Modification of T-cell receptor Vbeta repertoire in response to allergen stimulation in peanut allergy

BACKGROUND: Peanut is one of the most common foods causing allergic reactions and is the most common cause of fatal and near-fatal food-related anaphylaxis. Little is known of the immunologic mechanisms that underlie peanut allergy. OBJECTIVES: In this study we examined clonality of the T-cell response (TCR) to peanut in MHC class II identical, peanut allergy-discordant sibling pairs. METHODS: Four sibling pairs were investigated. The TCR repertoire was analyzed before and after in vitro stimulation of PBMCs with crude peanut or PHA, as control for general/nonspecific reactivity. Eighteen TCR-Vbeta families were examined by flow cytometry. Where significant differences in incidence of particular TCR-Vbeta families were observed, PCR familyspecific cDNA amplification and gene scanning were performed. RESULTS: After stimulation with peanut, no selective expansion of any TCR-Vbeta subpopulation was observed with flow cytometry, in either the peanut-allergic or nonallergic siblings, with the exception of 1 peanut-allergic subject who demonstrated a significant increase of TCR-Vbeta11(+) cells (0.3%-5.9% of the total CD3(+) cells). However, gene scanning revealed predominant single-size PCR products for TCRBV11 in all peanut-allergic subjects after peanut stimulation. TCRBV11 polyclo-nality was observed in allergic and nonallergic subjects before peanut stimulation and in nonallergic subjects after peanut stimulation. In comparison, all subjects, before and after stimulation with peanut, showed polyclonality for TCRBV2. CONCLUSIONS: Our results argue for clonal or oligoclonal TCRs to crude peanut and indicate that changes in the TCRBV11 subpopulation are restricted to peanut-allergic subjects after stimulation with crude peanut allergen.     

Pepsin-digested peanut contains T-cell epitopes but no IgE epitopes

Background: Peanuts are a common cause of food-induced anaphylaxis and fatalities. Previous studies have demonstrated that rush immunotherapy to crude peanut extract reduces clinical symptoms triggered by oral peanut challenges, but the immunotherapy was associated with an unacceptably high incidence of systemic allergic reactions. One approach to reduce the frequency of allergic reactions would be to use a modified peanut antigen with low allergenic properties. Objective: We sought to determine the immunologic characteristics of crude intact peanut extract before and after pepsin digestion. Methods: We used IgE immunoblotting and assessment of T-lymphocyte responses to intact and peptic digests of peanut extracts. Results: Western blot analysis of sera from 5 subjects with peanut allergy showed multiple IgE-reactive proteins in crude intact peanut extract that were eliminated after pepsin treatment of the peanut extract. In contrast, pepsin-digested peanut induced significant T-cell proliferation responses (stimulation index = 30) in vitro in PBMCs from 7 subjects with peanut allergy, albeit at lower levels than that induced by intact peanut (stimulation index = 66). Furthermore, IFN-γ production was induced by intact peanut and pepsin-digested peanut in a concentration-dependent manner. Importantly, T-cell lines generated in response to intact peanut also reacted to pepsin-digested peanut, indicating cross-reactive T-cell epitopes in intact and pepsin-digested peanut. Conclusion: These findings suggest that pepsin-digested peanut may be useful in peanut immunotherapy because pepsin digestion eliminates IgE reactivity but maintains T-cell reactivity. (J Allergy Clin Immunol 1999;104:473-7.)     

T cell receptor (TCR) V gene segment use in HLA-typed Japanese healthy subjects

The expression of 13 different α and β V gene segments of the T cell receptor for antigen (TCR) was examined, using V gene-specific MoAbs, on human peripheral blood T lymphocytes from 32 healthy Japanese subjects. In addition, to examine associations between TCR V gene products and HLA alleles, the HLA class I and class II types of all subjects were serologically determined. The reactivities of the anti-TCR V-specific MoAbs were, with some significant exceptions, similar to those previously described in healthy Caucasian subjects. We found a non-random V gene usage as well as a statistically significant bias of the expression of eight Vβ gene products towards the CD4⁺ subpopulation, and a significant skewness in the usage of Vα12 towards the CD8⁺ population. Some subjects showed increased reactivities (above 10%) of certain MoAbs, mainly in the CD8⁺ subpopulation. We found no distinct correlation between any certain HLA class I or II allele and TCR V gene usage in the CD8⁺ or CD4⁺ subpopulations, respectively. In conclusion, the pattern of anti-TCR V-specific MoAb reactivities found in CD4⁺ and CD8⁺ subsets of peripheral blood lymphocytes of healthy Japanese subjects was in general found to match that previously described in healthy Caucasian subjects.     

