A double-blind, placebo-controlled trial of local nasal immunotherapy in allergic rhinitis to Parietaria pollen

We assessed the efficacy and safety of local nasal immunotherapy (LNIT) using an extract in macronized powder form of Parietaria pollen, a very important allergenic plant in the Mediterranean and other parts of the world. Twenty-six patients aged 13–37 years, with seasonal allergic rhinitis to this pollen, were enrolled in a double-blind placebo-controlled trial, carried out from autumn 1991 to the end of June 1992. They were selected on the basis of a positive skin-prick test, radioallergosorbent test (RAST) and intranasal challenge to Parietaria antigen. Patients were randomly divided into two groups of 13; the first group was given Parietaria antigen, and the second placebo. We recorded mean weekly symptom scores and drug consumption for 17 weeks during the pollen season in the year 1992, and specific serum-IgE and IgG levels. Three patients in the active group withdrew from the study because of bronchial symptoms. A significant difference was observed in mean weekly nasal symptom scores, in drug consumption and in specific nasal threshold to Parietaria allergenic extract in the treated and control groups. No difference was observed in serum IgE and IgG levels. Serum IgE levels rose significantly only in the control group after the pollen season. This study indicates that LNIT may be a useful alternative to traditional subcutaneous immunotherapy in patients with allergic rhinitis.     

A study on airborne allergenic pollen content of the atmosphere of Naples

In this paper we describe the results of volumetric sampling of the airborne allcrgenic pollen content of the Naples atmosphere. These studies have been carried out continuously since 1 May 1979 until 31 December 1981 utilizing a Burkard volumetric spore trap. We found that the most important allergenic pollen in Naples air is Parietaria, with a very long-lasting period of pollination occurring from March to November. After Parietaria. Gramineae play an allergenic role frequently in association with the pollen of Olea, which is the most important pollen of all the trees in this area. In the summer/autumn seasons we observed in this area the pollination of mugwort (the unique plant of the Compositae) which was found to be of allergenic importance in Naples.     

Seasonal idiopathic rhinitis with local inflammatory response and specific IgE in absence of systemic response

Background: Patients with idiopathic rhinitis (IR) are considered to be nonallergic because they have a negative skin prick test (SPT) and allergen specific‐IgE in serum. The concept of localized mucosal allergy in the absence of atopy has recently been proposed. The immunological mechanisms involved in seasonal IR have not been sufficiently studied. We examined nasal mucosa inflammation, the presence of nasal specific‐IgE and the response to nasal allergen provocation test (NAPT) in patients with seasonal IR who presented symptoms only in spring. Methods: We evaluated 32 patients with seasonal IR and 35 with persistent allergic rhinitis to pollen (PAR‐P) and compared these with healthy controls and persons with PAR to house dust mite during the pollen season, as well as by NAPT out‐of‐season with grass and Olea europea. We measured the nasal leukocyte–lymphocyte phenotype (CD45, CD33, CD16, CD3, CD4 and CD8), eosinophil‐cationic‐protein, and total and specific‐IgE to grass and olive pollen in serum and nasal lavage and performed NAPT. Results: In the IR group, 62.5% had a positive NAPT (IR‐PosNAPT), 20/32 to grass, with four of these having a positive NAPT to olive pollen as well. IR‐PosNAPT patients showed a similar nasal leukocyte–lymphocyte profile to the PAR‐P patients and different to controls. We detected nasal specific‐IgE in 35% of IR‐PosNAPT patients. Conclusions: These results support the hypothesis that a subgroup of patients with IR have seasonal symptoms with evidence of a nasal allergic immune reaction in the absence of a positive SPT or serum specific IgE.     

Specific IgE serum concentration is associated with symptom severity in children with seasonal allergic rhinitis

