Lack of neo-sensitization to Pen a 1 in patients treated with mite sublingual immunotherapy.

BACKGROUND: Some studies reported the possible induction of food allergy, caused by neo-sensitization to cross-reacting allergens, during immunotherapy with aeroallergens, while other studies ruled out such possibility. OBJECTIVES: The aim of this study was to evaluate the development of neo-sensitization to Pen a 1 (tropomyosin) as well as the appearance of reactions after ingestion of foods containing tropomyosin as a consequence of sublingual mite immunization. MATERIALS AND METHODS: Specific IgE to Tropomyosin (rPen a 1) before and after mite sublingual immunotherapy in 134 subjects were measured. IgE-specific antibodies for mite extract and recombinant allergen Pen a 1 were evaluated using the immunoenzymatic CAP system (Phadia Diagnostics, Milan, Italy). RESULTS: All patients had rPen a 1 IgE negative results before and after mite SLIT and did not show positive shrimp extract skin reactivity and serological rPen a 1 IgE conversion after treatment. More important, no patient showed systemic reactions to crustacean ingestion. CONCLUSIONS: Patients did not show neo-sensitization to tropomyosin, a component of the extract (namely mite group 10) administered. An assessment of a patient's possible pre-existing sensitisation to tropomyosin by skin test and/or specific IgE prior to start mite extract immunotherapy is recommended. TRIAL REGISTRATION: This trial is registered in EudraCT, with the ID number of 2010-02035531.

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.

IgE profiles of Bermuda grass pollen sensitised patients evaluated by Phleum pratense allergens Phl P 1, 2, 4, 5, 6 , 7, 11, 12.

BACKGROUND: Despite the difference in geographical dominance of certain grasses, a high degree of allergenic similarity or cross-reactivity between Bermuda grass pollen (BGP) and timothy grass pollen (TGP) has been previously demonstrated. The aim of the present study was to ascertain the sensitisation to TGP in 411 patients known for their reactivity to BGP extracts by analysing their reactivity to crude timothy pollen extract and timothy pollen purified allergens, establishing their specific IgE-profiles. METHODS: Using the immunoenzymatic CAP method we evaluated IgE-specific antibodies for BGP- and TGP- extracts and the timothy recombinant (r) and natural (n) allergens rPhl p 1, rPhl p 2, nPhl p 4, rPhl p 5, rPhl p 6, rPhl p 7, rPhl p 11, and rPhl p 12. RESULTS: BGP-IgE positive patients (median = 8.0 kUA/l, 2.8-22.2 kUA/l 25th-75th percentile) simultaneously had IgE positive results for TGP (100% of subjects)(median = 48.9 kUA/l, 19.8- > 100 kUA/l 25th-75th percentile) and high prevalence of sensitization to 6/8 Phleum pratense allergens (Phl p 1, 2, 4, 5, 6, 11, markers of genuine sensitisation to TGP) other than profilin and calcium binding protein. More than 72% of BGP allergic patients were co-sensitised to rPhl p 1, rPhl p 2, nPhl p 4, rPhl p 5, rPhl p 6. A decrease of total and specific IgE with patients' age was observed. CONCLUSIONS: Our data show that all BGP-allergic patients simultaneously exhibit higher IgE antibody levels to recombinant and natural P. pratense allergens as well as to crude TGP extract. This suggests that when choosing an immunotherapeutic regimen for BGP-sensitised patients (after establishing their IgE profile via purified TGP-allergens), subcutaneous or sublingual TGP-extract vaccines in appropriate doses, in order to influence T epitope specificity, might be beneficial. Though extremely uncommon, in cases where a patient is exclusively BGP allergen-sensitised, BGP-extract therapy is the appropriate therapeutic response.

Evaluation of serum IgG4 antibodies specific to grass pollen allergen components in the follow up of allergic patients undergoing subcutaneous and sublingual immunotherapy.

BACKGROUND: A number of reports suggest that induction of IgG 'blocking antibodies' may be important for successful allergen immunotherapy. Nevertheless, a significant increase in specific IgG and IgG4 antibodies has not been consistently demonstrated for sublingual immunotherapy (SLIT). METHODS: The present observation included three groups of grass pollen allergic patients all submitted to three different allergen immunotherapeutic regimens in an open, non-placebo controlled clinical study: (i) 16 patients underwent a modified 'cluster' regimen of weekly injections of a standardized aluminium-absorbed Phleum pratense extract for 5 weeks, followed by 3 weeks of maintenance injections. (ii) Fifteen patients were treated with standardized timothy grass pollen-allergen oral vaccine. In the first session of a SLIT protocol without up-dosing, each patient received 2.4 ml of sublingual vaccine containing about 57 microg of Phl p 5 and received a maintenance dose of 24 microg of Phl p 5 once a day for 120 days. (iii) Fourteen subjects were treated with a standardized allergen extract containing 5-grass pollen mixture; a SLIT protocol was performed without up-dosing, administering a dose corresponding to about 10.0 microg/ml grass-pollen Group 5 and a maintenance dose of 4 microg of grass-pollen Group 5 once a day for 135 days. Patients' sera were characterized in detail by determining IgG4 antibodies to rPhl p 1, 2, 5, 6, 7, 11, 12 and nPhl p 4 and eosinophil cationic protein before the start of immunotherapy and during the peak of pollen season. RESULTS: No relevant systemic side effects were registered in patients treated with the modified cluster subcutaneous immunotherapy (SCIT) protocol and the two SLIT protocols without build-up phase. After SCIT all patients had high titres of serum allergen-specific IgG4 antibodies. High-dose SLIT led to an IgG4 increase comprising 25% of the SCIT level, while low-dose SLIT increased to 4% of the SCIT. Furthermore, the increase of specific IgG antibodies corresponds to a decrease of serum ECP during allergen exposure. CONCLUSIONS: These preliminary data seem to indicate that: (i) pre-seasonal high-dose SLIT protocol without build-up phase is safe and well-tolerated by allergic patients; (ii) compared to IgG4 levels induced by SCIT, only a high-dose SLIT regimen results in an appreciable serum specific IgG4 increase.