Detection of IgA antibodies to cat, β-lactoglobulin, and ovalbumin allergens in human milk

Background: The relationship between the development of allergy during infancy and breast-feeding remains controversial. This controversy may be due to individual variations in the composition of human milk. Antibodies to food antigens to which the mother is commonly exposed are present in the milk, but their relationship to allergy is still unknown. IgA antibodies to inhalant allergens have not been previously detected. Objective: Our purpose was to analyze secretory IgA antibody levels to cat, β-lactoglobulin, and ovalbumin allergens in colostrum and mature milk in relation to maternal allergy. Methods: Colostrum and samples of mature milk were obtained after 1 and 3 months of lactation from 53 nursing mothers (17 allergic and 36 nonallergic mothers) and were analyzed for total secretory IgA levels by ELISA and secretory IgA antibodies to cat, β-lactoglobulin, and ovalbumin by an enzyme-amplified ELISA. The specificity of the assays was confirmed by inhibition experiments. Results: Secretory IgA to cat, β-lactoglobulin, and ovalbumin allergens were detected in colostrum as well as mature milk. The levels of secretory IgA to ovalbumin were lower in colostrum from allergic mothers with P = .016, whereas the levels to β-lactoglobulin and cat were similar in the 2 groups. IgA antibodies to ovalbumin were detected in 94% of the colostrum samples from allergic and in all samples from nonallergic mothers, in 82% and 96%, respectively at 1 month, and 53% and 65% at 3 months. Fewer samples had detectable secretory IgA antibodies to β-lactoglobulin than to ovalbumin and cat, and only 33% and 10% of the samples from the allergic and nonallergic mothers, respectively, remained positive at 3 months. All the allergic mothers had detectable IgA to cat in colostrum, whereas 83% and 73% of the samples were positive at 1 and 3 months. The corresponding numbers were 93%, 81%, and 81% in the nonallergic mothers (not significant). Conclusion: Even a low level of exposure of the mucosa (eg, by inhalant allergens) can induce antibody secretion into the milk, both in allergic and nonallergic mothers. (J Allergy Clin Immunol 2000;105:1236-40.)     

Soy immunotherapy for peanut-allergic mice: modulation of the peanut-allergic response

BACKGROUND: Allergen-specific immunotherapy (IT) is an effective therapeutic modality to prevent further anaphylactic episodes in patients with insect sting hypersensitivity and is being investigated for peanut allergy. So far, peanut-specific IT has been unsuccessful because of the side effects of therapy. Soybean seed storage proteins share significant homology with the respective peanut allergens. OBJECTIVE: This study was undertaken in mice to investigate whether specific doses of soybean would desensitize peanut-allergic mice. METHODS: C3H/HeJ mice were sensitized to peanut with 3 intraperitoneal (IP) injections of crude peanut extract. The mice were desensitized by IP injections with either crude peanut or soybean extract for 4 weeks, 3 times a week. Controls included placebo desensitization with PBS and naive mice. After 2 weeks of rest, mice were challenged IP with crude peanut extract. Thirty minutes later, symptom scores and body temperatures were recorded. Serum immunoglobulins, peanut-induced splenocyte proliferation, and secreted cytokines were measured before and after desensitization. RESULTS: The clinical symptoms in the soybean- and peanut-desensitized animals were markedly reduced compared with the placebo-treated mice. Specific IgG1 levels to crude peanut were significantly lower in the soy IT group than in the peanut IT group. The cellular response to crude peanut was also downregulated in the soy IT group, as shown by decreased peanut-specific stimulation indices and a cytokine profile skewed toward a T H 1 response. CONCLUSIONS: Soy IT can be used to desensitize/downregulate peanut-specific response in peanut-allergic mice and could provide a new therapeutic intervention for peanut allergy.     

