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Molecular based allergic diagnosis Presented by Suparat Sirivimonpan, MD. October 18, 2013
Citation preview
Molecular-based allergy
diagnostics Suparat Sirivimonpan, MD.
18/10/2013
A WAO - ARIA - GA2LEN consensus
document on molecular-based allergy
diagnostics
World Allergy Organization Journal 2013, 6:17
Topic outline
Introduction Definitions and concepts Clinical application
Increase accuracy and resolve cross-reactivity
Assess the risk and type of reaction
Specific immunotherapy
Micro-array technology
Diagnosis
• Clinical : History, Physical examination • Allergic test
• Skin prick test
• Blood test
• Specific IgE
• Component resolve diagnosis (CRD)
crude extracts
Currently available tests detect only sensitization,
not clinical allergy, cannot predict prognosis and severity
Nature
Allergenic
source
contain a mixture of allergenic and
non-allergenic molecules
Introduction
• Molecular allergy (MA) diagnostics is increasingly entering routine care • More than 130 allergenic molecules are commercially available for in vitro sIgE testing • Clinicians and immunologists specifically trained in allergology must keep abreast of the new and rapidly evolving evidence available for MA diagnostics
World Allergy Organization Journal 2013, 6:17
Introduction
• WAO - ARIA - GA2LEN consensus document : practical guide for the indication, determination, and interpretation of MA diagnostics aimed for clinicians specifically trained in allergology
World Allergy Organization Journal 2013, 6:17
Definitions and concepts
Definitions and concepts
• Allergen extract • A crude, unfractionated mixture of allergenic and non-
allergenic proteins, polysaccharides, and lipids
• extraction from an allergen source
•Allergenic molecule (allergen component) • A molecule (i.e., protein or glycoprotein) bind sIgE antibodies “allergen”
• Allergens can be isolated from
• natural allergen sources (native, purified allergen)
• recombinant DNA technology (recombinant allergen)
World Allergy Organization Journal 2013, 6:17
Almost anything containing proteins can be an allergen source
- each allergen source contains many different allergenic protein (allergen component)
- each allergen component commonly has several different epitopes
- epitope is the actual three-dimensional binding site for an antibody
Allergen component
Clinical and Experimental Allergy;2010 ,40: 896-904
Definitions and concepts
Stability of allergens
•Acid pH : • susceptible to acid pH (peptic digestion) not able to cross
gastric barrier
(except possibly in patients treated with antacid drugs)
•Temperature (cooking or boiling) : • Temperature susceptibility does not maintain its
allergenicity after cooking/heating procedures
World Allergy Organization Journal 2013, 6:17
Protein stability
- allergen that stable to heat and digestion are more likely to cause severe reaction
- allergen that heat and digestion labile are more likely to be tolerated or only cause mild/local symptom
Allergen component
Clinical and Experimental Allergy;2010 ,40: 896-904
Definitions and concepts
• Primary allergen : • original sensitizing molecule (i.e., driving trigger)
•Secondary sensitization : • cross-reactivity
World Allergy Organization Journal 2013, 6:17
Definitions and concepts
Cross-reactivity • phenomenon of an IgE antibody recognizing, binding,
and inducing an immune response to similar allergenic molecules (homologues) present in different species
(reacts to both Bet v 1 in birch pollen and Cor a 1 in hazelnut PR10)
• ≥ 50-70% sequence homology between primary
structures of proteins
World Allergy Organization Journal 2013, 6:17
Definitions and concepts
Cross-reactivity • IgE cross-reactivity often occurs between the following:
a) Allergenic molecules in closely related species
b) Well preserved molecules with similar function present in widely different species that belong to the same protein family (tropomyosin : Der p 10 in house dust mite ,Pen m 1 in black tiger shrimp)
World Allergy Organization Journal 2013, 6:17
Definitions and concepts
Co-sensitization • Genuine sensitization to more than one allergen source (e.g., timothy grass and birch) • sensitization is not due to cross-reactivity
World Allergy Organization Journal 2013, 6:17
Definitions and concepts
Co-sensitization • Genuine sensitization to more than one allergen source (e.g., timothy grass and birch) • where the sensitization is not due to cross-reactivity
World Allergy Organization Journal 2013, 6:17
Definitions and concepts
sIgE sensitization • presence of allergen-specific IgE (sIgE) antibodies in the blood
• presence or absence of clinical symptoms
a) Mono-sensitization: - Sensitization to one allergen source (D. pteronyssinus) or to a
closely related taxonomical family or group of allergen sources (i.e., mites)
b) Poly- (or multi-) sensitization: - Sensitization to three or more allergen sources (e.g., mite,
birch, and grass pollen).
