Improvement of Clinical Response in Allergic Rhinitis Patients Treated with an Oral Immunostimulating Bacterial Lysate: In Vivo Immunological Effects

Effect of immunostimulation with bacterial lysate on the clinical course of allergic rhinitis and the level of γδT, iNKT and cytotoxic T cells in children sensitized to grass pollen allergens: A randomized controlled trial

Background

There are many drugs for allergic rhinitis (AR), however, these drugs show variable clinical effectiveness and some side effects. Therefore, new methods of AR pharmacotherapy are being sought.

Objectives

The objectives of this study were to evaluate the efficacy of polyvalent mechanical bacterial lysate (PMBL) therapy in improving the clinical course of grass pollen-induced AR (seasonal AR, SAR) in children and its effect on changes in the blood level of the γδT, iNKT and cytotoxic T cell subsets.

Methods

Fifty children with SAR were enrolled in this study and were randomly assigned to either the PMBL group or the placebo group. The severity of SAR symptoms was assessed using the total nasal symptom score (TNSS) and visual analogue scale (VAS). During two visits (V1, V2), peak nasal inspiratory flow (PNIF) was measured and peripheral blood was collected for immunological analyses. The study also included 2 telephone contacts (TC1, TC2).

Results

The severity of the nasal symptoms of SAR on the TNSS scale was revealed to have a significantly lower impact in the PMBL group vs the placebo group at measuring points TC1 and V2 (p = 0.01, p = 0.009, respectively). A statistically significantly lower mean severity of nasal symptoms of SAR on the VAS scale was recorded for children in the PMBL group compared to the placebo group at measuring points TC1, V2 and TC2 (p = 0.04, p = 0.04, p = 0.03, respectively). The compared groups do not show significant differences in terms of PNIF values at individual measuring points. There were no statistically significant changes in immune variables. For both groups, there was a statistically significant association between the level of Th1-like γδT cells and the severity of SAR symptoms expressed on the TNSS scale (p = 0.03) - the lower the level of Th1-like γδT cells, the higher the TNSS value.

Conclusion

Administration of sublingual PMBL tablets during the grass pollen season proves to have a high efficacy in alleviating SAR symptoms in children sensitized to grass pollen allergens. Th1-like γδT cells may be used as potential markers for SAR severity in children.

Clinical trial registration

ClinicalTrials.gov, identifier (NCT04802616).

The return of the mixed respiratory bacterial vaccine

Background: Orally or sublingually administered lysates of mixed respiratory pathogenic bacteria have been used in Europe, Asia, and other parts of the world, but not the United States, since the mid 1950s, first to prevent recurrent respiratory tract infections, later to prevent wheezing and asthma exacerbations associated with respiratory infections, and, more recently, for the treatment of allergic rhinitis. The apparent success of this treatment contrasts with the negative experience of treating with injections of similar mixed respiratory bacterial vaccines (MRBV or BV) to prevent asthma exacerbations associated with respiratory infections that was once common practice but abandoned ∼50 years ago. Methods: Textbooks and articles on the use of injected BVs to prevent asthma exacerbations associated with respiratory infections were reviewed, including a number of, randomized, double-blind, placebo controlled (RDBPC) studies the results of which were predominantly negative that contributed to the abandonment of this treatment. Also reviewed were more recent articles from Europe and China, which report both clinical and immunologic support for the use of the orally and sublingually administered mixed respiratory bacterial lysates (MRBL or BL). Results: A review of five RDBPC studies of the parenteral use of BVs for prevention of asthma exacerbations conducted by leading international allergists in the 1950s and 1960s showed, in a combined 532 patients, an overall reduction of asthma attacks by 4.9% over placebo. However, in five studies in 1126 patients of oral or sublingual treatment with BLs, the reduction in respiratory infections, wheezing episodes, and asthma exacerbations was 42.6% over placebo. Conclusion: Reported results with oral and sublingual BLs are far superior to the historical performance of injected BVs. Possible reasons for this difference are discussed, but none is clearly responsible for the difference in clinical results.