Evidence that enhanced nasal reactivity to bradykinin in patients with symptomatic allergy is mediated by neural reflexes

OBJECTIVE: The aim of this study was to determine whether allergic inflammation induces nasal hyperreactivity to bradykinin by enhancing neuronal responsiveness. METHODS: We compared the response to localized, unilateral nasal challenge with bradykinin in patients with perennial allergic rhinitis and nonallergic subjects, and in patients with seasonal allergic rhinitis challenged in and out of season. Weights of secretions from each nostril were recorded, and levels of albumin and lactoferrin in secretions recovered from each nostril were assayed. Contralateral administration of atropine (0.32 mg) was used to evaluate the role of cholinergic reflexes in nasal hyperresponsiveness to bradykinin. RESULTS: In patients with symptomatic allergy, bradykinin induced greater symptom scores than in asymptomatic atopic or nonallergic control subjects. Moreover, bradykinin caused sneezing in a majority of patients with symptomatic allergy but in none of the asymptomatic atopic or nonallergic control subjects. Only patients with symptomatic allergy showed dose-dependent bilateral increases in secretion weights and levels of the serous glandular marker, lactoferrin. In contrast, bradykinin induced similar increases in ipsilateral, but not contralateral, levels of albumin in all patient populations. Atropine inhibited contralateral secretion and lactoferrin production (p < 0.05) in patients with symptomatic allergy. CONCLUSION: The induction of sneezing and of atropine-inhibitable contralateral glandular secretion demonstrates that allergic inflammation causes nasal hyperreactivity to bradykinin, at least in part, by enhancing neuronal responsiveness. (J ALLERGY CLIN IMMUNOL 1996;97:1252-63.)     

Transforming growth factor-β in breast milk: A potential regulator of atopic disease at an early age

Background: According to data from animal and in vitro studies, transforming growth factor-β (TGF-β) has a crucial effect on 2 essential parts of the mucosal immune system: IgA production and oral tolerance induction. Objective: We sought to ascertain whether TGF-β in breast milk is associated with specific IgA production and atopic disease in human subjects. Methods: Forty-seven infants with several atopic family members were followed during their first year of life. The concentrations of TGF-β1 and TGF-β2 in maternal colostrum, mature milk, and the infants’ sera were determined. The enzyme-linked immunospot assay was used to assess the infants’ specific IgA production in response to β-lactoglobulin, casein, gliadin, and ovalbumin. Results: At 12 months, atopic dermatitis was confirmed in 29 of 47 infants; in 11, atopic disease had begun during exclusive breast-feeding (preweaning onset), whereas in 18 the disease manifested itself after weaning (postweaning onset). The concentrations of both TGF-β1 and TGF-β2 were higher in maternal colostrum, but not in mature milk and infants’ serum, in infants with postweaning-onset atopic disease compared with those with preweaning-onset disease (P = .0008 and P = .015, respectively). The concentration of TGF-β2 was, and that of TGF-β1 tended to be, higher in the colostrum of mothers whose infants had specific IgA-secreting cells at 3 months in response to at least one of the dietary antigens tested compared with those who did not have such cells (P = .048 and P = .076, respectively). Conclusion: TGF-β in colostrum may prevent the development of atopic disease during exclusive breast-feeding and promote specific IgA production in human subjects. (J Allergy Clin Immunol 1999;1251-7.)     

Lupin allergy in peanut-allergic children and teenagers

Background:  Lupin has now been introduced into food production in the UK. There is a concern that, on account of cross-reactivity, peanut-allergic children are at high risk for lupin allergy.
Aims:  To investigate the prevalence of lupin sensitization and allergy in children with peanut allergy compared with atopic controls.
Methods:  Children (<18 years) were recruited. Peanut-allergic subjects either had a convincing history of peanut allergy with diagnostic peanut skin prick test (SPT) or specific-immunoglobulin E (IgE) results or a positive food challenge. Control subjects were atopic but not peanut-allergic. All subjects had SPT to peanut and lupin. Sensitized subjects were offered a randomized, double-blind, placebo-controlled lupin challenge. Lupin allergy was defined as objective immediate hypersensitivity reaction at food challenge.
Results:  Forty-seven peanut-allergic children and 46 atopic controls were recruited. Sixteen peanut-allergic children were sensitized to lupin [34%, 95% confidence interval (CI): 21–49%]. Nine were challenged to lupin. Two reacted (itchy mouth and urticaria; itchy mouth and 20% drop in peak expiratory flow rate) giving a minimum prevalence of lupin allergy in peanut-allergic children of 4.0% (95% CI: 1–15%). Atopic controls were significantly ( P  = 0.001) less likely to be sensitized to lupin (4%, 95% CI: 1–15%) and had smaller wheals and serum-specific IgE results. None of the atopic controls reacted on lupin challenge, giving a rate of allergy in the atopic controls of 0% (95% CI: 0–8%).
Conclusions:  A small but significant number of children with peanut allergy are allergic to lupin. Sensitization to lupin is much rarer in nonpeanut-allergic atopic subjects.     

