Preseasonal intranasal immunotherapy with nebulized short ragweed extract

LNIT-Local nasal immunotherapy in allergic rhinitis: revisited evidence and perspectives

PURPOSE OF REVIEW

Allergen immunotherapy (AIT) is a personalized treatment approach for the allergic airway disease. The most common routes of administration are subcutaneous and sublingual. Local nasal immunotherapy (LNIT) presents another alternative route for allergen desensitization. Nasal mucosa is the first entry site of pathogens and numerous lymphoid organs are located in this area, making LNIT a favorable method for triggering immune tolerance. LNIT has shown promising results in reducing symptoms and medication use in allergic rhinitis patients. Over time, difficulties in dosing adjustments have made this method less popular. Recent advances in intranasal drug delivery systems warrant re-examination of LNIT as a viable option for the treatment of the allergic airway disease.

RECENT FINDINGS

The scope of the review includes evidences of LNIT in human trials including comparison with placebo and conventional method of immunotherapy. Recent articles regarding the mechanism of LNIT and the challenges of intranasal drug delivery are reviewed. Advances in the LNIT delivery system which have overcome previous limitations demonstrate promising effects.

SUMMARY

LNIT presents a judicious alternative for noninjection AIT. The evidences from previous clinical trials and the novel improvement of drug delivery system will lead into the future allergen vaccine production.

Local nasal immunotherapy for allergic rhinitis: A systematic review and meta-analysis

INTRODUCTION

Local nasal immunotherapy (LNIT), an alternative noninjection immunotherapy method, is theoretically an efficient method for inducing immunotolerance directly in the affected organ. LNIT is more convenient and less invasive than injection immunotherapy, with fewer systemic reactions. The development of adjuvants to overcome LNIT's limitations raises the possibility of it being an alternative allergen immunotherapy.

OBJECTIVES

To evaluate the clinical and immunological efficacy and safety of LNIT for patients with allergic rhinitis.

METHODS

A systematic search for randomized controlled trials comparing LNIT and placebo was performed using OVID Medline and Embase. Outcomes were total nasal symptom score (TNSS), symptom-medication score (SMS), medication score, immunological assessment, and nasal provocation threshold. Data were pooled for meta-analysis.

RESULTS

A total of 20 studies with 698 participants were included. The LNIT group had greater posttreatment improvement in TNSS, SMS, and medication score than control (TNSS: standardized mean difference [SMD], -1.37 [95% confidence interval [CI], -2.04 to -0.69]; SMS: SMD, -1.55 [95% CI, -2.83 to -0.28]; and medication score: SMD, -1.09 [95% CI, -1.35 to -0.83]). Immunological assessments showed no significant differences in serum-specific IgE (mean difference [MD], 6.35; 95% CI, -4.62 to 17.31), nasal IgE (MD, -0.59; 95% CI, -1.99 to 0.81), or nasal eosinophil cationic protein (MD, 7.63; 95% CI, -18.65 to 33.91). Only serum IgG significantly increased with LNIT (MD, 0.45; 95% CI, 0.20, 0.70). Posttreatment, nasal provocation threshold was higher with LNIT (MD, 27.30; 95% CI, 10.13-44.46). No significant adverse events were reported.

CONCLUSIONS

LNIT is a safe alternative allergen immunotherapy route without significant adverse events. It improves clinical symptoms, reduces medication usage, and increases the nasal provocation threshold.

A milestone in house dust-mite-allergen immunotherapy: the new sublingual tablet S-524101 (actair)

Subcutaneous allergen-specific immunotherapy has long been used in the treatment of allergic rhinitis and/or asthma and its efficacy has been confirmed. However, due to the discomfort of injections and the risk of severe adverse reactions, alternative routes of allergen administration have emerged. Delivery of allergens through the mucosal route had been proposed and investigated thoroughly, confirming the sublingual route to be the most efficacious. Later, the efficacy and safety of this route have been documented by numerous controlled trials both for house dust mite (HDM) and pollens. Recently, sublingual orodispersable grass pollen allergen tablets were in use followed by the newly developed HDM allergen tablets with satisfactory clinical results: Moreover, very recently 1 year of HDM tablet treatment was demonstrated to exert its clinical efficacy 1 year after discontinuation of tablet IT. The persistence of efficacy after only 1 year of treatment is a new and promising era. Currently, Sublingual Immunotherapy is the most easily administered and safe treatment option until more immunogenic, less allergenic and more efficient allergen extracts are developed.

