Food and Respiratory Allergy in Ghana Insights from population studies among children

Transcription

1 Food and Respiratory Allergy in Ghana Insights from population studies among children Abena S. Amoah Parasitology Department, Noguchi Memorial Institute for Medical Research, Accra, Ghana Parasitology Department, Leiden University Medical Center, Leiden, The Netherlands

2 P r e v a le n c e o f E IB (% ) P re v a le n c e o f S P T re a c tiv ity ( % ) Background: Allergies in Ghana Studies indicate that allergies are on the rise in Ghana Two surveys conducted 10 years apart in children (aged 9-16 years) in one area showed an increase in markers of allergy Exercise-Induced Bronchospasm Skin Prick Test Reactivity 1 5 p = p < Addo-Yobo et al, Plos Med 2007

3 P r e v a le n c e o f E IB (% ) P re v a le n c e o f S P T re a c tiv ity ( % ) Urban-rural differences in allergy outcomes Distinct urban-rural differences in allergy outcomes Within urban area differences in allergy outcomes based on socioeconomic status Exercise-Induced Bronchospasm Skin Prick Test Reactivity Data R u r a l U r b a n P o o r U r b a n R ic h 0 R u r a l U r b a n P o o r U r b a n R ic h Addo-Yobo et al., Plos Med 2007

4 Factors associated with the rural to urban gradient in allergy RURAL URBAN POOR URBAN RICH DECREASE IN INFECTION INCREASE IN POLLUTION INCREASE IN ALLERGY DIETARY CHANGES (RURAL DIET TO FAST-FOOD) Adapted from van Ree and Yazdanbakhsh, 2007

5 Objectives i. To determine urban-rural differences in the prevalence of aero-allergy in Southern Ghana ii. To determine urban-rural differences in the prevalence of food allergy in Southern Ghana iii. To examine associations between parasitic worm infections and allergy outcomes

6 Study area and population Greater Accra Region School-based cross-sectional study 13 Schools 8 Rural 5 Urban Target age-range: 5-16 years N= 2,331 recruited

7 Study Methodology: Allergic sensitization based on serum-specific IgE levels ImmunoCap /RAST Sensitization cut-off : >0.35 ku/l Allergen-specific IgE Mite (Der p) Cockroach (Bla g) Peanut (Ara h)

8 Study Methodology: Allergic sensitization by skin prick testing Allergen panel Aero-allergens Skin prick test positivity cut-off Average wheal size > 3mm Food Allergens

9 Study Methodology: Reported Symptoms Standardized questionnaire administered to parents or guardians of study subjects Symptoms of asthma & other allergic disorders: Adapted from the International Study of Asthma and Allergies in Childhood Weinmayr et al, Allergy 2010 Weinmayr et al, Eur Respir J 2008 Symptoms of adverse reactions to food: Adapted from EuroPrevall study Kummeling et al, Allergy 2009 Wong et al, Allergy 2009 Mills et al, Allergy 2007 Demographic and socioeconomic parameters

10 Study Methodology: Parasitological assessment Urine Stool Urine filtration Kato-Katz S. haematobium Intestinal helminths

11 S p e c ific Ig E > k U /L S k in P r ic k T e s t (W h e a l S iz e > 3 m m ) P re v a le n c e (% ) P re v a le n c e (% ) Results: Aero-allergy outcomes stratified by area (N=1385) * * * * * * M ite C o c k r o a c h P re v a le n c e (% ) M ite * * * C o c k r o a c h * p <0.05 ** p <0.01 *** p<0.001 S p e c ific Ig E A lle rg en 5 0 R e s p ir a to r y S y m p to m s (Y e s ) * * 0 W h e e z e (1 2 m o n th s ) A s th m a S y m p to m s

12 Worm infection and Skin Prick Test reactivity M IT E S P T C O C K R O A C H S P T S c h is to s o m a (+ v s -) * In te s tin a l H e lm in th (+ v s -) A d ju s te d O d d s R a tio (9 5 % C I) A d ju s te d O d d s R a tio (9 5 % C I) Logistic regression models adjusted for age, gender and area Wald s Test : * P<0.05

13 Worm infection and respiratory allergy symptoms W H E E Z E (1 2 m o n th s ) A S T H M A (E V E R ) S c h is to s o m a (+ v s -) In te s tin a l H e lm in th (+ v s -) A d ju s te d O d d s R a tio (9 5 % C I) A d ju s te d O d d s R a tio (9 5 % C I) Logistic regression models adjusted for age, gender and area Wald s Test : * P<0.05

14 Reported adverse reactions to food (N=1407) All children Rural children Urban children

15 Reported symptoms of adverse reactions to food (N=1407) All children Rural children Urban children 1 Tingling/swelling = swelling of the mouth, lips or throat 2 Rash/itch = itching of the skin including nettle sting-like rash

16 Ghana and peanuts (groundnuts) High peanut consumption Relatively few reports of adverse reactions to peanut Lack of avoidance of peanuts during pregnancy Early introduction of peanut as part of weaning foods

17 P r e v a le n c e (% ) Peanut allergy outcomes among urban and rural children in Ghana S p e c ific Ig E S k in P r ic k T e s t R e p o r te d S y m p to m s > k U /L > 3 m m (Y e s ) 2 5 N = * * * N = N = * p <0.05 ** p <0.01 *** p< * R U R AL U R B AN R U R AL U R B AN R U R AL U R B AN 0.6 P e a n u t A lle rg y O u tc o m e s

