- Email: [email protected]
Importance of Antigen Selection in the Detection of Autoantibodies against FcεRIα in Chronic Urticaria Patients
AB30 Abstracts
SATURDAY
116
Repeat Epinephrine Treatments For Stinging Insect Hypersensitivity Reactions Presenting To The Emergency Department S. A. Rudders1, D. P. Katzman2, A. Banerji2, S. Clark3, C. A. Camargo, Jr.2; 1Children’s Hospital Boston, Boston, MA, 2Massachusetts General Hospital, Boston, MA, 3University of Pittsburgh, Pittsburgh, PA. RATIONALE: There are sparse data on epinephrine treatment for stinging insect hypersensitivity (SIH) reactions. We sought to establish the frequency of receiving >1 dose of epinephrine in patients presenting to the emergency department (ED) with SIH reactions. METHODS: We performed a medical record review of all 155 patients with SIH reactions presenting to three Boston EDs between 1/1/01 and 12/31/06. Patients were identified by ICD9 codes 989.5, 995.0, 995.1 and 995.3. We focused on presentations and treatments, including the number of epinephrine treatments given before and during the ED visit. RESULTS: The cohort was 54% male and 71% white, with a median age of 33 years. A variety of insects triggered the reactions, especially bees (74%). 58% of patients were classified as local reactions, while 37% had systemic reactions (10% cutaneous systemic and 27% anaphylaxis). Among patients with systemic reactions, 83% were stung within 3 hours of ED arrival. Among those receiving treatments before ED arrival, 44% received epinephrine. While in the ED, patients with systemic reactions received antihistamines (77%), systemic corticosteroids (56%), and epinephrine (9%). Over the course of their reaction, 33% received epinephrine and among this subset, 16% received 2+ doses. Most patients with systemic reactions (68%) were discharged to home. At ED discharge, 67% received a prescription for self-injectable epinephrine and 13% had documentation of referral to an allergist. CONCLUSIONS: 16% of patients who receive epinephrine for a systemic SIH reaction require multiple doses. Further study is needed to identify risk factors for repeat epinephrine use.
117
Collateral Allergy: If You Don't Ask, They Won't Tell J. J. Dietrich1, R. W. England2; 1David Grant Medical Center, Travis AFB, CA, 2Wilford Hall Medical Center, Lackland AFB, CA. RATIONALE: Food allergy, stinging insect allergy, and latex allergy can all lead to potentially life threatening allergic reactions. Although AAAAI consultation and referral guidelines recommend patients with these conditions be referred to an allergist/immunologist for further evaluation and management, patients are often not referred. METHODS: We performed a retrospective medical record review of outpatient allergy/immunology (A/I) consults received at our institution from January 1, 2006 through December 31, 2006. We calculated the number of evaluations for food, insect, and latex allergy which were specifically requested in the consult. We compared this to the number of evaluations for these diagnoses which were neither requested in the consult nor previously evaluated, but which had an evaluation initiated by the allergist/immunologist after he or she identified the problem through a complete allergy history. RESULTS: Although not specifically requested in the consult, a thorough history obtained by the allergist/immunologist initiated 26.3% (70/266) of the total food allergy evaluations, 34.9% (38/109) of stinging insect allergy evaluations, and 46.9% (15/32) of latex allergy evaluations. Additionally, 2.8% (38/1341) of all patients presenting to our A/I clinic for reasons other than insect hypersensitivity gave a history of a systemic reaction to an insect sting which had not been evaluated previously. CONCLUSIONS: These results demonstrate that a large proportion of patients with possible food, insect, or latex allergy can be identified by means of a comprehensive allergy history. Inquiring about these collateral allergies can ensure proper evaluation, education, avoidance, and treatment are implemented for these potentially life threatening conditions.
J ALLERGY CLIN IMMUNOL FEBRUARY 2010
118
Importance of Antigen Selection in the Detection of Autoantibodies against FceRIa in Chronic Urticaria Patients M. Ling, J. Ge, M. L. Altrich, J. F. Halsey; IBT Laboratories, Lenexa, KS. RATIONALE: Among some chronic urticaria (CU) patients, an autoimmune etiology exists with auto-antibodies against FceRIa, IgE, or FceRII. Various methods including both binding and functional assays to detect autoantibodies against FceRIa have been reported. In some binding methods, a relatively high prevalence of autoantibodies in non-CU patients were reported. Therefore, we investigated the specificity of these binding reactions. METHODS: ELISA methods were evaluated to detect IgG antibodies to FceRIa. Multiple sources of FceRIa including recombinant proteins purified from High-Fiveä insect cell, E. Coli, and peptide mixes were evaluated as an antigen. The assay specificity was evaluated by inhibition experiments. RESULTS: The recombinant protein from insect cells appeared to be extensively glycosylated as it was 40 kDa compared to 22 kDa for the bacterial recombinant protein on a SDS-PAGE. In an ELISA method using the H-F recombinant protein, binding antibodies were detected in sera from both CU and non-CU patients. However this binding could be inhibited by a control H-F. lysate (inhibition ranged 60-95%) as well as the purified protein. In contrast, ELISAs using a bacterially prepared protein or peptide mixes showed good specificity. Inhibition with the control E. coli lysate was < 20% while that with the recombinant protein was >80%. The glycosylation of the recombinant protein may have significantly altered its conformation relative to the native FceRIa protein. CONCLUSIONS: Recombinant FceRIa antigen produced in High Five insect cells carry glycosylation motifs that appear immunogenic in a large proportion of humans, thus reducing the method’s specificity.
