Use of OM-85 BV in children suffering from recurrent respiratory tract infections and subnormal IgG subclass levels

Immunostimulants for preventing respiratory tract infection in children: A systematic review and meta-analysis

Childhood acute respiratory tract infections (ARTIs) are a significant cause of morbidity and mortality, so, immunostimulants have been used as a preventative measure. Despite this, there is no updated evidence regarding the safety and efficacy of immunostimulant drugs for this purpose. This study aimed to determine the effectiveness and safety of immunostimulants in preventing ARTIs in children based on the most recent scientific evidence. Data sources such as PubMed, Cochrane Central Register of Controlled Trials, Embase, Google Scholar, and Scopus were searched from 1965 to 10 January 2022 to identify randomized controlled trials (RCTs) comparing immunostimulants administered by any method, with placebo to prevent ARTIs on children under 18 years of age without immunodeficiencies, anatomical, genetic, or allergic conditions. In order to analyze data from the studies, we used Review Manager 5.4 (The Cochrane Collaboration, 2020), assessed the certainty of the evidence with Grading of Recommendations, Assessment, Development and Evaluations (GRADE), and assessed the quality and risk of bias of the studies using the RoB tool 1.0. Further, outcomes were combined and analyzed using meta-analysis, subgroup analysis, and sensitivity analysis. Throughout the review, we included 72 placebo-controlled clinical trials involving 12,229 children. The meta-analyses, however, included only 38 studies (52.8%) with 4643 children (38% of the total) with data on mean number of ARTIs. These studies demonstrated a reduction in the ARTIs (MD –1.12 [95%CI –1.39 to −0.85]) and ratio of means of ARTIs (0.61 [95%CI 0.54–0.69]), corresponding to a percentage reduction of 39% (95%CI, 46%–31%) with moderate-quality data. Nevertheless, since there was considerable to substantial heterogeneity and bias was unclear in all domains in 32 out of 72 trials, the quality of the evidence for efficacy was deemed low. Only 14 trials reported adverse events.

The review indicates that immunostimulants reduce the incidence of ARTIs by 40% on average in susceptible children, despite low-quality evidence, heterogeneity, and the possibility of publication bias. However, further studies are needed to establish immunostimulants' safety and efficacy profiles.

This review was conducted without the support of any funding and has no registered number.

Whether Immunostimulants Are Effective in Susceptible Children Suffering From Recurrent Respiratory Tract Infections: A Modeling Analysis Based on Literature Aggregate Data

Immunostimulants are gradually being used in the prevention and treatment of recurrent respiratory tract infections in susceptible children, but their drug effects have not been quantified. The purpose of this study was to confirm the efficacy of immunostimulants in the prevention and treatment of recurrent respiratory tract infections in susceptible children. A model-based meta-analysis was used to describe the time course of placebo and immunostimulants in the prevention of respiratory tract infections in children. The cumulative number of respiratory tract infections was used as an indicator of efficacy. A meta-analysis was used to analyze the incidence of drug-related adverse events. Fourteen articles with 2400 pediatric subjects were finally included in the analysis. The results showed that the cumulative number of respiratory tract infections increased linearly with time, with the incidence of respiratory tract infections in the placebo group being 0.65 (95% confidence interval [CI], 0.55-0.75) per month. OM-85 BV and pidotimod reduced the incidence of respiratory tract infections by 0.21 (95%CI, 0.16-0.26) and 0.19 (95%CI, 0.17-0.21) compared to placebo per month, respectively. Pidotimod and OM-85 BV can effectively reduce the incidence of respiratory tract infections in susceptible children, with no significant increase in the incidence of drug-related adverse events when compared with placebo (risk ratio values were 1.07 [95%CI, 0.66-1.71] and 1.31 [95%CI, 0.54-3.19], respectively). This study provides quantitative support for the application of immunostimulants for the prevention of recurrent respiratory tract infections in children.

Efficacy and safety of OM-85 in paediatric recurrent respiratory tract infections which could have a possible protective effect on COVID-19 pandemic: A meta-analysis

INTRODUCTION

The OM-85 (Broncho-Vaxom) consumption has drawn considerable attention in the prevention of recurrent respiratory tract infections. However, it has been reported that the relationship between OM-85 consumption and recurrent respiratory tract infections is variable. This meta-analysis was performed to evaluate this relationship.