World Allergy Organization Journal 2013, 6:17
Definitions and concepts
sIgE detection based on allergen extracts • Singleplex or multiplex platforms
• such as CAP, radioallergosorbent test (RAST)
• interchangeably
•
sIgE detection based on allergenic molecules • Singleplex or multiplex platforms
• identify cross-reacting molecules
World Allergy Organization Journal 2013, 6:17
•World Health Organization and International Union of Immunological Species (WHO/IUIS)
• Using their Latin family name (genus and species)
• Arachis hypogaea : Ara h (peanut) • A number : distinguish various allergens from the same species (e.g., Ara h 1, Ara h 2, etc.)
• The numbers are assigned to the allergens in the order of their identification
• Allergenic molecules are classified into protein families, according to their structure and biological function
•www.allergen.org
World Allergy Organization Journal 2013, 6:17
Systematic allergen nomenclature
Clinical and Experimental Allergy;2010 ,40: 896-904
Clinical application
Clinical application
• increased accuracy in allergy diagnosis and prognosis • plays an important role in three key aspects of allergy diagnosis: (1) Increase accuracy and resolve cross-reactivity
(2) Assess the risk and type of reaction
(3) Specific immunotherapy (patients and triggering allergens)
World Allergy Organization Journal 2013, 6:17
• Allergic individuals may produce IgE antibodies to allergens that are either unique to a single species or common to many
• Proteins within the same family share common epitopes
same IgE antibody can bind to similar structures present in allergens from different allergen sources
• These cross-reactive allergens give valuable information on potential sensitization and clinical reactions to several different sources
World Allergy Organization Journal 2013, 6:17
Increase accuracy and resolve cross-reactivity
•
World Allergy Organization Journal 2013, 6:17
World Allergy Organization Journal 2013, 6:17
World Allergy Organization Journal 2013, 6:17
Stab le
World Allergy Organization Journal 2013, 6:17
Stab le
World Allergy Organization Journal 2013, 6:17
Lab ile
World Allergy Organization Journal 2013, 6:17
Lab ile
Increase accuracy and resolve cross-reactivity
• While, MA studies have not fully elucidated the underlying mechanism governing cross-reactivity and symptom presentation analysis of the epitopes of key allergens will provide insight into this issue • Currently, a large number of purified or recombinant allergens are commercially available
World Allergy Organization Journal 2013, 6:17
World Allergy Organization Journal 2013, 6:17 Food
World Allergy Organization Journal 2013, 6:17 Food
World Allergy Organization Journal 2013, 6:17 Food
World Allergy Organization Journal 2013, 6:17 Aeroa lle rgens
World Allergy Organization Journal 2013, 6:17 Aeroa lle rgens
World Allergy Organization Journal 2013, 6:17 Aeroa lle rgens
World Allergy Organization Journal 2013, 6:17 O ther alle rgens
Increase accuracy and resolve cross-reactivity
Clinical uses of MA : • identify the offending allergenic molecule • distinguish specific molecules from markers of cross-reactivity
World Allergy Organization Journal 2013, 6:17
Increase accuracy and resolve cross-reactivity
• In the field of pollen-related food allergy : increase accuracy of diagnosis
* peanut allergic patients,
- Ara h 2 genuine marker,systemic reactions
-Ara h 8 cross-reactivity among food allergens ,Fagales tree pollen mild, oral reactions
•measuring IgE responses to certain food allergens may reduce the need for food challenges
•
World Allergy Organization Journal 2013, 6:17
Increase accuracy and resolve cross-reactivity
