Standardization of an Ash (Fraxinus excelsior) Pollen Allergen Extract

Real-life safety of 5-grass pollen tablet in 5-to-9-year-old children with allergic rhinoconjunctivitis

BACKGROUND

Although 5-grass pollen sublingual immunotherapy has a good safety profile in controlled clinical trials, additional safety information among pediatric patients in a real-world setting would be useful.

OBJECTIVE

To further document the safety of 5-grass tablet among children aged 5 to 9 years with allergic rhinoconjunctivitis (ARC).

METHODS

This multicenter, observational study included allergy immunotherapy-naïve 5- to 9-year-old children with grass pollen-induced ARC prescribed with 5-grass tablet daily (3-day dose escalation to 300 index of reactivity [IR]). Patients were followed up daily for safety and tolerability over the first 30 treatment days. Adverse events (AEs) and adverse drug reactions (ADRs) were analyzed descriptively.

RESULTS

Three hundred seven children (mean age, 7.1 years) were enrolled. Fifty-eight percent were confirmed as polysensitized, and 36% had mild-to-moderate asthma. Of 307 patients, 233 (76%) reported AEs, and 173/307 (56%) reported ADRs, most frequently mild application-site reactions (throat irritation, oral pruritus, oral paresthesia). Sixteen of 307 (5.2%) patients withdrew because of ADRs. In 143 of 173 (83%) patients, ADRs first occurred within 1 week of starting treatment. More than half of the ADRs lasted less than 2 days, and ADRs resolved spontaneously in 161 of 173 (93%) patients. Recurrences of ADRs were reported in 45 of 173 (26%) patients and were also mainly application-site reactions. No notable differences were found in ADRs related to whether patients had asthma at inclusion. Neither epinephrine use nor admission to intensive care unit was reported.

CONCLUSION

The safety profile of 5-grass tablet in pediatric ARC patients aged 5 to 9 years was consistent with safety findings in older patients, most ADRs being at the application site and mild to moderate. ClinicalTrials.gov identifier: NCT02295969; EUPAS registration number: 8104.

Safety Review of 5-Grass Pollen Tablet from Pooled Data of Clinical Trials

BACKGROUND

The 5-grass pollen sublingual tablet has been approved for the treatment of grass pollen-induced allergic rhinoconjunctivitis in subjects with or without intermittent asthma.

OBJECTIVE

To provide a comprehensive analysis of the safety profile of the 5-grass tablet on the basis of pooled data from 8 clinical trials.

METHODS

Subjects (5-65 years old) with medically confirmed grass pollen-induced allergic rhinoconjunctivitis were included in the double-blind studies. Those with intermittent asthma not requiring treatment other than inhaled beta-2 agonists could participate. Randomized subjects received a 5-grass or placebo tablet daily 2 or 4 months preseasonally and coseasonally (5 single-season studies, over 3 years in a long-term study) or outside the season (phase I studies). Adverse events were pooled and analyzed descriptively.

RESULTS

Among 2,512 subjects enrolled, 1,514 received the 5-grass tablet. A total of 1,038 adults and 154 pediatric (5-17 years old) subjects were treated with the 300 Index of Reactivity dose (vs 840 and 158 placebo recipients, respectively); 17% had intermittent asthma, and 62% were polysensitized. Adverse reactions (ADRs) reported in more than 10% of actively treated subjects were mild or moderate application-site reactions, for example, oral pruritus 25% (placebo 4%) and throat irritation 21% (placebo 3%). These generally occurred during the first week of treatment and decreased over time. They led to discontinuation in less than 2.5% of subjects. None of the 3 serious ADRs were reports of anaphylaxis. No notable differences were detected in terms of incidence, nature, and severity of ADRs between adult and pediatric populations, nor between subjects with or without asthma.

CONCLUSIONS

The pooled analysis in 1,514 subjects from 8 clinical studies demonstrates that the 5-grass pollen sublingual tablet has a similar good safety profile in adult and pediatric patients with or without mild, intermittent asthma.

Common solvents for making extraction of allergenic proteins from plants' pollens for prick tests and related factors: a technical review

Collecting information on influencing factors in developing consistent and high-quality extracts results in accurate diagnosis and effective treatment of type I allergy (IgE mediated). Furthermore, considering that a large number of allergens are currently in practice, any attempt to develop a more effective procedure for preparing extract may be useful. Nowadays, different saline solvents, temperature, incubation time, and PH are being incorporated for preparing allergen extracts. The objective of the current study was to clear and address the commonest of solvent buffers and allied conditions for making extracts of pollens of grasses, trees, and weeds. The literature review was done in Jan 2016 on PubMed and Google Scholar medical search engines without any time limitation. After reading abstracts of 87 articles, finally 37 relevant papers were selected and their full texts were retrieved. In conclusion, 24 full-text papers were recognized appropriate and chosen. The extracted information for papers has been described fully in the text. On the basis of these data, PBS buffer with PH 7.4, temperature of 4 °C and with overnight incubation time, may be the optimized condition in order to have a proper extract for carrying out skin prick tests.

