Local Immunotherapy of Seasonal Allergic Rhinitis in Children Due toParietaria officinalisPollen: A Preliminary Report

Injection allergen immunotherapy for asthma

BACKGROUND

Allergen specific immunotherapy has long been a controversial treatment for asthma. Although beneficial effects upon clinically relevant outcomes have been demonstrated in randomised controlled trials, there remains a risk of severe and sometimes fatal anaphylaxis. The recommendations of professional bodies have ranged from cautious acceptance to outright dismissal. With increasing interest in new allergen preparations and methods of delivery, we updated the systematic review of allergen specific immunotherapy for asthma.

OBJECTIVES

The objective of this review was to assess the effects of allergen specific immunotherapy for asthma.

SEARCH STRATEGY

We searched the Cochrane Airways Group Trials Register up to 2005, Dissertation Abstracts and Current Contents.

SELECTION CRITERIA

Randomised controlled trials using various forms of allergen specific immunotherapy to treat asthma and reporting at least one clinical outcome.

DATA COLLECTION AND ANALYSIS

Three authors independently assessed eligibility of studies for inclusion. Two authors independently performed quality assessment of studies.

MAIN RESULTS

Eighty-eight trials were included (13 new trials). There were 42 trials of immunotherapy for house mite allergy; 27 pollen allergy trials; 10 animal dander allergy trials; two Cladosporium mould allergy, two latex and six trials looking at multiple allergens. Concealment of allocation was assessed as clearly adequate in only 16 of these trials. Significant heterogeneity was present in a number of comparisons. Overall, there was a significant reduction in asthma symptoms and medication, and improvement in bronchial hyper-reactivity following immunotherapy. There was a significant improvement in asthma symptom scores (standardised mean difference -0.59, 95% confidence interval -0.83 to -0.35) and it would have been necessary to treat three patients (95% CI 3 to 5) with immunotherapy to avoid one deterioration in asthma symptoms. Overall it would have been necessary to treat four patients (95% CI 3 to 6) with immunotherapy to avoid one requiring increased medication. Allergen immunotherapy significantly reduced allergen specific bronchial hyper-reactivity, with some reduction in non-specific bronchial hyper-reactivity as well. There was no consistent effect on lung function. If 16 patients were treated with immunotherapy, one would be expected to develop a local adverse reaction. If nine patients were treated with immunotherapy, one would be expected to develop a systemic reaction (of any severity).

AUTHORS' CONCLUSIONS

Immunotherapy reduces asthma symptoms and use of asthma medications and improves bronchial hyper-reactivity. One trial found that the size of the benefit is possibly comparable to inhaled steroids. The possibility of local or systemic adverse effects (such as anaphylaxis) must be considered.

Sublingual immunotherapy with Dermatophagoides monomeric allergoid down-regulates allergen-specific immunoglobulin E and increases both interferon-gamma- and interleukin-10-production

BACKGROUND

The clinical efficacy and safety of sublingual immunotherapy (SLIT) for aeroallergens has been demonstrated in several trials, whereas the immunological changes induced by this treatment, which may account for the clinical improvement, are still unclear.

OBJECTIVE

To investigate the effects of a successful SLIT on the in vitro allergen-driven T cell response and cytokine secretion as well as on the serum levels of chemokines and of IgE, IgG1 and IgG4 antibodies (Abs).

MATERIALS AND METHODS

Twenty-five Dermatophagoides pteronyssinus (Dp)-sensitive patients with perennial rhinitic and/or rhinitic and asthmatic symptoms were randomized into two groups (13 untreated (UT) and 12 SLIT-treated) for a 1 year and half study. The proliferative response of peripheral blood mononuclear cell (PBMC) to purified Der p1 allergen, their cytokines (IFN-gamma, IL-4, IL-10 and TGF-beta) production and serum levels of chemokines associated with T helper type 1 (Th1) (CXCL10) or T helper type 2 (Th2) (CCL22) responses and of Dp-specific IgE, IgG1 and IgG4 Abs were evaluated before and after 6 months of treatment.

