New insights into the mechanisms of immunotherapy

β-Glucans in the treatment and prevention of allergic diseases

β-glucans are a group of biologically active polysaccharides of natural origin with a proven pleiotropic immunomodulation effect. Their efficacy has been confirmed in the therapeutic treatment and prevention of various infectious diseases, secondary immune defects and also of oncologic disorders. Allergic diseases are one of the most frequent diseases and their prevalence continues to increase. They develop as a consequence of dysregulation of the immune system, especially when there is failure in the equilibrium of the response of TH1/TH2 lymphocytes towards TH2. New therapeutic approaches in the treatment of immunopathological conditions (e.g. allergic or oncologic) are directed to restoring the equilibrium among different T lymphocyte subpopulations. Based on in vitro experiments, and also on animal and human clinical studies, there is much evidence for the importance of β-glucans in the treatment and also prevention of allergic diseases; this opens new perspectives on the use of this widespread and popular group of natural substances.

[Specific immunotherapy for allergic rhinitis. Current methods and innovative developments]

Apart from allergen avoidance and pharmaceutical medication, specific immunotherapy (SIT) represents the third most important mainstay in a balanced therapeutic concept for the treatment of allergic rhinitis. For subcutaneous immunotherapy (SCIT) there is evidence for therapeutic clinical effectiveness, duration of the therapeutic result, prevention of bronchial asthma, reduced generation of additional co-sensitization and safety of the procedure. The present guidelines on allergen-specific immunotherapy (SIT) were established by the German allergy societies in 2006. Another option for specific immunotherapy in future is the sublingual route (SLIT). This method might play an important role as in-vitro studies indicated that oral Langerhans cells are potential target cells involved in the tolerance-induction of SLIT. However, questions concerning SLIT and prevention of bronchial asthma, reduced generation of co-sensitization and long-term effects have not yet been fully clarified. Furthermore, this paper gives an overview on recent innovative strategies in SCIT and SLIT, such as cluster and rush schemes, pre-seasonal therapy, recombinant allergen extracts and additive therapy with adjuvants or IgE-specific antibodies, high-dosis SLIT preparation or allergen tablets.

Long-term allergen-specific immunotherapy correlates with long-term allergen-specific immunological tolerance

INTRODUCTION

One method of treatment for allergic diseases is allergen-specific immunotherapy (SIT). The clinical efficacy of SIT in pollen-induced allergic rhinitis has been demonstrated in several controlled clinical trials. There is no consensus about the protective effect of SIT. In this study, we evaluated the correlation between the duration of SIT and relapse of allergic rhinoconjunctivitis.

METHODS

We evaluated 148 patients who had received SIT between 1998 and 2006. All of the patients had allergic rhinoconjunctivitis. According to the data 116 had sensitivity to grass pollen and 32 to house dust. SIT was performed on 87 patients for 4 y (Group A) and 61 patients for 6 y (Group B).

RESULTS

All of the 148 patients were monitored regularly with no medication for 2 y after SIT. Thirty-one patients in Group A relapsed (36%); 11 patients in Group B relapsed (18%). Mean duration until relapse was 11.1+/-1.99 mo in Group A and 19.64+/-1.86 mo in Group B. During evaluation, symptom scores were 2.32+/-0.74 in Group A and 1.81+/-0.75 in Group B and serum total immunoglobulin E levels were 432.4+/-78.5 KU/lt in Group A and 288.6+/-55.3 KU/lt in Group B. There was significant difference between the groups (P < 0.05).

CONCLUSION

According to these results, long-term SIT therapy correlates with long-term, allergen-specific, acquired immunological tolerance.

Clinical efficacy and safety of preseasonal sublingual immunotherapy with grass pollen carbamylated allergoid in rhinitic patients. A double-blind, placebo-controlled study

BACKGROUND

The aim of this study was to confirm the clinical efficacy and safety of a preseasonal sublingual immunotherapy (SLIT) in a group of allergic patients with seasonal rhinoconjunctivitis with or without mild intermittent or mild persistent asthma. The immunotherapy was administered through the oral mucosa with a monomeric carbamylated allergoid (allergoid SLIT) for grass pollens. A secondary endpoint was to evaluate the effect of the allergoid SLIT on nasal reactivity.

