Diagnosis of cypress pollen allergy: in vivo and in vitro standardization of a Juniperus ashei pollen extract

Identification of Potential IgE-Binding Epitopes Contributing to the Cross-Reactivity of the Major Cupressaceae Pectate-Lyase Pollen Allergens (Group 1)

Pectate-lyase allergens, the group 1 of allergens from Cupressaceae pollen, consist of glycoproteins exhibiting an extremely well-conserved three-dimensional structure and sequential IgE-binding epitopes. Up to 10 IgE-binding epitopic regions were identified on the molecular surface, which essentially cluster at both extremities of the long, curved β-prism-shaped allergens. Most of these IgE-binding epitopes possess very similar conformations that provide insight into the IgE-binding cross-reactivity and cross-allergenicity commonly observed among Cupressaceae pollen allergens. Some of these epitopic regions coincide with putative N-glycosylation sites that most probably consist of glycotopes or cross-reactive carbohydrate determinants, recognized by the corresponding IgE antibodies from allergic patients. Pectate-lyase allergens of Cupressaceae pollen offer a nice example of structurally conserved allergens that are widely distributed in closely-related plants (Chamæcyparis, Cryptomeria, Cupressus, Hesperocyparis, Juniperus, Thuja) and responsible for frequent cross-allergenicity.

An improved pollen number counting method using a cell counter and mesh columns

BACKGROUND

The determination of pollen number is important in evolutionary, agricultural, and medical studies. Tree species of the Cupressaceae family cause serious pollinosis worldwide. Although Japanese cedar (Cryptomeria japonica) is the most important forestry species in Japan, it is also the biggest cause of pollinosis in the country. Japanese cedar trees have been selected for growth speed and superior morphological traits and then cloned. These clones may vary in their pollen production, but there has been little research on how many pollen grains are produced by a single male strobilus (flower). A recently reported method for counting pollen number with a cell counter was applicable to Arabidopsis species and wheat, but was not suitable for Japanese cedar because the strobilus does not open with heating (e.g. 60 °C, overnight).

RESULTS

Here, we report an improved pollen counting method for Japanese cedar using a precise and rapid cell counter in combination with home-made mesh columns. The male strobilus was gently crushed using a pestle. Large and small debris were then removed using 100- and 20-μm mesh columns, respectively. We successfully detected pollen sizes and numbers that differed between two clones using this method.

CONCLUSIONS

This improved method is not only suitable for counting pollen from Japanese cedar, but could also be applied to other species of the Cupressaceae family with hard scale tissue covering the pollen. Moreover, this method could be applied to a broader range of plant species, such as wheat, because there is no need to wait for anthesis and debris can be removed efficiently.

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.

New product development with the innovative biomolecular sublingual immunotherapy formulations for the management of allergic rhinitis

The molecular allergy technique, currently defined as component-resolved diagnosis, significantly improved the diagnosis of allergy, allowing for differentiation between molecules actually responsible for clinical symptoms (genuine sensitizers) and those simply cross-reacting or shared by several sources (panallergens), thus influencing the appropriate management of a patient's allergy. This also concerns allergen immunotherapy (AIT), which may be prescribed more precisely based on the component-resolved diagnosis results. However, the advance in diagnosis needs to be mirrored in AIT. According to consensus documents and to expectations of specialists, therapy should be based on standardized extracts containing measured amounts of the clinically relevant molecules, ie, the major allergens. The new generation of extracts for sublingual immunotherapy fulfills these requirements and are thus defined as biomolecular (BM). BM refers to natural extracts with a defined content of major allergens in micrograms. All Staloral BM products are indicated for the treatment of allergic rhinitis with or without asthma. The effectiveness of AIT is related to its ability to modify the immunological response of allergic subjects. The 5-grass and house dust mite extracts were evaluated addressing the T helper 1, T helper 2, and T helper 3 cells by polymerase chain reaction array on mRNA extracted from Waldeyer's ring tissue (adenoids). Sublingual immunotherapy with a defined content of major allergens in micrograms induced a strong downregulation of genes involved in T helper 2 and T helper 1 activation and function, allowing the definition of the immunologic effect as "bio-homeostatic". This clinical and immunological model must be implemented with respect to other allergens, thus expanding the application of a treatment with a unique disease-modifying capacity.

Prevalence and real clinical impact of Cupressus sempervirens and Juniperus communis sensitisations in Tuscan "Maremma", Italy

OBJECTIVE

The aim was to evaluate the impact of Cupressus sempervirens (Cs) and Juniperus communis (Jc) sensitisations in "Maremma" in southern Tuscany.