METHODS

A systematic literature search up-to May 2020 was performed and 14 studies were detected with 1859 paediatric subjects, of them 890 consumed OM-85. They were reporting relationships between OM-85 consumption and recurrent respiratory tract infections. Odds ratio (OR) or mean differences (MD) with 95% confidence intervals (CIs) was calculated to evaluate the prognostic role of OM-85 consumption and recurrent respiratory tract infections using the dichotomous or continuous method with a random or fixed-effect model.

RESULTS

OM-85 consumption was significantly related to lower frequency of respiratory tract infections (MD, -1.16; 95% CI, -1.66 to -0.65, P < .001); lower total duration of respiratory tract infections (MD, -19.51; 95% CI, -23.00 to -16.01, P < .001); lower incidence of respiratory tract infections (OR, 0.40; 95% CI, 0.21-0.77, P = .006); lower number of antibiotic courses (MD, -1.40; 95% CI, -2.63 to 0.17, P = .03); and lower antibiotic use (OR, 0.38; 95% CI, 0.29-0.52, P < .001). However, OM-85 consumption was not significantly related to adverse event rate (OR, 1.02; 95% CI, 0.52-2.03, P = .94); or to wheezing attacks frequency (MD, -0.25; 95% CI, -0.59 to 0.08, P = .14).

CONCLUSIONS

The impact of OM-85 consumption on recurrent respiratory tract infections may have a great effect as a tool to improve subjects' immunity against recurrent respiratory tract infections, which could be helpful in crucial situations, eg, COVID-19 pandemic. OM-85 non-consumers had an independent risk relationship with recurrent respiratory tract infections. This relationship forces us to recommend OM-85 consumption with those with a high risk of recurrent respiratory tract infections to avoid any possible complications.

Prevention of New Respiratory Episodes in Children with Recurrent Respiratory Infections: An Expert Consensus Statement

In healthy infants and young children, the development of respiratory tract infections (RTIs) is extremely common. In this paper, we present an international consensus of the available approaches for the prevention of recurrent RTIs in children, including the atopic/allergic ones as well as those with asthma. Few convincing measures for reducing the frequency and clinical relevance of recurrent respiratory episodes in RTI-prone children have been developed until now. Among the most recently suggested measures, immunotherapy is attractive, but only for OM-85 is there a sufficient number of well-conducted clinical trials confirming efficacy in RTIs prevention with an adequate safety profile. In the case of probiotics, it is not clear which bacteria can offer the best results and which dosage and schedule of administration are the most effective. The problems of dosage and the schedule of administration are not solved also for vitamin D, despite some promising efficacy results. While we wait for new knowledge, the elimination or reduction as much as possible of the environmental factors that favor RTIs, vaccination when available and/or indicated, and the systematic application of the traditional methods for infection prevention, such as hand washing, remain the best measures to prevent recurrent infections in RTI-prone children.

Paediatric Recurrent Ear, Nose and Throat Infections and Complications: Can We Do More?

Recurrent respiratory tract infections (rRTIs), of which there are three main groups—otitis media, tonsillitis and sinusopathies—are very common in paediatric populations and are associated with significant morbidity and mortality due to complications. These infections substantially reduce quality of life for paediatric patients and their families and are a significant personal, medical and economic burden on the patients, the patients’ families and the healthcare system. Most rRTIs are of viral origin; however, indiscriminate use of antibiotics in their treatment has led to development of bacterial resistance. Effective management of rRTIs to reduce the burden of disease and to avoid overuse of antibiotics has become a great therapeutic challenge. New strategies for the management of paediatric rRTIs include focus on prevention using non-specific immunomodulators to boost the body’s natural defences against infection and to downregulate infection- and allergen-induced airway inflammation. The oral immunomodulator, OM-85, a bacterial lysate, acts on the innate and adaptive branches of the immune system, conferring protection against viral and bacterial infections, and controls inflammation, thereby reducing tissue damage. OM-85 has demonstrated good tolerability and clinical efficacy in reducing the number and duration of RTIs in children with recurrent airway infections. It has also been reported to reduce the use of concomitant medications, including antibiotics, time to cure and school absenteeism. OM-85 is efficacious and well tolerated when administered concomitantly with inactivated influenza vaccine (IIV) and has been shown to reduce wheezing attacks induced by RTI in young children. Clinical results show that the greater the risk of rRTIs, the greater the benefit with OM-85. OM-85 may be considered a promising tool to add to the limited armamentarium of the ear, nose and throat (ENT) physician dealing with rRTIs and their complications, such as recurrent wheeze and asthma inception.

