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Hugh A Sampson

Publications and source records attributed to Hugh A Sampson.

At least 19 recordsLinked to original sources
PubMed2006

Standardization and performance evaluation of mononuclear cell cytokine secretion assays in a multicenter study.

BACKGROUND: Cryopreservation of peripheral blood mononuclear cells has been used to preserve and standardize immunologic measurements for multicenter studies, however, effects of cryopreservation on cytokine responses are incompletely understood. In designing immunologic studies for a new multicenter birth cohort study of childhood asthma, we performed a series of experiments to determine the effects of two different methods of cryopreservation on the cytokine responses of cord and peripheral blood mononuclear cells. RESULTS: Paired samples of PBMC were processed freshly, or after cryopreservation in a Nalgene container (NC) or a controlled-rate freezer (CRF). Although there were some differences between the methods, cryopreservation inhibited PHA-induced IL-10 secretion and Der f 1-induced IL-2 secretion, and augmented PHA-induced IL-2 secretion and spontaneous secretion of TNF-alpha. In separate experiments, NC cryopreservation inhibited secretion of several cytokines (IL-13, IL-10, IFN-gamma, TNF-alpha) by PHA-stimulated cord blood mononuclear cells. With the exception of PHA-induced IL-13, results from fresh and cryopreserved cord blood samples were not significantly correlated. Finally, in reproducibility studies involving processing of identical cell samples in up to 4 separate laboratories, variances in cytokine responses of fresh cells stimulated at separate sites did not exceed those in cryopreserved cells stimulated at a central site. CONCLUSION: Collectively, these studies indicate that cryopreservation can affect mononuclear cell cytokine response profiles, and that IL-10 secretion and antigen-induced responses may be especially vulnerable. These studies also demonstrate that mononuclear cell responses can be standardized for performance in a small number of laboratories for multicenter studies, and underscore the importance of measuring reproducibility and of testing whether cryopreservation techniques alter specific immunologic outcomes.

Algorithms↗
PubMed2006

The major glycoprotein allergen from Arachis hypogaea, Ara h 1, is a ligand of dendritic cell-specific ICAM-grabbing nonintegrin and acts as a Th2 adjuvant in vitro.

Nonmammalian glycan structures from helminths act as Th2 adjuvants. Some of these structures are also common on plant glycoproteins. We hypothesized that glycan structures present on peanut glycoallergens act as Th2 adjuvants. Peanut Ag (PNAg), but not deglycosylated PNAg, activated monocyte-derived dendritic cells (MDDCs) as measured by MHC/costimulatory molecule up-regulation, and by their ability to drive T cell proliferation. Furthermore, PNAg-activated MDDCs induced 2- to 3-fold more IL-4- and IL-13-secreting Th2 cells than immature or TNF/IL-1-activated MDDCs when cultured with naive CD4+ T cells. Human MDDCs rapidly internalized Ag in a calcium- and glycan-dependent manner consistent with recognition by C-type lectin. Dendritic cell (DC)-specific ICAM-grabbing nonintegrin (DC-SIGN) (CD209) was shown to recognize PNAg by enhanced uptake in transfected cell lines. To identify the DC-SIGN ligand from unfractionated PNAg, we expressed the extracellular portion of DC-SIGN as an Fc-fusion protein and used it to immunoprecipitate PNAg. A single glycoprotein was pulled down in a calcium-dependent manner, and its identity as Ara h 1 was proven by immunolabeling and mass spectrometry. Purified Ara h 1 was found to be sufficient for the induction of MDDCs that prime Th2-skewed T cell responses. Both PNAg and purified Ara h 1 induced Erk 1/2 phosphorylation of MDDCs, consistent with previous reports on the effect of Th2 adjuvants on DCs.

Adjuvants, Immunologic↗
PubMed2006

Skin prick test to egg white provides additional diagnostic utility to serum egg white-specific IgE antibody concentration in children.