Subcutaneous versus sublingual immunotherapy for allergic rhinitis and/or asthma

Subcutaneous allergen-specific immunotherapy has long been used in allergic rhinitis and/or asthma and has been recognized to be efficacious. However, owing to the inconvenience of injection and the risk of serious side effects, alternative concepts inspiring the search for effective noninjective routes, namely sublingual administration of allergens, have emerged. Sublingual immunotherapy (SLIT) appears to be associated with a lower incidence of systemic reactions. The clinical efficacy of subcutaneous immunotherapy (SCIT) is well established for both rhinitis and asthma. Meta-analyses relating to its efficacy on asthma and rhinitis are available. SLIT has also been validated in this respect. Comparative clinical studies of SLIT versus SCIT are scarce demonstrating both routes to be clinically efficient. Knowledge of the exact mechanism of action of SLIT has been increasing in the last decade. In addition, recent studies have proved similarities of the immunological changes with the treatment of both routes. Further comparative clinical and immunological studies of SLIT versus SCIT are needed to confirm the long-term efficacy and to complete the knowledge of immunological mechanisms of both routes. Moreover, better understanding of the interaction of allergen and oral mucosal dendritic cells during SLIT may allow improved targeting of SLIT vaccines.

Local and systemic IgE in the evaluation and treatment of allergy

Traditional descriptions of type I hypersensitivity and its manifestations center on systemic immunoglobulin E (IgE)-mediated reactions to inciting antigens. Hence, many current diagnostic and therapeutic measures are based on systemic skin testing for allergy, systemic pharmacotherapy, and immunotherapy. Recent developments in rhinology and pulmonology, particularly in defining the phenomenon of local IgE production in various airway inflammatory conditions, have an impact on both medical and surgical diagnosis and management of these conditions. This review includes a discussion of allergy as a systemic disease, current systemic diagnostic and management strategies for allergy, and local IgE presence and synthesis in the upper and lower airways.

Effect of local nasal immunotherapy on nasal blockage in pollen-induced allergic rhinitis of Guinea pigs

BACKGROUND

As a non-injection route for immunotherapy, local nasal immunotherapy has been examined in allergic rhinitis patients. However, it is unclear how the immunotherapy affects sneezing, biphasic nasal blockage and nasal hyperresponsiveness. Thus, we evaluated the therapeutic effects of nasal immunotherapy on the symptoms of guinea pig allergic rhinitis. Additionally, we also evaluated whether the immunotherapy relieved pollen-induced allergic conjunctivitis.

METHODS

Sensitized animals were repeatedly challenged by pollen inhalation once every week. After the 7th challenge, the pollen extract was intranasally administered 6 times a week until the 30th challenge. Sneezing frequency was counted after each of the challenges. As an indicator of nasal blockage, changes in specific airway resistance were measured. Nasal hyperresponsiveness was assessed by measuring leukotriene D(4)-induced nasal blockage. Additionally, during the immunotherapy, we applied pollen onto the ocular surface to induce the allergic conjunctivitis symptoms.

RESULTS

At the 11th-30th challenges, the nasal immunotherapy showed inhibition or a tendency to inhibit the biphasic nasal blockage although the inhibitions were variable at respective challenges. The development of nasal hyperresponsiveness was markedly suppressed by the immunotherapy. Nevertheless, neither sneezing nor antigen-specific IgE antibody production was substantially influenced by the immunotherapy. On the other hand, the nasal immunotherapy did not affect the induction of allergic conjunctivitis symptoms.

