Rye Grass Pollen Research Articles

Evaluation of IL10, TGF-B and Specific IgE and IgG Levels during Sublingual Rye Grass Immunotherapy

Background: Sublingual Immunotherapy (SLIT) is a safe mechanism for treatment of some allergic disorders. This study investigated the effect of SLIT on specific IgG, IgE, Interlukin 10 (IL10) and Transforming Growth Factor beta (TGF-β) levels. Material and methods: This randomized double blind trial was performed 2 months prior to the grass pollination till the end of the season for about 6 months. Patients (5-18 yrs old) with allergic rhinitis to rye grass pollen, randomly received grass pollen or placebo extract and specific IgG and IgE level were assessed. IL10 and TGF-β were also measured before and after treatment. Data were analyzed by SPSS software. Results: Twenty of 24 patients completed the study. We did not find any significant difference in specific IgG and IgE levels before and after study between the two groups, however there was statistically significant elevation of IL10 (PV=0.003) and TGF-β (PV=0.006) levels after immunotherapy in the intervention group. Conclusion: This study showed sublingual immunotherapy had significant effect on regulatory cytokines.

Subtropical grass pollen allergens are important for allergic respiratory diseases in subtropical regions

BackgroundGrass pollen allergens are a major cause of allergic respiratory disease but traditionally prescribing practice for grass pollen allergen-specific immunotherapy has favoured pollen extracts of temperate grasses. Here we aim to compare allergy to subtropical and temperate grass pollens in patients with allergic rhinitis from a subtropical region of Australia.MethodsSensitization to pollen extracts of the subtropical Bahia grass (Paspalum notatum), Johnson grass (Sorghum halepense) and Bermuda grass (Cynodon dactylon) as well as the temperate Ryegrass (Lolium perenne) were measured by skin prick in 233 subjects from Brisbane. Grass pollen-specific IgE reactivity was tested by ELISA and cross-inhibition ELISA.ResultsPatients with grass pollen allergy from a subtropical region showed higher skin prick diameters with subtropical Bahia grass and Bermuda grass pollens than with Johnson grass and Ryegrass pollens. IgE reactivity was higher with pollen of Bahia grass than Bermuda grass, Johnson grass and Ryegrass. Patients showed asymmetric cross-inhibition of IgE reactivity with subtropical grass pollens that was not blocked by temperate grass pollen allergens indicating the presence of species-specific IgE binding sites of subtropical grass pollen allergens that are not represented in temperate grass pollens.ConclusionsSubtropical grass pollens are more important allergen sources than temperate grass pollens for patients from a subtropical region. Targeting allergen-specific immunotherapy to subtropical grass pollen allergens in patients with allergic rhinitis in subtropical regions could improve treatment efficacy thereby reducing the burden of allergic rhinitis and asthma.

WITHDRAWN: Cernilton for benign prostatic hyperplasia.