• In patients sensitized to different pollen species
• detecting new relevant sensitizations
• by ruling out clinically irrelevant sensitizations caused by non-symptomatic cross-reactive allergens
• For example, MA diagnostics can help to distinguish baker’s asthma from pollen or wheat allergy
World Allergy Organization Journal 2013, 6:17
Increase accuracy and resolve cross-reactivity
• In conventional SPTs, some allergens can be poorly represented in extracts because of the biological variability of allergen source
* Dog allergic patients • Can f 5 prostate-derived allergen produced by male dogs
38% of dog allergic patients
• Allergen extracts used in skin tests : dog hair
skin tests routinely fail to identify patients’ sensitivity to
Can f 5 (low concentration in dog hair)
• IgE response to Can f 5 using MA diagnostics may enhance accuracy of dog allergy diagnosis
World Allergy Organization Journal 2013, 6:17
Increase accuracy and resolve cross-reactivity
• All allergy diagnostics, including MA, should be evaluated within framework of a patient’s clinical history
• IgE sensitization not necessarily imply clinical responsiveness
• This is of particular importance, since allergic patients respond in individualized manner to exposure to allergens from various sources
•i.e., every individual produces their own unique IgE antibody profile at molecular level
World Allergy Organization Journal 2013, 6:17
Assess the risk and type of reaction
• Ability to improve risk assessment, particularly for food allergies
• Different foods contain unique allergenic molecules that are stable or labile to heat & digestion
• stability of a molecule & patient’s clinical history : risk of systemic versus local reactions
• Labile local reactions (typically oral symptoms) and cooked food is often tolerated
• Stable allergens systemic reactions
• MA diagnostics may decrease the need for provocation testing and improve recommendations for allergen avoidance
World Allergy Organization Journal 2013, 6:17
Assess the risk and type of reaction
• Information may only be applicable to the specific population which has been studied
• Disease expression differ according to local exposures patterns characteristic of the geographical region
• ex. Peanut (USA, Spain, Sweden)
World Allergy Organization Journal 2013, 6:17
Food allergens
World Allergy Organization Journal 2013, 6:17
Allergens resistant to heat and digestion often trigger more severe
allergic reactions
Storage protein, LTP
Food allergens
• In addition, the amount of a molecule present in a food source is also a parameter to take into consideration
World Allergy Organization Journal 2013, 6:17
Food allergens
Peanut
• Ara h1,2,3 (storage proteins) genuine peanut reaction
• Ara h 8 (PR-10,Bet v 1-homologue) milder or local symptoms
• LTP (Ara h 9) southern Europe, prevalent sensitizing allergen
systemic and more severe reactions
• Further studies in other geographical regions
• Profilin or CCD sensitization no or local oral symptoms
heated peanuts may be
tolerated
World Allergy Organization Journal 2013, 6:17
Food allergens
Soy • Gly m 5 and/or Gly m 6 severe reactions • Gly m 4 (PR-10) OAS
• In birch pollen-allergic individuals, the combination of Gly m 4 sensitivity and intake of large amounts of mildly processed soy, such as soy drinks, can induce a severe reaction
• Profilin or CCD no, or local oral symptoms heated soy may be tolerated
World Allergy Organization Journal 2013, 6:17
Food allergens
Hazelnut • Cor a 1 (PR-10) local reactions like OAS • Cor a 8 (LTP) , storage proteins (Cor a 9,Cor a 14) severe symptoms • Profilin (Cor a 2) or CCD alone no or local oral symptoms heated hazelnuts may be tolerated.