CONCLUSIONS

Local nasal immunotherapy may be clinically useful for allergic nasal blockage associated with nasal hyperresponsiveness. The mechanisms responsible for this effectiveness might not be related to IgE production. Additionally, the effectiveness for nasal tissue was dissociated from that seen for the ocular tissue.

Local nasal specific immunotherapy for allergic rhinitis

The possibility of producing local hyposensitization by administering allergens via mucosal routes was envisaged at the beginning of 1900, and local nasal immunotherapy has been extensively studied since the 1970s. Presently, there are 21 randomized controlled trials being conducted with the most common allergens, consistently showing the clinical efficacy of local nasal immunotherapy for rhinitis. Other advantages are that it has an optimal safety profile and can be self-administered at home by the patient. Moreover, there are several data from animal models and from humans that confirm the immunomodulatory effect of intranasally administered antigens. On the other hand, local nasal immunotherapy seems to be effective only on rhinitis symptoms and requires a particular technique of administration. For these reasons, its clinical use is progressively declining in favour of the sublingual route although nasal immunotherapy is validated in official documents and remains a viable alternative to injection.

Noninjection routes for immunotherapy

Allergen specific immunotherapy, together with drugs and allergen avoidance, is a cornerstone in the management of respiratory allergy. The traditional subcutaneous route is burdened with the risk of severe adverse events; therefore, safer routes of administration (noninjection or local routes) have been investigated and developed. Controlled trials failed to demonstrate the clinical efficacy and the safety of oral and bronchial administration, and these routes have been abandoned. Local nasal immunotherapy proved effective and safe in 17 of 18 controlled trials; thus it is considered a viable route of immunotherapy. Nevertheless, nasal immunotherapy is effective in rhinitis only and requires a particular administration technique; therefore its use is slowly declining. The sublingual route is supported by numerous controlled trials showing its efficacy in asthma and rhinitis in adults and children. The safety profile, assessed in clinical trials and postmarketing surveillance studies, is satisfactory; the most frequent side effects are gastrointestinal complaints, which can be easily managed by proper dose adjusting. Sublingual immunotherapy is now accepted by the World Health Organization as a valid alternative to the subcutaneous route also in children. Although the long-lasting efficacy has been recently documented for the sublingual route, several points still need to be elucidated, including mechanisms of action, optimal dosage, cost-effectiveness, and adherence.

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.

Nasal immunotherapy in weed-induced allergic rhinitis

BACKGROUND

Nasal immunotherapy with single allergen extracts, following premedication with cromolyn, has been reported to be effective in treating seasonal and perennial allergic rhinitis.

METHODS

We conducted a double-blind, placebo-controlled study to assess the efficacy, tolerability, and mechanism of action of nasal immunotherapy for allergic rhinitis caused by weed pollens from three unrelated families. Twenty-seven weed-allergic patients underwent baseline nasal provocation and titrated skin test with a mixed weed extract containing ragweed, sage, and Chenopod extracts. Patients were randomized to receive either mixed weed extract or placebo. Nasal immunotherapy was self-administered daily to alternate nostrils preceded by 5.2 mg intranasal cromolyn. Beginning with 1:2500 wt/vol the concentration was increased to 1:10 wt/vol over an average period of 36 days. The maintenance dose (1:10 wt/vol) was administered daily for 12 to 16 weeks through the weed pollen season. Patients recorded nasal and eye symptoms and the use of rescue medications throughout the study. A nasal lavage for cytokine levels and nasal scraping with Rhinoprobe for nasal cytology were performed at the peak of the weed season. Nasal provocation and titrated skin tests with mixed weed extract were repeated after the weed season. Nasal lavage and scraping were also performed before and 24 hours after the final nasal provocation.