18 P e r c e n ta g e (% ) Subjects reporting adverse reactions to peanut (N=21) R e p o r te d P e a n u t S y m p to m s (N = 2 1 ) 6 0 R e a c tio n tim e fo llo w in g in g e s tio n (N = 2 1 ) D ia r r h o e a /V o m itin g Itc h in g /T in g lin g M o u th 4 0 H e a d a c h e s S tiffn e s s in jo in ts 2 0 R u n n y /s tu ffy n o s e R e d /s o r e /r u n n y e y e s 0 M in u te s H o u r s D a y s R e a c tio n T im e D iffic u lty s w a llo w in g B r e a th le s s n e s s F a in tin g / D iz z in e s s R a s h /Itc h P e rc e n ta g e (% )

19 Peanut allergy outcomes (complete data, N=1004) Peanut Specific IgE IgE ImmunoCap Peanut SPT Reactivity Cut-off : >0.35 Ku/L Cut-off : > 3mm Reported Symptoms to Peanut Questionnaire

20 Worm infection and peanut-specific IgE sensitization P e a n u t-s p e c ific Ig E > k u /L S. h a e m a to b iu m ( + v s. - ) * * * In t. h e lm in th ( + v s. - ) A d ju s te d O d d s R a tio (9 5 % C I) Logistic regression model adjusted for age, gender and area Wald s Test : *** P<0.001

21 S p e c ific I g E k U /L Peanut-specific IgE: recombinant peanut allergen responses Additional sera measurements in a subset (N=43): Specific IgE responses to purified peanut allergens Ara h 1, 2, 3 (seed storage proteins) Recombinant non-glycosylated allergen produced in an E. coli strain N = k U /L P e a n u t r A r a h 1 r A r a h 2 r A r a h 3 A lle r g e n s

22 S p e c ific I g E k U /L Peanut-specific IgE: Cross-reactive carbohydrate determinants Additional sera measurements in a subset (N=43) Specific IgE responses to bromelain as a marker of cross-reactive carbohydrate determinants (CCDs) which are carbohydrate epitopes on glycoproteins N = k U /L P e a n u t C C D A lle r g e n s

23 N-glycan induced IgE cross-reactivity P e a n u t-sp e c ific I g E (k U /L ) r = 0.8 9, p < Indications of the presence of IgE recognizing epitopes common to both peanut and bromelain Possible cross-reactivity due to N-glycan epitopes commonly found in plants and helminths C C D -s p e c ific Ig E (k U /L ) Core β(1,2)-xylose Core α(1,3)-fucose

24 % In h ib itio n % In h ib itio n Inhibition of IgE binding to peanut by bromelain & Schistosoma SEA A B C C D M a rk e r: B ro m e la in S c h is to s o m a E g g A n tig e n B ro m e la in (µ g ) S. h a e m a to b iu m S o lu b le E g g A n tig e n (µ g ) More than 80% inhibition with both bromelain and Schistosoma soluble egg antigen High levels of peanut-specific IgE as a result of carbohydrate crossreactivity

25 S p e c ific I g E k U /L Peanut-specific IgE: responses to recombinant Ara h 9 Additional sera measurements in a subset (N=43) Specific IgE responses to purified peanut allergen Ara h 9 (lipid transfer protein) Recombinant non-glycosylated allergen produced in an E. coli strain N = k U /L P e a n u t r A r a h 9 A lle r g e n s

26 Source: Ronald van Ree Stripped basophil histamine release assay Basophils from Dutch non-atopic donor Stripped basophils from Dutch non-atopic donor Basophils re-sensitized with IgE from Ghanaian donor and then stimulated with an allergen lactic acid treatment: removal of IgE incubation with serum: sensitization with IgE

27 Basophil histamine release- Ara h 9 & whole peanut Donor #1 Donor #2 ID AB051 ID GR211 Area RURAL Area URBAN IgE to whole peanut IgE to CCD 40.2 ku/l 1.8 ku/l IgE to whole peanut IgE to CCD 21.0 ku/l 4.9 ku/l IgE to rara h ku/l IgE to rara h ku/l

28 H is ta m in e re le a s e (% ) Basophil histamine release- Ara h 9 & whole peanut A B G R A ra h A ra h 9 W h o le P e a n u t W h o le P e a n u t H is ta m in e re le a s e (% ) A lle rg e n ( g /m l) A lle rg e n ( g /m l) IgE to whole peanut 40.2 ku/l IgE to CCD 1.8 ku/l IgE to rara h ku/l SPT to peanut - Reported Symptoms Yes IgE to whole peanut 21.0 ku/l IgE to CCD 4.9 ku/l IgE to rara h ku/l SPT to peanut + Reported Symptoms No

29 Conclusions Significant urban-rural differences in allergy outcomes Schistosoma infection negatively associated with mite SPT reactivity Indications of a protective effect High levels of allergen-specific IgE as a result of carbohydrate cross-reactivity Possible helminth involvement in inducing cross-reactivity Little evidence of IgE-mediated peanut allergy Biologically active IgE to Ara h 9 observed Factors associated with Ara h 9 sensitization in Ghana are currently unknown

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31 Acknowledgements Leiden University Medical Center Maria Yazdanbakhsh Yvonne Kruize Benedicta Obeng Franca Hartgers Firdaus Hamid Hae-Won Uh (MSTAT) Academic Medical Center Ronald van Ree Serge Versteeg Jaap Akkerdaas Laurian Zuidmeer-Jongejan Hospital Clinico San Carlos Montserrat Fernández-Rivas Noguchi Memorial Institute for Medical Research Daniel Boakye Irene Larbi Yvonne Aryeetey Elias Asuming-Brempong William van der Puije Dziedzom de Souza Richard Akuffo National Service Personnel FUNDING: London School of Hygiene & Tropical Medicine Laura Rodrigues Thermo Fisher Scientific Jonas Lidholm

32 Thank You