Six-Food Elimination Diet Is Less Effective During Pollen Season in Adults With Eosinophilic Esophagitis Sensitized to Pollens.

INTRODUCTION: The role of inhaled and swallowed aeroallergens in treatment outcomes of adult patients with eosinophilic esophagitis (EoE) is unclear. We hypothesized that the pollen season contributes to the failure of the 6-food elimination diet (SFED) in EoE. METHODS: We compared outcomes of patients with EoE who underwent SFED during vs outside of the pollen season. Consecutive adult patients with EoE who underwent SFED and skin prick test (SPT) for birch and grass pollen were included. Individual pollen sensitization and pollen count data were analyzed to define whether each patient had been assessed during or outside of the pollen season after SFED. All patients had active EoE (≥15 eosinophils/high-power field) before SFED and adhered to the diet under the supervision of a dietitian. RESULTS: Fifty-eight patients were included, 62.0% had positive SPT for birch and/or grass, whereas 37.9% had negative SPT. Overall, SFED response was 56.9% (95% confidence interval, 44.1%-68.8%). When stratifying response according to whether the assessment had been performed during or outside of the pollen season, patients sensitized to pollens showed significantly lower response to SFED during compared with outside of the pollen season (21.4% vs 77.3%; P = 0.003). In addition, during the pollen season, patients with pollen sensitization had significantly lower response to SFED compared with those without sensitization (21.4% vs 77.8%; P = 0.01). DISCUSSION: Pollens may have a role in sustaining esophageal eosinophilia in sensitized adults with EoE despite avoidance of trigger foods. The SPT for pollens may identify patients less likely to respond to the diet during the pollen season.

BSACI guideline for the diagnosis and management of pollen food syndrome in the UK.

Pollen food syndrome (PFS) is a highly prevalent food allergy affecting pollen-sensitized children and adults. Sufferers experience allergic symptoms when consuming raw plant foods, due to the homology between the pollen allergens and unstable proteins in these foods. The triggers involved can vary depending on the pollen sensitization, which in turn is affected by geographical location. The British Society of Allergy and Clinical Immunology (BSACI) Standards of Care Committee (SOCC) identified a need to develop a guideline for the diagnosis and management of PFS in the United Kingdom (UK). Guidelines produced by the BSACI use either the GRADE or SIGN methodology; due to a lack of high-quality evidence these recommendations were formulated using the SIGN guidelines, which is acknowledged to be less robust than the GRADE approach. The correct diagnosis of PFS ensures the avoidance of a misdiagnosis of a primary peanut or tree nut allergy or confusion with another plant food allergy to non-specific lipid transfer proteins. The characteristic foods involved, and rapid-onset oropharyngeal symptoms, mean PFS can often be diagnosed from the clinical history alone. However, reactions involving tree nuts, peanuts and soya milk or severe/atypical reactions to fruits and vegetables may require additional diagnostic tests. Management is through the exclusion of known trigger foods, which may appear to be simple, but is highly problematic if coupled with a pre-existing food allergy or for individuals following a vegetarian/vegan diet. Immunotherapy to pollens is not an effective treatment for PFS, and although oral or sublingual immunotherapy to foods seems more promising, large, controlled studies are needed. The typically mild symptoms of PFS can lead to an erroneous perception that this condition is always easily managed, but severe reactions can occur, and anxiety about the onset of symptoms to new foods can have a profound effect on quality of life.

Synchronous immune alterations mirror clinical response during allergen immunotherapy.