BACKGROUND: Levels of IgE antibody to egg white of greater than 7 kIU/L are highly predictive of clinical reactivity to egg, and lower levels often require evaluation with oral food challenge (OFC) to establish definitive diagnosis. OFCs have inherent risks, and diagnostic criteria indicating high likelihood of passing would be clinically useful. OBJECTIVE: We sought to determine whether the size of the skin prick test (SPT) to egg white adds diagnostic utility for children with low egg white-specific IgE antibody levels. METHODS: A retrospective analysis of clinical history, egg white-specific IgE antibody levels, SPT responses, and egg OFC outcomes was performed. RESULTS: Children who passed (n = 29) egg OFCs and those who failed (n = 45) did not differ significantly in age, clinical characteristics, or egg white-specific IgE levels. There were, however, significant differences between both egg white SPT wheal response size and egg/histamine SPT wheal index. Children who failed egg OFCs had a median wheal of 5.0 mm; those who passed had a median wheal of 3.0 mm (P = .003). Children who failed egg OFCs had a median egg/histamine index of 1.00; those who passed had a median index of 0.71 (P = .001). For egg white-specific IgE levels of less than 2.5 kIU/L, an SPT wheal of 3 mm or an egg/histamine index of 0.65 was associated with a 50% chance of passing. CONCLUSION: In children with low egg white-specific IgE levels, those with smaller SPT wheal responses to egg were more likely to pass an egg OFC than those with larger wheal responses. The size of the egg white SPT response might provide additional information to determine the timing of egg OFC. CLINICAL IMPLICATIONS: The size of the egg white SPT wheal response might provide the clinician with additional information to determine the timing of egg OFC in children with low egg white-specific IgE antibody levels.

Administration, Oral↗
PubMed2006

Lack of cross-reactivity between the Bacillus thuringiensis derived protein Cry1F in maize grain and dust mite Der p7 protein with human sera positive for Der p7-IgE.

Cry1F protein, derived from Bacillus thuringiensis, is effective at controlling lepidopteran pests and a synthetic Cry1F transgene was transferred into maize. For the safety assessment of genetically modified food crops, the allergenic potential of the introduced novel trait(s) is evaluated. Because no single parameter is currently predictive of allergic potential, a 'weight of evidence' approach has been proposed. As part of this assessment, the amino acid (aa) sequence of the Cry1F protein was compared to a database of known allergens using recommended criteria. The Cry1F protein did not show significant similarity or a match of eight contiguous identical aa with any allergen. However, a single six contiguous aa match was identified between Cry1F and the Der p7 protein of the dust mite, Dermatophagoides pteronyssinus. To investigate whether Cry1F was cross-reactive with Der p7, sera from 10 dust mite allergic patients containing Der p 7-specific IgE antibody were used to compare IgE-specific binding. No evidence of cross-reactivity was observed between Cry1F and Der p7. This study provides in vitro IgE sera screening data, that when considered in the context of other bioinformatic data [Hileman R.E., Silvanovich, A., Goodman R.E., Rice E.A., Holleschak G., Astwood J.D., Hefle S.L., 2002. Bioinformatic methods for allergenicity assessment using a comprehensive allergen database. Int. Arch. Allergy Immunol. 128, 280-291; Stadler, M.B., Stadler, B.M., 2003. Allergenicity prediction by protein sequence. FASEB J. 17, 1141-1143.], adds further evidence arguing against the use of a six contiguous identical amino acid search to identify potential cross-reactive allergens. Cry1F is heat labile, rapidly hydrolyzed in an in vitro pepsin resistance assay, not glycosylated and not from an allergenic source. Taken together, these data indicate a lack of allergenic concern for Cry1F.

Allergens↗
PubMed2006

Second symposium on the definition and management of anaphylaxis: summary report--second National Institute of Allergy and Infectious Disease/Food Allergy and Anaphylaxis Network symposium.

There is no universal agreement on the definition of anaphylaxis or the criteria for diagnosis. In July 2005, the National Institute of Allergy and Infectious Disease and Food Allergy and Anaphylaxis Network convened a second meeting on anaphylaxis, which included representatives from 16 different organizations or government bodies, including representatives from North America, Europe, and Australia, to continue working toward a universally accepted definition of anaphylaxis, establish clinical criteria that would accurately identify cases of anaphylaxis with high precision, further review the evidence on the most appropriate management of anaphylaxis, and outline the research needs in this area.

Journal Article↗
PubMed2006

9. Food allergy.

Food allergy, defined as an adverse immune response to food proteins, affects as many as 6% of young children and 3% to 4% of adults. Food-induced allergic reactions are responsible for a variety of symptoms involving the skin, gastrointestinal tract, and respiratory tract and might be caused by IgE-mediated and non-IgE-mediated (cellular) mechanisms. Our understanding of how food allergy represents an abrogation of normal oral tolerance is evolving. Although any food can provoke a reaction, relatively few foods are responsible for the vast majority of significant food-induced allergic reactions: milk, egg, peanuts, tree nuts, fish, and shellfish. A systematic approach to diagnosis includes a careful history, followed by laboratory studies, elimination diets, and often food challenges to confirm a diagnosis. Many food allergens have been characterized at a molecular level, which has increased our understanding of the immunopathogenesis of food allergy and might soon lead to novel diagnostic and therapeutic approaches. Currently, management of food allergies consists of educating the patient to avoid ingesting the responsible allergen and to initiate therapy in case of an unintended ingestion.