METHODS

811 consecutive outpatients (357 F - 57.86%; age: 36.9 ± 16.6) with suspected allergic respiratory symptoms underwent skin prick tests (SPT) for common allergens and for Cs and Jc.

RESULTS

SPT resulted negative in 295 (36.37%) subjects. A Cs/Jc sensitisation was found in 294 (36.25%): 289 (98.3%) were sensitised to Cs whereas 198 (67.34%) to Jc. There was a co-sensitisation between Cs and Jc in 193 (65.6%) subjects. Cs/Jc mono-sensitisation was found in 39 (13.6%) subjects. A higher number (p<0.0001) of Cs/Jc sensitised subjects reported winter (131-44.55%) and spring (124-42.2%) symptoms compared to Cs/Jc non-sensitised and non-allergic subjects. Most Cs/Jc sensitised subjects reported rhinitis and conjunctivitis (p<0.0001), whereas only few reported coughing and asthma (p<0.01). The most frequent co-sensitisation was with grass, olive and other trees in Cs/Jc subjects (p<0.001). Those who reported winter symptoms, likely influenced by Cupressaceae, rhinitis was the main symptom whereas asthma was less frequent. Cs/Jc sensitisation resulted to be a risk factor (OR: 1.73 [CI95% 1.18-2.55]) for rhinitis whereas the probability of being asthmatic was reduced (OR: 0.62 [CI95% 0.44-0.85]).

CONCLUSION

The prevalence of Cs/Jc sensitisation is about 36% in "Maremma". However, only in 44% of the patients, Cs/Jc seem to cause typical winter symptoms. Rhinitis is the predominant symptom, whereas asthma is less frequent. Testing Cupressaceae sensitisation using Jc pollen extract, rather than Cs, may result to be less sensitive.

GA2LEN skin test study III: minimum battery of test inhalent allergens needed in epidemiological studies in patients

BACKGROUND

The number of allergens to be tested in order to identify sensitized patients is important in order to have the most cost-effective approach in epidemiological studies.

OBJECTIVE

To define the minimal number and the type of skin prick test (SPT) allergens required to identify a patient as sensitized using results of the new Pan-European GA(2)LEN skin prick test study.

METHOD

In a large Pan-European multicenter (17 centers in 14 countries) patient based study, a standardized panel of 18 allergens has been prick tested using a standardized procedure. Conditional approach allowed to determine the allergens selection.

RESULT

Among the 3034 patients involved, 1996 (68.2%) were sensitized to at least one allergen. Overall, eight allergens (grass pollen, Dermatophagoides pteronyssinus, birch pollen, cat dander, Artemisia, olive pollen, Blatella and Alternaria) allowed to identified more than 95% of sensitized subjects. However, differences were observed between countries, two allergens being sufficient for Switzerland (grass pollen and cat dander) as opposed to nine for France (grass pollen, Dermatophagoides pteronyssinus, olive pollen, cat dander, Blatella, cypress, dog dander, alder and [Artemisia or Alternaria]). According to country, up to 13 allergens were needed to identify all sensitized subjects.

CONCLUSION

Eight to ten allergens allowed the identification of the majority of sensitized subjects. For clinical care of individual patients, the whole battery of 18 allergens is needed to appropriately assess sensitization across Europe.

Immunotherapy with an Aluminum Hydroxide-Adsorbed Juniperus ashei Foreign Pollen Extract in Seasonal Indigenous Cypress Pollen Rhinoconjunctivitis

BACKGROUND

The efficacy of standardized Juniperus ashei extract was assessed in patients with allergic rhinoconjunctivitis due to European cypress pollens.

METHODS

Forty adults with European cypress-allergic rhinoconjunctivitis were randomized to receive immunotherapy or a matched placebo. Specific immunotherapy was performed with a standardized, aluminum hydroxide-adsorbed J. ashei extract with a potency of 100 IR (arbitrary index of reactivity) containing 54 microg of Jun a 1/ml (Alustal, Stallergenes, France). Subcutaneous injections started in October 2000. The maintenance dose was 0.30 ml of the 100-IR concentration per month. Rhinitis and conjunctivitis symptoms were rated according to a 4-point score.

RESULTS

Seventeen patients from the treated group and 15 patients from the placebo group completed year 2001; 14 in each group completed year 2002. A statistically significant improvement (41%, p < 0.02) in the conjunctivitis symptom score was observed in actively treated patients compared to the placebo group at the peak of the 2001 pollen season. Improvement in rhinitis (17%) was not significant. This significant improvement was greater at the peak of the 2002 pollen season (63%, p < 0.01).

CONCLUSIONS

This study therefore indirectly validates the concept of treatment by major allergen because J. ashei is absent from the region in which this study was conducted.