World Allergy Organization Journal 2013, 6:17
Food allergens
Walnut • Storage protein (Jug r 1, Jug r 2) or LTP (Jug r 3) severe reactions • Walnut allergens have not been available on the market until recently, as is reflected by the lack of recent clinical studies • Profilin or CCD alone no, or local oral, symptoms heated walnut may be tolerated
World Allergy Organization Journal 2013, 6:17
Food allergens
Wheat • ω-5-gliadin (Tri a 19) immediate allergic reactions in children
systemic exercise-induced reactions in adults
• LTP (Tri a 14) some degree of cross-reactivity with other food LTPs
more knowledge is needed about its prevalence and clinical implication
• Profilin or CCD no, or local oral, symptoms
heated wheat may be tolerated
World Allergy Organization Journal 2013, 6:17
Food allergens
Rosaceae fruits • Apple, peach, Appricot, Plum • PR-10 proteins (Mal d 1, Pru p 1) or profilins (Pru p 4) local, oral reactions (sensitive to heat & digestion)
• LTP (Pru p 3) typical of the Mediterranean area
wide range of clinical expressions (from asymptomatic to anaphylaxis)
risk marker for severe reactions including cofactor (e.g., exercise, alcohol or drugs) dependent anaphylaxis
World Allergy Organization Journal 2013, 6:17
Food allergens
Egg • High levels of sIgE antibodies to ovomucoid (Gal d 1) risk factor for persistent egg allergy, including reactions to cooked/heated egg • Undetectable levels indicate tolerance to cooked egg
World Allergy Organization Journal 2013, 6:17
Food allergens
Milk • Casein (Bos d 8) and beta-lactoglobulin (Bos d 5) sIgE antibodies persistent allergy to milk, including heated milk • undetectable levels indicate tolerance to baked milk products
World Allergy Organization Journal 2013, 6:17
Food allergens
Fish • Parvalbumins (e.g., Gad c1 and Cyp c 1)
• major allergens in fish • typically stable to heat and digestion • high degree of cross-reactivity whereby patients sensitized to one parvalbumin may also
react to parvalbumins from other fish, including carp, cod, herring, plaice, mackerel, tuna, salmon, perch, and eel
World Allergy Organization Journal 2013, 6:17
Food allergens
Shellfish • Tropomyosin - high degree of cross-reactivity across a wide variety of species, including mites • Shrimp and other shellfish also contain other clinically relevant allergens - sarcoplasmic calcium-binding protein - arginine kinases
World Allergy Organization Journal 2013, 6:17
Food allergens
Meat allergy Galactose-α-1,3-galactose (α-Gal) • sugar structure found on glycoproteins and glycolipids of non-primate mammals and new world monkeys, but not on humans
• It is assumed that sensitization to α-Gal can be induced by tick bites or certain parasite infections
• α-Gal– sensitized patients delayed immediate type reactions to red meat (beef, pork, goat, deer)
• Anti-α-Gal-IgE severe allergic symptoms and with delayed-type anaphylaxis
World Allergy Organization Journal 2013, 6:17
Food allergens
Meat allergy • α-Gal : present on the chimeric antibody cetuximab
• Patients sensitized to α-Gal may react with anaphylactic reaction after the administration of cetuximab
• Testing for α-Gal before administration of cetuximab
• Bovine serum albumin (e.g. Bos d 6)
• heat labile allergen
• present both in milk and beef
• may cause cross-reactivity between different mammalian meat
World Allergy Organization Journal 2013, 6:17
Inhalants
Pet dander • Fel d 1 : asthma in cat-allergic individuals
• Lipocalins (Mus m 1, Equ c 1, Fel d 4, Can f 1, 2), kallikrein (Can f 5), and secretoglobin (Fel d 1) : severe asthma in Swedish children
• More knowledge is needed in the area of pet allergy
• many of the patients are poly-sensitized to several pets
• clinical history is often inconclusive
• cross-reactivities between e.g. cat, dog and horse is not fully clarified at the MA level
World Allergy Organization Journal 2013, 6:17
Inhalants
Pollen
• Research in pollen allergy has focused on distinguishing genuine allergens from those that are cross-reactive
• Little is known regarding specific markers of severe reactions