Promising Immunomodulatory Effects of Bacterial Lysates in Allergic Diseases

In light of an escalating prevalence of allergic disorders, it is crucial to fully comprehend their pathophysiology and etiology. Such knowledge would play a pivotal role in the search for new therapeutic approaches concerning not only diseases’ symptoms, but also their underlying causes. The hygiene hypothesis indicates a high correlation between limited exposure to pathogens in early childhood and the risk of developing allergic disorders. Bearing in mind the significance of respiratory and digestive systems’ mucous membrane’s first-line exposure to pathogens as well as its implications on the host’s immune response, a therapy targeted at aforesaid membranes could guarantee promising and extensive treatment outcomes. Recent years yielded valuable information about bacterial lysates (BLs) known for having immunomodulatory properties. They consist of antigen mixtures obtained through lysis of bacteria which are the most common etiologic agents of respiratory tract infections. They interact with dendritic cells located in the mucous membranes of the upper respiratory tract and the gastrointestinal tract by toll-like receptors. The dendritic cells present acquired antigens resulting in innate immune response development on the release of chemokines, both stimulating monocytes and NK cells maturation and promoting polymorphonuclear neutrophil migration. Moreover, they influence the adaptive immune system by stimulating an increase of specific antibodies against administered bacterial antigens. The significance of BLs includes not only an anti-inflammatory effect on local infections but also restoration of Th1/Th2 balance, as demonstrated mainly in animal models. They decrease Th2-related cytokine levels (IL-4, IL-13) and increase Th1-related cytokine levels (IFN-γ). The reestablishment of the balance of the immune response leads to lowering atopic reactions incidence which, in addition to reduced risk of inflammation, provides the alleviation and improvement of clinical manifestations of allergic disorders. In this review, we hereby describe mechanisms of BLs action, considering their significant immunomodulatory role in innate immunity. The correlation between local, innate, and adaptive immune responses and their impact on the clinical course of allergic disorders are discussed as well. To conclude our review, we present up-to-date literature regarding the outcomes of BLs implemented in atopic dermatitis, allergic rhinitis, and asthma prevention and treatment, especially in children.

Perspectives for the Use of Bacterial Lysates for the Treatment of Allergic Rhinitis: A Systematic Review

Bacterial lysates (BLs) are mixtures of bacterial antigens that have been used for many decades to minimize the risk of recurrent respiratory tract infections in both pediatric and adult populations. Research on the use of BLs is also conducted in allergology. Biomedical databases were searched for articles on the use of BLs in the treatment of allergic rhinitis (AR). After rejecting ineligible articles, six remaining reports were reviewed. Based on this review, it can be concluded that adding BL to standard therapy for seasonal or perennial AR reduces the severity of nasal symptoms and the need for antiallergic medications in both children and adults. Concurrently, these formulations have a high safety profile. An analysis of studies shows that the first effects of BLs therapy appear at the earliest 2–6 weeks after the start of treatment and persist at least 3 months after treatment.

A Case-Control Study on the Changes in Natural Killer Cell Activity following Administration of Polyvalent Mechanical Bacterial Lysate in Korean Adults with Recurrent Respiratory Tract Infection

Polyvalent mechanical bacterial lysate (PMBL) is used for the treatment and prevention of recurrent respiratory tract infections. Although PMBL is an immunostimulant, it remains unknown whether treatment with PMBL influences natural killer cell activity (NKA). Hence, this case-control study compared the changes in IFN-γ levels (surrogate index for NKA) following PMBL treatment or time passing between the PMBL-treated group and controls. The treatment group included adults who had a PMBL prescription for three months against recurrent respiratory tract infection from an outpatient clinic, while the control group had healthy adults visiting the health promotion center for periodic health check-ups. The control group (N = 506) showed no change in IFN-γ levels, while the treatment group (N = 301) showed a significant increase in mean from 462.8 to 749.3 pg/mL after PMBL treatment. In the subgroup with IFN-γ <500 pg/mL, IFN-γ levels significantly increased in both groups. However, the change in the treatment group (287 ± 822 pg/mL) was greater than that in the control group (58 ± 809 pg/mL), and the interaction between the visit and case/control was significant (p = 0.030) in a generalized estimating equation model. In conclusion, NKA increased in the subjects with recurrent respiratory tract infections with PMBL treatment.

Bacterial lysate treatment in allergic disease: A systematic review and meta-analysis

OBJECTIVE

The aim of this review was to assess the efficacy of bacterial lysate treatment in patients with allergic disease.