RESULTS

SLIT induced a significant reduction of symptom medication scores after 6, 12 and 18 months of treatment in comparison with UT patients. SLIT-treated patients showed a significant decrease in serum levels of DP-specific IgE Abs, whereas total IgE, and specific IgG1 and IgG4 Abs remained unchanged. The proliferative response of allergen-specific T cells to Der p1 in vitro after 6 months of treatment was reduced, while no effect was observed on T cell proliferation to recall antigen (streptokinase). Moreover, Der p1-driven IFN-gamma and IL-10 were significantly increased in culture supernatants of PBMC from 6 month-treated patients in comparison with those detected at the beginning of therapy.

CONCLUSIONS

These data suggest that the allergen-driven enhancement of IL-10- and IFN-gamma-producing T cells precedes and associates with SLIT-induced down-regulation of specific IgE, thus providing a rationale to explain the clinical benefit of SLIT in allergic patients.

Allergen immunotherapy for asthma

BACKGROUND

Allergen specific immunotherapy has long been a controversial treatment for asthma. Although beneficial effects upon clinically relevant outcomes have been demonstrated in randomised controlled trials, there remains a risk of severe and sometimes fatal anaphylaxis. The recommendations of professional bodies have ranged from cautious acceptance to outright dismissal. With increasing interest in new allergen preparations and new methods of delivery, it was time to conduct another systematic review of allergen specific immunotherapy for asthma.

OBJECTIVES

The objective of this review was to assess the effects of allergen specific immunotherapy for asthma.

SEARCH STRATEGY

We searched the Cochrane Airways Group trials register up to June 2001, MEDLINE, Dissertation Abstracts, Current Contents and reference lists of articles.

SELECTION CRITERIA

Randomised controlled trials using various forms of allergen specific immunotherapy to treat asthma and reporting at least one clinical outcome.

DATA COLLECTION AND ANALYSIS

Three reviewers independently assessed eligibility of studies for inclusion. Two reviewers independently performed quality assessment of studies.

MAIN RESULTS

Seventy-five trials were included (52 of 54 previously included trials and 23 new trials). A total of 3,506 participants (3,188 with asthma) were involved. There were 36 trials of immunotherapy for house mite allergy; 20 pollen allergy trials; ten animal dander allergy trials; two Cladosporium mould allergy, one latex and six trials looking at multiple allergens. Concealment of allocation was assessed as clearly adequate in only 15 of these trials. Significant heterogeneity was present in a number of comparisons. Overall, there was a significant reduction in asthma symptoms and medication and improvement in bronchial hyper-reactivity following immunotherapy. There was a significant improvement in asthma symptom scores (standardised mean difference -0.72, 95% confidence interval -0.99 to -0.33) and it would have been necessary to treat 4 (95%CI 3 to 5) patients with immunotherapy to avoid one deterioration in asthma symptoms. Overall it would have been necessary to treat 5 (95%CI 4 to 6) patients with immunotherapy to avoid one requiring increased medication. Allergen immunotherapy significantly reduced allergen specific bronchial hyper-reactivity, with some reduction in non-specific bronchial hyper-reactivity as well. There was no consistent effect on lung function.

REVIEWER'S CONCLUSIONS

Immunotherapy reduces asthma symptoms and use of asthma medications and improves bronchial hyper-reactivity. One trial found that the size of the benefit is possibly comparable to inhaled steroids. The possibility of adverse effects (such as anaphylaxis) must be considered.

Appropriate and inappropriate use of immunotherapy

OBJECTIVE

The primary objective of this review is to discuss indications for appropriate and inappropriate use of allergen immunotherapy (IT), including discussion of contraindications, adverse events, and alternative protocols and methods.