Effect of AA-2414, a thromboxane A2 receptor antagonist, on airway inflammation in subjects with asthma

Background: Asthma is a chronic inflammatory disease of the airways. The chemokines are potent chemoattractants for eosinophils and other types of cells associated with allergic inflammation. AA-2414, a new thromboxane A₂ receptor antagonist, reduces bronchial hyperresponsiveness in asthmatic subjects, but its mechanism of action is unclear. Objective: We tested the hypothesis that the beneficial effects of AA-2414 in asthma result from reduction in the number of inflammatory cells infiltrating the airway associated with inhibition of chemokine release. Methods: We studied bronchial biopsy specimens from 31 asthmatic subjects before and after oral treatment with AA-2414 (80 mg/day) or matched placebo for 4 months in a double-blind manner. Biopsy specimens were examined by immunohistochemistry. Each subject recorded symptom score and peak expiratory flow (PEF). Lung function and bronchial responsiveness to methacholine were measured before and after treatment. Results: After treatment, significant improvements in symptom score (P < .05), PEF (P < .01), diurnal variation of PEF (P < .01), and bronchial responsiveness (P < .01) were observed in the AA-2414 group compared with the placebo group. These improvements were accompanied by a significant decrease in the number of submucosal EG2⁺ eosinophils (P < .05). There was also a reduction in the number of cells expressing RANTES (P < .05) and macrophage inflammatory protein (MIP)-1α (P < .05) in the epithelium and of cells expressing monocyte chemotactic protein-3 (P < .01), RANTES (P < .05), MIP-1α (P < .01), and eotaxin (P < .01) in the submucosa in the AA-2414 treatment group. A significant correlation was found between the number of EG2⁺ eosinophils and numbers of monocyte chemotactic protein-3⁺ (r_s = 0.52, P < .005), MIP-1α⁺ (r_s = 0.34, P < .05), and eotaxin⁺ cells (r_s = 0.47, P < .01) in the submucosa. There was a significant negative correlation between the increase in bronchial responsiveness and the change in number of submucosal EG2⁺ cells (r_s = –0.65, P < .001). Conclusions: These findings suggest that AA-2414 treatment of patients with asthma may inhibit activated eosinophil infiltration in part by modulating the expression of chemokines in bronchial tissues. (J Allergy Clin Immunol 1999;103:1054-61.)     

Prevalence of an Ulcerative Colitis-Associated CD8+ T Cell Receptor β-Chain CDR3-Region Motif and Its Association with Disease Activity1

The normal human intestinal mucosa contains clonal T cell expansions. Clonal populations of T cells can be determined through evaluation of the idiotypic, hypervariable region of their T cell receptor (TCR). We have previously reported that there exists a highly conserved TCR pattern among intestinal CD8⁺ T cells in the majority of ulcerative colitis (UC) patients undergoing colectomy that was not present in normal control individuals. This TCR pattern, or motif, was characterized by particular -chain usage (TCRBV3 and TCRBJ1S6) and a defined length in the hypervariable third complementarity determining region (CDR3). The aim of this study was to assess the motif's relationship to disease activity. Subjects were 66 with UC, 19 with Crohn's disease, 14 inflammatory controls, and 6 normal controls. cDNA and gDNA were prepared from colonic biopsies and paraffin blocks, respectively, obtained from study subjects and used to assess TCRBV CDR3 region length and usage, as well as for cloning and sequencing of TCRs. The TCRBV CDR3 region was present in 25 of a series of 48 UC subjects but only 3 of 19 Crohn's disease patients and 3 of 14 inflammatory controls. The motif was more common in UC than either Crohn's disease or inflammatory controls (² = 7.5, P = 0.006, and ² = 4.1, P = 0.04, respectively). The motif's presence was not dependent upon histologic disease activity (either active or inactive UC). Clinical UC disease activity was also not significantly associated with an increased presence of the motif in 14 paired biopsies, which were taken during times of clinical activity or inactivity. There was a trend toward persistence of the motif, as it was present in 6 of 14 subjects over a 3- to 6-month time period. The previously described UC-associated TCRBV CDR3 region motif located in the intestinal CD8⁺ T-cell subset is found in a significant proportion of UC subjects. The TCR motif does not significantly discriminate active from inactive disease states. The persistent and diffuse nature of this TCR-associated motif in UC suggests that an ongoing T-cell response to a particular antigen(s) is occuring in this disorder.     

