The spectrum of allergic diseases Hugo Van Bever
The spectrum of allergic diseases Hugo Van Bever Department of Pediatrics National University Singapore APAPARI workshop – Hanoi, Vietnam – May 2008
skyline HDB flat 1. 2. 3. 4. Clean - well organized - tropical High prevalence of allergic diseases A lot of HDMs (Blomia tropicalis) Strange food allergies (bird nest, etc…)
Pediatric Allergy in Asia (APAPARI) Starting 1998 HR Lee SI Lee Morikawa Chen KH Hseih JL Huang P Vichyanond A Tam G Wong J Debruyn BW Lee H Van Bever S Siregar M Bautista
APAPARI – JACIN MEETING, JAKARTA – APRIL 2006
APAPARI - Education 1. Joint meetings with Allergy Societies - 2002: Japan (Tokyo) - 2003: Singapore (workshop) - 2004: Hong Kong (IPRAIC) - 2005: S-Korea (Seoul) - 2006: Indonesia (Jakarta) - 2007: Philippines (Manila) & WAO (Bangkok) - 2008: Singapore (SPS – Oct 2008) 2. Training courses on pediatric allergy - 2006: Jakarta (Indonesia) / Balikpapan (Borneo) - 2007: Phom Penh (Cambodia) / Jakarta / Ho Chi Minh (Vietnam) - 2008: Hanoi (Vietnam)
Vietnamese studies on paediatric allergy - ISAAC-based asthma and atopic symptoms among Hanoi school children. Nga NN et al. Pediatr Allergy Immunol 2003, 14, 272 -9. - Obesity is associated with increased risk of allergy in Vietnamese adolescents. Irei V et al. Eur J Clin Nutr 2005, 59, 571 -7. - Poor sanitation and helminth infection protect against skin sensitization in Vietnamese children: a cross-sectional study. Flohr C, et val. J Allergy Clin Immunol 2006, 118, 1305 – 11. - Prevalence of asthma and asthma-like symptoms in Dalat Highlands, Vietnam. Sing Med J 2007, 48, 294 – 303.
ISAAC-based asthma and atopic symptoms among Hanoi school children. Nga NN et al. Pediatr Allergy Immunol 2003, 14, 272 -9. - Hanoi -cross-sectional study -5 -11 year-old -Response rate 66. 4% - 969 responders
Cumulative prevalence of asthma, rhinitis and eczema in Singaporean children. 1 - 2 yrs-old 2002 -2003 4 - 6 yrs-old 2000 6 – 7 yrs-old 2001 12 – 15 yr-old 2001
Increase in prevalence of allergic diseases changes in the environment Induction of the expression of allergy HYGIENE HYPOTHESIS - asthma - rhinitis - eczema
Allergy = a feature and NOT a disease ! = … the ability to produce specific antibodies (Ig. E) to different substances of the environment (inhalant and food allergens)… Ig. E inflammation shock organs = swelling - narrowing symptoms
Allergic diseases … eczema healthy enteritis asthma ALLERGY rhinitis urticaria conjunctivitis migraine
Positive skin tests in 273 HEALTHY children at the age 6 -7 years (Belgium - 1996). ALLERGEN n % - HDM 21 8% - Cat dander 6 2% - Birch pollen 1 0% - Grass pollen 8 3% - ANY 29 11 %
Allergy, one feature with many faces AIRWAYS SKIN
Allergic diseases … mild to … severe
“ The Allergic March “
Environmental substances = allergens (proteins…) 1. Inhalant allergens house dust mites, pollen pets, moulds 2. Food allergens egg, cow’s milk, soy, wheat peanuts, fish, shrimp, etc… ( < 3 yrs) (> 3 yrs)
Contact with food allergens v eating – drinking v touching v smelling v breast milk - prenatal
Food allergens in house dust. Witteman AM, van Leeuwen J, van der Zee J, Aalberse RC. Int Arch Allergy Immunol. 1995 Aug; 107(4): 566 -8. microgr/g dust 10 1 0. 01 ovomucoid b-lactoglobulin The amount of ovomucoid and b-lactoglobulin in 11 house dust samples 0. 073 microg/g dust = detection limit ovomucoid 0. 016 microg/g dust = detection limit b-lactoglobulin
“ Kiss of death “ q 5% of adults with food allergy q Foods: peanuts, apple, pea, fish q Relationship: husband, boyfriend, etc. Hallett et al, NEJM 2002, 346, 1833
House Dust Mites Blomia tropicalis Dermatophagoides farinae
Asthma Rhinitis Eczema
House Dust Mites in Singapore • High temp and humidity provides perfect environment for HDMs • High counts (> 100 mites/g dust) of HDM are isolated in Singapore • A wide variety of mite species is isolated other than Dermatophagoides. • Blomia tropicalis is predominant.
Mite Species Present in Singaporean Mattresses Species B. tropicalis D. pteronyssinus S. brasiliensis T. granarius D. farinae A. malaysiensis C. malaccensis M. intermedius % (n = 50) 94 80 84 44 26 20 24 12 Chew FT 1999 Clin Exp Allergy 29: 201 -206
Allergic diseases 1. GENETIC CONSTITUTION 2. ENVIRONMENT - Prenatal (pregnancy) - Postnatal (first months of life)
Genetic constitution Parents 1. both are negative 2. mother negative – father positive 3. mother positive – father negative 4. both positive 5. both strongly positive Risk 18 % 40 % 50 % 70 % 90 %
Allergic diseases 1. GENETIC CONSTITUTION 2. ENVIRONMENT - Prenatal (pregnancy) - Postnatal (first months of life)
Direction of immune responses in early life allergic profile (Th 2 predominance) Allergic (Th 2) Birth Factors 1. constitution 2. bacterial load 3. allergen exposure Non-allergic (Th 1)
ATOPY = inbalance Th 1 Th 2 Th 3 regulatory T cells IL-10, TGF-b
T helper lymphocytes Modified from S. Romagnani CEA, 36, 1357– 1366
Roles of T cells / Allergic disease Orihara, Kanami et al. , WAO 2008
Postnatal immune deviation from allergic (Th 2) to non-allergic (Th 1) POSITIVE 1. Increased bacterial load - family size, farming - day care attendance - probiotics (Lactobacillus sp. ) prebiotics, etc. 2. Tolerance through high exposure to allergens (pets – other allergens) NEGATIVE 1. House dust mite – pollen (low doses) 2. RSV 3. Pollution (DEPs – cigarette) 4. Antibiotics - paracetamol
Diagnosis of allergy 1. History 2. Clinical examination 3. SPT = golden standard ! 4. Specific Ig. E 5. Other lab tests: ECP, cytokines, etc… 6. e. NO 7. Allergen provocation test (nasal, bronchial, etc…)
Unproven diagnostic tests for allergy… - Ig. G against everything you can dream - Electrodermal tests (“ Bioreasonance tests “) - Other “witchcraft” (“ Kinesiology ”)
APPLIED KINESIOLOGY
Skin prick testing = golden standard for diagnosing allergy in children & adults
- Slides: 37