Adult↗
PubMed2006

Second symposium on the definition and management of anaphylaxis: summary report--Second National Institute of Allergy and Infectious Disease/Food Allergy and Anaphylaxis Network symposium.

There is no universal agreement on the definition of anaphylaxis or the criteria for diagnosis. In July 2005, the National Institute of Allergy and Infectious Disease and Food Allergy and Anaphylaxis Network convened a second meeting on anaphylaxis, which included representatives from 16 different organizations or government bodies, including representatives from North America, Europe, and Australia, to continue working toward a universally accepted definition of anaphylaxis, establish clinical criteria that would accurately identify cases of anaphylaxis with high precision, further review the evidence on the most appropriate management of anaphylaxis, and outline the research needs in this area.

Anaphylaxis↗
PubMed2006

Predictive value of skin prick tests using recombinant allergens for diagnosis of peanut allergy.

BACKGROUND: Current diagnosis of peanut allergy relies on natural extracts that lack standardization. Recombinant DNA technology allows production of pure biochemically characterized proteins. Their usefulness for peanut allergy diagnosis is not established. OBJECTIVE: This study aimed to evaluate the diagnostic value of the 3 major recombinant peanut allergens. METHODS: Recombinant (r) Ara h 1, rAra h 2, and rAra h 3 were produced according to the recommendations of good manufacturing practice for recombinant allergens. Skin prick tests (SPTs) and IgE ELISA assays were performed in 30 patients with peanut allergy and 30 control subjects without food allergy: 15 nonatopic and 15 sensitized to birch pollen. Disease severity was graded by clinical scoring. RESULTS: All patients with peanut allergy showed positive SPT results to rAra h 2; 40% reacted with rAra h 1 and 27% with rAra h 3. No control subjects reacted with any of the recombinant allergens. Monosensitization to rAra h 2 was observed in 53% of patients. Neither SPT size nor levels of specific IgE were correlated with the disease severity. However, patients with monosensitization to rAra h 2 had a significantly lower severity score than polysensitized subjects and a lower level of specific IgE against peanut extract and rAra h 2. CONCLUSION: Skin prick tests to individual recombinant peanut allergens appear to be a safe and effective diagnostic tool. Cosensitization to rAra h 2 and rArah 1 and/or rAra h 3 is predictive of more severe reactions. CLINICAL IMPLICATIONS: Recombinant peanut allergens can be used by SPTs for diagnosis and evaluation of allergy severity.

Adolescent↗
PubMed2006

Adverse reactions to foods.

Food allergy encompasses a variety of immune-mediated adverse reactions to foods. IgE-mediated, cell-mediated, and mixed-mechanism food allergy disorders are recognized. Over the past 2 decades, the prevalence of food allergy doubled and its phenotypic expression increased in Westernized societies. Major food allergens have been identified for many common foods. Laboratory diagnosis of food allergy relies heavily on the detection of food-specific IgE antibodies, but novel approaches include tests for T-cell-mediated disorders and tests for prediction of tolerance. OFC remains the diagnostic standard for food allergy. Management of food allergy focuses on avoidance of the offending foods, nutritional support, and prompt recognition and treatment of acute food allergic reactions. Anti-IgE monoclonal antibody is the first potential therapy for food allergy that is under-going testing in clinical trials.

Adult↗
PubMed2006

Allergic eosinophilic gastroenteritis with protein-losing enteropathy: intestinal pathology, clinical course, and long-term follow-up.