Evolution of a CD3+/CD+ α/ β T-Cell Receptor+ Mature T-Cell Clone from CD3-CD7+ Sorted Human Bone Marrow Cells

In order to study extrathymic differentiation in vitro, CD7⁺CD3^- lymphocytes were sorted from normal human bone marrow and cultured under conditions of limiting dilution together with irradiated pooled allogeneic peripheral blood mononuclear cells (PBMC) and phytohemagglutinin (PHA) in the presence of 1000 U/ml of interleukin-2 (IL-2). One clone was obtained that failed to react with monoclonal antibody (mAb) TCRδ1 (TCRγ/δ-specific) or WT31 (TCR2, α/β-specific). From day 35 through day 74 in culture, the surface phenotype of this clone evolved into CD3⁺, CD4⁺, CD8^-, TCR2⁺, TCR1^-, and was further characterized as CD2⁺, CD45RO⁺, CD16^-, and CD56^-. The presence of mRNA for TCR α and γ but not ,and γ chains was confirmed by Northern blotting. Accessory cell-dependent autocrine proliferative responses to PHA (most likely driven by IL-2) were initially absent, but became measurable at the same time as the TCR was acquired. However, in the absence of PHA, the clone failed to respond to a panel of homozygous B-cell lines representing the majority of MHC class II alleles. Autoreactivity was also not demonstrable. Cytotoxicity was limited to MHC unrestricted “natural killer (NK)-like” lysis of K562 target cells, with no autocytotoxicity detected. Tle NK-like lysis diminished over time in parallel with the acquisition of surface TCR. The cloned cells were not suppressive for mature lymphocyte proliferation. After stimulation, the cells secreted tumor necrosis factor α and granulocyte/macrophage colony-stimulating factor (GM-CSF) detected by immunoassays, and T-cell growth factors, most likely IL-2, as detected by bioassays. Polymerase chain-reaction methods demonstrated the presence of mRNA for IL-2, IL-3, IL-4, IL-9, interferon-δ, and GM-CSF in these cells after stimulation with PHA and B-LCL.These results suggest that cells with the phenotype and some functional characteristics of mature T lymphocytes can evolve extrathymically in vitro from T-cell precursors sorted from normal human bone marrow.     

Unmet needs of children with peanut allergy: Aligning the risks and the evidence

BackgroundPeanut allergy is a potentially severe and lifelong allergy, with few effective treatments or preventive measures.ObjectiveTo convene an expert panel of allergists, pediatricians, and advocates to discuss and highlight unmet needs in the prevention and management of peanut allergies.MethodsLiterature searches of PubMed were performed. The panel evaluated published data on the prevention of peanut allergy, treatment of existing peanut allergy, and management of reactions after unintentional peanut exposures.ResultsThe following key unmet needs in the prevention and management of peanut allergy were identified: (1) enhancing and optimizing implementation of early peanut introduction as a means of preventing the development of peanut allergy, (2) developing knowledge translation strategies regarding the safety and efficacy data for current and emerging immunotherapies for peanut-allergic children to support their use in clinical practice, and (3) promoting understanding of true exposure risk in allergic individuals and ensuring access to epinephrine for unintentional exposures that provoke severe reactions. Practitioners should help educate caregivers about the actual risks associated with peanut allergy and its prevention and management so that treatment decisions can be evidence based rather than fear based. Support tools are needed to help address caregiver goals, expectations, and psychological barriers, as well as identify facilitators for prevention and treatment strategies.ConclusionThere are significant unmet needs in our understanding of peanut allergy; addressing these needs will help to enhance understanding of how to most effectively prevent and treat peanut allergy, as well as educate the food-allergic and nonallergic community regarding current evidence-based practices.     