BACKGROUND: Three years of treatment with either sublingual or subcutaneous allergen immunotherapy has been shown to be effective and to induce long-term tolerance. The Gauging Response in Allergic Rhinitis to Sublingual and Subcutaneous Immunotherapy (GRASS) trial demonstrated that 2 years of treatment through either route was effective in suppressing the response to nasal allergen challenge, although it was insufficient for inhibition 1 year after discontinuation. OBJECTIVE: We sought to examine in the GRASS trial the time course of immunologic changes during 2 years of sublingual and subcutaneous immunotherapy and for 1 year after treatment discontinuation. METHODS: We performed multimodal immunomonitoring to assess allergen-specific CD4 T-cell properties in parallel with analysis of local mucosal cytokine responses induced by nasal allergen exposure and humoral immune responses that included IgE-dependent basophil activation and measurement of serum inhibitory activity for allergen-IgE binding to B cells (IgE-facilitated allergen binding). RESULTS: All 3 of these distinct arms of the immune response displayed significant and coordinate alterations during 2 years of allergen desensitization, followed by reversal at 3 years, reflecting a lack of a durable immunologic effect. Although frequencies of antigen-specific TH2 cells in peripheral blood determined by using HLA class II tetramer analysis most closely paralleled clinical outcomes, IgE antibody-dependent functional assays remained inhibited in part 1 year after discontinuation. CONCLUSION: Two years of allergen immunotherapy were effective but insufficient for long-term tolerance. Allergen-specific TH2 cells most closely paralleled the transient clinical outcome, and it is likely that recurrence of the T-cell drivers of allergic immunity abrogated the potential for durable tolerance. On the other hand, the persistence of IgE blocking antibody 1 year after discontinuation might be an early indicator of a protolerogenic mechanism.

Intradermal grass pollen immunotherapy increases TH2 and IgE responses and worsens respiratory allergic symptoms.

BACKGROUND: Repeated low-dose grass pollen intradermal allergen injection suppresses allergen-induced cutaneous late-phase responses comparably with conventional subcutaneous and sublingual immunotherapy. OBJECTIVE: We sought to evaluate the efficacy and safety of grass pollen intradermal immunotherapy in the treatment of allergic rhinitis. METHODS: We randomly assigned 93 adults with grass pollen-induced allergic rhinitis to receive 7 preseasonal intradermal allergen injections (containing 7 ng of Phl p 5 major allergen) or a histamine control. The primary end point was daily combined symptom-medication scores during the 2013 pollen season (area under the curve). Analysis was by intention to treat. Skin biopsy specimens were collected after intradermal allergen challenges, and late-phase responses were measured 4 and 7, 10, or 13 months after treatment. RESULTS: There was no significant difference in the primary end point between treatment arms (active, n = 46; control, n = 47; median difference, 14; 95% CI, -172.5 to 215.1; P = .80). Among secondary end points, nasal symptoms were worse in the intradermal treatment group, as measured based on daily (median difference, 35; 95% CI, 4.0-67.5; P = .03) and visual analog scale (median difference, 53; 95% CI, -11.6 to 125.2; P = .05) scores. In a per-protocol analysis intradermal immunotherapy was further associated with worse asthma symptoms and fewer symptom-free days. Intradermal immunotherapy increased serum Phleum pratense-specific IgE levels (P = .001) compared with those in the control arm. T cells cultured from biopsy specimens of subjects undergoing intradermal immunotherapy had higher expression of the TH2 surface marker CRTH2 (P = .04) and lower expression of the TH1 marker CXCR3 (P = .01), respectively. Late-phase responses remained inhibited 7 months after treatment (P = .03). CONCLUSION: Intradermal allergen immunotherapy suppressed skin late-phase responses but was not clinically effective and resulted in worsening of respiratory allergic symptoms.

Peptide-induced immune regulation by a promiscuous and immunodominant CD4T-cell epitope of Timothy grass pollen: a role of Cbl-b and Itch in regulation.

