Date of this Version
Published in Annals of Allergy, Asthma & Immunology 118 (June 2017), pp 742–743e3. doi: 10.1016/j.anai.2017.04.011
The pathogenesis of atopic dermatitis (AD) is complex and related to allergic responses and defects in skin barrier function. In common with many atopic diseases, the prevalence of AD has been increasing across the world.1 One of the theories for this increase is increased hygiene and urbanization-related changes in the environment, which can affect the human microbiome.2 Previous studies have found associations between the composition of the early gut microbiome and development of atopic conditions, including AD.3 Although the rate of atopic conditions, including AD and food allergy, is increasing on all continents, the prevalence of these diseases is still lower in African countries.1 This is especially interesting because individuals of African origin who live in Western countries, such as African Americans, are at a higher risk for severe AD.4 This variation places Africa in a special position; studying African populations is necessary not only to find ways to prevent increases of allergy conditions in African countries but also to provide important clues to the causes of this global increasing of allergic conditions. Young children who have developed AD in African communities with a low incidence of atopic disease might be the transitional group. In the current study, we have, for the first time to our knowledge, analyzed the fecal microbiota composition of a group of young black African children aged 12 to 36 months old with and without AD living in the same community in Cape Town, South Africa. Our primary goal was to examine whether toddlers with AD and control toddlers from Cape Town have different microbiomes in terms of bacterial richness and diversity. We also aimed to investigate the differences in the relative abundance for different operational taxonomic units between these 2 groups. In our subgroup analyses, we further tested the effect of multiple environmental factors on the gut microbiome in these children.