DATA SOURCES

A review of the literature on indications, contraindications, adverse events, and alternative methods and protocols associated with allergen IT was conducted.

STUDY SELECTION

The opinion of the author was used to select and review relevant data.

RESULTS

Clinical trials have proven the benefit of allergen IT, for allergic rhinitis, asthma, and anaphylaxis because of stinging insects, such as Hymenoptera and fire ants. Allergen IT may improve quality of life and decrease medication requirement for allergic rhinitis and asthma, especially for younger patients, and probably will assist in the prevention of the progression of allergic disease from rhinitis to asthma. Subcutaneous allergen IT is well established as clinically effective through multiple, blinded, placebo-controlled studies. The data for alternate therapies and routes of therapy are extensively reviewed and critiqued.

CONCLUSIONS

Allergen IT is a highly valuable form of treatment of IgE-mediated diseases. Documentation of sensitivity to allergen sensitization associated with symptoms is critical before use of allergen IT. Symptoms should also be of sufficient duration and severity to warrant IT. Before allergen IT is used, there must be an available allergen extract that is suitable for treatment of the relative sensitivity. It is essential for patients receiving allergen IT to understand the treatment principle, the frequency of injections, the duration of treatment, the risk and signs of adverse events, the magnitude of the efficacy, and the essential nature of patient compliance. Subcutaneous allergen IT is the only current mode of therapy in the United States that has been shown to be effective.

A multicenter trial of specific local nasal immunotherapy

OBJECTIVE

To assess the efficacy and safety of specific local nasal immunotherapy (LNIT) in powder form in patients with allergic rhinitis, using subjective and objective parameters.

STUDY DESIGN

A double-blind randomized multicenter trial of 102 patients with allergic rhinitis who were treated with specific LNIT for 8 consecutive months.

METHODS

After identifying allergens with the skin prick test and sensitization threshold dose with the specific nasal provocation test, 102 patients were selected, of whom 55 were allergic to mites and 47 were allergic to Graminaceae or Parietaria pollen. The specific treatments were self-administered using an insufflator in two phases (phase 1: increasing doses; phase: 2, maintenance dose). Patients were evaluated before and after 32 weeks of treatment by subjective analysis of their self-reported symptoms and by objective analysis of nasal provocation test, nasal resistance by anterior rhinomanometry, and mucociliary clearance time.

RESULTS

Clinical efficacy of LNIT for allergy to mites and pollens was confirmed by the differences in the symptoms score between the active group and the placebo group. The nasal provocation test results confirmed that this difference was statistically significant. The rhinomanometric analysis gave positive results for the treated group mainly in LNIT for mites. No differences in mucociliary clearance time were found.

CONCLUSIONS

Specific LNIT is effective for allergic rhinitis and appears to offer considerable advantages over other hyposensitization methods. It can be done at home, patient compliance is good, and the treatment is safe.

Decrease of allergen-specific T-cell response induced by local nasal immunotherapy

BACKGROUND

The clinical efficacy and safety of local nasal immunotherapy (LNIT) with lyophilized 'macronized' powder has been demonstrated. However, the immunological changes possibly induced by LNIT which may account for the clinical improvement are still unclear.

OBJECTIVE

To investigate the effects of a successful LNIT-treatment on the allergen-driven T cell response, cytokine secretion and IgE and IgG antibody production.

METHODS

Three groups (untreated, subcutaneous immunotherapy- SIT- and LNIT-treated) of grass-sensitive patients suffering from seasonal rhinitic symptoms were ramdomized for the 2-year study. The proliferative response of PBMC to purified Rye-1 allergen and serum levels of grass-specific IgE and IgG were evaluated before treatment and during the 2-year subsequent pollination periods. The proliferative response of allergen-specific short-term T-cell lines, as well as production of allergen-driven cytokine by PBMC, were also assessed.

