CD14/Toll-like receptors interact with bacteria and regulatory T-cells in the development of childhood asthma.

Abstract

To the Editor: The susceptibility to asthma development in childhood is influenced by genetic as well as environmental factors, and interactions between these factors [1–3]. However, at present, their exact role is still largely undetermined. Genetic variations in the innate immune system may lead to different adaptive immune responses to bacteria and may therefore vary the development of asthma [2, 4, 5]. We performed a prospective longitudinal study in preschool children, in which we determined polymorphisms in Toll-like receptors ( TLR s) and CD14 , the presence of bacteria, and the proportion of regulatory T-cells (Treg) all in relation to an asthma diagnosis at 6 years of age. We hypothesise that specific genetic variants in genes that affect the innate immune system influence the response to bacteria and the recruitment of Treg in preschool children, leading to an increased likelihood of asthma at 6 years of age. The Asthma DEtection and Monitoring (ADEM) study is a long-term prospective case–control study. A detailed protocol of this study has previously been published [6]. A total of 202 children who had experienced at least two wheezing episodes during their lifetime (International Study of Asthma and Allergies in Childhood (ISAAC) questionnaire) [7] and 50 children without wheezing episodes were included at 2–4 years of age. The children were randomly selected from a random population sample in Limburg, the Netherlands, based on the presence or absence of recurrent wheeze [6]. During the initial visit, saliva or buccal cells (DNA), nasal and throat swabs (bacterial cultures), and blood (Treg) were collected. Participants were genotyped for six single nucleotide polymorphisms in TLR2 , TLR4 , TLR9 and CD14 (Sequenom …