Benign prostatic hyperplasia (BPH), nonmalignant enlargement of the prostate, can lead to obstructive and irritative lower urinary tract symptoms (LUTS). The pharmacologic use of plants and herbs (phytotherapy) for the treatment of LUTS associated with BPH has been growing steadily. Cernilton, prepared from the rye-grass pollen Secale cereale, is one of the several phytotherapeutic agents available for the treatment of BPH. This systematic review aims to assess the effects of Cernilton on urinary symptoms and flow measures in men with benign prostatic hyperplasia (BPH). Trials were searched in computerized general and specialized databases (MEDLINE, EMBASE, Cochrane Library, Phytodok), by checking bibliographies, and by contacting manufacturers and researchers. Trials were eligible if they were: (1) randomized controlled trials or controlled clinical trials comparing Cernilton with placebo or other BPH medications in men with BPH; and (2) included clinical outcomes such as urologic symptom scales, symptoms, or urodynamic measurements. Information on patients, interventions, and outcomes was extracted by at least two independent reviewers using a standard form. Main outcome measure for comparing the effects of Cernilton with placebo and standard BPH medications were the change in urologic symptoms scales. Secondary outcomes included changes in nocturia as well as urodynamic measures (peak and mean urine flow, residual volume, prostate size). Main outcome measure for side effects was the number of men reporting side effects. Four hundred forty-four men were enrolled in two placebo-controlled and two comparative trials lasting from 12 to 24 weeks. Three studies used a double-blind method although treatment allocation concealment was unclear in all. Cernilton improved "self rated urinary symptoms" (percent reporting satisfactory or improving symptoms) versus placebo and Tadenan. The weighted risk ratio (RR) for self-rated improvement versus placebo was 2.40 (95% CI = 1.21 to 4.75), and the weighted RR versus Tadenan was 1.42 (95% CI = 1.21 to 4.75). Cernilton reduced nocturia compared with placebo and Paraprost. Versus placebo, the weighted RR was 2.05 (95% CI = 1.41 to 3.00), and versus Paraprost, the WMD was -0.40 times per evening (95% CI = -0.73 to -0.07). Cernilton was not more effective than placebo or the comparative study agents in improving urinary flow rates, residual volume or prostate size. Adverse events were rare and mild. The withdrawal rate for Cernilton was 4.8% compared to 2.7% for placebo and 5.2% for Paraprost. The Cernilton trials analyzed were limited by short duration, limited number of enrollees, gaps in reported outcomes, and unknown quality of the preparations utilized. The comparative trials lacked a proven active control. The available evidence suggests Cernilton is well tolerated and modestly improves overall urologic symptoms including nocturia. Additional randomized placebo and active-controlled trials are needed to evaluate the long-term clinical effectiveness and safety of Cernilton.

Increased presentations to emergency departments for asthma associated with rye grass pollen season in inland NSW

This study measured the frequency and geographical extent of peaks in asthma presentations to emergency departments in inland NSW; it assessed the characteristics of patients who presented at peak presentation times during the rye grass pollination season (October-November) and at other times of the year. Data describing over 13 years of daily emergency department presentations with a provisional diagnosis of asthma at nine inland NSW base hospitals were assembled. Days of counts in the top 0.1 percentile for each emergency department were classified as peak asthma count days. While the rye grass pollen season accounts for only 17% of days in the year, 53% of peak asthma count days fell within that period. Patients aged over 14 years represented 74% of visits on peak asthma count days during the pollen season and 50% on peak days at other times of the year. Under the right climatic conditions, rye grass pollen may be responsible for presentations for acute asthma to emergency departments in inland NSW.

The Effector T Cell Response to Ryegrass Pollen Is Counterregulated by Simultaneous Induction of Regulatory T Cells

Allergy is associated with pathological Th2 responses to otherwise harmless environmental Ags. In contrast, nonallergic individuals mount nonpathological immune responses to allergens, partly attributed to regulatory T cell (Treg) activity. Although thymus-derived natural Tregs have been shown to maintain tolerance to self-Ags and prevent autoimmunity, the generation of Tregs specific to non-self-Ags is less well understood. We investigated the potential for induction of Tregs from PBMCs of ryegrass pollen-allergic or healthy subjects by stimulation in vitro with ryegrass pollen extract in the absence of additional exogenous stimuli. We found that two subsets of proliferating CD4(+) T cells were induced, one expressing intermediate levels of Foxp3 (and IFN-gamma, IL-4, IL-17, or IL-2) and the other expressing high levels of Foxp3 (and no effector cytokines). After enrichment based on CD39 expression, the Foxp3(hi) subset suppressed CD4(+) T cell proliferation and IFN-gamma production. The Foxp3(hi) Treg originated from both conversion of dividing non-Tregs (CD4(+)CD25(-)CD127(hi)) and expansion of natural Tregs (CD4(+)CD25(+)CD127(lo)). Stable functional Tregs expressing high levels of Foxp3 were induced simultaneously with effector T cells by allergen stimulation. Induction of Foxp3(hi) Tregs was reduced in allergic subjects. These results indicate that the cogeneration of Foxp3(hi) Tregs in response to allergen may be a mechanism for controlling allergic reactions in healthy individuals, which is impaired in those with allergies.