METHOD

Randomized controlled trials (RCTs) of bacterial lysate therapy for patients with allergic diseases (asthma, atopic dermatitis, and allergic rhinitis) were searched using PubMed, EMBASE, Cochrane, China National Knowledge Infrastructure, Chinese Biomedical literature, and Wanfang databases up to March 2020. Based on the guidelines of the Cochrane collaboration, risk of bias was assessed.

RESULTS

This meta-analysis based on 19 studies comparing bacterial lysate-treated patients with a control group showed a 24% (RR: 1.24, 95% CI [1.19, 1.30]) increase in improvement of allergy symptom control. In addition, the improvement of asthma symptom control was 22% (RR: 1.22, 95% CI [1.14, 1.26]) higher in the bacterial lysate treatment group. Moreover, the levels of immunoglobulin (IgA and IgG), T lymphocyte subtype (CD3+, CD4+, CD4+/CD8+, Th1), and cytokines (IFN-γ, IL-2, and IL-12) were increased in the treated group compared with controls. There was no significant difference in adverse event rate between the two groups.

CONCLUSION

Treatment with bacterial lysate improves symptom control in patients with allergic diseases on the basis of routine therapy. No adverse risk was found in this meta-analysis.

Polyvalent Mechanical Bacterial Lysate Administration Improves the Clinical Course of Grass Pollen-Induced Allergic Rhinitis in Children: A Randomized Controlled Trial

BACKGROUND

Recent studies highlight the immunoregulatory potential of bacterial lysates, indicating their potential use in the prevention and treatment of allergic diseases.

OBJECTIVE

To investigate the clinical efficacy of polyvalent mechanical bacterial lysates (PMBLs) in children with grass pollen-induced allergic rhinitis.

METHODS

Seventy children with seasonal allergic rhinitis were enrolled to this study and were randomly assigned to the PMBL and placebo groups. Severity of seasonal allergic rhinitis symptoms was assessed by the total nasal symptom score, total ocular symptom score, and visual analogue scale. During 3 visits, peak nasal inspiratory flow was measured, and nasal smears for the presence of eosinophils and nasal lavage fluids for the presence of allergen-specific IgE against timothy grass pollen allergens were sampled.

RESULTS

A statistically significant decrease in total nasal symptom score (P = .001), total ocular symptom score (P = .04), and visual analogue scale score for nasal and eye symptoms (P < .001 and P < .001, respectively) and an increase in peak nasal inspiratory flow (P = .04) were observed in the PMBL group versus the placebo group. During the grass pollen season, an increase and then a decrease in the number of eosinophils in nasal smears was observed in both groups; however, the number of eosinophils was significantly lower in the PMBL group versus the placebo group. No significant changes in allergen-specific IgE concentrations were observed in the PMBL group, whereas in the placebo group a statistically significant increase in allergen-specific IgE concentration was observed.

CONCLUSIONS

Sublingual administration of PMBLs during the grass pollen season offers significant efficacy in alleviating seasonal allergic rhinitis symptoms in children sensitized to grass pollen allergens. PMBLs probably affect mucosal immunity, weakening the response of T_H2 cells.

Immunoactive preparations and regulatory responses in the respiratory tract: potential for clinical application in chronic inflammatory airway diseases

Introduction: The prevalence of chronic inflammatory airway diseases is rising. Their treatment with corticosteroids increases infection risk, while overuse of antimicrobial agents may increase morbidity and antimicrobial resistance. Nonspecific immunomodulatory compounds alter immune responses to both infectious and atopic challenges. These compounds may offer an alternative approach for symptom reduction and prophylaxis against both infections and exacerbations in chronic inflammatory airway disease.Areas covered: We assessed the available data on the efficacy of nonspecific immunomodulators including bacterial lysates, synthetic compounds, and vaccines in chronic rhinosinusitis (CRS); allergic and non-allergic rhinitis; chronic obstructive pulmonary disease (COPD), and asthma. A search of PubMed was carried out using the 'Clinical Trials' filter for each condition and immunomodulatory product detailed below, where available, data from meta-analyses were reported.Expert opinion: Pre-clinical data has revealed a coherent mechanistic path of action for oral immunomodulators on the respiratory immune system, principally via the gut-lung immune axis. In patients with asthma, allergic rhinitis, CRS, and COPD immunomodulatory therapy reduces symptoms, exacerbations, hospitalizations, and drug consumption. However, data are heterogeneous, and study quality remains limited. A lack of high-quality recent trials remains the major unmet research need in the field.

