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

A critical analysis of the effect of OM-85 for the prevention of recurrent respiratory tract infections or wheezing/asthma from systematic reviews with meta-analysis

Acute respiratory tract infections (RTIs) are one of the most common causes of pediatric consultations/hospitalizations and a major trigger for asthma exacerbations. Some consensus statements have recommended the use of immunostimulants to boost natural defenses against severe or repeated infections. One of the most common immunostimulants is OM-85; while several randomized clinical trials (RCTs) have evaluated its efficacy in preventing acute RTIs and wheezing/asthma exacerbations, results have been conflicting. Similarly, various systematic reviews with meta-analyses (SRMs) on OM-85 have used different strategies, populations, and outcomes; moreover, SRM conclusions are limited when the original studies are highly heterogeneous or have a low quality, hindering the generalizability of the findings. Here we summarize the evidence on the effect of OM-85 to prevent acute RTIs, wheezing/asthma episodes, or loss of asthma control in children, by including and critically evaluating all SRMs published to date. We searched for SRMs on OM-85 in three publication databases and found nine SRMs (seven for RTI, and two for wheezing/asthma). Among those, one had a high confidence evaluation of quality (AMSTAR-2 tool) and found a reduction in the total number of acute RTIs among the OM-85 group. Overall, no strong recommendations can be derived from the existing literature, mainly due to the high heterogeneity among included RCTs and SRMs. Further, large, high-quality RCTs are needed to confirm the true efficacy of OM-85 for the prevention of acute RTIs, asthma development, and asthma exacerbations.

Advances in Bacterial Lysate Immunotherapy for Infectious Diseases and Cancer

Antigenic cell fragments, pathogen-associated molecular patterns, and other immunostimulants in bacterial lysates or extracts may induce local and systemic immune responses in specific and nonspecific paradigms. Based on current knowledge, this review aimed to determine whether bacterial lysate has comparable functions in infectious diseases and cancer treatment. In infectious diseases, including respiratory and urinary tract infections, immune system activation by bacterial lysate can identify and combat pathogens. Commercially available bacterial lysates, including OM-85, Ismigen, Lantigen B, and LW 50020, were effective in children and adults in treating respiratory tract infections, chronic obstructive pulmonary disease, rhinitis, and rhinosinusitis with varying degrees of success. Moreover, OM-89, Uromune, Urovac, Urivac, and ExPEC4V showed therapeutic benefits in controlling urinary tract infections in adults, especially women. Bacterial lysate-based therapeutics are safe, well-tolerated, and have few side effects, making them a good alternative for infectious disease management. Furthermore, a nonspecific immunomodulation by bacterial lysates may stimulate innate immunity, benefiting cancer treatment. "Coley's vaccine" has been used to treat sarcomas, carcinomas, lymphomas, melanomas, and myelomas with varying outcomes. Later, several similar bacterial lysate-based therapeutics have been developed to treat cancers, including bladder cancer, non-small cell lung cancer, and myeloma; among them, BCG for in situ bladder cancer is well-known. Proinflammatory cytokines, including IL-1, IL-6, IL-12, and TNF-α, may activate bacterial antigen-specific adaptive responses that could restore tumor antigen recognition and response by tumor-specific type 1 helper cells and cytotoxic T cells; therefore, bacterial lysates are worth investigating as a vaccination adjuvants or add-on therapies for several cancers.

Short-term administration of Qipian®, a mixed bacterial lysate, inhibits airway inflammation in ovalbumin-induced mouse asthma by modulating cellular, humoral and neurogenic immune responses

AIMS

Qipian® is a commercialized agent composed of extracts of three genera of commensal bacteria, and its mechanism of action on asthma is unclear. This study aimed to examine the impact of Qipian® on airway inflammation and investigate the underlying mechanisms.