Background: The impact of allergen‐specific and total IgE serum levels before and during the pollen season on symptom severity as well as efficacy of treatment with anti‐IgE requires further delineation. Methods: Birch and grass pollen allergic patients aged 6–17 years with seasonal allergic rhinitis (SAR) were analyzed for the association of IgE serum concentration with symptom severity and rescue medication use (combination: symptom load, SL) during the grass pollen season. Reference group A (n = 53) received placebo, while group B (n = 54) received Omalizumab (anti‐IgE) monotherapy before and during the grass pollen season. Results: Patients on placebo with high baseline specific grass pollen IgE (>50 kU/l) had a significantly higher SL compared with those with low IgE levels (≤50 kU/l): SL 1.28 vs 0.61, P = 0.015. This association was nonexistent in patients treated with anti‐IgE. In contrast, baseline total IgE levels did not correlate with SL in any group. Patients with anti‐IgE treatment and high free total IgE levels (>16.7 ng/ml) had a significantly higher SL compared with those with low free total IgE levels (≤16.7 ng/ml): SL 0.63 vs 0.23, P = 0.031. Conclusions: Baseline specific IgE, but not total IgE, is associated with symptom severity during the pollen season in children with SAR. Likewise, the symptom load in SAR patients with anti‐IgE correlates with free total IgE levels. Although further research in larger populations is needed to confirm our findings, our data suggest that specific IgE can be used as a parameter for patient selection for this kind of treatment.     

PI3-Kinase Regulates Eosinophil and Neutrophil Degranulation in Patients with Allergic Rhinitis and Allergic Asthma Irrespective of Allergen Challenge Model

The PI3K pathway plays a major role in many vital cell processes. Our primary aim was to investigate signalling through PI3K for in vitro degranulation from allergen-primed eosinophils and neutrophils in allergic rhinitis and allergic asthma after seasonal and experimental allergen challenge. Nine patients with allergic rhinitis, eight with allergic asthma and four controls were studied during birch pollen season and after nasal and bronchial allergen challenge. Primed blood eosinophils and neutrophils were stimulated for in vitro degranulation with C3b-coated Sephadex particles, after prior incubation with Wortmannin, a PI3K inhibitor. The released amounts of eosinophil cationic protein (ECP), eosinophil peroxidase (EPO) and myeloperoxidase (MPO) were measured by radioimmunoassay. Wortmannin (10⁻⁶ to 10⁻⁹ M) inhibited ECP, EPO and MPO release in a dose-dependent manner in allergic rhinitis and allergic asthma in all three allergen challenge models. Inhibition of ECP release tended to be lower in the asthmatics in all allergen challenge models, statistically significant compared to the controls during season for 10⁻⁸ M Wortmannin (p = 0.01). A clear propensity towards less inhibition in the rhinitic patients was seen after nasal and bronchial challenge compared to seasonal exposure, significant for ECP (10⁻⁸ M Wortmannin; p = 0.034 and 0.002, respectively). Signalling through PI3K is clearly involved in ECP, EPO and MPO release in allergic rhinitis and allergic asthma irrespective of allergen challenge model. Allergic asthma demonstrated less inhibition of ECP release via PI3K during pollen season, indicating that other pathways play a greater role in eosinophil degranulation in allergic asthma than allergic rhinitis.     

Effect of seasonal exposure to pollen on specific bronchial sensitivity in allergic patients

Bronchial provocation tests with aerosol of birch extract were performed before and after pollen season in 11 sensitized subjects. Changes of metacholine bronchial responsiveness and serum-specific IgE level were also assessed. In five patients who did not take steroids to control their symptoms, both early and late asthmatic responses to inhaled allergen were enhanced after season, whereas IgE serum level, but not methacholine sensitivity, was significantly increased. In six patients who needed steroids, neither responses to allergen nor IgE serum level and methacholine sensitivity were significantly changed after season. For the whole group, the increase in immediate bronchial sensitivity to allergen was positively correlated with the increase in specific IgE antibodies. We conclude that seasonal exposure to pollen has, in sensitized patients, a priming effect on bronchial mucosa that may be blunted by steroid treatment. The increased production of specific IgE antibodies appears to be an important mechanism for this priming effect.     

Reaginic allergy to Parthenium pollen: evaluation by skin test and RAST

The pollen of Parthenium hysterophorus, an alien weed growing wild in India was found to be a potential source of allergic rhinitis. A clinical survey showed that 34% of the patients suffering from rhinitis and 12% suffering from bronchial asthma gave positive skin-prick test reactions to Parthenium pollen antigen extracts. Parthenium-specific IgE was detected in the sera of sixteen out of twenty-four patients suffering from seasonal rhinitis. There was 66% correlation between skin test and RAST.     

SOME IMMUNOLOGICAL ASPECTS OF PATIENTS WITH RHINITIS IN LEBANON

ABSTRACT

Background: Hitherto immunological determinates in Lebanese patients with rhinitis have not been investigated.