Clinical significance of cross-reactivity between tobacco and latex

Background Allergen cross-reactivity between tobacco and other species of Solanaceae family (tomato, potato, aubergine and egg plant) have been reported. We have recently studied IgE response to tobacco in asthmatic patients sensitised to Lolium perenne (Perennial rye grass pollen) and have found that 30% of the tobacco responsive patients also have latex sensitisation. Objective The aim of our study was to investigate the possibility of cross-reactivity between tobacco and latex in asthmatic patients with IgE response to latex. Methods A study was performed on tobacco and latex exposure in 15 patients who suffered from asthma and latex sensitisation and who were randomly chosen from our database of latex-sensitive patients. To identify tobacco and latex as possible allergens that might cause clinical specific responses, all these patients were tested with prick-tests, specific IgE to tobacco, latex and related allergens, bronchial challenge, and patch tests with tobacco, latex and nicotine. Immunological response was evaluated with immunoblotting, immunoblotting-inhibition and EAST-inhibition tests. Results Positive prick and bronchial challenge with specific IgE>0.35 kU/L to tobacco was demonstrated in 11 asthmatics who were also sensitised to rye grass. Tobacco IgE level was related with sensitisation to latex ( p<0.002), but not to other vegetables belonging to the Solanaceae family. EAST-inhibition and immunoblotting-inhibition showed the existence of cross-reactivity between tobacco and latex. Conclusions Cross-reactivity exists between latex and tobacco allergens. Smoker patients with IgE response to tobacco may be a risk population for latex sensitisation.

Food allergy in children: threshold distribution curves for 6 major food allergens

Background The subtropical Bahia grass (Paspalum notatum) is an important source of pollen allergens with an extended season of pollination and wide distribution in warmer climates. The immunological relationship between pollen allergens of Bahia grass and temperate grasses is unresolved. Methods Serum IgE reactivity of grass pollen-allergic patients with Bahia, Ryegrass and Bermuda grass pollen extracts and their purified group 1 allergens, Pas n 1, Lol p 1 and Cyn d 1, were compared by immunoblotting, ELISA, inhibition ELISA, basophil activation by flow cytometry and molecular modeling. Results Differences in antibody recognition of allergenic components between Bahia grass and Ryegrass pollen were observed by immunoblotting. Eight grass pollen-allergic patients from a temperate region showed greater serum IgE reactivity with Ryegrass pollen than Bahia grass by ELISA. For seven of these sera, Ryegrass pollen inhibited IgE reactivity with Bahia grass pollen but not the converse. For 51 sera from grass pollen-allergic patients in this temperate region, IgE reactivity with Lol p 1 was greater than Pas n 1 or Cyn d 1. IgE reactivity with Lol p 1 was not inhibited by Pas n 1 or Cyn d 1, but Pas n 1 IgE reactivity was inhibited by Lol p 1. Two group 1 grass pollen allergen-specific mAb distinguished between temperate and subtropical grass pollens. Basophil activation for three patients tested was greater by Ryegrass pollen than Bahia or Bermuda grass, and by Lol p 1 than Pas n 1 or Cyn d 1. In contrast, two patients from a subtropical region had higher serum IgE reactivity with Bahia grass pollen than Ryegrass and Bahia grass pollen inhibited IgE reactivity with Ryegrass. A structural model of Pas n 1 showed amino acids implicated in IgE epitopes of other group 1 allergens were juxtaposed on the surface. Conclusion Allergens from subtropical Bahia grass pollen, including Pas n 1, share antigenic determinants with temperate grass pollen allergens, but patients exhibit higher serum IgE reactivity to their locally predominant grass pollen. Basophil activation by Bahia grass pollen and Pas n 1 in patients from a temperate climate indicates clinically relevant cross-sensitization between temperate and subtropical grass pollens.