MATERIALS AND METHODS

Qipian® or dexamethasone (DEX) was administered before OVA challenge in an ovalbumin-induced asthma mouse model, and then asthmatic symptoms were observed and scored. Samples of lung tissues, blood, and bronchoalveolar lavage fluid (BALF) were collected, and eosinophils (Eos), immunoglobins (Igs), and type 1 T helper (Th1)/Th2 cell cytokines were measured. Mucus production in the lung was assessed by periodic acid-Schiff (PAS) staining. The effects of Qipian® on dendritic and T regulatory (Treg) cells were investigated using flow cytometry.

KEY FINDINGS

The short-term administration of Qipian® significantly inhibited the cardinal features of allergic asthma, including an elevated asthmatic behaviour score, airway inflammation and immune response. Histological analysis of the lungs showed that Qipian® attenuated airway inflammatory cell infiltration and mucus hyperproduction. Qipian® restored Th1/Th2 imbalance by decreasing interleukin (IL)-4, IL-5, and IL-13 while increasing interferon (IFN)-γ and IL-10. Further investigation revealed that Qipian® treatment induced the upregulation of CD4+CD25+Foxp3+ Treg cells and CD103+ DCs and downregulation of tachykinins neurokinin A (NKA) and NKB in the lung.

SIGNIFICANCE

Our findings suggested that short-term treatment with Qipian® could alleviate inflammation in allergic asthma through restoring the Th1/Th2 balance by recruiting Treg cells to airways and inducing the proliferation of CD103+ DCs, which actually provides a new treatment option for asthma.

Broncho-Vaxom bacterial lysate prevents asthma via acetate enhancement in mouse model

PURPOSE

Broncho-Vaxom (BV) is known to attenuate allergic airway inflammation and chronic bronchitis in humans, but the underlying mechanism of this gut-mediated immunity remains unclear. This study investigated the effects of an oral BV on gut and systemic short-chain fatty acids (SCFAs) and immune responses.

METHODS

Oral BV was administered daily for 15 days prior to commencing the study in an asthma mouse model. Asthma was induced by ovalbumin (OVA) sensitization followed by a challenge with 1% OVA by inhalation. Asthmatic phenotypes, gut- and systemic- immune responses, and SCFAs in the cecum and blood were then investigated.

RESULTS

Airway hyperresponsiveness, total immunoglobulin E production, and pulmonary inflammation were all significantly suppressed by BV. The interleukin-13 level was also suppressed, whereas TGF-β expression was increased, in the lungs of the BV-treated mice. The regulatory T (Treg) cell numbers were increased in the small intestine, and the acetate level was increased in the cecum and serum after BV treatment. The levels of acetate in the cecum and serum were negatively correlated with airway hyperresponsiveness and with the eosinophil numbers in the BAL fluid of the OVA-induced mice. There was a positive correlation between the acetate levels in the feces and serum and the lung expression of TGF-β in the asthma mice.

CONCLUSIONS

Oral BV administration appears to prevent allergic inflammation by enhancing Treg cell proliferation and acetate production in an asthmatic mouse model.

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).

Recent advances and potentiality of postbiotics in the food industry: Composition, inactivation methods, current applications in metabolic syndrome, and future trends

Postbiotics are defined as "preparation of inanimate microorganisms and/or their components that confers a health benefit on the host". Postbiotics have unique advantages over probiotics, such as stability, safety, and wide application. Although postbiotics are research hotspots, the research on them is still very limited. This review provides comprehensive information on the scope of postbiotics, the preparation methods of inanimate microorganisms, and the application and mechanisms of postbiotics in metabolic syndrome (MetS). Furthermore, the application trends of postbiotics in the food industry are reviewed. It was found that postbiotics mainly include inactivated microorganisms, microbial lysates, cell components, and metabolites. Thermal treatments are the main methods to prepare inanimate microorganisms as postbiotics, while non-thermal treatments, such as ionizing radiation, ultraviolet light, ultrasound, and supercritical CO2, show great potential in postbiotic preparation. Postbiotics could ameliorate MetS through multiple pathways including the modulation of gut microbiota, the enhancement of intestinal barrier, the regulation of inflammation and immunity, and the modulation of hormone homeostasis. Additionally, postbiotics have great potential in the food industry as functional food supplements, food quality improvers, and food preservatives. In addition, the SWOT analyses showed that the development of postbiotics in the food industry exists both opportunities and challenges.