Cost-effectiveness analysis of OM-85 vs placebo in the prevention of acute respiratory tract infections (ARTIs) in children that attend day-care centers

BACKGROUND

Children that attend day-care centers frequently contract acute respiratory tract infections (ARTIs). ARTIs represent a burden for both children and parents. Systematic reviews on the use of immunostimulants for the prevention of juvenile recurrent ARTIs have provided moderate evidence of efficacy and safety. The aim of the study was to establish whether the immunostimulant, OM-85, was cost-effective in preventing ARTIs in children 2-6 years old that attended day-care centers or preschools in Mexico. We performed a systematic review to evaluate the efficacy of OM-85. For costs, we assumed an institutional perspective, which included the costs of care and supplies over a study period of six months, during the autumn-winter seasons. We created decision trees and constructed a model to identify pharmacoeconomic parameters. We generated 1000 estimations with the bootstrap method to calculate descriptive statistics of pharmacoeconomic parameters. We evaluated cost-effectiveness compared to treatment without immunostimulants.

RESULTS

The mean (SD) incidences of ARTIs were 5.59 ± 0.29 without immunostimulants and 2.97 ± 0.32 with OM-85, during the study period. The mean (25th, 75th percentile) direct costs of ARTIs were 57.04 (37.11, 76.39) US$ (US dollars) without immunostimulants and 48.53 (37.35, 58.93) US$ with OM-85, with a mean increment of - 8.51(- 17.08, 0.75) US$, and a mean cost-effectiveness of - 17.94 (- 36.48, 1.66) US$. The direct costs plus the cost of one parent missing work to care for the child with ARTI were 125.76 (102.83, 150.16) US$, without immunostimulant and 85.21 (72.15, 98.81) US$, with OM-85. The increment was - 40.55 (- 68.29, - 13.95) US$, and the cost-effectiveness was - 86.89 (- 142.37, - 29.34) US$.Part of the cost reduction was ascribed to the reduced use of medications, particularly antibiotics.

CONCLUSIONS

Our results were consistent with previous clinical studies conducted in closed institutions in Mexico. OM-85 reduced the number of ARTIs and the frequency of antibiotics use. We concluded that OM-85 was cost-effective for preventing ARTIs in children that attended day-care centers, particularly when parental absenteeism was covered by the institutions.

Impact of a mixed bacterial lysate (OM-85 BV) on the immunogenicity, safety and tolerability of inactivated influenza vaccine in children with recurrent respiratory tract infection

It is known that the immunogenicity and efficacy of conventional inactivated influenza vaccines (IIVs) are not completely satisfactory in children. The aim of this prospective, randomised, single-blind study was to compare the immune response to, and the effectiveness and safety of, an IIV (Fluarix, GlaxoSmithKline Biologicals, Rixensart, Belgium) administered to 68 children aged 36-59 months affected by recurrent respiratory tract infections (RRTIs) who were vaccinated with (n=33) or without (n=35) the mixed bacterial lysate OM-85 BV (Broncho-vaxom, Vifor Pharma, Geneva, Switzerland). OM-85 BV had no effect on seroconversion or seroprotection rates, geometric mean titres, or dendritic cells, which were not significantly different between the two groups. Moreover, OM-85 BV did not significantly increase the pool of the memory B cells that produce IgG and IgM antibodies against the influenza antigens. However, respiratory morbidity was significantly lower in the children treated with OM-85 BV (p<0.05), thus confirming its positive effect on the incidence of RRTIs. There was no difference in the incidence of adverse events between the two groups. These findings show that the immune response of children to influenza vaccine is not significantly influenced by the administration of OM-85 BV. However, the use of OM-85 before and at the same time as IIV seems to reduce respiratory morbidity, and seems to be safe and well tolerated.