RESULTS

Both SIT and LNIT induced a significant reduction of symptom scores during the pollination season. SIT, but not LNIT, induced a significant change in serum levels of allergen-specific IgE and IgG antibody. By contrast, both SIT and LNIT reduced the increase of the proliferative response of allergen-specific T cells driven by natural allergen exposure and significantly decreased T cell proliferation to low doses of allergen, as shown also by the mitogenic index of allergen-specific T-cell lines. A reduced IL-4 and IFNgamma production by PBMC of LNIT- and SIT-treated patients was also observed in the absence of a clearcut TH2-TH1 switch.

CONCLUSIONS

These data suggest that a common mechanism of both LNIT and SIT is the induction of T-cell tolerance, thus providing a rational basis to explain why LNIT may be clinically successful in allergic patients with rhinits.

Clinical efficacy and safety of local nasal immunotherapy

Local nasal immunotherapy represents an alternative route of allergen administration. It was proposed to overcome the risk of systemic reactions rarely reported during the traditional subcutaneous immunotherapy. Some studies carried out in the past generally showed good efficacy but poor tolerability. The aqueous extracts mostly used in these studies carry some drawbacks such as the volume effect, self-digestion and the difficulty of administering reproducible dosages. The recent availability of allergen extracts in powder form has led to better stability and standardization. The studies carried out with these freeze-dried allergens showed clinical efficacy and good tolerability in perennial (mite, cat) and seasonal (grass, birch, Parietaria) allergic rhinitis. According to these findings this new local nasal immunotherapy with extract in powder form represents a suitable alternative to the traditional immunotherapy in the treatment of allergic rhinitis.

Local nasal immunotherapy: experimental evidences and general considerations

The possibility of local hyposensitization in allergies was envisaged since the first decades of the century and then sporadically employed, whereas controlled clinical trials of local nasal immunotherapy (LNIT) were performed only during the last 20 years. Studies currently available agree on the clinical efficacy of the treatment. LNIT was demonstrated capable of reducing symptoms both in pollen- and mite-induced rhinitis, and of modifying the specific target organ responsivity. Indeed, aqueous extracts appeared to be more effective than modified ones but were also charged by troublesome local side effects, while the recently introduced powdered extracts seemed to overcome this problem, maintaining a favourable clinical effectiveness. In a recent study we demonstrated a significant effect of LNIT on local allergic inflammation. LNIT reduced both the inflammatory infiltration and ICAM-1 expression on nasal epithelial cells upon specific nasal challenge. The effects on specific challenge appeared long-lasting, but the clinical efficacy seemed to depend strictly upon preseasonal treatment. LNIT with powdered extracts appears an effective, safe and well-tolerated treatment for allergic rhinitis. Nevertheless, its particular administration technique requires a careful choice of patients. Finally, a socioeconomical analysis shows a favourable cost/benefit ratio for LNIT if compared to classic subcutaneous immunotherapy.

Preseasonal intranasal immunotherapy in birch-alder allergic rhinitis. A double-blind study

A double-blind, placebo-controlled study was carried out to test the clinical efficacy and safety of local nasal immunotherapy (LNIT) in powder form. Twenty-two patients suffering from allergic rhinitis strictly associated with early spring symptoms, with positive skin prick tests and RAST for birch-alder, all responders to a specific nasal provocation test (NPT), received randomly active or placebo treatment for 4 months. Immunotherapy consisted of administration of a set of capsules containing progressively increasing amounts of birch (Betula pendula) and speckled alder (Alnus incana) allergens in powder form with controlled granulometry. The active (birch-alder) and placebo (lactose) group completed the treatment according to a similar schedule. During the pollen season (March-April), the patients who took the active treatment reported less sneezing and rhinorrhea than the placebo group, on the basis of a symptoms score, and the differences were statistically significant; the need for drugs (terfenadine) was also significantly reduced. These findings agreed well with the results of specific NPT after the treatment; only patients in the active group had a higher threshold dose of nasal specific reactivity to birch-alder allergens than in tests before the LNIT.