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.

Effectiveness of polyvalent bacterial lysate for pediatric asthma control: a retrospective propensity score-matched cohort study

BACKGROUND

Previous studies showed bacterial lysates were effective for pediatric asthma. However, evidence of polyvalent bacterial lysate Qipian is lacking.

METHODS

In this real-world retrospective cohort study, data of children with asthma, aged six months to 14 years old, attending to Jiangxi Provincial Children's Hospital from January 2021 to April 2022, prescribed routine treatment for asthma plus Qipian (Qipian group) or not (control group) were extracted. To minimize the impact of confounders on the outcomes, baseline characteristics were utilized to perform propensity score matching through a multivariable logistic regression model. After matching, asthma control, exacerbation, etc. were compared.

RESULTS

Totally, 795 patients were included (337 in the Qipian group and 458 in the control group), with 278 pairs (556 patients) matched. Most baseline characteristics were well-balanced. The proportion of males were 68.3% and 70.1% in the two groups. The Qipian group favored better asthma control, with more "controlled" [3-month: 257 (92.4%) vs. 240 (86.3%); 6-month: 246 (88.5%) vs. 235 (84.5%)], and fewer "poorly/very poorly controlled" patients, compared with the control group (P=0.004 and 0.025, respectively). Patients in the Qipian group had lower risks of exacerbation. Incidence rate ratios (IRR) for any exacerbation were 0.56 [95% confidence interval (CI): 0.33 to 0.93] in the 3-month period and 0.83 (95% CI: 0.55 to 1.26) in the 6-month period. IRR for severe exacerbations were 0.09 (95% CI: 0.01 to 0.71) in the 3-month period and 0.20 (95% CI: 0.06 to 0.70) in the 6-month period (compared to the control group). Qipian significantly reduced the cumulative dose of short-acting beta-agonist (3-month: 3.22±10.37 vs. 8.08±16.71 mg; P<0.001; 6-month: 6.56±16.23 vs. 11.81±24.41 mg; P=0.002). There was no difference in incidences of respiratory tract infection or fever due to respiratory tract infection between the two groups. Numbers of antibacterial agent prescription were fewer in the Qipian group compared to the control group (3-month: 0.67±1.16 vs. 1.04±1.45; P=0.001; 6-month: 1.14±1.69 vs. 1.51±2.12; P=0.023).

CONCLUSIONS

According to this retrospective study, Qipian may be effective for improved pediatric asthma control. Safety profile and mechanisms of action of Qipian need further investigation. Further randomized controlled trials are warranted to confirm our results.

Comparing available treatments for pollen-induced allergic rhinitis in children

INTRODUCTION

Pollen-induced allergic rhinitis (PIAR) is a widespread disease in children, and its prevalence is rapidly evolving. In addition, it may be associated with other atopic diseases, in particular asthma. In most cases, PIAR can be treated effectively by avoiding exposure to responsible allergens and using symptomatic treatments, including intranasal/oral antihistamines or/and nasal corticosteroids, according to ARIA guidelines. In recent decades, new medicines have been studied and developed: allergen-specific immunotherapy (AIT), anti-IgE antibodies, and probiotics. In addition, nutraceuticals have also been used as add-on treatments. This review aims to discuss and compare the old and new therapeutic strategies for PIAR in children.

AREAS COVERED

Allergic rhinitis is a type 2 inflammatory disease. The management of patients with PIAR entails medications, AIT, and ancillary therapies. In addition, children with PIAR and associated severe asthma may be inclusively treated with biologics. Namely, subjects with allergic comorbidities could benefit from biological agents. However, AIT presently remains the unique causal treatment for PIAR.

EXPERT OPINION

New strategies may include combined treatments, mainly concerning fixed associations with antihistamines and corticosteroids, nutraceutical products, and new AIT formulations.

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.