Prevention of respiratory tract infections with bacterial lysate OM-85 bronchomunal in children and adults: a state of the art

Respiratory tract infections (RTIs) are a leading cause of morbidity and also represent a cause of death in some parts of the world. The treatment of RTIs implies a continuous search for stronger therapies and represents an economical burden for health services and society. In this context the prevention of infections is absolutely required. The use of bacterial lysates as immuno-modulators to boost immunological response is widely debated. Aim of this review is to summarize the main clinical studies on the effect of the bacterial lysate OM-85 in treating RTIs in susceptible subjects - namely children and chronic obstructive pulmonary disease (COPD)-affected adults. Results from clinical trials and recent systematic reviews are reported.The results show that mean number of RTIs decreases upon treatment with OM-85, as measured by frequency of exacerbations or number of antibiotic courses. Data from systematic reviews indicated that OM-85 is particularly beneficial in children at high risk of RTIs. In COPD-affected adults, clinical studies showed that treatment with OM-85 reduced exacerbations, although systematic reviews did not legitimate the protective effect of OM-85 toward COPD as significant.The use of OM-85 could be efficacious in reducing exacerbation frequency of RTIs in children and adults at risk. However further high-quality studies are needed to better explain the mechanism of action and confirm the beneficial results of OM85.

Prevention of infection in immunosuppressive patients with autoimmune nephrosis by using an immunostimulating bacterial lysate Broncho-vaxom

The utilization of immunosuppressive agents presents patients with autoimmune nephrosis at a high risk of infection. The present trial was to investigate the efficacy and safety of Broncho-Vaxom on preventing infection in immunosuppressive patients with autoimmune nephrosis.

METHODS

40 patients with autoimmune nephrosis were randomly divided into two groups. The control group (20 cases) routinely received corticosteroid and (or) immunosuppressive therapy, while the treatment group (20 cases) received a capsule containing 7 mg Broncho-Vaxom daily for the first 10 d of each month for 3 consecutive months on the basis of conventional corticosteroid and (or) immunosuppressive therapy. The condition of infection and blood lymphocyte were assessed.

RESULTS

4 patients in the treatment group and 5 patients in the control group were lost during the follow-up period. 25% of patients in the treatment group and 40% of patients in the control group suffered infection. There was no difference in the incidence of infection between the two groups (p > 0.05), while Broncho-Vaxom treated patients suffered a shorter infection period and of which fewer patients need to receive antibiotics therapy (p < 0.05). After the treatment with Broncho-Vaxom, the total number of blood T lymphocyte, proportion of CD4 (+) T lymphocyte, CD4 (+) /CD8 (+) reduced less and the serum IgG rose more obviously (p < 0.05), but the blood lymphocyte, B lymphocyte, CD8 (+) T lymphocyte, IgA and IgM have no differences between the two groups (p > 0.05).

CONCLUSION

Broncho-Vaxom might be a good choice for preventing the respiratory infection in nephrosis, especially in the patients under the therapy of immunosuppressive agents.

Comparative effects of levamisole, Staphylococcus, and Freund's adjuvant on rat immunization with excretory and secretory antigens of Trichinella spiralis muscle larvae

A comparison was made of the effects of levamisole, the bacterial fractions of Staphylococcus, and Freund's adjuvant on the immunization of rats with the excretory and secretory antigens of Trichinella spiralis muscle larvae. Wistar rats were immunized with the antigen and a saline solution, levamisole (LV), Staphylococcus (ST), or Freund's adjuvant (FA). After immunization, rats were infected, and the parasite burden at muscular phase was calculated for each group. Levels of IgG1 and IgG2 antibodies, as well as levels of two cytokines, IL-4 and IFN-γ, were evaluated during the immunization and postinfection periods. Differences were found in the kinetics of antibody production between groups (p < 0.01). In all cases, there was reactivity with the main 45-, 50-, and 55-kDa antigens of Trichinella muscle larvae. Immunization with FA and ST enhanced the production of IgG1, but only FA showed a significant increase in the production of IFN-γ (p < 0.01), resulting in 86% protection against the infection. In contrast, only 60-70% protection was attained in the ST and LV groups (p < 0.01). These data support the idea that levamisole and Staphylococcus can be used as adjuvant to enhance the humoral response and, at the same time, demonstrate that IFN-γ could be involved in protection against Trichinella.