OBJECTIVES: A subset of patients with allergic eosinophilic gastroenteritis (AEG) has anemia and hypoalbuminemia caused by protein-losing enteropathy (PLE). Our goals were to describe the response to therapy and the long-term outcome of patients in this subgroup and to evaluate their gastric and intestinal biopsies for distinguishing features that might explain their protein and blood loss. METHODS: Patients with AEG + PLE were identified retrospectively and compared with controls and with patients with AEG only. Immunohistochemical staining for tryptase, a mast cell mediator, was performed on gastric and duodenal tissues. Eosinophils identified by hematoxylin/eosin stain and mast cells identified as tryptase-positive cells were counted in one high-power field area with maximal cell infiltration. RESULTS: Although all patients had excellent response to therapy with amino acid-based formula and tolerated gradual introduction of some foods with time, food-responsive disease persisted in all patients over 2.5 to 5.5 years of follow-up. Routine histological evaluation did not show any features differentiating AEG + PLE from AEG. When eosinophils and mast cells were counted in intestinal biopsies, however, significantly more mast cells were found in biopsies of the AEG + PLE group despite comparable numbers of eosinophils. In contrast, in gastric biopsies, eosinophils were more prominent in AEG + PLE, but mast cell numbers were similar in all groups. CONCLUSIONS: Patients with AEG + PLE responded well to therapy with amino acid-based formula. Food hypersensitivities did not completely resolve over up to 5.5 years. Intestinal mast cells were significantly increased in maximally infiltrated areas of the intestine, possibly causing increased intestinal permeability and protein loss.

Eosinophils↗
PubMed2005

The Chinese herbal medicine formula FAHF-2 completely blocks anaphylactic reactions in a murine model of peanut allergy.

BACKGROUND: Peanut allergy is potentially life threatening. There is no curative therapy for this disorder. We previously found that an herbal formula, food allergy herbal formula (FAHF)-1, blocked peanut-induced anaphylaxis in a murine model when challenged immediately posttherapy. OBJECTIVE: To test whether FAHF-2, an improved herbal formula, from which 2 herbs, Zhi Fu Zi (Radix Lateralis Aconiti Carmichaeli Praeparata) and Xi Xin (Herba Asari), were eliminated, is equally effective to FAHF-1, and if so, whether protection persists after therapy is discontinued. METHODS: Mice allergic to peanut treated with FAHF-2 for 7 weeks were challenged 1, 3, or 5 weeks posttherapy. Anaphylactic scores, core body temperatures, vascular leakage, and plasma histamine levels after peanut challenge were determined. Serum peanut-specific antibody levels and splenocyte cytokine profiles were also measured. RESULTS: After challenges, all sham-treated mice developed severe anaphylactic signs, significant decrease in rectal temperatures, significantly increased plasma histamine levels, and marked vascular leakage. In contrast, no sign of anaphylactic reactions, decrease in rectal temperatures, or elevation of plasma histamine levels was observed in FAHF-2-treated mice in 5 separate experiments. IgE levels were significantly reduced by FAHF-2 treatment and remained significantly lower as long as 5 weeks posttherapy. Splenocytes from FAHF-2-treated mice showed significantly reduced IL-4, IL-5, and IL-13, and enhanced IFN-gamma production to recall peanut stimulation in vitro . CONCLUSION: FAHF-2 treatment completely eliminated anaphylaxis in mice allergic to peanut challenged as long as 5 weeks posttherapy. This result was associated with downregulation of T H 2 responses. FAHF-2 may be a potentially effective and safe therapy for peanut allergy.

Administration, Oral↗
PubMed2005

Food allergen sensitization in inner-city children with asthma.

BACKGROUND: Asthma continues to be an increasing cause of morbidity in the pediatric population, and studies have shown an association between food sensitivity and asthma. OBJECTIVE: We investigated the degree of food allergen sensitization in inner-city patients with asthma. METHODS: Five hundred four random serum samples from the National Cooperative Inner City Asthma Study were evaluated for specific IgE (UniCap) to 6 common food allergens (egg, milk, soy, peanut, wheat, and fish). Statistical analyses were performed to determine food sensitization prevalence and its association with asthma morbidity. RESULTS: Forty-five percent of patients had evidence of sensitization (food-specific IgE > or = 0.35 kU/L) to at least 1 food. Nineteen percent had IgE levels at > or = 50% positive predictive value for clinical reactivity to at least 1 food, with 4% of patients having levels > 95% positive predictive value for food allergy. Children sensitized to foods had higher rates of asthma hospitalization (P < .01) and required more steroid medications (P = .025). Sensitization to foods also correlated with sensitization to more indoor and outdoor aeroallergens (P < .001). CONCLUSION: Food allergen sensitization is highly prevalent in the inner-city population with asthma, and it is associated with increased asthma healthcare and medication use. Therefore, food allergen sensitivity may be a marker for increased asthma severity.

Animals↗