119
Dust Mite Allergen Reduction Study A. K. Haynes1, M. Sever1, P. W. Crockett2, R. Jaramillo2, A. Zombeck2, R. Crohn2, D. Zeldin1; 1National Institute of Environmental Health Sciences, Research Triangle Park, NC, 2SRA International, Durham, NC. RATIONALE: Asthmatics are encouraged to employ interventions to reduce exposure to indoor allergens, but often lack objective evidence to confirm the efficacy of their efforts. In-home test kits and education may influence dust mite allergen reduction. METHODS: This randomized controlled trial enrolled 60 households of children aged 5-15 years with parent-reported dust mite allergy and allergen concentrations 2mg/g in the child’s bedroom. The intervention group (N 5 30) received educational materials and in-home dust mite test kits at baseline, 1, 2, 5, and 8 months. The control group (N 5 30) received only educational materials. Nonparametric sign tests were performed to determine the likelihood of mite levels decreasing vs. increasing. RESULTS: At baseline and 8 months, 37% and 61% of intervention households, respectively, had dust mite concentrations <2 mg/g and 7% and 4%, respectively, had >10mg/g in bed. At baseline and 8 months, 26% and 74% of intervention households, respectively, had dust mite concentrations <2 mg/g and 7% and 0%, respectively, had >10 mg/g on bedroom floor. Decreased dust mite levels from baseline to months 1, 2, 5 and 8 were statistically significant in floor (p < 0.002) and from baseline to months 2 and 5 in bed (p < 0.02). CONCLUSIONS: There was an increase in the number of tests with dust mite concentrations 2 ug/g and a decrease in the number of tests with dust mite concentrations >10 mg/g in the intervention group. Use of in-home test kits along with educational materials reduced dust mite allergen in bedrooms of children with reported dust mite allergy. The study had limited power to test other potential covariates.
SATURDAY
116
Repeat Epinephrine Treatments For Stinging Insect Hypersensitivity Reactions Presenting To The Emergency Department S. A. Rudders1, D. P. Katzman2, A. Banerji2, S. Clark3, C. A. Camargo, Jr.2; 1Children’s Hospital Boston, Boston, MA, 2Massachusetts General Hospital, Boston, MA, 3University of Pittsburgh, Pittsburgh, PA. RATIONALE: There are sparse data on epinephrine treatment for stinging insect hypersensitivity (SIH) reactions. We sought to establish the frequency of receiving >1 dose of epinephrine in patients presenting to the emergency department (ED) with SIH reactions. METHODS: We performed a medical record review of all 155 patients with SIH reactions presenting to three Boston EDs between 1/1/01 and 12/31/06. Patients were identified by ICD9 codes 989.5, 995.0, 995.1 and 995.3. We focused on presentations and treatments, including the number of epinephrine treatments given before and during the ED visit. RESULTS: The cohort was 54% male and 71% white, with a median age of 33 years. A variety of insects triggered the reactions, especially bees (74%). 58% of patients were classified as local reactions, while 37% had systemic reactions (10% cutaneous systemic and 27% anaphylaxis). Among patients with systemic reactions, 83% were stung within 3 hours of ED arrival. Among those receiving treatments before ED arrival, 44% received epinephrine. While in the ED, patients with systemic reactions received antihistamines (77%), systemic corticosteroids (56%), and epinephrine (9%). Over the course of their reaction, 33% received epinephrine and among this subset, 16% received 2+ doses. Most patients with systemic reactions (68%) were discharged to home. At ED discharge, 67% received a prescription for self-injectable epinephrine and 13% had documentation of referral to an allergist. CONCLUSIONS: 16% of patients who receive epinephrine for a systemic SIH reaction require multiple doses. Further study is needed to identify risk factors for repeat epinephrine use.