METHODS AND RESULTS

A single-center, randomized, double-blind, placebo-controlled study was performed. Patients were selected and randomly allocated to two groups: one group received active treatment (allergoid SLIT) for 2 years and the other received placebo. Both groups received the necessary drug treatment throughout the trial. Thirty-three outpatients (20 men and 13 women, mean age: 30 years; range: 19-43) attending our center were enrolled in the study. Symptoms and medications were scored on diary cards during the pollen season. An allergen nasal challenge was performed at baseline and after 2 years of SLIT to evaluate nasal reactivity. Because the clinical scores were non-normally distributed, the Mann-Whitney and the Chi-square tests for intergroup comparisons and the Wilcoxon test for intragroup comparisons were used. The results were evaluated after 1 and 2 years of treatment. Between the first and second years of treatment, no changes in the scores for the placebo group were found, while for the active vaccine group significant decreases were found in rhinorrhea (p < 0.03), sneezing (p < 0.03), and conjunctivitis (p < 0.02). Symptom scores after nasal challenge decreased (p < 0.03) after 2 years' treatment. Nasal steroid use significantly decreased in the active treatment group during May and June in both the years of treatment (p < 0.02). Only two mild local adverse events were reported in the active group and none was reported in the placebo group.

CONCLUSIONS

The results of this study show that the allergoid SLIT is safe and effective in decreasing symptom scores and drug use in rhinitic patients allergic to grass pollen.

T cell and antibody responses in remitting–relapsing experimental autoimmune encephalomyelitis in (C57BL/6×SJL) F1 mice

To characterize T cell and antibody responses in remitting-relapsing experimental autoimmune encephalomyelitis (RR-EAE), we compared myelin oligodendrocyte glycoprotein (MOG)-induced RR-EAE in C57BL/6 (B6) x SJL (F1) mice and chronic-progressive EAE (CP-EAE) in B6 mice at week 8 p.i. when clinical scores were comparable. Although these two strains exhibited similar inflammation/demyelination pattern and MOG-induced T cell responses, RR-EAE mice produced significantly higher levels of anti-MOG IgG1/IgG2a antibodies. Further, lymphocytes of RR-EAE mice proliferated vigorously to the secondary epitope myelin basic protein (MBP) 1-11. These results support a potential involvement of anti-MOG antibodies and epitope spreading in T cell responses in the development of MOG-induced RR-EAE model.

Allergic rhinitis: past, present and the future

Allergic rhinitis represents a global health issue affecting between 10% to 25% of the world population, with increasing prevalence over the last decade. Although often trivialized by patients and doctors, allergic rhinitis is a significant cause of morbidity, in addition to its substantial economic impact. While allergic rhinitis is an inflammatory disorder of the upper airways, inflammation alone is insufficient to explain the chronic nature of the disease. An exciting concept which has recently emerged in asthma concerns the role of the bronchial epithelium as a key regulator of airway inflammatory and remodelling responses in asthma. It has been shown by our group that the disruption and alteration in the function of the lower airway epithelium in asthma leads to the generation of a variety of stimuli that lead to the restructuring of the airway wall. This raises interesting questions regarding a similar role for the upper airway epithelium in allergic rhinitis. This review aims to interpret past and current research into allergic rhinitis, and to address specific areas where future research is warranted, particularly in relation to the possibility of an altered upper airway epithelial phenotype in allergic rhinitis.

Modulation of the Th1/Th2 bias by an immunoglobulin histamine complex in the ovalbumin allergy mouse model

Vaccination with the antiallergic drug Histaglobin is used to treat a broad range of human allergic diseases including bronchial asthma, allergic rhinitis, and atopic dermatitis. In order to further elucidate its functional activity, Histaglobin was investigated in an in vivo mouse allergy model. Mice were sensitized with ovalbumin either prior to or after Histaglobin treatment, and its antiallergic potential was evaluated. Ovalbumin-sensitized mice exhibited increased serum levels of IL-4, tumor necrosis factor alpha (TNF-alpha), and an increase of total and ovalbumin-specific IgE; total and ovalbumin-specific IgG levels were also elevated. Subsequent administration (therapeutic treatment) of Histaglobin resulted in a decrease of total and specific serum IgE levels; total and specific IgG1 serum levels were reduced by more than 50% and 45%, respectively; the mice displayed a down-regulation of IL-4 and TNF-alpha serum levels and showed increased levels of IFN-gamma and IgG2a. Mice pretreated with Histaglobin, prior to ovalbumin sensitization (prophylactic treatment), were found to be widely unresponsive to ovalbumin. They exhibited higher serum levels of IFN-gamma and IgG2a (total and specific) compared to saline-treated control mice. The inhibitory effects were still observed 1 month post-immunization. Our data, indicating a Histaglobin-induced modulation of the Th1/Th2 balance in favour of Th1, correspond with the well-known antiallergic activity of Histaglobin observed in patients.

