||BACKGROUND: Systemic low-grade inflammation has been demonstrated in a range of the frequent noncommunicable diseases (NCDs) proposing a shared mechanism, but is largely unexplored in relation to allergic sensitization. We therefore aimed to investigate the possible association with childhood allergic sensitization. METHODS: High sensitivity C-reactive protein (hs-CRP), interleukin-1beta (IL-1beta), IL-6, tumor necrosis factor-alpha (TNF-alpha) and chemokine (C-X-C motif) ligand 8 (CXCL8) were measured in plasma at age 6mo (N=214) and 7yrs (N=277) in children from the Copenhagen Prospective Studies on Asthma in Childhood2000 (COPSAC2000 ) birth cohort. Allergic sensitization against common inhalant and food allergens was determined longitudinally at age (1/2), 1(1/2), 4 and 6yrs by specific-IgE assessments and skin prick tests. Associations between inflammatory biomarkers and sensitization phenotypes were tested with logistic regression and principle component analyses (PCA). RESULTS: Adjusted for gender, recent infections and a CRP genetic risk-score, hs-CRP at 7yrs was associated with concurrent elevated specific-IgE against any allergen (adjusted OR (aOR) =1.40; 95% CI, 1.14-1.72; p=0.001), aeroallergens (aOR, 1.43; 1.15-1.77; p=0.001), food allergens (aOR, 1.31; 95% CI, 1.02-1.67; p=0.04), sensitization without any clinical allergy symptoms (aOR=1.40; 1.06-1.85; p=0.02), and with similar findings for skin prick tests. The other inflammatory markers were not univariantly associated with sensitization, but multi-parametric PCA suggested a specific inflammatory response among sensitized children. Inflammatory markers at age 6mo were not associated with subsequent development of sensitization phenotypes. CONCLUSIONS: Elevated hs-CRP is associated with allergic sensitization in school-aged children suggesting systemic low-grade inflammation as a phenotypic characteristic of this early onset NCD. This article is protected by copyright. All rights reserved.