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Atopic dermatitis is strongly associated with IgE-mediated food allergy in infants attending a dermatology department
S100 Abstracts
A New 67 kDa Recombinant Aedes aegypti Salivary Allergen rAed a 4 in the Diagnosis of Mosquito Allergy Li, A. N. Beckett1, F. E. R. Simons2, C. Li1, T. Zhang1, Z. Peng3; 1University of Manitoba, Winnipeg, MB, CANADA, 2Pediatics, University of Manitoba, Winnipeg, MB, CANADA, 3Pediatics and Immunology, University of Manitoba, Winnipeg, MB, CANADA. RATIONALE: Accurate diagnosis of mosquito allergy has been hampered by the labourious task of obtaining mosquito salivary allergens. We previously studied 3 recombinant Aedes aegypti salivary allergens (rAed a 1, rAed a 2, and rAed a 3), and wanted to express, purify and characterize another allergen, a 67 kDa alpha-glucosidase, Aed a 4. METHODS: rAed a 4 was expressed using a baculovirus/insect cell system, purified by a combination of anion- and cation-exchange chromatography, and identified by immunoblotting. Aedes aegypti saliva extract was prepared in our laboratory. An indirect enzyme-linked immunosorbent assay (ELISA) was developed to measure rAed a 4and mosquito saliva-specific IgE antibodies in sera from 25 individuals with allergic reactions to mosquito bites. Twenty controls had no history of mosquito allergy and negative bite tests from laboratory-reared mosquitos. RESULTS: Purified rAed a 4 bound to the IgE in mosquito-allergic sera, as detected by ELISA and immunoblotting. The binding of rAed a 4 to IgE could be inhibited in a dose-dependent manner by addition of an Aedes aegypti extract. Using the mean of the controls plus 1.5 SD as a cut-off level, the positivity of rAed a 4 specific-IgE was 36% in the allergic sera and 10% in the controls (p < 0.01), and that of saliva specific-IgE was 84% and 5% in the allergics and controls, respectively. CONCLUSIONS: rAed a 4 is identical to natural Aed a 4. Along with rAed a 1, rAed a 2, and rAed a 3, it is useful in the diagnosis of mosquito allergy. Funding: CIHR
399
SUNDAY
Serum Thymus and Activation-Regulated Chemokine (TARC) and Cutaneous T Cell-Attracting Chemokine (CTACK) Levels as Markers of Disease Activity in Childhood Atopic Dermatitis T. Song, Y. Shin, B. Kwon, S. Choi, M. Sohn, K. Kim; Pediatrics and Institute of Allergy, Yonsei University College of Medicine, Seoul, REPUBLIC OF KOREA. RATIONALE: Thymus and activation-regulated chemokine(TARC) and cutaneous T cell-attracting chemokine(CTACK) are responsible for the trafficking of Th2 lymphocytes into sites of allergic inflammation. We tested whether these cytokines are useful markers for childhood atopic dermatitis. METHODS: Serum TARC and CTACK levels, serum total IgE level, TEC, platelet count, sepcific IgE level were measured in 401 children. They were characterized as having IgE-mediated atopic dermatitis(n=157), non IgE-mediated atopic dermatitis(n=107), or as healthy control subjects(n=137). RESULTS: Both TARC and CTACK levels in AD significantly higher than those in healthy control subjects(152.9±187.8 vs 56.7±60.7, 2861.1 vs 2022.7 pg/ml, p=0.00). CTARK levels in Ig-E mediated AD are significantly higher than those in non IgE mediated subjects(3051.3±1993.3 vs 2582.0±2042.3 pg/ml, p=0.01). Serum TARC and CTACK levels significantly correlated with disease activity in children with AD(p<0.05). Serum TARC and CTACK levels show significantly correlations with total IgE level(r=0.327, r=0.271)(p<0.05), total eosinophil counts(r=0.134, r=0.141)(p<0.05) and platelet counts(r=0.173, r=0.017)(p<0.05). Serum TARC levels significantly correlated with serum CTACK levels(r=0.410, p=0.00). CONCLUSIONS: Serum TARC and CTACK levels are obsective parameters for disease severity for childhood atopic dermatitis.