IL-1 receptor–type expression in relation to atopy

Background: IL-1 has 2 receptors, type I (IL-1RI) and type II (IL-1RII), which have 2 forms each, membrane (m) and soluble (s). When IL-1 binds to mIL-1RI, the active receptor, an inflammatory response is initiated, which does not occur when IL-1 binds to mIL-1RII, the decoy receptor. Both sIL-1RI and sIL-1RII function as IL-1–mopping mechanisms. We hypothesized that the ratio of active (mIL-1RI) to inactive (mIL-1RII, sIL-1RI, and sIL-1RII) receptors is important in determining the amount of inflammation produced in allergic reactions. Objective: Our aim was to compare the concentrations of mIL-1RI and mIL-1RII on cultured PBLs and sIL-1RI, sIL-1RII, and IL-1β in sera and supernatants of cultured PBMCs from atopic and nonatopic subjects. Methods: The membrane receptors, soluble receptors, and IL-1β concentrations were measured by ELISA with specific mAbs. Results: Although there was no difference in the level of serum IL-1β between the 2 groups, PBMCs from atopic persons spontaneously secreted higher levels of IL-1β than those from nonatopic donors (P < .05). PBLs from atopic subjects compared with those from nonatopic individuals expressed higher mIL-1RI (P < .0001) and mIL-1RII (P < .05). Levels of both the soluble receptors from both serum (P < .0001) and PBMCs (P < .05) of nonatopic donors were higher than those found in atopic donors. Conclusion: This augmentation of mIL-1RI concomitant with a reduction in soluble receptors may be an important contributory factor to the inflammation that occurs with allergen exposure. (J Allergy Clin Immunol 1999;103:1100-7.)     

Roles of mammalian structural units, ligand cluster and polyvalency in the Abrus precatorius agglutinin and glycoprotein recognition process

Previous studies on one of the toxic type 2 ribosome inactivating proteins (RIP), Abrus precatorius agglutinin (APA), have shown that the recognition domains of APA are restricted to monomers of Galβ1-3GalNAc (T, Thomsen-Friedenreich glycotope) and Galβ1-3/4GlcNAc (blood group precursor type I/II sequences); which are essential but play a minor role in the recognition process. In this study, APA recognition factors were expanded to include ligand clusters and polyvalent glycotopes by enzyme-linked lectinosorbent binding and inhibition assays. Based on the results of molar relative potency, the essential mammalian structural units are Galβ1-3GalNAcα/β1- (T_α/T_β) > Galα1-4Gal (E) > Galβ1-3/4GlcNAc (I/II) and avidity for tri-/di-antennary II_β, T, E and II monomers was found to be 7.1 × 10², 4.0, 5.5, 3.7 and 2.4 times higher than monomeric Gal. Among natural polyvalent glycotopes or clusters, high-density polyvalent T_α and complex multivalent I_β/II_β glycotopes greatly enhanced the affinity for APA over 10⁴ times. Based on these results, it is concluded that contribution of monomeric T_α, II_β, I_β, E_β and their clusters and polyvalency play critical roles in this recognition process. The binding intensities of these factors in decreasing order are: polyvalent T_α, II_β/I_β and E_β > tri-antennary II_β  monomeric T_α, T_β, I and II > Gal  GalNAc (weak). As one of type 2 RIP lectins, these recognition factors of the B chain are likely to be crucial for attachment and endocytosis. A comparison of the differential recognition factors and combining sites of APA with those of other lectins (Ricinus communis agglutinin, RCA₁ and ricin) is also illustrated.     