C7 Anti-infective activity of immunomodulators

Infectious diseases continue to impact human morbidity and mortality. Every individual is vulnerable to microbial infections regardless of socioeconomic status, gender, age group or ethnic background. There has been an explosion of international air travel with an estimated 2 billion passengers travelling on commercial airlines every year. The rapid expansion of globalization and mass tourism has facilitated the spread of disease-causing pathogens from one continent to another at unprecedented rates.

The oral administration of bacterial extracts prevents asthma via the recruitment of regulatory T cells to the airways

The prevalence of asthma has steadily increased during the last decade, probably as the result of changes in the environment, including reduced microbial exposure during infancy. Accordingly, experimental studies have shown that deliberate infections with live pathogens prevent the development of allergic airway diseases in mice. Bacterial extracts are currently used in children suffering from repeated upper respiratory tract infections. In the present study, we have investigated whether bacterial extracts, commercially available as Broncho-Vaxom (BV), could prevent allergic airway disease in mice. Oral treatment with BV suppressed airway inflammation through interleukin-10 (IL-10)-dependent and MyD88 (myeloid differentiation primary response gene (88))-dependent mechanisms and induced the conversion of FoxP3 (forkhead box P3)(-) T cells into FoxP3(+) regulatory T cells. Furthermore, CD4(+) T cells purified from the trachea of BV-treated mice conferred protection against airway inflammation when adoptively transferred into sensitized mice. Therefore, treatment with BV could possibly be a safe and efficient strategy to prevent the development of allergic diseases in children.

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.

OM-85 BV, an immunostimulant in pediatric recurrent respiratory tract infections: a systematic review

BACKGROUND

This study was conducted to assess the efficacy of OM-85 BV (Broncho-Vaxom) in the prevention of pediatric recurrent respiratory tract infections (RTIs). Available evidence suggests that defining recurrent RTIs as >or=3 infections per fall-winter semester is both medically and epidemiologically justified. Therefore, this criterion was chosen as a primary endpoint.

METHODS

Trials were identified through consultation of bibliographic databases and other channels. Eleven non-blinded studies plus one dealing with primary prevention were excluded and eight randomized controlled trials were included in the meta-analysis. The data were compared at 6 months, which represented the end of most studies. The complete database was examined according to the guidelines of the Cochrane collaboration.

RESULTS

The mean age of children and the number of RTIs in the preceding year were comparable at admission. Of the patients in the OM-85 BV treated population (n=435), 32% had recurrent RTIs (that is, >or=3 RTIs/6 months) vs. 58.2% in the placebo treated population (n=416; P<0.001). Sensitivity analysis showed that this was not driven by any particular trial. The results of this review were also positive for the active treatment regarding the secondary variables, which were represented by the number of patients with at least one RTI and the mean number of RTIs.

CONCLUSIONS

This meta-analysis shows, as observed in several individual trials, that the population treated with OM-85 BV had significantly and consistently fewer cases of recurrent RTIs. The data suggest that the effect is greater in patients at increased risk of recurrent RTIs.

Oral purified bacterial extracts in acute respiratory tract infections in childhood: a systematic quantitative review

BACKGROUND

Recurrent acute respiratory tract infections (ARTI) are a common problem in childhood. Some evidence suggests a benefit regarding the prevention of ARTI in children treated with the immunomodulator OM-85 BV (Bronchovaxom).

METHODS

We summarised the evidence on the effectiveness of the immunomodulator OM-85 BV in the prevention of ARTI in children. We searched randomised comparisons of oral purified bacterial extracts against inactive controls in children with respiratory tract diseases in nine electronic databases and reference lists of included studies. We extracted salient features of each study, calculated relative risks (RR) or weighted mean differences (WMD) and performed meta-analyses using random-effects models.

