[5] Hourihane JO. Prevalence and severity of food allergyneed
for control. Allergy. 1998;53(46 Suppl):84-88.
[6] Royal College of Physicians and Royal College of
Pathologists. Good allergy practicestandards of care
for providers and purchasers of allergy services within the
National Health Service. Clin Exp Allergy. 1995;25(7):586-595.
[7] Joyce DP, Chapman KR, Balter M, Kesten S. Asthma
and allergy avoidance knowledge and behavior in postpartum
women. Ann Allergy Asthma Immunol. 1997;79(1):35-42.
[8] Rachelefsky GS. National guidelines needed to manage
rhinitis and prevent complications. Ann Allergy Asthma
Immunol. 1999;82(3):296-305.
[9] Wilson SJ, Walzer M. Absorption of undigested proteins
in human beings. IV. Absorption of unaltered egg protein
in infants. Am J Dis Child. 1935;50:49-54.
[10] Rinkel HJ. Food Allergy. J Kansas Med Soc.
1936;37:177.
[11] Deamer WC, Gerrard JW, Speer F. Cows milk:
a critical review. J Fam Pract. 1979;9(2):223-232.
[12] Schnyder B, Pichler WJ. Food intolerance and
food allergy. Scweiz Med Wochenschr. 1999;129(24):9280933.
[13] Kitts D, Yuan Y. Joneja J, et al. Adverse reactions
to food constituents: allergy, intolerance , and autoimmunity. Can
J Physiol Pharmacol. 1997;75(4):241-254.
[14] Eseverri JL, Cozzo M, Marin AM, Botey J. Epidemiology
and chronology of allergic diseases and their risk factors. Allergol
Immunopathol (Madr). 1998;26(3):90-97
[15] Joyce DP, Chapman KR, Balter M, Kesten S. Asthma
and allergy avoidance knowledge and behavior in postpartum
women. Ann Allergy Asthma Immunol. 1997;79(1):35-42.
[16] Jolicoeur LM, Boyer JG, Reeder CE, Turner J.
Influence of asthma or allergies on the utilization of health
care resources and quality of life of college students. J
Asthma. 1994;31(4):251-267.
[17] Eigenmann PA, Sicherer SH, Borkowski TA, et al. Prevalence
of IgE-mediated food allergy among children with atopic dermatitis. Pediatrics.
1998;101(3):E8.
[18] Hill DJ, Hosking CS, Heine RG. Clinical spectrum
of food allergy in children in Australia and South-East Asia:
identification and targets for treatment. Ann Med.
1999;31(4):272-281.
[19] Kulig M, Bergmann R, Klettke U, et al. Natural
course of sensitization to food and inhalant allergens during
the first 6 years of life. J Allergy Clin Immunol.
1999;103(6):1173-1179.
[20] Moneret Vautrin DA. Cows milk allergy. Allerg
Immunol (Paris). 1999;31(6):201-210.
[21] Rance R, Kanny G, Dutau G, Moneret Vautrin DA.
Food allergens in children. Arch Pediatr. 1999;6(Suppl1):61S-66S.
[22] Opper FH, Burakoff R. Food allergy and intolerance. Gastroenterologist.
1993;1(3):211-220.
[23] Sampson HA. Food allergy. JAMA. 1997;278(22):1888-1894.
[24] Bell IR, Schwartz GE, Peterson JM, et al. Possible
time-dependent sensitization to xenobiotics: self-reported
illness from chemical odors, foods, and opiate drugs in an
older adult population. Arch Environ Health. 1993;48(5):315-327.
[25] Hourihane JO. Prevalence and severity of food
allergyneed for control. Allergy. 1998;53(46
Suppl):84-88.
[26] Ahmed T, Sumazaki R, Shin K, et al. Humoral immune
and clinical responses to food antigens following acute diarrhoea
in children. J Paediatr Child Health. 1998;34(3):229-232.
[27] Eseverri JL, Cozzo M, Marin AM, Botey J. Epidemiology
and chronology of allergic diseases and their risk factors. Allergol
Immunopathol (Madr). 1998;26(3):90-97.
[28] Taub EL. Food allergy and the allergic patient.
Springfield: Thomas. 1978.
[29] Rance R, Kanny G, Dutau G, Moneret Vautrin DA.
Food allergens in children. Arch Pediatr. 1999;6(Suppl1):61S-66S.
[30] Ortega Cisneros M, Vidales Diaz MA, del Rio Navarro
BE, Sienra Monge JJ. Cutaneous reactivity to foods among
patients with allergic rhinoconjunctivitis. Rev Alerg
Mex. 1997;44(6):153-157.
[31] Rance R, Kanny G, Dutau G, Moneret Vautrin DA.