• Some sensitivities to specific allergens (ex.Ole e 9 ,LTP Ole e 7)
• may be markers of more severe symptoms in pollen allergy
• increasing the risk of systemic reactions during immunotherapy
World Allergy Organization Journal 2013, 6:17
Inhalants
Pollen • Profilin sensitization
• common among pollen allergic patients
• associated with mild or no clinical symptoms
• minority of patients: risk factor for more severe reactions in olive pollen-allergic individuals and in patients allergic to certain plant foods like melon or citrus
World Allergy Organization Journal 2013, 6:17
Inhalants
Mites • No specific sensitization profile has been described as a risk factor for lower airway disease or disease severity • Higher sIgE/IgG4 ratio for Der p 2 has been associated with asthma
• Der p 10 (tropomyosin)
• minor allergen in mite-allergic patients
• risk for allergic reactions to shellfish or snail, which can be severe
World Allergy Organization Journal 2013, 6:17
Inhalants
Molds Aspergillus fumigatus • Asp f 2, 4, and 6 may suggest ABPA
• Asp f 1 and/or Asp f 3 may be more indicative of allergic asthma
• These associations must still be confirmed in other patient populations
World Allergy Organization Journal 2013, 6:17
Inhalants
Cockroach • Per a 2 correlates with severity of airway allergy in cockroach-allergic patients
• Per a 2 is currently not commercially available for in vitro testing
• Per a 2 homologue Bla g 2 is available
• Cross-reactive tropomyosin (Bla g 7)
risk for allergic reactions to shellfish or snail, which can be severe
World Allergy Organization Journal 2013, 6:17
Other allergens
Latex • Sensitization to Hev b 8 (profilin)
• seems to be clinically irrelevant
• not related to clinical latex reactions
• The other latex allergens are linked to clinical reactions
• No association between allergens and severity of reactions
• The cross-reactive allergen responsible for the so called latex-fruit syndrome are not fully clarified
• although data indicate that Hev b 5, 6 and 11 play a role
World Allergy Organization Journal 2013, 6:17
Other allergens
Hymenoptera venoms
• Most hymenoptera venom allergens possess CCDs
responsible for a portion of clinically irrelevant IgE antibody cross-reactivity between bee and wasp venom
• Detection of recombinant venom allergens can discriminate between genuine venom sensitization and cross-reactivity due to CCDs in patients with double-positive IgE results from traditional venom tests that are based on allergen extract
World Allergy Organization Journal 2013, 6:17
Specific immunotherapy (SIT)
• Correct diagnosis, selection of truly eligible patients, and identification of primary sensitizing allergen(s) are important for optimal and cost-effective patient management
• In some patients, a detailed clinical history and traditional extract-based IgE testing (SPT and/or in vitro sIgE) is sufficient to identify the relevant allergen(s)
• Patient demonstrates polysensitization : traditional diagnostic tests based on allergen extracts and their clinical history is not sufficient to clarify the nature of the sensitization
• may occur in a relatively high proportion of patients
World Allergy Organization Journal 2013, 6:17
Specific immunotherapy
• Mixing numerous allergens appears to achieve good clinical efficacy
• there may be an inability to identify the responsible allergen in the case
of adverse events
• Certain proteins (e.g., profilins, polcalcins, LTPs, PR10, tropomyosins) are highly conserved in a wide variety of species
• The use of recombinant/purified allergens would allow for the discrimination between genuine sensitizations and cross reactivities
World Allergy Organization Journal 2013, 6:17
Grass, Pollen
World Allergy Organization Journal 2013, 6:17
In the example mentioned above a patient with sIgE antibodies against Phl p 1 and Phl p 5 but no sIgE to Bet v
1 is truly sensitized to grass
If sIgE antibodies to Phl p 12 (profilin) were also detected, profilin sensitization would probably be responsible
for the positive SPT result obtained with birch extract, which contains profilin as well.