400
J ALLERGY CLIN IMMUNOL FEBRUARY 2005
Titres of IgE ab to Mite and Cat Allergens in Patients With Asthma or Atopic Dermatitis: Use of Streptavidin CAP N. J. Custis1, E. A. Erwin1, J. A. Woodfolk1, J. Crane2, K. Wickens2, T. A. E. Platts-Mills1; 1University of Virginia, Charlottesville, VA, 2Wellington School of Medicine and Health Sciences, Wellington, NEW ZEALAND. RATIONALE: To use the Streptavidin CAP method to investigate the relationship between IgE ab and total IgE. METHODS: Streptavidin coupled to a high-capacity immunosorbent (CAP) was used to bind biotinylated purified allergens from mite (Der p 1 and Der p 2), cat (Fel d 1), and dog (Can f 1). IgE ab to these allergens was measured in 199 sera from children living in New Zealand as well as adults with atopic dermatitis (AD) seen at the University of Virginia. The results were validated by serial dilution of sera with high and low levels of IgE ab and were quantified in IU/ml using a standard curve. RESULTS: Values for IgE ab to Der p 1, Der p 2, and Fel d 1 correlated with values measured by conventional CAP assay (r2 = 0.80, 0.83, and 0.95 respectively; p< 0.001 in each case). Furthermore, the values for IgE ab in sera from children with high exposure to mite and cat allergens demonstrated ten fold higher levels of IgE ab to Der p 1 and Der p 2 than to Fel d 1 (p<0.001). IgE ab to purified allergens can represent >10% of the total IgE in both AD and asthma. CONCLUSIONS: The results confirm major differences in the quantities of IgE ab specific for mite and cat allergens among children with high exposure to both allergens. In addition, the results provide evidence about the high quantities of IgE ab to purified inhalant allergens in patients with AD or asthma. Funding: NIH
401
Atopic Dermatitis Is Strongly Associated With IgE-Mediated Food Allergy in Infants Attending a Dermatology Department D. J. Hill1, R. G. Heine1, C. S. Hosking1, J. C. Su2, G. A. Varigos2, J. B. Carlin3; 1Dept of Allergy, Royal Children’s Hospital, Melbourne, Victoria, AUSTRALIA, 2Dept of Dermatology, Royal Children’s Hospital, Melbourne, Victoria, AUSTRALIA, 3Clinical Epidemiology and Biostatistics Unit, Royal Children’s Hospital, Melbourne, Victoria, AUSTRALIA. RATIONALE: Ten per cent of infants have atopic dermatitis (AD) of moderate severity. IgE-mediated food allergy (FA) is reportedly higher in patients referred to allergy clinics compared to dermatology cohorts. METHODS: We prospectively studied the prevalence of FA in 51 consecutive infants (mean age 8.1 mo, range 5-12 mo; 39 M, 12 F) with moderate AD attending the Dermatology Department at this university-affiliated pediatric teaching hospital. A clinical history was taken and AD severity assessed by SCORAD. Skin prick testing (SPT) was performed in all infants, and in 39 food-specific IgE serum antibodies measured by CAP-system FEIA (Pharmacia, Uppsala, Sweden). FA was diagnosed if the SPT or CAP-FEIA level to cow milk, egg or peanut exceeded the reference >95%-positive predictive cut-off values for positive challenges. RESULTS: The mean age of onset of AD was 12.0±7.8 weeks. Thirtyone (61%) of infants were exclusively breast-fed at onset of AD; two (4%) reported a FA reaction (egg, peanut) prior to referral. The mean SCORAD at enrolment was 17.7±11.6 (range 0-48). Based on SPT, 43/51 infants (84%, 95% confidence interval 71%-93%) had evidence of FA (cow milk 16%, egg 72%, peanut 51%); 2 additional infants initially FA-negative were FA-positive within 12 months. CAP-system FEIA identified 33/39 infants (85%, 95% confidence interval 69%-94%) with FA (cow milk 22%, egg 82%, peanut 23%). Forty-six (90%) infants were found allergic to at least one food item by either SPT or CAP system-FEIA. CONCLUSIONS: AD was strongly associated with IgE-mediated FA in infants referred to a Dermatology Department.