RESULTS

Thirteen studies (2,721 patients) of low to moderate quality tested OM-85 BV. Patients and outcomes differed substantially, which impeded pooling results of more than two trials. Two studies (240 patients) reporting on the number of patients with less than three infections over 6 month of follow-up in children not in day care showed a trend for benefit RR 0.82 (95% CI, 0.65-1.02). One out of two studies examining the number of children not in day care without infections over 4-6 month reported a significant RR of 0.42 (95% CI, 0.21-0.82) whereas the smaller, second study did not [RR 0.92 (95% CI, 0.58-1.46)]. Two studies reporting the number of antibiotic courses indicated a benefit for the intervention arm [WMD 2.0 (95% CI, 1.7-2.3)]. Two out of the three studies showed a reduction of length of episodes of 4-6 days whereas a third study showed no difference between the two groups.

CONCLUSION

Evidence in favour of OM-85 BV in the prevention of ARTI in children is weak. There is a trend for fewer and shorter infections and a reduction of antibiotic use.

Immunostimulants for preventing respiratory tract infection in children

BACKGROUND

Acute respiratory tract infections (ARTIs) are a major cause of childhood morbidity and mortality. Immunostimulants (IS) may reduce the incidence of ARTIs.

OBJECTIVES

To determine the efficacy and safety of IS in preventing ARTIs in children.

SEARCH STRATEGY

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library Issue 4, 2005); MEDLINE (January 1966 to January 2006); and EMBASE (January 1990 to January 2006); PASCAL (up to January 2006); SciSearch (up to January 2006); and IPA (up to January 2006) for reports of trials. Investigators in the field were also contacted. Ongoing studies were searched in the trial registration web site, metaRegister of Controlled Trials.

SELECTION CRITERIA

All comparative trials which enrolled patients less than 18 years of age were included. The intervention of interest was the use of an IS medication administered by any method for preventing ARTIs. Clinical trials using random or quasi-random allocation and comparing IS medication or medications to placebo were included.

DATA COLLECTION AND ANALYSIS

The outcome on ARTIs was analyzed both as the mean number of ARTIs by group and as a percent change in the rate of ARTIs. Meta-analysis was undertaken using a random-effects model and results were presented as weighted mean differences (WMD) with 95% confidence intervals (CI). The trials search, quality assessment and data extraction were undertaken independently by two authors. A funnel plot suggested there may be publication bias in the trials identified.

MAIN RESULTS

Thirty-four placebo controlled trials (3877 participants) provided data in a form suitable for inclusion in the meta-analysis. When compared with placebo, the use of IS was shown to reduce ARTIs measured as the total numbers of ARTIs (WMD -1.27; 95% CI -1.58 to -0.97) and the difference in ARTIs rates (WMD -39.68%; 95% CI -47.27% to -32.09%). The trial quality was generally poor and a high level of statistical heterogeneity was evident. The subgroup analysis of bacterial IS studies produced similar results, with lower heterogeneity. No difference in adverse events was evident between the placebo and IS groups

AUTHORS' CONCLUSIONS

This review showed that IS reduces the incidence of ARTIs in children, by 40% on average. However, due to significant heterogeneity and the poor quality of the trials this positive result should be interpreted with caution. The safety profile of IS appears to be good. Further high-quality trials are needed and we encourage national health authorities to conduct large, multicenter, double-blind, placebo-controlled trials on the role of IS in the prevention of ARTIs.

Transforming growth factor-beta and natural killer T-cells are involved in the protective effect of a bacterial extract on type 1 diabetes

The onset of type 1 diabetes in NOD mice is delayed by oral administration of a bacterial extract (OM-85) and can be completely prevented by its intraperitoneal administration. Optimal prevention is observed when starting treatment at 3 or 6 weeks of age, and some effect is still observed with treatment at 10 weeks of age. Using genetically deficient mice and cytokine-neutralizing monoclonal antibodies, we demonstrate here that the therapeutic effect does not involve T-helper type 2 cytokines (interleukin [IL]-4 and -10) but is tightly dependent on transforming growth factor (TGF)-beta. Natural killer T-cells also participate in the therapeutic effect because CD1d(-/-) NOD mice are partially resistant to the protective effect of OM-85. The question remains of the specificity of the protective effect of OM-85, which may include proinflammatory components. It will thus be important to further characterize the molecular components that afford protection from type 1 diabetes. Lipopolysaccharide is excluded, but other Toll-like receptor (TLR) agonists could be involved because OM-85 stimulated dendritic cells and induced TGF-beta production by splenocytes in a TLR-2-, TLR-4-, and MyD88-dependent fashion.