Nonspecific immunomodulators for recurrent respiratory tract infections, wheezing and asthma in children: a systematic review of mechanistic and clinical evidence

PURPOSE OF REVIEW

To provide an overview of the mechanistic and clinical evidence for the use of nonspecific immunomodulators in paediatric respiratory tract infection (RTI) and wheezing/asthma prophylaxis.

RECENT FINDINGS

Nonspecific immunomodulators have a long history of empirical use for the prevention of RTIs in vulnerable populations, such as children. The past decade has seen an increase in both the number and quality of studies providing mechanistic and clinical evidence for the prophylactic potential of nonspecific immunomodulators against both respiratory infections and wheezing/asthma in the paediatric population. Orally administered immunomodulators result in the mounting of innate and adaptive immune responses to infection in the respiratory mucosa and anti-inflammatory effects in proinflammatory environments. Clinical data reflect these mechanistic effects in reductions in the recurrence of respiratory infections and wheezing events in high-risk paediatric populations. A new generation of clinical studies is currently underway with the power to position the nonspecific bacterial lysate immunomodulator OM-85 as a potential antiasthma prophylactic.

SUMMARY

An established mechanistic and clinical role for prophylaxis against paediatric respiratory infections by nonspecific immunomodulators exists. Clinical trials underway promise to provide high-quality data to establish whether a similar role exists in wheezing/asthma prevention.

Mechanical bacterial lysate administration prevents exacerbation in allergic asthmatic children-The EOLIA study

BACKGROUND

Despite progress in asthma management, prevention of asthma exacerbation remains challenging in school-aged children with allergic asthma. New therapeutic approaches are needed. Previously, a chemical bacterial lysate has been successfully used in preschool children to reduce wheezing attacks. We assessed the effect of Polyvalent Mechanical Bacterial Lysate (PMBL^® ) Tablet on asthma clinical course and control in 6- to 16-year-old children with partly controlled or uncontrolled allergic asthma.

METHODS

A randomized, double-blind, placebo-controlled, parallel-group study was performed in 152 patients exhibiting allergic asthma assigned to receive Placebo or PMBL^® . Eligible patients underwent four visits during the 9-month study. Asthma control level was assessed by ACT/C-ACT score.

RESULTS

The main criterion was not achieved as ACT/C-ACT changes were similar in both groups at the end of the 3-month treatment period. However, the mean number (±SD) of asthma exacerbations was significantly lower with PMBL^® Tablet than with Placebo at Week 12 (0.3 ± 0.6 vs 0.8 ± 1.1, P = .009) and over the total study period (1.1 ± 1.3 vs 1.9 ± 2.0, P = .01). Consistently, the mean number of days with exacerbation per patient was significantly lower with PMBL^® Tablet (13.3 ± 11.2 vs 19.8 ± 15.7 over the whole study, P = .009). Treatment with PMBL^® Tablet prolonged the time to second exacerbation by 55% (Hazard Ratio [HR]=0.45; 95% Confidence Interval [CI] 0.27 to 0.77, P = .002) and to third exacerbation by 74% (HR=0.26; 95% CI 0.12 to 0.58, P < .001). No serious adverse event related to PMBL^® Tablet administration was recorded.

CONCLUSION

Administration of PMBL^® Tablet represents a safe and effective means for significantly reducing the rate of exacerbations in school-aged allergic asthmatic children. (EudraCT 2013-000737-12 and NCT02541331).

Broncho-Vaxom attenuates allergic airway inflammation by restoring GSK3β-related T regulatory cell insufficiency

Background

Oral administration of bacterial extracts (eg, Broncho-Vaxom (BV)) has been proposed to attenuate asthma through modulating Treg cells. However, the underlying mechanism has not been fully characterized. This study sought to assess the effects of oral administration of BV on GSK-3β expression and Treg cells in ovalbumin (OVA)-induced asthmatic mice models.

Method

Asthmatic mice models were established with OVA challenge and treated with oral administration of BV. Next, infiltration of inflammatory cells including eosinophil and neutrophils, mucous metaplasia, levels of Th1/Th2/Treg-typed cytokines and expression of GSK3β and Foxp3 were examined in asthmatic mice models by histological analysis, Bio-Plex and western blot, respectively. Moreover, the frequencies of Treg cells were evaluated in cultured splenocytes by flow cytometry in the presence of BV or GSK3β siRNA interference.