The interaction between early life upper respiratory tract infection and birth during the pollen season on rye‐sensitized hay fever and ryegrass sensitization – a birth cohort study

Studies on early life viral respiratory infection and subsequent atopic disease in childhood have conflicting findings. Animal models show that viral respiratory infection in conjunction with allergen presentation can enhance sensitization. This prospective study assesses the influence of an upper respiratory tract infection (URI) in the first month of life and the season of birth on the development of hay fever and ryegrass allergen sensitization in childhood. From a Tasmanian cohort born during 1988 and 1989, a group of 498 children were followed up at 8 yr and another different group of 415 children were followed up at 16 yr. The ryegrass pollen season in Tasmania occurs in November and December. Forty-four (9.6%) children in Follow-up sample 1 and 47 (12.5%) children in Follow-up sample 2 were born in the pollen season. The parental report of an early upper respiratory tract infection (EURI) was documented prospectively by a home interview at 1 month of age (median age 5.1 wk). Sensitization to ryegrass and house dust mite (HDM) was determined at 8 yr of age by skin prick testing and at 16 yr by ImmunoCap. Ryegrass sensitized hay fever was defined as a positive response to a question on hay fever plus the presence of ryegrass allergy. For children tested at age 8 and born in the pollen season, a EURI by postnatal interview was associated with an increased risk of ryegrass sensitization (OR 5.80 95% CI 1.07, 31.31) but not for children with a EURI born outside the pollen season (OR 0.62 95% CI 0.35, 1.08). Similarly, EURI was significantly associated with early onset (< or = 8 yr) ryegrass sensitized hay fever for children born in the pollen season (AOR 4.78 95% CI 1.17, 19.47) but was not associated with early onset ryegrass sensitized hay fever for children born outside the pollen season (AOR 0.76 95% CI 0.43, 1.33). These findings suggest that early life viral URI interacts with ryegrass allergen exposure in the development of ryegrass allergen sensitization and ryegrass sensitized hay fever symptoms.

Novel IgE Recognized Components of Lolium perenne Pollen Extract: Comparative Proteomics Evaluation of Allergic Patients Sensitization Profiles

In the last years, proteomic investigation provided a powerful tool in molecular characterization of complex allergen sources with relevant implications in both diagnosis and immunotherapic treatment of allergies. We followed a proteomic approach to characterize ryegrass (Lolium perenne) pollen, a common cause of seasonal allergic diseases affecting an increasing part of world population. Peptide shotgun experiments performed on nanoLiquid Ultra Pressure Chromatography coupled with fast Q-TOF MS-MS/MS acquisition protocols (MS(E)) and 2-DE immunoblot combined with MALDI-TOF-TOF analysis allowed the detection of all previously identified ryegrass allergens. Comparative analysis of immunoblot highlighted a class of patients characterized by a more complex 2-DE pattern associated with increased levels of IgE antibodies and by higher susceptibility to multiple sensitization toward different allergen sources. Cluster analysis revealed that all these patients recognized profilin, considered the main cross-reactive allergen in grass pollen. Furthermore, mass spectrometry analysis revealed the presence of other IgE reactive components in ryegrass pollen that might be involved in polysensitization, such as cyclophilin, fructosyltransferase and legumin-like protein.