Objective: To identify causative allergens in Lebanese patients with allergic rhinitis and determine possible correlation's among serum allergen specific antibody, polyclonal IgE, IL-4, IL-5 and peripheral eosinophil levels.

Methods: One hundred and thirteen patients with a long lasting history of nasal obstruction, rhinorrhea, sneezing and nasal itching were investigated. Serum allergen specific antibodies using a panel of 10 potential allergens, IL-4 and IL-5 levels were determined by enzyme immunoassays. Polyclonal IgE levels were estimated by an immunochromatographic assay and eosinophil counts by a Coulter STKS counter.

Results: Based on the presence of serum allergen-specific IgE antibodies, 74 patients were considered to have an allergic etiology. Polyclonal IgE levels were elevated in 41 of the 74 allergic rhinitis patients while the other 33 patients had normal serum levels. In the remaining 39 specific IgE antibody-negative patients, 32 had normal, and 7 had elevated, polyclonal IgE levels. IgE specific antibodies to more than one allergen were detected in 59 of 74 patients. The most common causative allergens were mite, Dermatophagoides pteronyssinus, Dpt (83.8%) and Dermatophagoides farinae, Df (78.4%). Analysis of the data indicated that elevated polyclonal IgE levels correlated with the concentration of serum specific IgE antibodies and the number of the detected causative allergens per patient. Fifty-nine of 74 allergic rhinitis patients had elevated IL-4 levels and 44 had elevated IL-5 levels. The number of allergic patients with both elevated IL-4 and IL-5 levels was 24. Finally, only 9 allergic rhinitis patients had peripheral eosinophilia.

Conclusion: Mite Dpt and Df were the most common causative agents of allergic rhinitis in the Lebanese group studied. A prerequisite for Specific Immunotherapy is the identification of the causative allergen. Determinations of polyclonal IgE level and peripheral eosinophil count alone, as an aid to diagnosis are insufficient and may be misleading. On the other hand, determination of all the parameters studied in conjunction appears to be of diagnostic value.     

Detection of allergen-specific IgE in tears of grass pollen-allergic patients with allergic rhinoconjunctivitis

Background Allergic conjunctivitis is a common symptom amongst Type I (IgE-mediated) allergic diseases; and mosl frequently seen as rhinoconjunctivitis. However, the site of production and the significance of allergen specific IgE needs further elucidation. Objective We investigated whether the presence of IgE in tears of grass pollen allergic patients correlated with disease and clinical symptoms, whether the IgE binding pattern to the different grass pollen antigens was diflferent in sera and tears, and whether IgA antibodies to grass pollen allergens were present in tears. Finally, we looked whether specific IgE was produced locally or was exudated from serum. Methods Sera from 44 grass pollen allergic patients suffering from either allergic rhinitis (n=11) or allergic rhinoconjunctivitis (n= 33) and from healthy controls (n= l) were used for the experiments. Binding of specific IgE and IgA antibodies to the differyent groups of grass pollen allergens (Phleum pratense) was evaluated by means of immunobtotting. Results Specific IgE was detected in sera as well as in tears of allergic patients, whereby tear-derived allergen-specific IgE exerted similar specificities to the corresponding IgE from serum. The correlation between symptoms of ocular allergy and the presence of allergen-specific IgE in tears was highly significant (P 0.0001). In contrast, only a poor correlation was found between specific and/or total IgE in sera and the manifestation of ocular allergy (P = 0.73). Conclusion Allergen-specific IgE antibodies in tears seem to be produced locally rather than exsudated from serum. IgE in tears seems to be responsible for allergic conjunctivitis. IgA in tears cannot exert a protective function since the IgA antibodies recognize different antigens in a grass pollen (Phleum pratense) extract than IgE antibodies. The highly significant correlation between allergic conjunctivitis and the presence of specific tear IgE emphasizes the diagnostic value of immunoblots with tear IgE, especially in cases in which serum provides inconclusive results.     