Results

We found significant decrease of infiltrated inflammatory cells in bronchoalveolar lavage fluid (BALF) in asthmatic mice models after oral administration of BV. Oral administration of BV was shown to significantly suppress mucus metaplasia, Th2-typed cytokine levels and GSK3β expression while increasing Foxp3 production in asthmatic mice models. Moreover, BV significantly enhanced GSK3β-related expansion of Treg cells in cultured spleen cells in vitro.

Conclusion

Our findings provide evidence that oral administration of BV is capable of attenuating airway inflammation in asthmatic mice models, which may be associated with GSK3β-related expansion of Treg cells.

Administration of a polyvalent mechanical bacterial lysate to elderly patients with COPD: Effects on circulating T, B and NK cells

The modifications of the subsets of circulating lymphocytes were evaluated in a group of patients with COPD undergoing treatment with a polyvalent mechanical bacterial lysate (PMBL), a drug that is able to significantly modify the natural history of these patients. Using multicolor immune-florescence and flow cytometry, T, B subsets and NK cells were extensively studied both in the group of treated patients and in a disease and age matched controls. Despite the age, in treated patients, T and NK cells were significantly increased in numbers of circulating cells, but not in percentages, while B cells remained unmodified. CD3+4+T cells were increased in treated patients, while CD3+CD8T cells were unmodified by the treatment. Activated T cells were increased but Treg, resulted reduced both in percentage than in absolute numbers. Transitional B cells resulted increased (in percentage and in absolute numbers) in their late maturation step (T3), while only early Naïve B cells were increased by the treatment, while other naïve subpopulations were unmodified. Memory B cells were reduced in percentage (but remained unmodified as absolute numbers), while the most immature form of memory B cells was significantly increased. Finally, both switch memory B cells and plasma cells resulted unmodified by the PMBL treatment. These results clearly indicated that the administration of the PMBL, even in elderly patients with COPD, was able to induce a significant immune-stimulation and these results, at cellular level, clearly support the evidence that the mechanism of action of PMBL is strictly related to a direct effect on immune-competent cells.

May we strengthen the human natural defenses with bacterial lysates?

During the last twenty years bacterial lysates have gained a new interest and their use has obtained a progressively larger consensus in the medical practice. They are commonly used as immunomodulators, in order to up-regulate immune responses against infectious damages. As a matter of fact, the role of these lysate seems relevant in upper and lower respiratory tract infections prevention, frequently observed both in paediatric and elder ages, and which represent a relevant problem also in terms of socio-economical implications. The effects of bacterial lysates as immunostimulatory agents have become the central point of many studies. The aim of those in vivo and in vitro studies was to understand and evaluate the capacity of this kind of treatments to create a better answer of the immune system against microbial infections, eventually leading to a reduction in their number. All the in vivo and in vitro findings analyzed support the evidence that bacterial lysates are powerful inducers of a specific immune response against bacterial infections. Both in paediatric and adult clinical trials, a positive trend has been found in terms of overall reduction of infection rates and duration, beneficial effect on symptoms, reduction in antibiotics use and possibility to improve the patient's quality of life in several diseases. Further well-designed trials in terms of blinding and randomization procedures and including a higher number of patients, selected according to the disease and its severity, are needed.

Impact of Porcine Orexin a on Glucagon Plasma Concentrations in Pigs

In 1998, Orexin A was added to the long list of orexigenic neuropeptides of the brain's physiology. Orexin A is involved in the central control of appetite and in energy homeostasis, as well as in the regulation of many other physiological functions. It is produced by a small cluster of the brain's neurons, located mainly in and around the lateral hypothalamic area. This site is known to be involved in regulating feeding in mammals. An intracerebroventricular injection of Orexin A into the rat's brain causes an impressive increase in the consumption of food, while an intravenous injection induces changes on glucagon plasma concentrations in rats. In addition, there are signs of changes on glucagon plasma concentrations when Orexin A acts on individual pancreatic islets of rats. In this study, we investigated the potential effects of the central administration of porcine Orexin A on glucagon plasma concentrations in pigs, and examined whether these changes are associated with the possible effect of the neuropeptide on the enteroinsular axis.