Asthma Prevention by Lactobacillus Rhamnosus in a Mouse Model is Associated With CD4(+)CD25(+)Foxp3(+) T Cells.

PURPOSE: Probiotic bacteria can induce immune regulation or immune tolerance in allergic diseases. The underlying mechanisms have been recently investigated, but are still unclear. The aim of this study was to evaluate the protective effects of the probiotic Lactobacillus rhamnosus (Lcr35) in a mouse model of asthma and to identify its mechanism of action. METHODS: Lcr35 was administered daily by the oral route at a dosage of 1×10(9) CFU/mouse in BALB/c mice for 7 days before the first sensitization. Clinical parameters and regulatory T (Treg) cells were examined. The role of CD4(+)CD25(+)Foxp3(+) Treg cells was analyzed using a Treg cell-depleting anti-CD25 monoclonal antibody (mAb). RESULTS: Airway hyperresponsiveness, total IgE production, pulmonary eosinophilic inflammation, and splenic lymphocyte proliferation were suppressed after Lcr35 treatment. Th1 (IFN-γ) and Th2 (IL-4, IL-5, and IL-13) cytokines in the serum were suppressed, and the percentage of CD4(+)CD25(+)Foxp3(+) Treg cells in the spleen was significantly increased in the Lcr35 treatment group. Anti-CD25 mAb administration abolished the protective effects of Lcr35, indicating that CD4(+) CD25(+)Foxp3(+) Treg cells are essential in mediating the activity of Lcr35. CONCLUSIONS: Oral administration of Lcr35 attenuated the features of allergic asthma in a mouse model and induced immune regulation by a CD4(+)CD25(+)Foxp3(+) Treg cell-mediated mechanism.

The Effects of Lactobacillus rhamnosus on the Prevention of Asthma in a Murine Model.

PURPOSE: Lactobacilli are probiotic bacteria that are effective in the management of allergic diseases or gastroenteritis. It is hypothesized that such probiotics have immunoregulatory properties and promote mucosal tolerance. Our goal was to investigate whether Lactobacillus casei rhamnosus Lcr35 could inhibit airway inflammation in an ovalbumin (OVA)-induced murine model of asthma. METHODS: BALB/c mice aged 6 weeks were used in the present study. Lactobacillus casei rhamnosus Lcr35 was administered daily, starting 1 week prior to the first OVA sensitization (group 1) and 2 days before the first 1% OVA airway challenge (group 2). Mice that received only saline at both sensitization and airway challenge time points were used as negative controls (group 3), and those that had OVA-induced asthma were used as positive controls (group 4). Airway responsiveness to methacholine was assessed, and bronchoalveolar lavage (BAL) was performed. At the endpoint of the study, total IgE as well as OVA-specific IgE, IgG(1) and IgG(2a) in serum was measured by enzyme-linked immunosorbent assay. Lung pathology was also evaluated. RESULTS: Airway hyperresponsiveness, total cell counts and the proportion of eosinophils in BAL fluid were significantly decreased in group 1 compared with group 4 (P<0.05). Total serum IgE levels were also significantly decreased in group 1 compared with group 4. Serum levels of OVA-specific IgE, IgG(1) and IgG(2a) were not significantly influenced by treatment with Lcr35. There was significantly less peribronchial and perivascular infiltration of inflammatory cells in group 1 compared with group 4; however, there were no significant differences in methacholine challenge, BAL, serology or histology between groups 2 and 4. CONCLUSIONS: Oral treatment with Lcr35 prior to sensitization can attenuate airway inflammation and hyperreactivity in a mouse model of allergic airway inflammation. These results suggest that Lcr35 may have potential for preventing asthma.

Association of IL-13 polymorphisms with leukotriene receptor antagonist drug responsiveness in Korean children with exercise-induced bronchoconstriction.

BACKGROUND: IL-13 is a pivotal cytokine in allergic inflammation and bronchial hyperresponsiveness, and is known to influence leukotriene levels. OBJECTIVE: We investigated whether IL-13 polymorphisms may be associated with clinical phenotypes and drug responsiveness to the leukotriene receptor antagonist (LTRA) in Korean asthmatic children with exercise-induced bronchoconstriction (EIB). METHODS: We enrolled 242 normal controls and 374 patients with asthma. Of the asthmatic patients, 100 performed exercise challenge tests before and after receiving montelukast (5 mg/day) for 8 weeks and included 80 subjects in drug responsiveness analysis. We assessed IL-13 polymorphisms (-1512A/C, -1112C/T, +2044G/A) through PCR-restriction fragment length polymorphism analysis. RESULTS: Significantly higher total IgE levels and maximum percent fall in forced expiratory volume in 1 s (FEV1) (%) after exercise challenge test were found in asthmatic patients carrying one or two copies of the IL-13 +2044A versus those homozygous for +2044G (P=0.011 and 0.040, respectively). We further noted a correlation of total IgE with maximum percent fall in FEV1 (%) in asthmatic patients, as well as a reverse correlation with improvement of maximum percent fall in FEV1 (%) after exercise challenge tests. Finally, we observed a significant association between responsiveness to montelukast and IL-13 -1112C/T polymorphism and the haplotype of IL-13 polymorphisms. CONCLUSION: The IL-13 +2044G/A polymorphism may be associated with atopy and EIB severity in Korean children with EIB, and thus could potentially be considered as a disease-modifying gene. Moreover, the IL-13 -1112C/T polymorphism and the haplotype of IL-13 polymorphisms seem to be associated with LTRA drug responsiveness, and thus might prove useful as a target for modulation of LTRA drug responsiveness.