Identification of italian cypress (Cupressus sempervirens) pollen allergen Cup s 3 using homology and cross-reactivity

BACKGROUND

The prevalence of seasonal allergic diseases of the upper airways is increasing in industrialized countries. The Cupressaceae are important causes of pollinosis, particularly in Europe.

OBJECTIVE

To determine whether the pollen from Cupressus sempervirens (Italian cypress) contains a pathogenesis-related group 5 (PR-5) protein, similar to that found in other allergenic Cupressaceae pollens.

METHODS

Messenger RNA was purified from Italian cypress pollen, and complementary DNA (cDNA) was synthesized. cDNAs for PR-5 proteins were amplified by polymerase chain reaction and extended by rapid amplification of cDNA ends methods. Recombinant Cup s 3 was expressed in Escherichia coli as a fusion protein. Inhibition enzyme-linked immunosorbent assays were used to test the allergenicity of Cup s 3.

RESULTS

Three cDNAs were cloned. These clones had approximately 95% identity to Jun a 3 and Cup a 3. Recombinant Cup s 3.0102 maltose-binding protein inhibited the IgE from most patients from binding to an extract of Italian cypress. The extent of inhibition suggested that antibodies to Cup s 3 were a prominent component of the IgE response to Italian cypress pollen.

CONCLUSION

Cup s 3, an allergen of Italian cypress pollen, was identified based on cross-reactivity and homology with other pollen PR-5 proteins, despite an apparently low level of protein expression. Variations in the content of Cup s 3 in the pollen from different regions or trees should be considered in the choice of extracts for diagnosis and specific immunotherapy for Italian cypress pollen hypersensitivity.

Standardization of an Ash (Fraxinus excelsior) Pollen Allergen Extract

BACKGROUND

Ash tree (Fraxinus excelsior) is the main representative of the Oleaceae family in temperate zones. Diagnosis of ash pollen allergy is made difficult due to (1) an overlapping pollinization period with Betulaceae, (2) non-inclusion in current diagnostic assays, and (3) some cross- reactivity with minor allergens from Betulaceae. The aim of this study was to calibrate an ash pollen in-house reference preparation (IHRP) in allergic patients in order to produce standardized products for diagnosis and immunotherapy purposes.

METHODS

Ash pollen IHRP was extracted, ultrafiltered and freeze dried. Allergens in the extract were detected after 2-dimensional PAGE using specific sera and a monoclonal antibody. The Fra e 1 content of IHRP was evaluated by quantitative immunoprint. Forty-eight subjects from the North-East of France exhibiting clinical symptoms, a positive skin test and specific IgE levels > or =class 2 to ash pollen were recruited. IgE immunoprints were performed to select patients sensitized to the ash Fra e 1 allergen as opposed to cross-reacting allergens. Serial 10-fold dilutions of the IHRP were tested by skin prick tests in order to determine the concentration inducing a geometrical mean wheal diameter of 7 mm, said to correspond to an index of reactivity (IR) of 100 per millilitre.

RESULTS

IgE-reactive molecules in IHRP comprise Fra e 1, Fra e 2, a 9-kDa molecule (presumably Fra e 3), as well as a doublet at 15 kDa and high molecular weight allergens. The 100 IR concentration of IHRP inducing a geometrical mean wheal diameter of 7 mm in 22 patients sensitized to Fra e 1 corresponds to the 1/126 (w/v) extraction ratio (i.e. 259 microg/ml of protein by Bradford) and contains 17 microg/ml of Fra e 1. The variability in total activity of 5 batches of standardized extracts was found to be significantly reduced when compared with 7 non-standardized extracts.

CONCLUSION

An ash pollen IHRP was defined and molecularly characterized. Its successful standardization at 100 IR/ml in patients specifically sensitized to Fra e 1 allowed a skin reactivity-based calibration in properly diagnosed patients. Such a standardized ash pollen extract is a reliable tool to support immunotherapy of ash pollen allergy.

Variation of T-cell activation in allergic subjects during natural pollen exposure

BACKGROUND

Allergic inflammation is characterized by a Th2 activation. However, little is known about dynamics of T-cell cytokine production during natural allergen exposure. The aim of this study was to assess the Th1/Th2 balance in cypress allergic patients compared with controls, and variations of this balance over the pollen season.

METHODS

Twenty cypress allergic patients and 10 controls were studied, distributed during two consecutive pollen seasons. Cytokine production was assessed by flow cytometry and ELISA. The variation of cytokine production during the pollen season was analyzed among patients in four occasions, and the preseason values were compared with controls. IL-13 and IFN-gamma-containing T cells were assessed among whole blood cells and PBMC. In addition the effect of specific stimulation by Juniperus ashei pollen extract was studied.