BACKGROUND: T-cell targeted peptide epitope tolerogens from grass pollen allergens may be useful in treating seasonal allergic rhinitis, but there is urgent need for optimisation of approaches from improved understanding of mechanism. OBJECTIVE: We sought to identify human leukocyte antigen (HLA)-DR1-restricted epitopes from the Timothy grass pollen allergen, Phleum pratense, and characterise T-cell immune regulation following intranasal administration of a single, immunodominant epitope. METHODS: T-cell epitopes within P pratense were identified using HLA-DR1 transgenic mice and tetramer-guided epitope mapping (TGEM) in HLA-DR1-positive individuals with grass allergy. An immunodominant epitope was tested in HLA-DR1 transgenics for impact on responses to whole Phl p5 b or peptide. Microarrays and quantitative PCR were used to characterise T-cell immunity. RESULTS: Peptide 26 (p26) was identified in HLA-DR1 transgenic mice and by TGEM analysis of HLA-DR1-positive individuals with grass allergy. p26 shows promiscuous binding to a wide range of HLA class II alleles, making it of relevance across immunogenetically diverse patients. The epitope is conserved in rye and velvet grass, making it applicable across a spectrum of grass pollen allergy. Intranasal pretreatment of mice with p26 results in significantly reduced T-cell responses. Transcriptomic array analysis in mice showed T-cell regulation in the intranasal treatment group associated with increased expression of members of the Cbl-b and Itch E3 ubiquitin ligase pathway. CONCLUSIONS: We defined an immunodominant P pratense epitope, p26, with broad binding across multiple HLA class II alleles. Intranasal treatment of mice with p26 results in T-cell regulation to whole allergen, involving the Cbl-b and Itch regulatory pathway.

Repeated low-dose intradermal allergen injection suppresses allergen-induced cutaneous late responses.

BACKGROUND: Subcutaneous immunotherapy with high-dose grass pollen was first described more than 100 years ago. This treatment suppresses allergen-induced cutaneous late responses, with lesser effects on early responses. In contrast, low-dose subcutaneous immunotherapy has not shown clinical benefit. Uncontrolled reports from the early 20th century describe low-dose allergen inoculation directly into the dermis, an immunologically active area containing abundant dendritic cells and lymphatics. OBJECTIVE: We sought to investigate the effect of low-dose intradermal grass pollen administration on cutaneous reactivity to allergen. METHODS: Thirty adults sensitized to grass and tree pollens were randomized to receive (1) 6 repeat intradermal injections at 2-week intervals of grass pollen extract (estimated 7 ng of the major grass allergen Phl p 5 per injection), (2) 2 intradermal injections separated by 10 weeks, or (3) a single intradermal injection at 10 weeks. At the end of the study, cutaneous early and late responses were measured after double-blind intradermal injection with grass and birch pollen. RESULTS: Participants who received 6 fortnightly intradermal grass pollen injections had markedly smaller cutaneous late responses to grass pollen than control subjects who received 2 injections separated by 10 weeks (P < .01) or a single injection (P < .001) and showed induction of grass pollen-specific IgG antibodies. Suppression was observed whether late responses were measured on the arms or the back. However, early responses were equivalent in all groups. CONCLUSION: Low-dose intradermal allergen, like conventional subcutaneous high-dose immmunotherapy, suppresses allergen-induced cutaneous late responses in a manner that is allergen specific, systemic, and associated with induction of IgG antibodies.

Grass pollen immunotherapy: IL-10 induction and suppression of late responses precedes IgG4 inhibitory antibody activity.

