Asthma and mode of birth delivery: a study in 5-year-old Dutch twins

The role of monocytes and natural killers' immunophenotypic subsets in bronchial asthma in children

Objective: Childhood bronchial asthma (BA) is a globally significant chronic disease with major health consequences. Recently, focus on the role of the innate immune system has been highlighted. Therefore, this study explores the role of circulating monocytes and natural killer (NK) clusters in childhood asthma.Methods: This case-control study enrolled 50 children with asthma divided equally into severe and mild groups and 26 healthy children. Flow-cytometry analysis was used to identify circulating blood monocytes and natural killers' subsets. In addition, pulmonary function test (spirometry) for children with asthma was performed.Results: This study showed significant negative correlations between frequency of total circulating, classical, intermediate, and nonclassical monocytes with ratio of forced expiratory volume/forced vital capacity (FEV1/FVC) (r = -0.637, P < 0.001; r = -0.575, P < 0.001; r = -0.657, P < 0.001; r = -0.329, P = 0.004, respectively). Also, there was significant negative correlations between frequency of total NKs and CD56^dim CD16+ NK with FEV1/FVC (r = -0.584, P < 0.001) and (r = -0.579, P < 0.001). Significant predictors of childhood asthma severity were frequencies of total monocytes, total NKs, intermediate monocytes, and CD56^dimCD16+ NK.Conclusion: Finally, we concluded that the FEV1/FVC is linked to aberrations of monocytes' and natural killers' immunophenotypic subsets in children with asthma. The frequencies of total monocytes and NK are significant predictors of severity of childhood asthma. The frequencies of CD14^high CD16+ intermediate monocytes and CD56^dim CD16+ NK cells are the best independent predictors of severity in children with asthma.

Maternofetal Transfer of Antibodies and the Influence of Maternal Atopic Status on the Neonate

Background

Epidemiologic evidence has shown that sensitization of allergic diseases develops early in life, even before birth. The gestational environment, including maternal atopic status and transplacentally transferred antibodies to allergens, may be of importance in the sensitization process.

Objective

To investigate maternofetal transfer of antibodies and the influence of maternal atopic status on the neonatal immune response.

Methods

Fifty-seven healthy pregnant women who underwent elective cesarean section (ECS) were recruited. Total and specific IgE (Phadiatop) levels in cord blood (CB) and maternal blood (MB) were determined using the ImmunoCAP assay. MB- and CB-specific IgG1 and IgA1 antibodies against ovalbumin and house dust mite were analyzed by enzyme linked immunosorbent assay. The cytokines, interleukin (IL)-13, interferon (IFN)-γ, and IL-10 in the supernatant of cultured CB mononuclear cells were quantified by enzyme linked immunosorbent assay. Two subgroups were defined based on the maternal levels of specific IgE (atopic group, Phadiatop IgE more than or equal to 0.35 kilo international units of allergen-specific antibody (KUA)/L; nonatopic group, Phadiatop IgE less than 0.35 KUA/L).

Results

Although total IgE was detectable in all MB samples, it could only be detected in 7% (4/57) of the CB samples. Specific IgE was detectable in all MB samples but undetectable in all CB samples. There was no correlation of total IgE between mothers and their neonates. The concentrations of IL-10, IL-13, and allergen-specific IgG1 and IgA1 in the CB samples did not differ significantly between the atopic and nonatopic groups. IFN-γ was undetectable in the CB samples.

Conclusions

Maternal IgE cannot be transferred to the child in utero. Maternal atopic status has no significant effect on neonatal immune responses.

Exploring the origins of asthma: Lessons from twin studies

This thesis explores the contribution of twin studies, particularly those studies originating from the Danish Twin Registry, to the understanding of the aetiology of asthma. First, it is explored how twin studies have established the contribution of genetic and environmental factors to the variation in the susceptibility to asthma, and to the variation in several aspects of the clinical expression of the disease such as its age at onset, its symptomatology, its intermediate phenotypes, and its relationship with other atopic diseases. Next, it is explored how twin studies have corroborated theories explaining asthma's recent increase in prevalence, and last, how these fit with the explanations of the epidemiological trends in other common chronic diseases of modernity.

Is elective cesarean section associated with a higher risk of asthma? A meta-analysis

Abstract Background: Recent meta-analyses indicate that children delivered by cesarean section have increased risk for asthma. However, the studies included in these previous meta-analyses showed significant heterogeneity. Furthermore, no previous meta-analysis has distinguished the association of elective and emergency CS, spontaneous and instrumental vaginal deliveries (VD) with the odds of asthma.

OBJECTIVE

To examine the association between specific mode of delivery and the prevalence of asthma.

METHODS

PUBMED, Google Scholar, EMBASE, and MEDLINE were searched to identify relevant studies. Odds ratio (OR) and 95% confidence interval (CI) were calculated from the prevalence of asthma in children born by elective CS, emergent CS, instrumental VD and spontaneous VD. Meta-analysis was then used to derive a combined OR. Heterogeneity between studies was also tested in the findings.

RESULTS

A total of 26 studies were identified. The overall meta-analysis revealed an increase in the risk of asthma in children delivered by CS (OR=1.16, 95% CI 1.14, 1.29), and no evidence of heterogeneity was found (I(2)=24.6%). Elective and emergency CS moderately increased the risk of asthma (OR=1.21, 95% CI 1.17, 1.25; I(2)=39.9%; OR=1.23, 95% CI 1.19-1.26). The risk of asthma was also higher in the children born by instrumental VD (OR=1.07, 95% CI, 1.04-1.11) but with evidence of heterogeneity (I(2)=54.9%).

CONCLUSION

About 20% increase in the subsequent risk of asthma was both found in children delivered by elective and emergency CS. The increasing rates of CS worldwide might partly explain the concomitant rise in asthma during the same time period.