RESULTS

Compared with controls, IL-13-producing T cells were increased in allergics in any case. By contrast, compared with controls, allergic IFN-gamma-producing T cells were decreased in whole blood, but not in PBMC, and were increased after specific stimulation. During the season, an increase in IFN-gamma- and a decrease in IL-13-producing T cells occurred in patients, whatever the culture conditions.

CONCLUSION

These results show that the allergic T-cell activation is not limited to a Th2 profile: allergen-stimulated T cells are able to produce IFN-gamma at baseline, and the Th1/Th2 ratio increases during the pollen season.

Quantification assay for the major allergen of Cupressus sempervirens pollen, Cup s 1, by sandwich ELISA

BACKGROUND

The Cupressaceae are an important cause of pollinosis, particularly in Mediterranean countries. Cypress pollen allergenic extracts are difficult to produce since they have a low protein and a high carbohydrate content and consequently accurate standardization of these extracts is essential for diagnosis and immunotherapy.

METHOD

Natural Cup s 1 was purified by a combination of hydrophobic interaction, gel filtration and ion exchange chromatographies and its enzymatic activity was analyzed. The allergen was used as reference material in the ELISA standard curve. The assay was based on a specific monoclonal antibody (3D2) immobilized on ELISA plates and used to capture Cup s 1. Bound proteins were detected by a combination of biotinylated specific antiserum and peroxidase-conjugated streptavidin.

RESULTS

Purified Cup s 1 is a functional pectate lyase enzyme with a specific activity of 750 U/mg protein. The developed ELISA measured Cup s 1 concentrations ranging from 31.25 to 250 ng/ml in the lineal portion of the standard curve. The intra-assay and inter-assay variation coefficients in the working range were less than 8.1 % and 16 %, respectively. The assay was highly sensitive, with a detection limit of 3.8 ng/ml. The dose-response curves obtained with C. sempervirens pollen extracts and extracts belonging to other species from the Cupressaceae family showed a good parallelism compared with those obtained using the purified allergen, indicating that the same protein was measured.

CONCLUSIONS

The assay described is sensitive, specific and reproducible for the quantification of Cup s 1 in C. sempervirens pollen extracts for clinical use. This ELISA could also be useful for other Cupressaceae-related pollen extracts.

Allergy to cypress pollen

Although Cupressus sempervirens has been spread over southern Europe since antiquity, cypress pollen allergy has not been reported until 1945. In France, the very first case reports were published in 1962. Since then, the prevalence of cypress pollinosis seems to demonstrate an upward trend, concomitantly with the increased use of cypress trees as ornamental plants, as wind breaks and as hedges. Hyposensitization, using improved pollen extracts, is increasingly prescribed. Besides, prevention measures begin to be implemented. Such measures include avoidance of planting new cypress trees, especially near human populations' centres, trimming of cypress hedges before the pollination season and agronomical research for hypoallergenic trees. Altogether, such new developments in cypress allergy deserve an update review.

Quantification of the major allergen from cypress (Cupressus arizonica) pollen, Cup a 1, by monoclonal antibody-based ELISA

BACKGROUND

Cypress pollen allergy is an important cause of rhinoconjunctivitis and asthma in Mediterranean countries. Cypress allergenic extracts are difficult to produce since they have low protein and high carbohydrate content, thus accurate standardization of them is essential to guarantee their quality. The aim of this study is to develop a sandwich ELISA for the quantification of Cup a 1, the major allergen of cypress (Cupressus arizonica) pollen extract.

METHODS

Monoclonal antibodies directed to purified Cup a 1 were produced. Two of them (9C7 as capture antibody and 3D2 as the tracer) were selected to develop a quantitative sandwich ELISA. This ELISA was subsequently evaluated and compared with other techniques.

RESULTS

The described ELISA is very sensitive with a detection limit of 8.7 ng/ml and a practical working range of 62.5-1,000 ng/ml. The assay is also highly reproducible with intra-assay and interassay coefficients of variation of less than 10%. The purified Cup a 1, used as standard, presents pectate lyase enzymatic activity. The assay also detected Cup a 1-like proteins in pollen from other Cupressaceae. A good correlation was obtained between Cup a 1 content of 12 C. arizonica pollen extracts and their IgE-binding activity.

CONCLUSIONS

The described Cup a 1 ELISA is sensitive, specific and reproducible and can be used for the quantification of Cup a 1 in C. arizonica and other related pollen extracts. It also provides a reliable indication of the allergenic activity of the whole cypress pollen extract.