Fraxinus pollen and allergen concentrations in Ourense (South-western Europe)

In temperate zones of North-Central Europe the sensitization to ash pollen is a recognized problem, also extended to the Northern areas of the Mediterranean basin. Some observations in Switzerland suggest that ash pollen season could be as important as birch pollen period. The allergenic significance of this pollen has been poorly studied in Southern Europe as the amounts of ash pollen are low. Due to the high degree of family relationship with the olive pollen major allergen (backed by a sequence identity of 88%), the Fraxinus pollen could be a significant cause of early respiratory allergy in sensitized people to olive pollen as consequence of cross-reactivity processes. Ash tree flowers in the Northwestern Spain during the winter months. The atmospheric presence of Ole e 1-like proteins (which could be related with the Fra a 1 presence) can be accurately detected using Ole e 1 antibodies. The correlation analysis showed high Spearman correlation coefficients between pollen content and rainfall (R(2)=-0.333, p<0.01) or allergen concentration and maximum temperature (R(2)=-0.271, p<0.01). In addiction CCA analysis showed not significant differences (p<0.05) between the component 1 and 2 variables. PCFA analysis plots showed that the allergen concentrations are related to the presence of the Fraxinus pollen in the air, facilitating the wind speed its submicronic allergen proteins dispersion. In order to forecast the Fraxinus allergy risk periods, two regression equations were developed with Adjusted R(2) values around 0.48-0.49. The t-test for dependent samples shows no significant differences between the observed data and the estimated by the equations. The combination of the airborne pollen content and the allergen quantification must be assessed in the epidemiologic study of allergic respiratory diseases.

Ash pollen allergy: reliable detection of sensitization on the basis of IgE to Ole e 1

Background: Alongside hazel, alder and birch pollen allergies, ash pollen allergy is a relevant cause of hay fever during spring in the European region. For some considerable time, ash pollen allergy was not routinely investigated and its clinical relevance may well have been underestimated, particularly since ash and birch tree pollination times are largely the same. Ash pollen extracts are not yet well standardized and diagnosis is therefore sometimes unreliable. Olive pollen, on the other hand, is strongly cross-reactive with ash pollen and is apparently better standardized. Therefore, the main allergen of olive pollen, Ole e 1, has been postulated as a reliable alternative for the detection of ash pollen sensitization. Methods: To determine to what extent specific IgE against Ole e 1 in patients with ash pollen allergy is relevant, we included 183 subjects with ash pollen allergy displaying typical symptoms in March/April and positive skin prick test specific IgE against Ole e 1 (t224) and ash pollen (t25) and various birch allergens (Bet v 1, Bet v 2/v 4) in a retrospective study. Results: A significant correlation was seen between specific IgE against Ole e 1 and ash pollen, but also to a slightly lesser extent between IgE against Ole e 1 and skin prick test with ash pollen, the latter being even higher than IgE and skin prick test both with ash pollen. No relevant correlation was found with birch pollen allergens, demonstrating the very limited cross-reactivity between ash and birch pollen. Conclusion: It appears appropriate to determine specific IgE against Ole e 1 instead of IgE against ash pollen to detect persons with ash pollen allergy. Our findings may also support the idea of using possibly better standardized or more widely available olive pollen extracts instead of ash pollen extract for allergen-specific immunotherapy.

The spectrum of olive pollen allergens. From structures to diagnosis and treatment

Olive tree is one of the main allergy sources in Mediterranean countries. The identification of the allergenic repertoire from olive pollen has been essential for the development of rational strategies of standardization, diagnosis, and immunotherapy, all of them focused to increase the life quality of the patients. From its complex allergogram, twelve allergens - Ole e 1 to Ole e 12 - have been identified and characterized to date. Most of them have been cloned and produced as recombinant forms, whose availability have allowed analyzing their three-dimensional structures, mapping their T-cell and B-cell epitopes, and determining the precise allergenic profile of patients for a subsequent patient-tailored immunotherapy. Protein mutant, hypoallergenic derivatives, or recombinant fragments have been also useful experimental tools to analyze the immune recognition of allergens. To test these molecules before using them for clinic purposes, a mouse model of allergic sensitizations has been used. This model has been helpful for assaying different prophylactic approaches based on tolerance induction by intranasal administration of allergens or hypoallergens, used as free or integrated in different delivery systems, and their findings suggest a promising utilization as nasal vaccines. Exosomes - nanovesicles isolated from bronchoalveolar lavage fluid of tolerogenic mice - have shown immunomodulatory properties, being able to protect mice against sensitization to Ole e 1.