RESULTS

During the peak weeks of the weed season the group receiving mixed weed extract by nasal instillation, compared with those treated with placebo, had significantly lower total nasal symptom scores, total eye symptom scores, and symptom medication scores. There were no significant differences in the nasal cytology or cytokines levels between the two groups, except for elevated IL-10 in the nasal lavage in the treated group at the peak of the season. Nasal symptoms and medication use were higher preseasonally in the active treatment group.

CONCLUSION

Nasal immunotherapy with aqueous mixed weed extract administered with cromolyn sodium pretreatment for 17 to 21 weeks was effective in reducing both nasal and ocular symptoms of weed pollen-induced allergic rhinitis. There were increased nasal symptoms in the treated group preseasonally.

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.

Nasal immunotherapy in pollen-sensitive children

Subcutaneous specific immunotherapy has a considerable risk of side effects, including severe life-threatening ones or even death. The disadvantages and problems of this kind of therapy gave rise to looking for new ways of hyposensitization. In allergic rhinitis the local (nasal) immunotherapy may be effective. We studied the efficacy of local nasal immunotherapy (Allerkin) in grass and ragweed allergic children suffering from seasonal atopic rhinitis.

PATIENTS

36 children (12 with grass pollen, 12 with ragweed pollen immunotherapy, 12 controls).

METHODS

nasal provocation tests with increasing doses of Allerkin, skin prick test, diary cards. Schedule of the investigations: enrollment of the patients and nasal provocation tests; grass pollen and ragweed pollen preseasonal immunotherapy with increasing doses of Allerkin; during pollen season registration by symptoms and drug consumption; after the season nasal provocation tests.

RESULTS

grass immunotherapy: nasal provocation threshold increased (P < 0.01), symptoms became fewer (P < 0.01) and drug consumption was less in the active group compared to control. Similar but less expressed tendencies were seen in the ragweed group. After the second year of immunotherapy the need for steroid treatment was significantly (P < 0.05) fewer in the immunotherapy group than in the control group. No side effects appeared during the course of immunotherapy, but some patients suffered from mild sneezing or nasal discharge after the Allerkin application.

CONCLUSION

local (nasal) immunotherapy is an effective, safe and not troublesome alternative to systemic immunotherapy.

Specific nasal provocation test with powder allergen

Reported here are the results of a large-scale trial conducted under the guidance of Prof. Giovanni Motta, which I coordinated. A total of 656 patients with nasal hyperreactivity were recruited in 51 Italian centres (18 in the north of Italy, 20 in central Italy and 13 in the south). The trial's results were as follows. 1) A clear clinical prevalence of sensitization to different allergens in the different areas of Italy, which could be roughly classified thus: a) in Northern Italy birch and grasses were in the main species; b) in Central Italy mites prevailed but oleaceae were also significant; c) in Southern Italy parietaria and oleaceae were the prevailing species. 2) Most cases were sensitive to several allergens, although a considerable proportion (22%) actually presented reactions only to one allergen and those responding account of the patients sensitive to only one allergen and those responding to a main allergen, the proportion of patients reacting clinically to only one allergen rises to 64%. 4) The specific nasal provocation test (sNPT) offers specificity comparable to in vivo diagnostic methods such as the prick test, and in vitro methods such as RAST, but is much more sensitive. 5) The sNPT can be done in any season. 6) The sNPT is highly specific below a threshold value of nasal reactivity, which can be identified for each allergen studied and expressed in Allergenic Units. 7) In patients in whom the prick test shows multiple sensitivity, the specific NPT identifies the allergen presumably responsible for the nasal reactions (main allergen). In the light of these findings double-blind specific immunotherapy was started, to last 1 year, in 107 patients (49 given placebo and 58 active treatment), with nasal allergy to grasses, parietaria and mites. The results of this treatment were as follows: 74.1% of patients presented a reduction in nasal resistance, measured by dynamic anterior rhinomanometry, indicating relief of nasal obstruction; mucociliary transport time became normal in 81% of patients, meaning that rhinorrhoea had become less marked; there was significant rise in the nasal reactivity threshold in 74.1% of patients, illustrating the degree of desensitization achieved; nasal IgA increased by 62.5% of patients and IgG in 55.2% indicating improvement in the local immunological picture. No such improvements were detectable in the patients given placebo. In conclusion, therefore, the findings of this trial in allergic rhinitis underline that the specific NPT proved more sensitive than other in vivo and in vitro diagnostic methods and is unquestionably a fundamental investigational approach for assessing nasal allergies, identifying the allergens causing the symptoms and setting up rational local immunotherapy. The sNPT also showed the efficacy of specific intranasal 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.