TNF-alpha (-308 G/A) and CD14 (-159T/C) polymorphisms in the bronchial responsiveness of Korean children with asthma.

BACKGROUND: TNF-alpha is a pivotal proinflammatory cytokine increased in asthmatic airways. The TNF-alpha gene family might be linked to asthma or bronchial hyperresponsiveness (BHR), and TNF-alpha production might be modulated by CD14(+) cells. OBJECTIVE: We investigated the association between asthma susceptibility or asthma-related phenotypes and TNF-alpha (-308G/A) polymorphism and examined the combined effect with CD14 (-159T/C) polymorphism in Korean children. METHODS: Asthmatic (n = 788) and control (n = 153) children were evaluated for asthma phenotypes. Genotypes were determined by using the single-base extension method and PCR-restriction fragment length polymorphism. RESULTS: There was no difference between asthmatic children and control subjects in terms of the allele frequencies of TNF-alpha (-308G/A) and CD14 (-159T/C). Significantly lower PC(20) values were seen in asthmatic (P = .016) children with the TNF-alpha risk allele (-308A). Higher frequencies of 1 or 2 copies of the risk allele were found in asthmatic children with moderate-to-severe BHR to methacholine and exercise compared with control children (adjusted odds ratio of 2.57 [95% CI, 1.30-5.08] and adjusted odds ratio of 2.04 [95% CI 0.99-4.20], respectively). In addition, asthmatic children with risk alleles at both loci had significantly greater BHR than those homozygous for the common alleles (P = .018). CONCLUSION: The TNF-alpha promoter polymorphism (-308G/A) might be associated with severe BHR in Korean children with asthma. In addition, these children show a synergistic effect between the TNF-alpha promoter (-308A) and CD14 promoter (-159C) polymorphisms in terms of BHR. CLINICAL IMPLICATIONS: The TNF-alpha polymorphism might be a disease-modifying gene in asthma and modulated by the CD14 gene.

Eosinophils play a major role in the severity of exercise-induced bronchoconstriction in children with asthma.

Exercise-induced bronchoconstriction (EIB) was associated with eosinophilic airway inflammation, bronchial hyperresponsiveness (BHR), atopy and airway obstruction. To understand the pathogenesis of EIB, we determine whether eosinophil is more related to the mechanism of EIB than atopy, BHR and airway obstruction. This study comprised 268 asthmatic children who underwent lung function test, methacholine challenge test, exercise challenge test, and blood tests for total IgE levels and total eosinophil counts (TEC). Urine eosinophil protein X (EPX) levels after exercise were measured by using ELISA method. EIB was observed in 195 of 268 asthmatics (72.8%). Asthmatics with EIB showed significantly increased TEC (P < 0.01) and decreased log PC(20) as compared with asthmatics without EIB. Maximal percent fall in FEV(1) after exercise was significantly correlated with TEC, log IgE, FEF(25-75%), log PC(20) (P < 0.001, respectively) and FEV(1) (P = 0.013). When the same study was carried out in nonatopic asthmatics, those with EIB showed significantly increased TEC (P = 0.01) compared with those without EIB; however, log PC(20), FEV(1), and FEF(25-75%) showed no significant differences between the two groups of nonatopic asthmatics. In addition, there was a significant correlation between the severity of EIB and TEC in nonatopic asthmatics. Urine EPX/Cr levels after exercise were correlated with the severity of EIB (r = 0.238, P = 0.014). Blood eosinophils and urine EPX/Cr after exercise correlate significantly with the maximal percent fall in FEV(1) after exercise, therefore EIB may reflect a state of eosinophilic inflammation in the airway of asthmatic children.

Gene-gene interaction between IL-13 and IL-13Ralpha1 is associated with total IgE in Korean children with atopic asthma.

Interleukin (IL)-13, which is essential for IgE synthesis, mediates its effects by binding with a receptor composed of IL-4Ralpha and IL-13Ralpha1. We investigated the effects of IL-13 and IL-13Ralpha1 polymorphisms in Korean children with asthma, and whether these have been associated with IgE production. We enrolled 358 atopic asthmatic, 111 non-atopic asthmatic, and 146 non-atopic healthy children. IL-13 and IL-13Ralpha1 genotypes were identified using the PCR-RFLP method. There was an association between the asthma susceptibility and homozygosity for risk allele of IL-13 G+2044A. In children with atopic asthma, risk alleles in IL-13 (A-1512C and C-1112T) and IL-13Ralpha1 (A+1398G) showed increased total IgE (P=0.012, 0.015 and 0.017, respectively). Three-loci haplotype analysis for IL-13 showed that the haplotype composed of -1512C, -1112T and +2044A was associated with higher total IgE than other tested haplotypes in children with atopic asthma (P=0.003). The gene-gene interaction between risk alleles of each IL-13 promoter polymorphism and IL-13Ralpha1 polymorphism was associated with higher total IgE in children with atopic asthma (P=0.002, 0.010). These findings indicate that the IL-13 G+2044A is associated with asthma development and the IL-13 and IL-13Ralpha1 polymorphisms may interact to enhance IgE production.