IgE, IgG and IgA antibodies in serum and nasal secretion during parenteral hyposensitization

Eighteen adult patients with allergic rhinitis due to Timothy pollen were observed for 36 weeks before, during and after the grass pollen season. Eight patients were treated by parenteral hyposensitization with grass pollen extract, and ten patients who were given no immunotherapy served as controls. Timothy-specific IgE, IgG and IgA antibodies in samples of serum and nasal secretion were quantified by radioimmunological technique. In comparison with the control group, the serum concentration of Timothy-specific IgE antibodies increased significantly (P <0.05) during the preseasonal hyposensitization treatment and then decreased significantly (P <0.05) during and after the pollen season while this therapy was being continued. In the hyposensitized patients the serum concentration of both IgG and IgA antibodies increased highly significantly (P <0.01 and P <0.001, respectively) during immunotherapy. In nasal secretion quantitative changes of the three types of antibodies were usually less pronounced or not detectable at all. The concentration of IgG antibodies, however, showed some increase in the nasal secretion during hyposensitization. These minor increases in allergen-specific IgG and IgA antibodies in nasal secretion might explain why parenteral hyposensitization in allergic rhinitis often does not give complete relief from symptoms.     

Variability of Total and Free IgE Levels and IgE Receptor Expression in Allergic Subjects in and Out of Pollen Season

The inter‐ and intra‐individual variability and seasonal variation of IgE, and high (FcεRI)‐ and low‐affinity (CD23) IgE receptor expression in blood of seasonal allergic rhinitis (SAR) subjects, is not well studied. Thirty‐two otherwise healthy subjects with a history of SAR to birch pollen and a positive skin prick test to birch pollen were sampled three times out of the pollen season and three times during the pollen season. FcεRI and CD23 expressions were analysed using flow cytometry. Total IgE was analysed using ImmunoCAP^® and free IgE was analysed with a novel customised research assay using an IgG‐FcεRI‐chimera protein coupled to ImmunoCAP as capture reagent, ImmunoCAP‐specific IgE conjugate and ImmunoCAP IgE calibrators. The performance of the free IgE assay was compared well with the reference ImmunoCAP total IgE assay. The working range of the assay was 0.35–200 kU/l IgE. FcεRI expression on basophils and CD23 expression on B cells showed low intrasubject variability both in and out of the pollen season (<10% CV). There was a small seasonal difference with lower total IgE levels (120 versus 128 kU/l; P = 0.004) and FcεRI expression (283 versus 325 mean fluorescence intensity (MFI); P < 0.001) during the pollen season. IgE, FcεRI expression and CD23 expression fulfilled biomarker and assay requirements of variability, and allergen exposure affected the biomarkers only to a minor degree. The free IgE assay may be used for measurement of free IgE levels in patients after anti‐IgE antibody treatment.     

Standardization of pollen allergens of Parthenium hysterophoms and selection of an in-house reference extract

A standardized in-house reference extract from the pollen of Parthenium hysterophoms, which is responsible for the high incidence of allergic rhinitis in India, was generated and examined by skin test, radio-allergosorbent test inhibition and isoelectric focusing. Parthenium reference allergen discs and positive reference serum were also generated. These reference reagents could not only be used for the quantitation of Panhenium-specific IgE in the sera of rhinitis patients but also for the evaluation of allergenic activity (relative potency and lot-to-lot variation) of different batches of Parthenium pollen.     

Changes in airway inflammation following nasal allergic challenge in patients with seasonal rhinitis

BACKGROUND: Seasonal allergic rhinitis could predispose to the development of chronic bronchial inflammation as observed in asthma. However, direct links between nasal inflammation, bronchial inflammation and airway responsiveness in patients with seasonal allergic rhinitis and without asthma are not fully understood. The aim of this study was to analyse the changes induced by allergic nasal challenge outside the pollen season in airway responsiveness and bronchial inflammation of patients with seasonal allergic rhinitis. METHODS: Nine patients were evaluated after either grass pollens or placebo nasal challenge in a randomized cross-over double-blinded trial. Nasal parameters were recorded hourly and airway responsiveness was assessed by methacholine challenge. Cytological examinations and cytokine measurements were performed in nasal lavage and induced sputum. Eosinophil activation was investigated by eosinophil-cationic protein expression and secretion. RESULTS: Airway responsiveness was increased after allergic nasal challenge. Total eosinophils and eosinophils expressing eosinophil-cationic protein were increased in induced sputum after allergic nasal challenge. Both eosinophil number and eosinophil-cationic protein concentration in induced sputum were correlated to methacholine responsiveness. CONCLUSIONS: These results suggest that eosinophils participate to the bronchial inflammation in patients with seasonal allergic rhinitis following allergic nasal challenge outside the pollen season and might explain changes in airway responsiveness.     