Identification of grass pollen allergens by two-dimensional gel electrophoresis and serological screening.

Approximately 50% of allergic patients are sensitized against grass pollen allergens. The characterization of specific immunoglobulin E (IgE) reactivity to allergen components in pollen-allergic patients is fundamental for clinical diagnosis and for immunotherapy. Complex allergen extracts are commonly used in diagnostic tests as well as in immunotherapy preparations, but their composition in single allergenic molecules is only partially known. Diagnostic tests which utilize recombinant or immuno-purified allergens have been made available in clinical practice. They allow to obtain specific profiles of IgE reactivity, but the panel of available molecules is far from complete. Here, we used a proteomic approach in order to detect grass allergens from a natural protein extract. A five-grass pollen extract used for diagnosis and immunotherapy was resolved by two dimensional gel electrophoresis (2-DE), and assayed with 9 sera from pollen-allergic patients whose sensitization profile was dissected by using IgE reactivity to recombinant allergens. 2-DE immunoreactivity patterns were matched with IgE reactivity to identify protein spots as candidate allergens. Identity was confirmed by mass spectrometry analysis. We identified 6 out of 8 expected clinically relevant allergens in the natural grass extract. Moreover, we identified different molecular isoforms of single allergens, thus obtaining a more detailed profile of IgE reactivity. Some discrepancies in protein isoform profile and sera immunoreactivity between recombinant and native allergen 5 from Phleum pratense were observed and a new putative allergen was described. The proteomic approach applied to the analysis of a natural allergen allows the comprehensive evaluation of the sensitization profile of allergic patients and the identification of new allergens.

Prevalence of serum IgE antibodies to the Staphylococcus aureus enterotoxins (SAE, SEB, SEC, SED, TSST-1) in patients with persistent allergic rhinitis.

BACKGROUND: Enterotoxins produced by Staphylococcus aureus and their specific IgE antibodies were thought to be important in worsening atopic dermatitis. However, few studies have documented an association between S. aureus or its exotoxins and exacerbations of upper airway/nasal disease. In the current study, we determined the prevalence of serum-specific IgE towards staphylococcal enterotoxin A, B, C, D (SEA, SEB, SEC, SED) and toxic shock syndrome toxin 1 (TSST-1) in patients suffering from rhinitis and/or asthma due to allergy. Therefore, we examined whether SEA, SEB, SEC, SED and TSST-1 were important in worsening the clinical status of patients allergic to house dust mites by means of assessing serum eosinophil cationic protein (ECP), which is thought to be a reliable marker of asthma and rhinitis severity. METHODS: 198 patients with persistent allergic rhinitis and/or asthma due to house dust mites were evaluated. Specific IgE towards SEA, SEB, SEC, SED, TSST-1, timothy grass and birch pollen recombinant allergens, and other aeroallergen extracts from common allergen sources were evaluated by the Pharmacia CAP System. Serum ECP was assessed, too. RESULTS: The percentages of sensitization to staphylococcal enterotoxins of 198 house dust mite-allergic patients were as follows: TSST-1-specific IgE 24.7% (n=49), SEC-specific IgE 22.2% (n=44), SEB-specific IgE 15.1% (n=30), SEA-specific IgE 9.1% (n=18), and SED-specific IgE 5.5% (n=11). Out of 198 individuals allergic to house dust mites 136 patients suffering from persistent rhinitis were subdivided into two subgroups: 53 patients with serum-specific IgE to at least one staphylococcal enterotoxin and 83 patients without specific IgE towards staphylococcal enterotoxins. Patients sensitive to staphylococcal enterotoxins had higher serum ECP levels than patients lacking specific IgE to SEA, SEB, SEC, SED and TSST-1(geometric mean 24.3 vs. 16.6 microg/100 ml; p=0.029), as well as total IgE levels (geometric mean 564 vs. 161 kU/l, p=0.00063) and specific IgE to Dermatophagoides pteronyssinus (geometric mean 16.7 vs. 6.6 kU/l; p=0.0235) and Dermatophagoides farinae (geometric mean 18.6 vs. 7.8 kU/l; p=0.0246). CONCLUSION: A status of sensitization to staphylococcal enterotoxins seems to be a factor increasing serum ECP, which is thought to be a reliable marker of clinical severity of allergic disease. Therefore, the evaluation of SEA, SEB, SEC, SED and TSST-1-specific IgE antibodies may have additional significance for the prognosis of persistent allergic diseases of the upper airway.