Ambrosia artemisiifolia L. temperature-responsive traits influencing the prevalence and severity of pollinosis: a study in controlled conditions.

BACKGROUND: Ambrosia artemisiifolia L. is one of the most important sources of allergenic pollen in many regions of the world. Its health impact increased over the last decades and is expected to further increase in consequence of climate change. However little information is available on the specific role played by temperature on allergy rising. The aim of this work was to evaluate the effect of temperature on A. artemisiifolia growth, flowering and pollen allergenicity, the major plant functional traits influencing the prevalence and severity of pollinosis. RESULTS: Plants were grown in controlled conditions at three thermal regimes: "Low" (LT: 18-14 °C light-dark), "Intermediate" (IT: 24-20 °C light-dark) and "High" (HT: 30-26 °C light-dark). During plant development, plant vegetative and reproductive morpho-functional traits were measured and, at the end of plant life-cycle, mature pollen was collected and analyzed for its allergenic properties by slot blot, 1D- and 2D-western blot (by using a pool of sera from ragweed-allergic patients) and liquid chromatography-tandem mass spectrometry. A. artemisiifolia showed a great development plasticity leading to a broad temperature tolerance. Shoot architecture, growth rate, number of male inflorescence and pollen allergenicity were temperature-responsive traits. Pollen allergenicity increased in parallel with temperature and differences were related to allergen synthesis and Amb a 1-IgE-binding. Flavonoids whose concentration in pollen decreased with the increase of temperature, were recognized as the cause of the negligible Amb a 1-IgE binding in LT pollen. CONCLUSIONS: Results show that temperature governs plant development and pollen allergenicity influencing the temporal and spatial magnitude of subject exposure to allergens.

IgE Cross-Reactivity between Humulus japonicus and Humulus lupulus.

PURPOSE: Japanese hop (Humulus japonicus) is a major cause of weed pollinosis in East Asia. However, supplies of commercial allergen extract from this plant have not met clinical demand. The pollen of common hop (Humulus lupulus), a closely related species, may provide an alternative source if there is strong IgE cross-reactivity between these two species. We aimed to compare the IgE cross-reactivity and allergenicity of common hop and Japanese hop pollen. MATERIALS AND METHODS: Cross-reactivity was measured by inhibition ELISA. One- and two-dimensional (2D) gel analyses combined with IgE immunoblotting and mass spectrometry [liquid chromatography coupled to electrospray ionization tandem mass spectrometry (LC-ESI-MS/MS)] were performed to detect IgE-reactive pollen components. RESULTS: Up to 16.7% of IgE reactivity to Japanese hop was inhibited by common hop. A 12-kDa protein component of Japanese hop pollen that showed the most potent IgE reaction was absent from common hop. Six IgE-reactive components from Japanese hop were detected by 2D gel electrophoresis and LC-ESI-MS/MS, but showed low Mascot scores, preventing positive identification. CONCLUSION: No significant IgE cross-reaction was observed for Japanese and common hop pollen allergens. Development of allergy diagnostic and immunotherapeutic reagents based on Japanese hop pollen are urgently needed.

Vitamin D3 improves the effects of low dose Der p 2 allergoid treatment in Der p 2 sensitized BALB/c mice.

BACKGROUND: Airborne allergens can induce an immunological chronic disease characterized by airway hyper responsiveness and inflammation, mediated by exaggerated Th2 immune response. Allergen-specific immunotherapy (AIT) is effective for treating this condition because it is able to modify its natural course by opposing the underlying pathogenic mechanisms and determining immune suppression, immune deviation and tolerance. The rational for the present study was to investigate the possibility of improving allergoid-based IT in terms of efficacy and safety. Recently, 1α,25-dihydroxyvitamin D3 (VD3), the active metabolite of vitamin D3, was described to be a potent inducer of T regulatory cells and to be a good adjuvant in AIT settings. METHODS: We investigated whether the co-administration of VD3 could potentiate the effect of AIT even when added to a low dose of chemically-modified monomeric allergoid of Der p 2 (d2-OID), in a Derp p 2 (d2)-sensitized BALB/c mice model. Control groups where treated with sham, VD3 alone or d2-OID only. RESULTS: The d2-OID alone was not fully successful, as expected for a low dose. VD3 administration was associated with some valuable, although limited, changes in the immunological parameters in the lung. On the contrary, the VD3 adjuvated allergoid vaccine induced the most prominent reduction of airway eosinophilia and Th2 cytokines and concomitant increase of T regulatory cells and IL-10 in the lung and Der p 2-specific IgG2a in the serum. CONCLUSIONS: The addition of VD3 to a conventional AIT protocol would allow the reduction of allergoid dose needed and therefore, the production costs. Moreover, beneficial immunomodulatory effects have been achieved by the oral administration which might favour the management of the therapy by the patients and their adherence, possibly enhancing the efficacy of the treatment.