Immunotherapy with Alpare® in patients with respiratory allergy to Parietaria pollen: a two year double-blind placebo-controlled study

Allergy to Parietaria judaica pollen causes significant morbidity in many areas of the world. In addition to rhinitis, patients who are allergic to this pollen have a high incidence of asthma. The pollinating season is long, making this particular allergy challenging for clinicians to treat. This study was designed to determine if immunotherapy with an alum adsorbed partially purified Parietaria extract (Alpare Parietaria) containing a targeted maintenance dose of 12 500 BUs was effective in decreasing rhinitis symptoms in patients allergic to Parieiaria. Using a double-blind placebo-controlled technique 36 patients received placebo or active extract for 2 years. Twenty (11 placebo and nine active) completed the 2 year study. Efficacy of treatment was evaluated by determining changes in skin reactivity, visual analog scores, diary symptom scores and end of study assessments. Reactions were monitored as well. Skin-test suppression was marginally significant in the actively treated group after 1 year and showed even more significant suppression after the second year. Nasal block, rhinorrhoea and sneezing all were significantly decreased in the active group. The nasal provocation test did not show a significant change after 1 year, in either group, but after 2 years of treatment the active group did show significant improvement. Although almost all patients in the actively treated group experienced local reactions, the incidence of systemic reactions was not different between the two groups. In conclusion, immunotherapy with this extract at this dose was effective in ameliorated rhinitis symptoms in patients allergic to Parietaria judaica.     

Allergen-Induced Synthesis of Interleukin-5, but not of IgE, is a Key Mechanism Linked to Symptomatic Episodes of Seasonal Allergic Rhinitis in Sensitized Individuals

Some individuals with detectable levels of Japanese cedar (Criptomeria japonica) pollen-specific immunoglobulin (Ig)E in serum have no apparent nasal symptoms during the pollen season. The response of CD4⁺ T-helper (Th) cells to the pollen allergen might differ fundamentally between asymptomatic and symptomatic individuals who are already sensitized to the pollen. The aim of this study was to discern the possible differences in responses of peripheral blood mononuclear cells (PBMCs) to the pollen allergen between asymptomatic and symptomatic subjects who have been sensitized to the pollen. This study included 20 non-atopic healthy volunteers (non-atopic group) and 48 patients who had detectable levels of the pollen-specific IgE before the pollen season in 1997. In the review of nasal symptoms during the pollen season 1997, 24 patients had typical symptoms of seasonal allergic rhinitis (symptomatic group), and the remainder had no seasonal aggravation of nasal symptoms (asymptomatic group). Peripheral blood mononuclear cells (1.0 × 10⁷ cells/well) were obtained from each individual during the pollen season and cultured in the absence or presence of 12.5 μg of Cry j 1 for 4 days. The concentrations of IgE, interleukin-5 (IL-5), and interferon-gamma (IFN-γ) in the culture supernatants were measured. The levels of IgE produced by Cry j 1-stimulated PBMCs of the asymptomatic and symptomatic groups were significantly higher than those of the non-atopic group, but did not differ between the asymptomatic and symptomatic groups. The levels of IL-5 produced by Cry j 1-stimulated PBMCs did not differ significantly between the non-atopic group and the asymptomatic group, but the levels of IL-5 were significantly higher in the symptomatic group than in the asymptomatic group as well as the non-atopic group. The levels of IFN-γ produced by Cry j-1 stimulated PBMCs did not differ significantly among the three groups. In conclusion, our study has suggested that Japanese cedar pollen-induced synthesis of IL-5, but not of IgE or IFN-γ, is likely to be a key mechanism linked to the symptomatic episode of seasonal allergic rhinitis in individuals sensitized to the pollen.     

Evaluation of allergen-specific IgE antibodies by a newly developed mast allergy system

MAST, which stand for multiple antigen simultaneous test, uses enzyme-linked anti-human IgE and chemiluminogenic substate to determine IgE. This system is characterized by simultaneous analysis of multiple allergen items, up to 35, together with total IgE determination. We evaluated usefulness of this MAST system using 191 serum samples obtained from patients with bronchial asthma, allergic rhinitis and/or atopic dermatitis. It was found that there were statistically significant correlations between IgE antibody quantification by MAST and RAST in 24 out of 35 allergen items, with correlation coefficients more than r = 0.60. These included Dermatophagoides farinae and pteronyssinus, Japanese cedar pollen, orchard grass, Alternaria, Candida as inhalant allergens; egg white, milk, soybeans, wheat and rice as food allergens. It was also evaluated how many allergen-specific IgE antibodies could be detected in one serum sample. More than six allergen-specific IgE antibodies were simultaneously detected in 33% of 191 cases, indicating the importance of multiple-allergen analysis. These results indicate the clinical usefulness of the MAST allergy system in detecting IgE antibodies in allergic subjects.     