SIT would be prescribed for grass only
• if a patient is sensitized to a traditional house dust mite extract
• but their IgE antibodies against Der p 10 (tropomyosin) and not to Der p 1, 2/
Der f 1, 2
• SIT for mites should not be given, because mite extracts mainly contain Der
p 1, 2/Der f 1, 2 and have variable or low amounts of Der p 10
World Allergy Organization Journal 2013, 6:17
HDM
Hymenoptera venom
• Sensitization to the major allergens Api m 1 of honeybee and Ves v 5 and/or
Ves v 1 of yellow jackets may be helpful in discriminating between true double
bee and wasp sensitization and cross-reactivity due to CCDs
World Allergy Organization Journal 2013, 6:17
Specific immunotherapy
• Most commercial allergen extracts used in SIT are well standardized for major allergens • contain only minimal or variable amounts of minor allergens • Patients with sensitization to minor allergens alone will likely not receive sufficient amounts of allergen to achieve a successful outcome by SIT
World Allergy Organization Journal 2013, 6:17
Specific immunotherapy
• Theoretically, identification of molecules tailored SIT?? • In practice, this does not seem feasible 1. number of possible combination of sensitization profiles is large when taking into consideration all allergenic sources 2. recombinant vaccines do not perform better than traditional allergen extracts, as observed in some studies 3. each single recombinant/purified allergen would need to be individually tested and registered, which carries a substantial financial burden for manufacturers • reality of patient-tailored SIT is still a distant prospect
World Allergy Organization Journal 2013, 6:17
Micro-array technology
Micro-array technology
• MA diagnostics has been available on singleplex platforms
• ImmunoCAP, ImmuLite, and HyTech platforms
• single allergens together with the corresponding allergen extract
• Multiplex technology :
• measure sIgE antibodies against multiple allergens in a single assay
• testing of a large number of allergens using a small amount of serum
World Allergy Organization Journal 2013, 6:17
ImmunoCAP Immuno-Solid Phase Allergen Chip (ISAC) (Phadia AB)
World Allergy Organization Journal 2013, 6:17 Fluorescence is measured with a laser scanner and results are evaluated using a Microarray Image Analysis (MIA) software, which provides an automatic readout of the results.
ISAC
• Using a standard calibration curve, results are reported within a range of 0.3 - 100 ISAC Standardized Units (ISU-E)
• giving a semi-quantitative indication of IgE antibody levels
World Allergy Organization Journal 2013, 6:17
ISAC
• ImmunoCAP
• results : kU/L
• not interchangeable
• correlate well
• ImmunoCAP technology measures IgE binding under conditions of excess of immobilized allergen
• ISAC uses low amounts of immobilized allergen allowing for competition with allergen-specific isotypes other than IgE
World Allergy Organization Journal 2013, 6:17
World Allergy Organization Journal 2013, 6:17
When comparing ISAC with other sIgE measuring assays, concordance of results vary between allergens tested
ISAC
• Results of the ISAC assay are reproducible at a level that is generally accepted and agreed upon
• Special attention : samples contain low levels of sIgE
(0.3–1 ISU-E), higher degree of variability
• Comparative data with the ImmuLite or HyTech platforms are not available in the literature
World Allergy Organization Journal 2013, 6:17
at low sIgE levels ImmunoCAP is more sensitive than ISAC
ISAC
• ISAC is generally not recommended for monitoring quantitative IgE levels over time in clinical routine
•Because there is a higher degree of between assay variability for ISAC
compared to ImmunoCAP
• The interpretation of the results may be challenging 1. clinical relevance of the different allergens must be considered 2. results must be evaluated in relation to traditional diagnostic tests 3. results must be evaluated with regard to the patient’s clinical history (most important)
World Allergy Organization Journal 2013, 6:17
Micro-array technology