T cell responses to major peanut allergens in children with and without peanut allergy

Background T cell responses involved in peanut allergy are poorly understood. Objective To investigate T cell responses towards major peanut allergens in peanut‐allergic (PA) subjects compared with peanut‐sensitized (PS) non‐allergic children and non‐atopic (NA) controls. Methods Eighteen PA children, seven non‐allergic PS children and 11 NA adults were included. Peripheral blood mononuclear cells were stimulated with a crude peanut extract (CPE). Short‐term T cell lines were generated and subsequently stimulated with CPE and purified Ara h 1, Ara h 2, Ara h 3 and Ara h 6. The proliferation and production of IL‐13, IFN‐γ, IL‐10 and TNF‐α were analysed. Results Proliferation to CPE and major allergens was enhanced in PA subjects. The primary response to CPE was comparable with PS subjects, with increased production of IL‐13 and IFN‐γ compared with NA. Production of IL‐10 was not observed. In short‐term T cell lines, the response to CPE was stronger in PA than in PS and NA subjects. Only PA children had a detectable response to major peanut allergens, characterized by IL‐13 production. The response was the highest after Ara h 3 stimulation, and the lowest after Ara h 2 stimulation. No significant correlation was observed between peanut‐specific IgE levels and T cell responses to CPE. Conclusion T cell responses to CPE in PA and PS children were characterized by Th1 and Th2 cytokines. Only PA children showed enhanced Th2 responses to Ara h 1, Ara h 3 and Ara h 6. Cite this as: A. E. Flinterman, S. G. M. A. Pasmans, C. F. den Hartog Jager, M. O. Hoekstra, C. A. F. M. Bruijnzeel‐Koomen, E. F. Knol and E. van Hoffen, Clinical & Experimental Allergy, 2010 (40) 590–597.     

Mucosal T-cell phenotypes in persistent atopic and nonatopic rhinitis show an association with mast cells

Background: Allergic rhinitis is characterized by selective expansion of T cell subsets with a CD4+ phenotype. Recently, we identified a subpopulation of nonallergic rhinitis subjects with increased epithelial mast cell and eosinophil populations, suggestive of local mucosal allergy. Previously, T cell subsets have not been characterized in this subselection of nonallergic subjects and furthermore, their relationship to mast cell and basophil effector cells remain unidentified. Objective: To determine if a subpopulation of nonallergic subjects with idiopathic rhinitis (IR) have localized allergy confined to their nasal mucosa by comparing the T cell subsets and major histocompatibility complex (MHC) II expressing cells to persistent allergic rhinitis (PAR). Furthermore, the relationship between T cell subsets and mast cells/basophils was investigated. Methods: None of the symptomatic patients in this study were clinically allergen‐challenged. Nasal turbinate mucosa was removed from patients with PAR, IR and normal controls. Morphometry was performed on immunostained sections for T cell subset populations including CD3+, CD4+, CD8+, CD25+, CD45RA+, CD45RO+, human leucocyte antigen (HLA)‐DRα (MHC class II), mast cell tryptase and for basophils. Results: Subjects with persistent allergic rhinitis differed to normal controls in showing significantly increased numbers of total (CD3+), activated (CD25+) and allergen‐naïve (CD45RA+) T lymphocytes in their nasal mucosa (P < 0.025). The naïve CD45RA+ memory T cells correlated to mucosal mast cells in PAR (P = 0.03). IR patients differ to allergic subjects in showing significantly reduced numbers of epithelial HLA‐DRα+ cells (P = 0.007), but increased numbers of CD8+ lymphocytes (P = 0.02). The CD8+ T cells correlated with mucosal mast cell numbers (P = 0.02). In both rhinitis groups, basophils were present in very low numbers obviating the need for statistical analysis. Conclusion: PAR is characterized by increased numbers of CD3+, CD25+ and CD45RA+ T lymphocytes compared with normal mucosa. Allergic and nonallergic rhinitis groups can be separated by significant differences in the number of epithelial antigen presenting cells (APCs) (HLA‐DRα+) and sub‐epithelial activated (CD25+) T cells. Moreover, IR patients do not significantly differ to their allergic counterparts with respect to total (CD3+) and naïve (CD45RA+) T cell numbers, or numbers of epithelial activated (CD25+) lymphocytes. IR subjects show significantly increased numbers of CD8+ lymphocytes compared with control mucosa and although our findings suggest that the initiating inflammatory events may differ, both rhinitis groups show a similarity in pathology involving mucosal mast cells with an association to infiltrating T cells.