Food allergens in children. Arch Pediatr. 1999;6(Suppl1):61S-66S.
[32] Muhlemann RJ, Wuthrich B. Food allergies 1983-1987. Scheiz
Med Wochenschr. 1991;121(46)1696-1200.
[33] Kulig M, Bergmann R, Klettke U, et al. Natural
course of sensitization to food and inhalant allergens during
the first 6 years of life. J Allergy Clin Immunol.
1999;103(6):1173-1179
[34] Ewan PW. Clinical study of peanut and nut allergy
in 62 consecutive patients: new features and associations. BMJ.
1996;312(7038):1074-1078.
[35] Wilson NW, Self TW, Hamburger RN. Severe cows
milk induced colitis in an exclusively breast-fed neonate.
Case report and clinical review of cows milk allergy. Clin
Pediatr (Phila). 1990;29(2):77-80.
[36] Pelto L, Salminen S, Lilius EM, et al. Milk hypersensitivity key
to poorly defined gastrointestinal symptoms in adults. Allergy.
1998;53(3):307-310.
[37] Garrett MH, Rayment PR, Hooper MA, et al. Indoor
airborne fungal spores, house dampness and associations with
environmental factors and respiratory health in children. Clin
Exp Allergy. 1998;28(4):459-467.
[38] Joyce DP, Chapman KR, Balter M, Kesten S. Asthma
and allergy avoidance knowledge and behavior in postpartum
women. Ann Allergy Asthma Immunol. 1997;79(1):35-42.
[39] Buchanan HM, Preston SJ, Brooks PM, Buchanan
WW. Is diet important in rheumatoid arthritis? Br J Rheumatol.
1991;30(2):125-134.
[40] Van d Laar MA, Aalbers M, Bruins FG, et al. Food
intolerance in rheumatoid arthritis. II. Clinical and histological
aspects. Am Rheum Dis. 1992;51(3):303-306.
[41] Schrander JJ, Marcelis C, deVried MP, van Santen
Hoeufft HM. Does food intolerance play a role in juvenile
chronic arthritis? Br J Rheumatol. 1997;36(8):905-908.
[42] Cuesta Herranz J, Lazaro M, de las Heras M. Peach
allergy pattern: experience in 70 patients. Allergy.
1998;53(1):78-82.
[43] Corrado G, Luzzi I, Lucarelli S, et al. Positive
association between Helicobacter pylori infection and food
allergy in children. Scand J Gastroenterol. 1998;33(11):1135-1139.
[44] Rance R, Kanny G, Dutau G, Moneret Vautrin DA.
Food allergens in children. Arch Pediatr. 1999;6(Suppl1):61S-66S.
[45] Nolan A, Lamey PJ, Milligan KA, Forsyth A. Recurrent
aphthous ulceration and food sensitivity. J Oral Pathol
Med. 1991;20(10):473-475.
[46] Kitts D, Yuan Y. Joneja J, et al. Adverse reactions
to food constituents: allergy, intolerance , and autoimmunity. Can
J Physiol Pharmacol. 1997;75(4):241-254.
[47] Ahmed I, Kamota I, Sumazaki R, et al. Circulating
antibodies to common food antigens in Japanese children with
IDDM. Diabetes Care. 1997;20(1):74-76.
[48] Trotsky MB. Neurogenic vascular headaches, food
and chemical triggers. Ear Nose Throat J. 1994;73(4):228-230,
225-236.
[49] Egger J, Carter CH, Soothill JF, Wilson J. Effect
of diet treatment on enuresis in children with migraine or
hyperkinetic behavior. Clin Pediatr (Phila). 1992;31(5):302-307.
[50] King WP. Food hypersensitivity in otolaryngology.
Manifestations, diagnosis, and treatment. Otolaryngol
Clin North Am. 1992;25(1):163-179.
[51] King WP. Food hypersensitivity in otolaryngology.
Manifestations, diagnosis, and treatment. Otolaryngol
Clin North Am. 1992;25(1):163-179.
[52] Majamaa H, Miettinen A, Laine S, Isolauri E.
Intestinal inflammation in children with atopic eczema: a
faecal eosinophil cationic protein and tumour necrosis factor-alpha
as non-invasive indicators of food allergy. Clin Exp
Allergy. 1998;26(2):181-187.
[53] Eysink PE, De Jong MH, Bindels PJ, et al. Relation
between IgG antibodies to foods and IgE antibodies to milk,
egg, car, dog, and/or mite in a cross-sectional study. Clin
Exp Allergy. 1999;29(5):604-610.
[54] Dreborg S. Skin testing in the diagnosis of food
allergy. Allergy Proc. 1991;12(4):251-254. |