• ISAC results for some allergen sources such as cashew nut, sesame, dog, mugwort, and ragweed can be negative, even when the extract-based test is positive
triggering allergen is not present on the chip
World Allergy Organization Journal 2013, 6:17
•
World Allergy Organization Journal 2013, 6:17
Patients most likely to benefit from MA diagnostics
• Patients who are poly-sensitized, have an unclear symptom and/or sensitization pattern, or who do not respond to their treatment
• Patients with documented poly-sensitization to one or more inhalants, but also suffering from food allergy (i.e., from less severe manifestations such as OAS to more severe, including anaphylaxis, asthma or eczema)
World Allergy Organization Journal 2013, 6:17
Mono-sensitized patients with a clear case history and symptom profile may not benefit from MA diagnostics compared to traditional diagnostic tests
Molecular-based allergy diagnostics
• MA diagnostics may offer additional information for - early diagnosis of allergies - aid in the monitoring of the evolution of the allergic disease - useful for preventive indications to the patient
World Allergy Organization Journal 2013, 6:17
Unmet needs!
1) Large-scale, population-based multicenter studies : categories of patients
2) Large studies that include well-characterized patients and healthy, sensitized controls representative of different geographical regions
3) Cost-utility studies :
compare effectiveness of MA diagnostics with the traditional in vitro sIgE or SPT
World Allergy Organization Journal 2013, 6:17
Unmet needs!
4) Identification and clinical evaluation of the most relevant allergens have to be further investigated in many allergen sources.(e.g., nuts, molds, tree and weed pollen)
5) Training efforts in both the clinical and research settings
6) Development of clinical decision support is needed to prevent misinterpretation and improve knowledge as the amount of information obtained from MA diagnostics may be complex, especially as the evidence for MA is rapidly progressing.
World Allergy Organization Journal 2013, 6:17
• International guidelines recommendation
For the majority of patients, first- and second-line investigation is sufficient to define the nature of a
patient’s allergy
For experienced users MA may be included in second-line testing
World Allergy Organization Journal 2013, 6:17
1st Step : a thorough clinical case history
2nd Step : allergen extract-based IgE tests (in vitro specific IgE or skin prick test) identification of the allergen source
SPT and in vitro sIgE tests provide similar information associated advantages and disadvantages of both types of tests are dependent on the clinical case
3rd Step : Molecular-based allergy (MA) diagnostics used for select patients in whom first- and second-line investigations were inconclusive
• MA diagnostics is increasingly entering routine care and can improve management of allergic patients Benefit (1) Increase accuracy and resolve cross-reactivity (2) Assess the risk and type of reaction (3) Specific immunotherapy
World Allergy Organization Journal 2013, 6:17
Conclusions
- small serum or blood sample - broad spectrum analysis of a patient’s IgE profile
• Sensitivity compared to ImmunoCAP is still often lower • ISAC can have high clinical relevance by detecting sensitization patterns to important allergens and cross-reacting groups
World Allergy Organization Journal 2013, 6:17
Conclusions
Disadvantage • Interpretation of such sensitization in clinically unresponsive patients is difficult or even impossible • Relatively expensive compared with traditional tests economic consideration or budget limitations
• the search for more, clinically relevant molecules is needed and ongoing
World Allergy Organization Journal 2013, 6:17
Conclusions
• Although MA diagnostics is a complex area, it provides novel and relevant information for the allergist and will soon become a standard tool in the allergist’s armamentarium • Educational programs training allergists on the use and interpretation of MA are highly needed •
World Allergy Organization Journal 2013, 6:17
Conclusions
Thank you