402
A New 67 kDa Recombinant Aedes aegypti Salivary Allergen rAed a 4 in the Diagnosis of Mosquito Allergy Li, A. N. Beckett1, F. E. R. Simons2, C. Li1, T. Zhang1, Z. Peng3; 1University of Manitoba, Winnipeg, MB, CANADA, 2Pediatics, University of Manitoba, Winnipeg, MB, CANADA, 3Pediatics and Immunology, University of Manitoba, Winnipeg, MB, CANADA. RATIONALE: Accurate diagnosis of mosquito allergy has been hampered by the labourious task of obtaining mosquito salivary allergens. We previously studied 3 recombinant Aedes aegypti salivary allergens (rAed a 1, rAed a 2, and rAed a 3), and wanted to express, purify and characterize another allergen, a 67 kDa alpha-glucosidase, Aed a 4. METHODS: rAed a 4 was expressed using a baculovirus/insect cell system, purified by a combination of anion- and cation-exchange chromatography, and identified by immunoblotting. Aedes aegypti saliva extract was prepared in our laboratory. An indirect enzyme-linked immunosorbent assay (ELISA) was developed to measure rAed a 4and mosquito saliva-specific IgE antibodies in sera from 25 individuals with allergic reactions to mosquito bites. Twenty controls had no history of mosquito allergy and negative bite tests from laboratory-reared mosquitos. RESULTS: Purified rAed a 4 bound to the IgE in mosquito-allergic sera, as detected by ELISA and immunoblotting. The binding of rAed a 4 to IgE could be inhibited in a dose-dependent manner by addition of an Aedes aegypti extract. Using the mean of the controls plus 1.5 SD as a cut-off level, the positivity of rAed a 4 specific-IgE was 36% in the allergic sera and 10% in the controls (p < 0.01), and that of saliva specific-IgE was 84% and 5% in the allergics and controls, respectively. CONCLUSIONS: rAed a 4 is identical to natural Aed a 4. Along with rAed a 1, rAed a 2, and rAed a 3, it is useful in the diagnosis of mosquito allergy. Funding: CIHR
399
SUNDAY
Serum Thymus and Activation-Regulated Chemokine (TARC) and Cutaneous T Cell-Attracting Chemokine (CTACK) Levels as Markers of Disease Activity in Childhood Atopic Dermatitis T. Song, Y. Shin, B. Kwon, S. Choi, M. Sohn, K. Kim; Pediatrics and Institute of Allergy, Yonsei University College of Medicine, Seoul, REPUBLIC OF KOREA. RATIONALE: Thymus and activation-regulated chemokine(TARC) and cutaneous T cell-attracting chemokine(CTACK) are responsible for the trafficking of Th2 lymphocytes into sites of allergic inflammation. We tested whether these cytokines are useful markers for childhood atopic dermatitis. METHODS: Serum TARC and CTACK levels, serum total IgE level, TEC, platelet count, sepcific IgE level were measured in 401 children. They were characterized as having IgE-mediated atopic dermatitis(n=157), non IgE-mediated atopic dermatitis(n=107), or as healthy control subjects(n=137). RESULTS: Both TARC and CTACK levels in AD significantly higher than those in healthy control subjects(152.9±187.8 vs 56.7±60.7, 2861.1 vs 2022.7 pg/ml, p=0.00). CTARK levels in Ig-E mediated AD are significantly higher than those in non IgE mediated subjects(3051.3±1993.3 vs 2582.0±2042.3 pg/ml, p=0.01). Serum TARC and CTACK levels significantly correlated with disease activity in children with AD(p<0.05). Serum TARC and CTACK levels show significantly correlations with total IgE level(r=0.327, r=0.271)(p<0.05), total eosinophil counts(r=0.134, r=0.141)(p<0.05) and platelet counts(r=0.173, r=0.017)(p<0.05). Serum TARC levels significantly correlated with serum CTACK levels(r=0.410, p=0.00). CONCLUSIONS: Serum TARC and CTACK levels are obsective parameters for disease severity for childhood atopic dermatitis.