BACKGROUND: Grass pollen immunotherapy is an effective treatment for seasonal allergic rhinitis that provides the opportunity to study the induction and maintenance of allergen-specific immune tolerance. OBJECTIVES: We investigated the relationship between clinical responsiveness, regulatory cytokine production, and antibody responses to allergen during 1 year of immunotherapy. METHODS: Eighteen subjects with severe seasonal allergic rhinitis were randomized double-blind to receive active or placebo injections of an alum-adsorbed grass pollen vaccine (Alutard SQ). Subjects underwent repeated testing of early- and late-phase skin responses to intradermal allergen, and cellular responses to grass pollen allergen were tested. Sera were tested for allergen-specific IgG4, IgA, and inhibitory activity in biologic assays of IgE responses. RESULTS: Grass pollen immunotherapy was effective in reducing overall symptom scores (P < .05) and conjunctival reactivity (P < .05). In the active group significant IL-10 production occurred early at low allergen doses and at a similar time as inhibition of late skin responses at 2 to 4 weeks. Serum allergen-specific IgG4, IgA, and inhibitory antibody activity for basophil histamine release and IgE-facilitated allergen binding to B cells occurred later, at 6 to 12 weeks, at higher allergen doses and preceded inhibition of early skin responses. CONCLUSION: IL-10 responses occur early but at immunotherapy doses that are not clinically effective. Later induction of inhibitory antibodies, including IgG4 and IgA, might be required for efficacy through modulation of IgE-mediated events.

Grass pollen immunotherapy induces mucosal and peripheral IL-10 responses and blocking IgG activity.

T regulatory cells and IL-10 have been implicated in the mechanism of immunotherapy in patients with systemic anaphylaxis following bee stings. We studied the role of IL-10 in the induction of clinical, cellular, and humoral tolerance during immunotherapy for local mucosal allergy in subjects with seasonal pollinosis. Local and systemic IL-10 responses and serum Ab concentrations were measured before/after a double-blind trial of grass pollen (Phleum pratense, Phl P) immunotherapy. We observed local increases in IL-10 mRNA-positive cells in the nasal mucosa after 2 years of immunotherapy, but only during the pollen season. IL-10 protein-positive cells were also increased and correlated with IL-10 mRNA(+) cells. These changes were not observed in placebo-treated subjects or in healthy controls. Fifteen and 35% of IL-10 mRNA signals were colocalized to CD3(+) T cells and CD68(+) macrophages, respectively, whereas only 1-2% of total CD3(+) cells and 4% of macrophages expressed IL-10. Following immunotherapy, peripheral T cells cultured in the presence of grass pollen extract also produced IL-10. Immunotherapy resulted in blunting of seasonal increases in serum allergen Phl p 5-specific IgE, 60- to 80-fold increases in Phl p 5-specific IgG, and 100-fold increases in Phl p 5-specific IgG4. Post-immunotherapy serum exhibited inhibitory activity, which coeluted with IgG4, and blocked IgE-facilitated binding of allergen-IgE complexes to B cells. Both the increases in IgG and the IgG "blocking" activity correlated with the patients' overall assessment of improvement. Thus, grass pollen immunotherapy may induce allergen-specific, IL-10-dependent "protective" IgG4 responses.

Inhibition of allergen-IgE binding to B cells by IgG antibodies after grass pollen immunotherapy.

BACKGROUND: Among atopic individuals, levels of allergen-specific IgG antibodies have been inversely associated with the degree of allergen sensitization. Additionally, allergen-specific IgG antibodies are markedly increased by allergen injection immunotherapy. These observations have led to proposals that allergen-specific IgG antibodies might have protective properties in atopic individuals. OBJECTIVE: We hypothesized that after grass pollen immunotherapy, these antibodies disrupt IgE-dependent allergen processing by antigen-presenting cells. METHODS: We have developed a novel flow cytometric assay based on detection of allergen-IgE binding to the low-affinity IgE receptor on B cells to examine the blocking effects of sera collected from 18 patients who participated in a double-blind, controlled trial of grass pollen immunotherapy for 1 year. RESULTS: In all 10 patients who received active therapy, there was induction of activity that inhibited allergen-IgE binding to B cells (P =.02, vs placebo subjects), as well as subsequent allergen presentation to T cells. This activity copurified with IgG and was allergen specific, because sera taken from patients treated with grass pollen immunotherapy but who were also birch pollen sensitive did not inhibit IgE-birch pollen allergen binding to B cells. CONCLUSION: We conclude that allergen-specific IgG antibodies induced by immunotherapy can disrupt formation of allergen-IgE complexes that bind to antigen-presenting cells and facilitate allergen presentation.