Generation and characterization of anti-chitinase monoclonal antibodies

Class IV chitinase, an allergenic protein of Vitis vinifera (grape), was purified by anion exchange chromatography and used for immunization of Balb/c mice. Monoclonal antibodies (MAbs) were raised by hybridoma technology using Sp2/0 myeloma cells. Finally after three limiting dilutions, six stable clones were generated. Antibody isotyping showed that IgG(2a), IgG(2b), and IgM were produced by one, two, and three of the clones, respectively. All of the MAbs had kappa light chain. The affinities were in the range of 3 × 10(8) to 1.2 × 10(9) M(-1). The MAbs were specific for grape chitinase as confirmed by Western blotting. In conclusion, we successfully produced several MAbs against grape class IV chitinase, which could be used for assessment of this allergen in different grape cultivars.

Evaluation of ash pollen sensitization pattern using proteomic approach with individual sera from allergic patients

BACKGROUND

In Europe, sensitization to ash pollen induces pollinosis with cross-reactivities with other pollen sources. The aim of the study was to identify the repertoire of ash pollen allergens and evaluate the extent of the diversity of the IgE response in ash allergic patients.

METHODS

The IgE reactivities of 114 ash pollen- and eight grass pollen-sensitized patients were screened by 1D immunoblot (SDS-PAGE) against ash pollen extract. The IgE reactivities of 13 ash pollen- and two grass pollen-sensitized patients were then evaluated in 2D immunoblots. Some IgE- and non-IgE-reactive proteins were identified by mass spectrometry.

RESULTS

In 1D analysis, 86% of sera showed binding to Fra e 1 (18-20 kDa), 23% to Fra e 2 (14 kDa), 3% to Fra e 3 (10 kDa) and 57% to High Molecular Weight allergens (HMW, >30 kDa). Individual analysis of 2D immunoblots showed several IgE-binding protein areas among which three were more often recognized: (i) Fra e 1 comprising, at least, 15 isoforms, (ii) a series of acidic spots (45 kDa), and (iii) Fra e 2, the ash profilin. HMW allergens could be resolved in four areas; two unidentified, one homologous to beta-galactosidase and the other to sugar transport proteins. A malate deshydrogenase and calmodulin were shown to be IgE-binding proteins and 10 non-IgE reactive proteins were identified.

CONCLUSIONS

No direct correlation was evidenced between IgE profile and the degree of sensitization even though 2 spectrotypes could be distinguished. Our data contribute to a better delineation of ash pollen allergens and patterns of sensitization.

Efficacy and safety of 5-grass-pollen sublingual immunotherapy tablets in pediatric allergic rhinoconjunctivitis

BACKGROUND

The efficacy and safety of the 300-index of reactivity (IR) dose of 5-grass-pollen sublingual immunotherapy (SLIT) tablets (Stallergènes, Antony, France) have been demonstrated for the treatment of hay fever in adults.

OBJECTIVE

We sought to assess the efficacy and safety of this tablet in children and adolescents with grass pollen-related allergic rhinitis.

METHODS

In this multinational, randomized, double-blind, placebo-controlled study, 278 children (5-17 years of age) with grass pollen-related rhinoconjunctivitis (confirmed by means of a positive grass pollen skin prick test response and serum-specific IgE measurement) received once-daily SLIT tablets or placebo. Treatment was initiated 4 months before the estimated pollen season and continued throughout the season. The primary outcome was the rhinoconjunctivitis total symptom score (RTSS), a sum of 6 individual symptom scores: sneezing, runny nose, itchy nose, nasal congestion, watery eyes, and itchy eyes. Secondary end points included rescue medication intake, individual scores, and safety.

RESULTS

The intent-to-treat population included 266 children (mean age, 10.9 +/- 3.22 years). The RTSS for the 300-IR group was highly significantly different from that of the placebo group (P = .001). The 300-IR group showed a mean improvement for the RTSS of 28.0% over that seen with placebo and a median improvement of 39.3%. Significant differences between the 300-IR and placebo groups were also observed regarding rescue medication score and proportion of days using rescue medication during the pollen season (P = .0064 and P = .0146, respectively). Adverse events were generally mild or moderate in intensity and expected. No serious side effects were reported.

CONCLUSION

Five-grass-pollen SLIT tablets (300 IR) reduce both symptom scores and rescue medication use in children and adolescents with grass pollen-related rhinoconjunctivitis.