400
J ALLERGY CLIN IMMUNOL FEBRUARY 2005
Titres of IgE ab to Mite and Cat Allergens in Patients With Asthma or Atopic Dermatitis: Use of Streptavidin CAP N. J. Custis1, E. A. Erwin1, J. A. Woodfolk1, J. Crane2, K. Wickens2, T. A. E. Platts-Mills1; 1University of Virginia, Charlottesville, VA, 2Wellington School of Medicine and Health Sciences, Wellington, NEW ZEALAND. RATIONALE: To use the Streptavidin CAP method to investigate the relationship between IgE ab and total IgE. METHODS: Streptavidin coupled to a high-capacity immunosorbent (CAP) was used to bind biotinylated purified allergens from mite (Der p 1 and Der p 2), cat (Fel d 1), and dog (Can f 1). IgE ab to these allergens was measured in 199 sera from children living in New Zealand as well as adults with atopic dermatitis (AD) seen at the University of Virginia. The results were validated by serial dilution of sera with high and low levels of IgE ab and were quantified in IU/ml using a standard curve. RESULTS: Values for IgE ab to Der p 1, Der p 2, and Fel d 1 correlated with values measured by conventional CAP assay (r2 = 0.80, 0.83, and 0.95 respectively; p< 0.001 in each case). Furthermore, the values for IgE ab in sera from children with high exposure to mite and cat allergens demonstrated ten fold higher levels of IgE ab to Der p 1 and Der p 2 than to Fel d 1 (p<0.001). IgE ab to purified allergens can represent >10% of the total IgE in both AD and asthma. CONCLUSIONS: The results confirm major differences in the quantities of IgE ab specific for mite and cat allergens among children with high exposure to both allergens. In addition, the results provide evidence about the high quantities of IgE ab to purified inhalant allergens in patients with AD or asthma. Funding: NIH
401
Atopic Dermatitis Is Strongly Associated With IgE-Mediated Food Allergy in Infants Attending a Dermatology Department D. J. Hill1, R. G. Heine1, C. S. Hosking1, J. C. Su2, G. A. Varigos2, J. B. Carlin3; 1Dept of Allergy, Royal Children’s Hospital, Melbourne, Victoria, AUSTRALIA, 2Dept of Dermatology, Royal Children’s Hospital, Melbourne, Victoria, AUSTRALIA, 3Clinical Epidemiology and Biostatistics Unit, Royal Children’s Hospital, Melbourne, Victoria, AUSTRALIA. RATIONALE: Ten per cent of infants have atopic dermatitis (AD) of moderate severity. IgE-mediated food allergy (FA) is reportedly higher in patients referred to allergy clinics compared to dermatology cohorts. METHODS: We prospectively studied the prevalence of FA in 51 consecutive infants (mean age 8.1 mo, range 5-12 mo; 39 M, 12 F) with moderate AD attending the Dermatology Department at this university-affiliated pediatric teaching hospital. A clinical history was taken and AD severity assessed by SCORAD. Skin prick testing (SPT) was performed in all infants, and in 39 food-specific IgE serum antibodies measured by CAP-system FEIA (Pharmacia, Uppsala, Sweden). FA was diagnosed if the SPT or CAP-FEIA level to cow milk, egg or peanut exceeded the reference >95%-positive predictive cut-off values for positive challenges. RESULTS: The mean age of onset of AD was 12.0±7.8 weeks. Thirtyone (61%) of infants were exclusively breast-fed at onset of AD; two (4%) reported a FA reaction (egg, peanut) prior to referral. The mean SCORAD at enrolment was 17.7±11.6 (range 0-48). Based on SPT, 43/51 infants (84%, 95% confidence interval 71%-93%) had evidence of FA (cow milk 16%, egg 72%, peanut 51%); 2 additional infants initially FA-negative were FA-positive within 12 months. CAP-system FEIA identified 33/39 infants (85%, 95% confidence interval 69%-94%) with FA (cow milk 22%, egg 82%, peanut 23%). Forty-six (90%) infants were found allergic to at least one food item by either SPT or CAP system-FEIA. CONCLUSIONS: AD was strongly associated with IgE-mediated FA in infants referred to a Dermatology Department.
402