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.

The association of infant urinary adrenal steroids with the risk of childhood asthma development.

BACKGROUND: Adrenal steroids play important roles in early-life development. However, our understanding of the effects of perinatal adrenal steroids on the development of childhood asthma is incomplete. OBJECTIVE: To evaluate the associations between early-life adrenal steroid levels and childhood asthma. METHODS: Participants included the Infant Susceptibility to Pulmonary Infections and Asthma following Respiratory Syncytial Virus Exposure birth cohort children with untargeted urinary metabolomics data measured during early infancy (n = 264) and nasal immune mediator data measured concurrently at age 2 to 6 months (n = 76). A total of 11 adrenal steroid compounds were identified using untargeted metabolomics and 6 asthma-relevant nasal immune mediators from multiplex assays were a priori selected. Current asthma at ages 5 and 6 years was ascertained using validated questionnaires. Associations were tested using logistic and linear regression with confounders adjustment. RESULTS: Pregnenetriol disulfate (adjusted odds ratio [aOR] = 0.20, 95% CI = 0.06-0.68) and 3a,21-dihydroxy-5b-pregnane-11,20-dione-21-glucuronide (aOR = 0.34, 95% CI = 0.14-0.75) were inversely associated with childhood asthma at 5 and 6 years after multiple testing adjustment. There was a significant interaction effect of pregnanediol-3-glucuronide by biological sex assigned at birth (aOR = 0.11, 95% CI = 0.02-0.51, for those with female sex) on childhood asthma. Pregnenetriol disulfate was inversely associated with granulocyte-macrophage colony-stimulating factor (ß = -0.45, q-value = 0.05). 3a,21-dihydroxy-5b-pregnane-11,20-dione 21-glucuronide was inversely associated with interleukin [IL]-4 (ß = -0.29, q-value = 0.02), IL-5 (ß = -0.35, q-value = 0.006), IL-13 (ß = -0.26, q-value = 0.02), granulocyte-macrophage colony-stimulating factor (ß = -0.35, q-value = 0.006), and fibroblast growth factor-ß (ß = -0.24, q-value = 0.01) after multiple testing adjustment. CONCLUSION: The inverse association between adrenal steroids downstream of progesterone and 17-hydroxypregnenolone and the odds of childhood asthma and nasopharyngeal type 2 immune biomarkers suggest that increased early-life adrenal steroids may suppress type 2 inflammation and protect against the development of childhood asthma.