Intranasal corticosteroids for allergic rhinitis

Intranasal corticosteroids are accepted as safe and effective first-line therapy for allergic rhinitis. Several intranasal corticosteroids are available: beclomethasone dipropionate, budesonide, flunisolide, fluticasone propionate, mometasone furoate, and triamcinolone acetonide. All are efficacious in treating seasonal allergic rhinitis and as prophylaxis for perennial allergic rhinitis. In general, they relieve nasal congestion and itching, rhinorrhea, and sneezing that occur in the early and late phases of allergic response, with studies showing almost complete prevention of late-phase symptoms. The rationale for topical intranasal corticosteroids in the treatment of allergic rhinitis is that adequate drug concentrations can be achieved at receptor sites in the nasal mucosa. This leads to symptom control and reduces the risk of systemic adverse effects. Adverse reactions usually are limited to the nasal mucosa, such as dryness, burning and stinging, and sneezing, together with headache and epistaxis in 5-10% of patients regardless of formulation or compound. Differences among agents are limited to potency, patient preference, dosing regimens, and delivery, device and vehicle.

Short-term preseasonal birch pollen allergoid immunotherapy influences symptoms, specific nasal provocation and cytokine levels in nasal secretions, but not peripheral T-cell responses, in patients with allergic rhinitis

BACKGROUND

[corrected] Birch pollen allergic rhinitis can be sufficiently treated with specific subcutaneous allergoid immunotherapy (IT). However, little is known about the clinical and immunological effects of short-term therapy protocols.

OBJECTIVE

To investigate the clinical efficacy of a birch pollen allergoid IT using seven preseasonal injections and to evaluate immunological parameters that might explain clinical findings.

METHODS

Thirty-seven patients were included into the study and randomized to either a symptomatic treatment or allergoid IT plus symptomatic treatment. Patients were examined during the pre-IT season, at two extraseasonal visits both before and after IT and during the post-IT season. At each visit, nasal secretion samples were taken and analysed for levels of IL-4, IL-5 and IFNgamma. In addition, short-term birch-specific T-cell lines (TCLs) were cultured from peripheral blood mononuclear cells of 10 patients of the IT group, both before and after IT, and the ratios of lymphocyte subpopulations were determined. Cytokine production by TCLs (IL-4, IL-5, IFNgamma, IL-10) and proliferation of TCLs in response to stimulation with birch pollen allergen were measured.

RESULTS

It was possible to evaluate 27 patients in accordance with the study protocol. Clinical symptoms and medication intake were reduced as a result of the IT as were nasal secretion levels of IL-5 (P = 0.007). IFNgamma was increased in nasal secretions (P = 0.01), while IL-4 was not measurable in most samples. No effect was found on proliferation of birch pollen-reactive TCLs, cytokine production by TCLs and the frequency and ratio of CD4+ and CD8bright or CD45RA+ and CD45RO+ cells in peripheral blood (all P > 0.05). Conclusion Preseasonal IT with a birch pollen allergoid is clinically effective in allergic rhinitis and influences cytokine production in the nose, but does not modulate the measured responses of peripheral blood T cells.

The effect of short-term immunotherapy with molecular standardized grass and rye allergens on eosinophil cationic protein and tryptase in nasal secretions

BACKGROUND

Activation of mast cells and eosinophils under pollen exposure can be inhibited by specific immunotherapy.

OBJECTIVE

The effect of short-term immunotherapy with 7 preseasonal injections of molecular standardized allergens from grass and rye pollen on eosinophil cationic protein (ECP) and tryptase levels in nasal secretions has been compared with symptomatic drug treatment in an open, randomized study with 48 patients.

METHODS

Nasal reactivity and mediator levels in nasal secretions were measured at baseline, before season, in season, and after season.

RESULTS

Symptom scores in the immunotherapy group were 134.5 (95% CI, 65 to 336) versus 386. 0 (95% CI, 185 to 563), significantly lower as in the drug-treated group. ECP and tryptase levels increased significantly during natural allergen exposition. The seasonal levels in the immunotherapy group were significantly lower than in the drug-treated group with 272.1 ng/mL (252.0 to 293.9 ng/mL; immunotherapy) versus 470.4 ng/mL (SEM, 435.6 to 508.0 ng/mL; drugs) for ECP and with 8.73 ng/mL (SEM, 8.20 to 9.29 ng/mL) versus 17.47 ng/mL (16.42 to 18.60 ng/mL) for tryptase (all, P <.001). The ECP level induced by nasal provocation was 105.6 ng/mL (99.0 to 112.6 ng/mL) versus 180.4 ng/mL (169.2 to 192.4 ng/mL), significantly lower (P <.001) in the immunotherapy group, as was the tryptase level with 12.12 ng/mL (11.53 to 12.75 ng/mL) versus 8.19 ng/mL (7. 79 to 8.62 ng/mL; P <.001) at the after-season visit.

CONCLUSION

Short-term immunotherapy is able to reduce tryptase and ECP in nasal secretions more effectively than drug treatment in patients with allergic rhinitis.