BACKGROUND: Childhood asthma is characterized by chronic airway Integrative genomic analysis of airway inflammation on genetic and may help to unravel mechanisms of childhood asthma. We aimed to employ integrative genomic approach investigating inflammation markers on DNA, protein level at preschool age in relationship to asthma development. a prospective study, 252 preschool children (202 recurrent wheezers, 50 from the Asthma DEtection and Monitoring (ADEM) study were followed of six. Genetic variants, mRNA expression in peripheral blood and protein levels in exhaled breath condensate for intercellular molecule 1 (ICAM1), interleukin (IL)4, IL8, IL10, IL13, and tumor alpha were analyzed at preschool age. At six years of age, a (healthy, transient wheeze, or asthma) was based on symptoms, lung medication use. RESULTS: The ICAM1 rs5498 A allele was positively asthma development (p = 0.02) and ICAM1 gene expression (p = 0.01). expression was positively associated with exhaled levels of soluble 0.04) which in turn was positively associated with asthma development (p Furthermore, rs1800872 and rs1800896 in IL10 were associated with mRNA expression (p < 0.01). Exhaled levels of IL4, IL10, and IL13 were associated with asthma development (p < 0.01). CONCLUSIONS: In this prospective study, we demonstrated that ICAM1 is associated with asthma development on DNA, mRNA, and protein level. Thus, ICAM1 is likely to be in the development of childhood asthma.