117
Collateral Allergy: If You Don't Ask, They Won't Tell J. J. Dietrich1, R. W. England2; 1David Grant Medical Center, Travis AFB, CA, 2Wilford Hall Medical Center, Lackland AFB, CA. RATIONALE: Food allergy, stinging insect allergy, and latex allergy can all lead to potentially life threatening allergic reactions. Although AAAAI consultation and referral guidelines recommend patients with these conditions be referred to an allergist/immunologist for further evaluation and management, patients are often not referred. METHODS: We performed a retrospective medical record review of outpatient allergy/immunology (A/I) consults received at our institution from January 1, 2006 through December 31, 2006. We calculated the number of evaluations for food, insect, and latex allergy which were specifically requested in the consult. We compared this to the number of evaluations for these diagnoses which were neither requested in the consult nor previously evaluated, but which had an evaluation initiated by the allergist/immunologist after he or she identified the problem through a complete allergy history. RESULTS: Although not specifically requested in the consult, a thorough history obtained by the allergist/immunologist initiated 26.3% (70/266) of the total food allergy evaluations, 34.9% (38/109) of stinging insect allergy evaluations, and 46.9% (15/32) of latex allergy evaluations. Additionally, 2.8% (38/1341) of all patients presenting to our A/I clinic for reasons other than insect hypersensitivity gave a history of a systemic reaction to an insect sting which had not been evaluated previously. CONCLUSIONS: These results demonstrate that a large proportion of patients with possible food, insect, or latex allergy can be identified by means of a comprehensive allergy history. Inquiring about these collateral allergies can ensure proper evaluation, education, avoidance, and treatment are implemented for these potentially life threatening conditions.
J ALLERGY CLIN IMMUNOL FEBRUARY 2010
118
Importance of Antigen Selection in the Detection of Autoantibodies against FceRIa in Chronic Urticaria Patients M. Ling, J. Ge, M. L. Altrich, J. F. Halsey; IBT Laboratories, Lenexa, KS. RATIONALE: Among some chronic urticaria (CU) patients, an autoimmune etiology exists with auto-antibodies against FceRIa, IgE, or FceRII. Various methods including both binding and functional assays to detect autoantibodies against FceRIa have been reported. In some binding methods, a relatively high prevalence of autoantibodies in non-CU patients were reported. Therefore, we investigated the specificity of these binding reactions. METHODS: ELISA methods were evaluated to detect IgG antibodies to FceRIa. Multiple sources of FceRIa including recombinant proteins purified from High-Fiveä insect cell, E. Coli, and peptide mixes were evaluated as an antigen. The assay specificity was evaluated by inhibition experiments. RESULTS: The recombinant protein from insect cells appeared to be extensively glycosylated as it was 40 kDa compared to 22 kDa for the bacterial recombinant protein on a SDS-PAGE. In an ELISA method using the H-F recombinant protein, binding antibodies were detected in sera from both CU and non-CU patients. However this binding could be inhibited by a control H-F. lysate (inhibition ranged 60-95%) as well as the purified protein. In contrast, ELISAs using a bacterially prepared protein or peptide mixes showed good specificity. Inhibition with the control E. coli lysate was < 20% while that with the recombinant protein was >80%. The glycosylation of the recombinant protein may have significantly altered its conformation relative to the native FceRIa protein. CONCLUSIONS: Recombinant FceRIa antigen produced in High Five insect cells carry glycosylation motifs that appear immunogenic in a large proportion of humans, thus reducing the method’s specificity.
119
Dust Mite Allergen Reduction Study A. K. Haynes1, M. Sever1, P. W. Crockett2, R. Jaramillo2, A. Zombeck2, R. Crohn2, D. Zeldin1; 1National Institute of Environmental Health Sciences, Research Triangle Park, NC, 2SRA International, Durham, NC. RATIONALE: Asthmatics are encouraged to employ interventions to reduce exposure to indoor allergens, but often lack objective evidence to confirm the efficacy of their efforts. In-home test kits and education may influence dust mite allergen reduction. METHODS: This randomized controlled trial enrolled 60 households of children aged 5-15 years with parent-reported dust mite allergy and allergen concentrations 2mg/g in the child’s bedroom. The intervention group (N 5 30) received educational materials and in-home dust mite test kits at baseline, 1, 2, 5, and 8 months. The control group (N 5 30) received only educational materials. Nonparametric sign tests were performed to determine the likelihood of mite levels decreasing vs. increasing. RESULTS: At baseline and 8 months, 37% and 61% of intervention households, respectively, had dust mite concentrations <2 mg/g and 7% and 4%, respectively, had >10mg/g in bed. At baseline and 8 months, 26% and 74% of intervention households, respectively, had dust mite concentrations <2 mg/g and 7% and 0%, respectively, had >10 mg/g on bedroom floor. Decreased dust mite levels from baseline to months 1, 2, 5 and 8 were statistically significant in floor (p < 0.002) and from baseline to months 2 and 5 in bed (p < 0.02). CONCLUSIONS: There was an increase in the number of tests with dust mite concentrations 2 ug/g and a decrease in the number of tests with dust mite concentrations >10 mg/g in the intervention group. Use of in-home test kits along with educational materials reduced dust mite allergen in bedrooms of children with reported dust mite allergy. The study had limited power to test other potential covariates.