Evaluation of Molecular Basis of Cross Reactivity between Rye and Bermuda Grass Pollen Allergens

Allergenic cross reactivity between the members of the Pooids (Lolium perenne, Phleum pratense, and Poa pratensis) and Chloridoids (Cynodon dactylon and Paspalum notatum) is well established. Studies using crude extracts in the past have demonstrated limited cross reactivity between the Pooids and the Chloridoids suggesting separate diagnosis and therapy. However, little is known regarding the molecular basis for the limited cross reactivity observed between the 2 groups of grasses. The present study was undertaken to gain insights into the molecular basis of cross allergenicity between the major allergens from rye and Bermuda grass pollens. Immunoblot inhibition tests were carried out to determine the specificity of the proteins involved in cross reactivity. Crude pollen extract and bacterially expressed and purified recombinant Lol p 1and Lol p 5 from rye grass were subjected to cross inhibition experiments with crude and purified recombinant Cyn d 1 from Bermuda grass using sera from patients allergic to rye grass pollen. The immunoblot inhibition studies revealed a high degree of cross inhibition between the group 1 allergens. In contrast, a complete lack of inhibition was observed between Bermuda grass group 1 allergen rCyn d 1, and rye grass group 5 allergen rLol p 5. Crude rye grass extract strongly inhibited IgE reactivity to Bermuda grass, whereas crude Bermuda grass pollen extract showed a weaker inhibition. Our data suggests that a possible explanation for the limited cross reactivity between the Pooids and Chloridoids may, in part, be due to the absence of group 5 allergen from Chloridoid grasses. This approach of using purified proteins may be applied to better characterize the cross allergenicity patterns between different grass pollen allergens.

Modulation of immune response to Lol p I by pretreatment with anti-idiotypic antibody is not restricted to the idiotypic expression.

To study the role of anti-idiotypic antibodies in the regulation of the immune response to Lol p I (the major allergenic component of rye grass pollen), we have recently generated a panel of three MoAbs directed against distinct epitopes of Lolp I and an anti-idiotypic MoAb directed against the idiotype borne by one of the anti-Lol p I MoAbs (290A-167). The effects of pretreatment with this anti-idiotypic MoAb in BALB/c mice before immunization with the antigen have been examined. The anti-idiotypic MoAb or unrelated MoAb were given weekly for 8 weeks intraperitoneally. Mice then received the antigen (2 micrograms) adsorbed with alum (2 mg) at weeks 9, 11 and 13. Serum anti-Lol p I antibodies (IgG or IgE) and specific idiotypic responses were measured. Anti-Lol p I IgG antibodies could be detected before immunization with Lol p I only in mice pretreated with anti-idiotypic MoAb. Immunization with Lol p I induced an anti-Lol p I IgG response in both groups, but this response was higher in mice that received anti-idiotypic MoAb. Similar profiles were seen for specific IgE antibodies and idiotypic responses. Surprisingly, idiotypes borne by other anti-Lol p I MoAbs (539A-6 and 348A-6) had also been enhanced after pretreatment with the anti-290A-167 MoAb. These observations suggested that the pretreatment with this anti-idiotypic MoAb modulates not only the expression of the respective idiotype, but also affects other idiotype responses.

Cross-reactivity Between Tobacco and Latex in Asthmatic Sensitive Patients

Recently, allergen cross-reactivity was observed between tobacco and other species of Solanaceae family (tomato, potato, aubergine). We have recently studied IgE response to tobacco in asthmatic patients sensitised to Lolium perenne (rye grass pollen) and have found that 30% of tobacco responsive patients had also latex sensitisation.

The temporal sequence of allergic sensitization and onset of infantile eczema.

Eczema is commonly associated with sensitization in infants, but the causative role of sensitization in the development of eczema has been questioned. To determine if allergic sensitization increases the risk of developing eczema, or alternatively, if eczema increases the risk of developing allergic sensitization. We used data from the Melbourne Atopy Cohort Study, a prospective birth cohort of 552 infants with a family history of atopic disease. The main outcomes were risk of developing eczema from 6 months to 7 years of age in asymptomatic infants; and risk of developing sensitization, as measured by skin prick tests to milk, egg white, peanut, house dust mite, rye grass pollen and cat extracts, in previously unsensitized infants. Sensitization to food extracts at 6 months was associated with an increased risk of developing eczema [hazard ratio (HR) 1.63, 95% confidence interval 1.13-2.35] up to 7 years of age, after excluding infants with eczema in the first 6 months. However, eczema in the first 6 months was also associated with increased risk of new sensitization at both 1 year (HR 2.34, 1.38-3.98) and 2 years (HR 3.47, 1.65-7.32). In some infants, sensitization precedes and predicts the development of eczema, while in others eczema precedes and predicts the development of sensitization. This indicates that there are multiple pathways to atopic eczema.

