Environmental influence on the development of childhood immunity

The Role of Human Milk Immunomodulators in Protecting Against Viral Bronchiolitis and Development of Chronic Wheezing Illness

Infants who are breastfed are at an immunological advantage when compared with formula fed infants, evidenced by decreased incidence of infections and diminished propensity for long term conditions, including chronic wheeze and/or asthma. Exclusive breastfeeding reduces the duration of hospital admission, risk of respiratory failure and requirement for supplemental oxygen in infants hospitalised with bronchiolitis suggesting a potentially protective mechanism. This review examines the evidence and potential pathways for protection by immunomodulatory factors in human milk against the most common viral cause of bronchiolitis, respiratory syncytial virus (RSV), and subsequent recurrent wheeze in infants. Further investigations into the interplay between respiratory virus infections such as RSV and how they affect, and are affected by, human milk immunomodulators is necessary if we are to gain a true understanding of how breastfeeding protects many infants but not all against infections, and how this relates to long-term protection against conditions such as chronic wheezing illness or asthma.

Changing of fecal flora and clinical effect of L. salivarius LS01 in adults with atopic dermatitis

GOAL

To evaluate cytokine stimulation with 3 strains of Lactobacillus salivarius in vitro and to assess changes in intestinal microflora and clinical improvements in adults with atopic dermatitis (AD) induced by the strain showing the best immunomodulatory features.

BACKGROUND

AD is a common skin disease in children and adults. It is characterized by chronic inflammation, eczema, and increasing intestinal permeability. Various studies have shown that patients with AD presented some modifications in the intestinal microbiota composition; as a result, intestinal microflora is thought to have a pivotal role in this disease.

METHODS

Thirty-eight patients aged from 18 to 46 years with moderate/severe AD were recruited. Subjects were randomized in a double-blind placebo-controlled study to receive active treatment with L. salivarius LS01: probiotic (n=19) or placebo (n=19). Cytokine production was determined by means of specific quantitative enzyme-linked immunosorbent assays. Intestinal bacterial groups were quantified using conventional culture techniques, whereas L. salivarius LS01 was identified using polymerase chain reaction and pulse field gel electrophoresis.

RESULTS

L. salivarius LS01 showed the best immunomodulatory features and it was chosen for the second phase of the study. AD subjects showed a reduction in their SCORAD score after probiotic treatment and a significant decrease in the staphylococci load compared with the placebo group. Moreover, L. salivarius LS01 showed the ability to reduce the production of Th2 cytokines, maintaining the production of Th1 cytokines stable.

CONCLUSIONS

Treatment with the L. salivarius LS01 strain seems to positively modify clinical and immunologic status and dermatology life quality in a group of adults affected by moderate/severe AD, leading to a rebalancing of altered intestinal microbiota.

Role of CD4(+) T cells in the modulation of neurotrophin production in mice exposed to low-level toluene

To investigate the role of CD4(+) T cells in neurotrophin production following toluene exposure, male C3H mice were exposed to filtered air (control) or 9 ppm of toluene in a nose-only exposure chamber for 30 min on 3 consecutive days followed by weekly sessions for 4 weeks. All the mice were immunized with ovalbumin and some groups of mice were treated with anti-CD4 antibody. BDNF content in BAL fluid and NGF content in plasma were significantly increased in toluene-exposed mice. However, treatment with anti-CD4 mAb completely abrogated these effects. These findings suggest that the CD4(+) T cells may be involved in the toluene-induced modulation of neurotrophin production.

No effects of probiotics on atopic dermatitis in infancy: a randomized placebo-controlled trial

BACKGROUND

Studies have been performed suggesting that administration of probiotics may have therapeutic and/or preventive benefits in the development of sensitization and atopic disease, particularly in infants with atopic dermatitis (AD).

OBJECTIVE

The purpose of this study was to evaluate the clinical and immunological effects of supplementation of a hydrolysed formula with two probiotic strains of bacteria on symptoms of AD in infancy.

METHODS

We conducted a randomized, double-blind, placebo-controlled study. After 4-6 weeks of baseline and double-blind, placebo-controlled challenges for diagnosis of cow's milk allergy (CMA), infants less than 5 months old with AD received a hydrolysed whey-based formula as placebo (n = 17), or supplemented with either Lactobacillus rhamnosus (n = 17) or Lactobacillus GG (n = 16) for 3 months. Before, during and after intervention, the clinical severity of AD was evaluated using SCORing index Atopic Dermatitis (SCORAD). Allergic sensitization was evaluated by measurement of total IgE and a panel of food-specific IgEs as well as skin prick testing for cow's milk. Inflammatory parameters were blood eosinophils, eosinophil protein X in urine, fecal alpha-1-antitrypsin and production of IL-4, IL-5 and IFN-gamma by peripheral blood mononuclear cells after polyclonal stimulation.