Detection of pan-allergens in commercial pollen extracts for allergen immunotherapy.

BACKGROUND: Up to 50% of patients with pollen allergy are sensitized to at least 1 of the 2 pollen pan-allergens profilin and polcalcin. These allergens could have clinical relevance but the content of profilin and polcalcin in commercial extracts for allergen immunotherapy (AIT) is unknown. OBJECTIVE: To detect these pan-allergens in commercial pollen extracts for AIT from various sources. METHODS: Immunoglobulin E (IgE) reactivity to Phl p 7 and Bet v 2 of sera from 18 adults hypersensitive to profilin and/or polcalcin was investigated by enzyme-linked immunosorbent assay before and after absorption with grass, birch, ragweed, pellitory, and olive pollen extracts for AIT from different producers. Immunoblot inhibition experiments also were carried out using the same allergens. RESULTS: Birch, grass, ragweed, and olive pollen extracts for AIT contained large amounts of profilin, inducing 80% to 90% inhibition in most cases; Parietaria AIT extract appeared to contain little profilin. On immunoblot, grass and birch pollen extracts for sublingual AIT completely absorbed IgE specific for rBet v 2. Interestingly, only grass pollen extracts induced a significant inhibition of IgE binding to rPhl p 7 on enzyme-linked immunosorbent assay and immunoblot. A grass pollen allergoid lost most of its inhibitory potency, suggesting a much weakened affinity for specific IgE. CONCLUSION: With the exception of Parietaria, commercial extracts for AIT of most pollens are rich in profilin and, hence, potentially able to desensitize to this allergen; in contrast, only grass pollen extracts seem rich in polcalcin. These are the pollens to use in case of severe symptoms induced by pollen pan-allergens.

The nature of melon allergy in ragweed-allergic subjects: A study of 1000 patients.

Previous studies suggest cross-reactivity between specific ragweed pollen and melon allergens. This study was designed to clarify the origin of the cross-reactivity between ragweed pollen and the gourd family. One thousand ragweed-allergic subjects were interviewed about the presence of oral allergy syndrome (OAS) induced by melon or watermelon and were divided into reactive to ≤3 seasonal allergen sources or >3 seasonal allergen sources. Patients reporting melon and/or watermelon allergy underwent a skin-prick test (SPT) with fresh melon and, after 2006, also with profilin-enriched date palm pollen extract. Because no IgE reactivity to melon extract was detected in vitro, ELISA was performed using date palm pollen extract, and inhibition experiments were performed using grass pollen, date palm profilin, and bovine serum albumin (BSA) as inhibitors. Six hundred forty-six and 354 subjects reacted to ≤3 seasonal allergens or >3 seasonal allergens, respectively; 4/646 (1%) and 81/354 (23%) reported a history of melon/watermelon-induced OAS (p < 0.0001). Forty-three of 46 (93%) melon reactors scored positive on SPT with the profilin-enriched extract, which was positive in 0/2 (0%) versus 43/44 (98%) reactive to ≤3 or >3 seasonal allergen sources, respectively (p < 0.0001). in vitro, serum from melon-allergic subjects showed a strong IgE reactivity to the profilin-enriched date palm pollen extract, which was abolished by preabsorption with both grass pollen extract and date palm pollen extract, but not by BSA. In ragweed pollen-allergic subjects, melon allergy is most likely associated with cross-sensitization to the plant pan-allergen profilin and not to specific ragweed pollen allergens. This study confirms the association between profilin sensitization and melon allergy.

Molecular cloning and characterization of Cup a 4, a new allergen from Cupressus arizonica.

Sensitization to Cupressaceae pollen has become one of the most important causes of pollinosis in Western countries during winter and early spring. However, the characterization of the extracts, the allergens involved and the cross-reactivity with other pollen sources still remain poorly studied; in the case of Cupressus arizonica only two allergens have been described so far. A new allergen from C. arizonica pollen, Cup a 4, was cloned and expressed in Escherichia coli as an N-terminally His-tag recombinant protein that was characterized biochemically, immunologically and by circular dichroism spectroscopy. The new allergen has high sequence identity with Prickly Juniper allergen Jun o 4 and contains four EF-hand domains. The recombinant protein has structural similarities with other calcium binding allergens such as Ole e 3, Ole e 8 and Phl p 7. Cup a 4 is expressed in mature pollen grains and shares antigenic properties with the recombinant form. Sera from 9.6% C. arizonica allergic patients contain specific IgE antibodies against recombinant Cup a 4.

Effect of sublingual immunotherapy with grass monomeric allergoid on allergen-specific T-cell proliferation and interleukin 10 production.