Tobacco as an allergen in bronchial disease

Skin testing and sera measurements have verified the existence of tobacco specific IgE. However, the few published studies on this matter report conflicting results concerning their clinical significance. To verify if a specific clinical allergenic response against tobacco might be possible in allergenic and nonallergenic bronchial diseases. We performed a cross-sectional observational case-control analysis on 180 patients with asthma, chronic obstructive pulmonary disease (COPD), and bronchial carcinoma and controls who were randomly chosen. Skin prick tests and serum specific IgE to tobacco and related allergens, bronchial challenge with cigarettes and tobacco extract, patch tests with tobacco and nicotine, sodium dodecyl sulfate-polyacrylamide gel electrophoresis immunoblotting, and Enzyme AllergoSorbent Test (EAST) inhibition were performed. Twenty-eight patients had positive tobacco skin prick test results. The association among positive skin prick test results, IgE, and bronchial challenge was strong (P < .001). Tobacco sensitivity was higher in patients with pollen asthma than in patients with COPD and carcinoma and negative in patients with intrinsic asthma and controls. A positive bronchial challenge result was related to the length of habit (P < .001) and the tobacco index in patients who had stopped smoking (P < .001). Delayed bronchial and patch response was more common in patients with COPD (P < .001). Tobacco IgE response (EAST) was related to sensitivity to Lolium perenne (rye grass) pollen (P < .001) but not to other vegetables that belong to the Solanaceae family. EAST inhibition showed cross-reactivity between tobacco and Lolium pollen. Tobacco may be responsible for a specific IgE response. Patients with pollen asthma were those with more positive responses to tobacco due to cross-reactivity between Lolium and tobacco allergens.

Meteorological Effects May Alter the Incidence of Rye-grass Pollen Related Asthma

RATIONALE: Rye-grass pollen releases numerous respirable fragments upon exposure to high relative humidity (RH). These range in diameter from 30 nm to 4 μm. Also, wind tunnel experiments showed that a minimum wind speed of 6 mph was required to release rye-grass pollen and pollen fragments from their anthers.

Doença alérgica polínica: polens alergógenos e seus principais alérgenos

Pacientes com alergia a pólen de gramíneas, comumente denominada polinose, freqüentemente apresentam reatividade a alérgenos de pólen de inúmeras gramíneas devido às reatividades cruzadas entre anticorpos IgE dirigidos contra proteínas presentes nos polens de gramíneas. Nesse contexto, pólen de Italian ryegrass (Lolium multiflorum), ou azevém anual, gramínea da família Poaceae cultivada no Sul do Brasil, é considerado o principal agente sensibilizante em pacientes com polinose. Nessa região, o azevém é capaz de produzir grande quantidade de pólen. Adicionalmente, outras gramíneas da família Poaceae crescem naturalmente no Sul, entretanto, sem relevância clínica. Extratos de pólen derivados de gramíneas homólogas ou heterólogas são freqüentemente empregados no diagnóstico e tratamento da alergia sazonal a pólen, sendo que para esses fins não se encontra comercialmente disponível no Brasil extrato padronizado de pólen de L. multiflorum. Futuros estudos serão importantes para melhor caracterizar a reatividade cruzada entre alérgenos de pólen de L. multiflorum e alérgenos de outras gramíneas com o objetivo de aprimorar o diagnóstico e imunoterapia de pacientes com alergia a pólen causada por L. multiflorum.