Induction of IL-10+CD4+CD25+ T cells by grass pollen immunotherapy.

BACKGROUND: Immunotherapy involves the modulation of allergen-specific T-cell responses, either T(H)2-to-T(H)1 immune deviation or, in bee venom-treated patients, induction of IL-10 production by CD4+CD25+ T cells. IL-10-producing CD4+CD25+ regulatory T cells have emerged as potential mediators of immune tolerance in numerous murine models of immunopathology. OBJECTIVE: The aim of this study was to evaluate the role of IL-10 production and CD4+CD25+ T cells in the response to grass pollen immunotherapy. METHODS: PBMCs were isolated from patients after 1 year of grass pollen immunotherapy and from matched untreated atopic and healthy control subjects. After 6 days of in vitro stimulation with Phleum pratense, production of IL-10, IL-5, IL-4, and IFN-gamma and proliferation and numbers of CD4+CD25+ T cells were measured. T cells were then stimulated for a further 5 hours with phorbol 12-myristate 13-acetate and ionomycin and assessed for intracellular IL-10 by means of flow cytometry. RESULTS: Patients undergoing immunotherapy produced significantly more IL-10 than atopic control subjects (patients undergoing immunotherapy, 116 +/- 21 pg/mL [n = 11]; atopic patients, 30 +/- 5 pg/mL [n = 11]; P <.001), and the number of CD4+CD25+ cells identified after allergen stimulation was also greater in the immunotherapy group. The numbers of CD4+CD25+ T cells correlated positively with activation as measured by proliferation in both of the control groups but not in the immunotherapy group. Moreover, only T cells from patients undergoing immunotherapy were positive for intracellular IL-10, and these were almost exclusively CD4+CD25+ cells. CONCLUSION: Grass pollen immunotherapy results in a population of circulating T cells that express the IL-10(+) CD4+CD25+ phenotype in response to allergen restimulation.

Grass pollen immunotherapy for hayfever is associated with increases in local nasal but not peripheral Th1:Th2 cytokine ratios.

Grass pollen immunotherapy is the only treatment for hayfever that is both effective and confers long-term benefit. Immunotherapy may act by altering the local nasal mucosal T helper type 2 (Th2) to type 1 (Th1) cytokine balance either by down-regulation and/or immune deviation of T-lymphocyte responses. There is controversy as to whether these changes are detectable in peripheral blood. We therefore examined both local nasal and peripheral T-cell responses to allergen exposure in the same subjects before and after immunotherapy. In a double-blind trial of grass pollen immunotherapy, nasal biopsies were obtained at baseline and during the peak pollen season following 2 years of immunotherapy. Placebo-treated patients showed a seasonal increase in CD3(+) T cells (P = 0.02) and in interleukin-5 (IL-5) mRNA(+) cells (P = 0.03) and no change in interferon-gamma (IFN-gamma ) mRNA(+) cells (P = 0.2) in the nasal mucosa. In contrast, in the immunotherapy-treated group, there were no changes in the number of CD3(+) T cells (P = 0.3) and IL-5 mRNA+ cells (P = 0.2) but a significant increase in the number of IFN-gamma mRNA(+) cells (P = 0.03). Furthermore, clinical improvement in the immunotherapy-treated group was accompanied by a seasonal increase in the ratio of IFN-gamma to IL-5 mRNA(+) cells in the nasal mucosa (P = 0.03). In contrast, there were no significant changes in peripheral T-cell proliferative responses or cytokine production for IFN-gamma or IL-5 in response to grass pollen either within or between the two treatment groups. We conclude that successful grass pollen immunotherapy was associated with an increase in the ratio of IFN-gamma to IL-5 mRNA(+) cells in the nasal mucosa, whereas these changes were not reflected by alterations in peripheral blood T-cell proliferative responses or cytokine production before/after treatment.