BACKGROUND: Sublingual immunotherapy (SLIT) is safe and efficacious in the treatment of patients with allergic rhinitis. Although favorable clinical effects have been observed with controlled trials as early as a few months since the beginning of treatment, few biological changes induced by SLIT have been demonstrated. OBJECTIVE: To investigate in grass-allergic patients the effect of a 2-month SLIT regimen, administered with a simplified protocol without up-dosing, on proliferation and production of cytokines characteristic of the regulatory T-cell phenotype (interleukin 10 [IL-10] and transforming growth factor beta [TGF-beta]) by allergen-specific T cells. METHODS: Patients were recruited to the study in January 2006. SLIT was performed by self-administration and was continued for 60 days from February to April 2006. Eleven grass pollen-allergic patients with seasonal rhinitis were treated daily before the pollen season for 2 months with a modified allergen (monomeric allergoid) derived from a 3-grass pollen extract. Allergen-specific proliferation and production of IL-10 and TGF-beta were measured on peripheral blood mononuclear cells at baseline and treatment end. Tetanus toxoid served as the control antigen. RESULTS: After SLIT, allergen-specific (P = .002) but not tetanus toxoid-specific proliferation decreased, whereas IL-10 transcription increased (P < .001). TGB-beta transcription was also increased after treatment, although not statistically significantly (P = .06). Changes in proliferation to allergen and in IL-10 transcription were correlated (r = -0.82, P = .003). CONCLUSIONS: A short-term course of SLIT with modified allergen in grass-allergic patients is associated with the reduction of allergen-specific proliferation and with the up-regulation of the IL-10 regulatory cytokine.

Detection of some safe plant-derived foods for LTP-allergic patients.

BACKGROUND: Lipid transfer protein (LTP) is a widely cross-reacting plant pan-allergen. Adverse reactions to Rosaceae, tree nuts, peanut, beer, maize, mustard, asparagus, grapes, mulberry, cabbage, dates, orange, fig, kiwi, lupine, fennel, celery, tomato, eggplant, lettuce, chestnut and pineapple have been recorded. OBJECTIVE: To detect vegetable foods to be regarded as safe for LTP-allergic patients. METHODS: Tolerance/intolerance to a large spectrum of vegetable foods other than Rosaceae, tree nuts and peanut was assessed by interview in 49 subjects monosensitized to LTP and in three distinct groups of controls monosensitized to Bet v 1 (n = 24) or Bet v 2 (n = 18), or sensitized to both LTP and birch pollen (n = 16), all with a history of vegetable food allergy. Patients and controls underwent skin prick test (SPT) with a large spectrum of vegetable foods. The absence of IgE reactivity to foods that were negative in both clinical history and SPT was confirmed by immunoblot analysis and their clinical tolerance was finally assessed by open oral challenge (50 g per food). RESULTS: All patients reported tolerance and showed negative SPT to carrot, potato, banana and melon; these foods scored positive in SPT and elicited clinical symptoms in a significant proportion of patients from all three control groups. All patients tolerated these four foods on oral challenge. Immunoblot analysis confirmed the lack of IgE reactivity to these foods by LTP-allergic patients. CONCLUSION: Carrot, potato, banana and melon seem safe for LTP-allergic patients. This finding may be helpful for a better management of allergy to LTP.

Parietaria profilin shows only limited cross-reactivity with birch and grass profilins.

BACKGROUND: In patients showing multiple reactivity to seasonal airborne allergens, a skin prick test (SPT) with Parietaria pollen scores frequently negative, suggesting that profilin from Parietaria might not share IgE-binding epitopes with profilin from botanically unrelated airborne allergens. This study investigated the immunologic cross-reactivity between profilins from Parietaria, grass and birch pollen. METHODS: 36 patients hypersensitive to birch profilin, Bet v 2, underwent SPT with Parietaria, and IgE to both whole Parietaria pollen and Phleum profilin were sought in their sera by ELISA. In ELISA inhibition studies, IgE reactivity to Phleum profilin was measured before and after absorption of sera from Parietaria reactors with both whole Parietaria pollen extract, and Par j 1/Par j 2 fraction. Further, their IgE reactivity to whole Parietaria pollen was measured before and after absorption with the Par j 1/Par j 2 fraction. RESULTS: All sera showed IgE reactivity to Phleum profilin. Only 14/36 (39%) patients had a positive SPT to Parietaria and 17/36 (47%) showed IgE to Parietaria. Absorption of sera from Parietaria reactors with whole Parietaria extract caused a marked reduction in IgE reactivity to grass profilin; in contrast, absorption of sera with the Par j 1/Par j 2 fraction did not exert any inhibitory effect on IgE reactivity to grass profilin. Absorption of sera with the Par j 1/Par j 2 fraction markedly reduced IgE reactivity to whole Parietaria extract in 8/9 cases. CONCLUSION: Less than 50% of patients sensitized to birch and grass profilin cross-react to Parietaria profilin. In most cases, cross-reactors are hypersensitive to major, specific Parietaria allergens as well. This findings may be of practical relevance when the prescription of specific immunotherapy is considered.