Local nasal immunotherapy: efficacy of low-dose aqueous ragweed extract

In previous studies preseasonal local nasal immunotherapy (LNIT) with moderate doses of aqueous ragweed extract (mean total dose 59 micrograms of AgE and 139 micrograms of AgE) was an effective treatment for ragweed hay fever; however, local adverse reactions during therapy were common. This study evaluated the clinical and immunologic responses to LNIT by use of lower doses of aqueous ragweed extract in order to minimize these adverse reactions. Patients were administered preseasonal LNIT for 7 wk and received a mean total dose of 4.7 micrograms of AgE. During the ragweed season, symptom/medication scores (SMS) of the treated patients were equivalent to SMS of untreated patients. Serum ragweed-specific IgE and nasal secretory ragweed-specific IgA rose slightly in the treated patients but not to the extent observed in previous studies. After the ragweed season treated and untreated patients had a substantial increase in serum ragweed IgE antibody titers. No correlation could be found between antibody responses and SMS. This study indicates that LNIT with lower doses of aqueous ragweed extract is clinically ineffective.

Local nasal immunotherapy for ragweed-allergic rhinitis. III. A second year of treatment

In 1979, pre-seasonal local nasal immunotherapy (LNIT) was found to be an effective treatment for ragweed hay fever. In 1980, this study was continued to evaluate the clinical and immunologic responses of a second year of LNIT. Patients received either pre-seasonal treatment with an unmodified ragweed extract (RW) or a polymerized ragweed extract (PRW), or no treatment. The results of the second year of treatment were the same as the first year. Adverse reactions were significantly higher in the RW-treated group than in the PRW-treated group (P less than 0.001). Symptom/medication scores (SMS) in the RW-treated group were significantly lower than in the control group (P less than 0.005). Although SMS in the PRW-treated group were lower than in the control group, this difference was not significant. The immunologic response was evaluated by measurements of serum (S) RW-specific IgE and IgG and nasal secretory (NS) RW-specific IgE, IgG, and IgA. After treatment, serum IgE titres and secretory IgA titres rose in the RW-treated patients. Nasal secretory-IgG and NS-IgA titres increased with PRW treatment. The only immunologic response observed in the control group was a rise in S-IgE titres after the ragweed season. There was no substantial difference in immunologic measurements observed in the 1979 and 1980 seasons, except that the pre-treatment NS-IgE level was higher in 1980 (P less than 0.02). No significant correlations were found between antibody response and SMS. This study supports the efficacy of LNIT but does not support the protective role for NS-ragweed-specific IgA or IgG.

Intranasal immunotherapy and polymerized grass pollen allergens

The effects of immunotherapy by intranasal insufflation of Lolium perenne allergens modified with glutaraldehyde (Glu-Rye) was tested by a stratified placebo-controlled trial in 16 adult subjects with hay fever. The purpose of this pilot study was to determine whether the treatment could reduce nasal sensitivity to allergen in provocation tests. Modification of the allergen was shown to include polymerization and reduced allergenicity, but retained immunogenicity. Nasal sensitivity to unmodified L. perenne allergens was measured by threshold-type quantitative nasal challenge and posterior rhinometry for measurement of nasal airway resistance. In challenge tests after a 10-week course of intranasal preseasonal treatment with Glu-Rye, nasal sensitivity was reduced, but this effect was not maintained when testing was repeated 9 months after treatment. Post-seasonal serum levels of IgE antibodies to L. perenne were also not significantly affected by the treatment.