RESULTS

No statistically significant effects of probiotic supplementation on SCORAD, sensitization, inflammatory parameters or cytokine production between groups were found. Only four infants were diagnosed with CMA.

CONCLUSION

We found no clinical or immunological effect of the probiotic bacteria used in infants with AD. Our results indicate that oral supplementation with these probiotic bacterial strains will not have a significant impact on the symptoms of infantile AD.

Ethnicity, childhood environment and atopic disorder

BACKGROUND

The International Study of Asthma and Allergies in Childhood (ISAAC) has demonstrated large differences in the prevalence of atopic disorders in children between different regions in the world. Populations with a higher standard of living and a more westernized lifestyle tend to have higher rates of atopy and asthma. Many hypotheses regarding environmental causes of atopic disorder focus on the early childhood environment.

OBJECTIVE

To study the influence of ethnicity and country of birth for the prevalence of atopic disorders.

METHODS

The prevalence of atopic disorders in Swedish residents born in Turkey and Chile, who settled in Sweden as adults in the 1980s, was compared with their own Swedish-born children and a sample of Swedish-born parents and their children in interview data from the Survey of Living Conditions in 1996. The study group included 1734 adults 27-60 years of age and their 2964 children aged 3-15.

RESULTS

The Chilean-born parents and their children had the highest risk for allergic asthma; adjusted odds ratios (ORs) 2.2 (1.2-4.0) and 2.7 (1.6-4.5), respectively, and allergic rhino-conjunctivitis; OR 1.6 (1.1-3) and 1.6 (1.1-2.5) in both groups, when compared with the Swedish-born parents and their children. The Turkish-born parents and their children had the lowest risk for allergic rhino-conjunctivitis; both groups had OR 0.6 (0. 4-0.9) and the children in this group also had the lowest risk for eczema; OR; 0.4 (0.3-0.7). The risk for all atopic disorders was lower in the Turkish group compared with the Chileans.

CONCLUSION

This study demonstrates that ethnicity is an important determinant of atopic disorder independent of the external childhood environment. The value of international comparisons of environment and risk for atopic disorders can be questioned until more is known about factors related to ethnicity, such as genetic susceptibility and diet, for the development of atopy.

Migration and atopic disorder in Swedish conscripts

We have studied asthma and allergic rhinitis prevalence in Swedish conscripts born 1973-1977 according to the military service conscription register in relation to the socio-economic status and country of birth of the conscripts and their parents, and age when granted residency in Sweden. There was an increase in prevalence of asthma and allergic rhinitis over time in all groups irrespective of country of birth or ethnic origin. Conscripts who themselves were born in Africa, Asia, Latin America and the Mediterranean had a significantly lower risk for asthma and allergic rhinitis than Swedish-born conscripts. The risk of atopic disorder among the foreign-born conscripts increased with time of residency in Sweden. Conscripts with mothers from Latin America, Asia and Africa were identified as having the highest risk for atopic disorder among Swedish-born conscripts with high socio-economic status; the adjusted risk ratio (RR) for asthma was 2.6 (95% CI 1.7-4.0) and that for allergic rhinitis was 2.0 (1.5-2.6). The conscripts with mothers from the Mediterranean had the lowest risk for atopic disorders of the Swedish-born conscripts with low socio-economic status; the RR for asthma was 0.43 (0.34-0.56) and that for allergic rhinitis was 0.84 (0.76-0.93). This study demonstrates that factors related to migration and ethnicity are important determinants of atopic disorder among Swedish conscripts.

Age at adoption, ethnicity and atopic disorder: a study of internationally adopted young men in Sweden

Epidemiological and laboratory studies have implied that the environment during early childhood is important for the risk of developing atopic disorders. In this study we analyzed the prevalence of asthma, hayfever and eczema among 1901 internationally adopted young men at the military-induction medical examination in relation to indicators of their early childhood environment. The adopted young men who came to Sweden before 2 years of age suffered from asthma, hayfever and eczema significantly more often than those who came to Sweden between 2 and 6 years of age; the risk ratios (RR) were 1.6, 2.5 and 2.1, respectively. The young men who were born in the Far East were identified as being particularly susceptible to the development of hayfever and eczema, with RRs of 1.3 and 1.7. This study demonstrates that the environment during the first 6 years of life has a profound influence on the risk of suffering from atopic disorders as young adults.