Consultation and referral guidelines citing the evidence: How the allergist-immunologist can help

Consultation and referral guidelines citing the evidence: How the allergist-immunologist can help

Bahia grass pollen specific IgE is common in seasonal rhinitis patients but has limited cross‐reactivity with Ryegrass

Perennial Ryegrass is a major cause of rhinitis in spring and early summer. Bahia grass, Paspalum notatum, flowers late into summer and could account for allergic rhinitis at this time. We determined the frequency of serum immunoglobulin (Ig)E reactivity with Bahia grass in Ryegrass pollen allergic patients and investigated IgE cross-reactivity between Bahia and Ryegrass. Serum from 33 Ryegrass pollen allergic patients and 12 nonatopic donors were tested for IgE reactivity with Bahia and Ryegrass pollen extracts (PE) by enzyme-linked immunosorbent assay (ELISA), western blotting and inhibition ELISA. Allergen-specific antibodies from a pool of sera from allergic donors were affinity purified and tested for IgE cross-reactivity. Seventy-eight per cent of the sera had IgE reactivity with Bahia grass, but more weakly than with Ryegrass. Antibodies eluted from the major Ryegrass pollen allergens, Lol p 1 and Lol p 5, showed IgE reactivity with allergens of Ryegrass and Canary but not Bahia or Bermuda grasses. Timothy, Canary and Ryegrass inhibited IgE reactivity with Ryegrass and Bahia grass, whereas Bahia, Johnson and Bermuda grass did not inhibit IgE reactivity with Ryegrass. The majority of Ryegrass allergic patients also showed serum IgE reactivity with Bahia grass PE. However, Bahia grass and Ryegrass had only limited IgE cross-reactivity indicating that Bahia grass should be considered in diagnosis and treatment of patients with hay fever late in the grass pollen season.

Transgenic ryegrasses (Lolium spp.) with down-regulation of main pollen allergens

Ryegrass pollen (Lolium species) is a widespread source of air-borne allergens and is a major cause of hayfever and seasonal allergic asthma, which affect approximately 25% of the population in cool temperate climates. The main allergens of ryegrass pollen are the proteins Lol p 1 and Lol p 2. These proteins belong to two major classes of grass pollen allergens to which over 90% of pollen-allergic patients are sensitive. The functional role in planta of these pollen allergen proteins remains largely unknown. Here we describe the generation and analysis of transgenic plants with reduced levels of the main ryegrass pollen allergens, Lol p 1 and Lol p 2 in the most important worldwide cultivated ryegrass species, L. perenne and L. multiflorum. These transgenic plants will allow the study of the functional role in planta of these pollen proteins and the determination of potential for development of hypo-allergenic ryegrass cultivars.

Age-related T cell responses to allergens in childhood.

T cell priming, as determined by allergen-induced proliferative responses, is believed to occur principally in early childhood in both atopic and non-atopic infants under the influence of multiple factors including environmental allergen exposure. It is considered that T cell priming with expansion of Th2 cells is a crucial factor in the development of atopic disease. To examine T cell priming to commonly encountered allergens in childhood in relation to age. In a cross-sectional study T cell proliferation in relation to age was examined for three common allergens, ovalbumin (OVA), house dust mite (HDM) and rye grass pollen (RYE), in atopic and non-atopic children. The effect of age on Th1 (IFN-gamma) and Th2 (IL-5 and IL-13) cytokine production in response to these allergens was investigated to examine the possibility of immune deviation with time. A significant increase in T cell proliferation with age was observed with RYE among atopic children only. However, the same was not observed with the two other allergens studied (i.e. OVA and HDM). In addition, RYE-induced (but not HDM or OVA) cytokine production showed an increased Th2 deviation with age as reflected in the increasing IL-5/IFN-gamma and IL-13/IFN-gamma ratios only among the atopic subjects with rye grass pollen sensitivity. These findings suggest that grass pollen sensitivity in childhood is accompanied by a progressive accumulation of allergen-primed T cells and progressive deviation of the allergen-induced cytokine response towards a Th2 response in atopic subjects throughout childhood.