Seasonal asthma caused by airborne Platanus pollen

This work describes three patients suffering from bronchial asthma after being naturally exposed to airborne plane-tree pollen. The three patients gave immediate response in skin tests and dual response in bronchial provocations using Platanus hybrida extract. There was specific seric IgE activity against this/these antigen(s) with the CAP system. The three patients also showed significant correlation (P < 0·001) between their rhinitis and asthma symptom-scores registered on their diary cards and plane-tree pollen counts, collected using the Burkard spore trap. Among 187 patients living in Madrid and who came to our centre with a history of rhinitis and/or seasonal asthma, we found a prevalence of positive skin-prick tests to Platanus of 56%, only surpassed by gramineous pollen (Dactylis glomerata and/or Trisetum paniceum) 92% and Olea europaea 63%. The aerobiological sampling of the pollen content of the air in Madrid, carried out between 1 January 1979 and 31 December 1993 revealed an airborne presence (per cent of total yearly pollen count, mean of 1979–1993) of 14·9% for the Platanus, 14·8% for grasses, 9·8% for Olea and 3·6% for Plantago. The Platanus is one of the most frequently found pollens in the atmosphere over Madrid. At present, in this geographical area, a high percentage of patients with pollinosis are sensitive to this pollen. At least in some of these patients Platanus pollen is capable of inducing rhinitis and bronchial asthma.     

Bronchial histamine reactivity: its relationship to the reactivity of the bronchi to allergens

The aim of this study was to examine the proposal that the magnitude of the response of the bronchi to an immediate allergic reaction depends not only on the degree of sensitization of the bronchi by allergen specific IgE antibody but also on the reactivity of the bronchi to the vasoactive mediators which are released during immediate allergic reactions. This was done by determining the bronchial reactivity to Dermatophagoides pteronyssinus and to histamine of both symptomatic and asymptomatic groups of atopic subjects who had comparable serum levels of D. pteronyssinus specific IgE. Positive bronchial responses to the D. pteronyssinus extract were recorded with both the symptomatic and asymptomatic subjects, the mean bronchial threshold dose of allergen being significantly higher in the asymptomatic than in the asthmatic patients. There was a highly significant correlation between the serum level of allergen specific IgE and the bronchial threshold dose of allergen extract and also between the bronchial threshold dose of allergen extract and of histamine in all groups of subjects. The ability to predict bronchial reactivity to the allergen from the serum level of allergen specific IgE within each group was significantly better if the bronchial reactivity to histamine was included in the correlation analysis. This supports the hypothesis that whether a particular subject who is producing specific IgE antibody will develop symptoms on the inhalation of that allergen depends not only on the amount of allergen which he inhales and on the degree of sensitization of his bronchi but also on the reactivity of his bronchi to the vasoactive mediators which are released by allergen–IgE interaction.     

Specific cellular and humoral immunity in children with grass pollen asthma

Lymphocyte stimulation, as determined by incorporation of thymidine, to rye grass extract in twenty-three children with bronchial reactivity to rye grass and to house dust mite, did not differ significantly from four children with reactivity to house dust mite alone, or from nine children with asthma but without a bronchial response to these allergens. Sixteen children underwent hyposensitization with rye grass extract or treatment with placebo. There was no consistent effect of hyposensitization on the lymphocyte stimulation indices to rye grass. A decrease in lymphocyte responsiveness occurred to rye grass and to house dust mite after the grass pollen season but was not statistically significant. Analysis of changes in lymphocyte responsiveness to both house dust mite and rye grass of the children most highly sensitized to rye allergen, showed that the lymphocyte responsiveness to rye grass fell during the pollen season (P<0.05) but this effect was not seen with house dust mite. The study suggests that a decrease in lymphocyte responsiveness to rye grass allergen in children with large amounts of anti-rye IgE antibodies is antigen specific and may be seen following seasonal exposure.