Validation of an Early Life Candidate Biomarker for Childhood Asthma

Objective The objective of our study is to validate a plasma proteomic signature, discovered by an antibody array approach, that accompanies asthma risk in early life. Methods A previous antibody array study identified 4 asthma‐associated proteins (erythropoietin [EPO], galectin‐3, soluble GP130, and eotaxin‐3) in 11 plasma samples obtained at age 3 from children with asthma and 12 without (assessed at age 9) from a birth cohort enrolled nonselectively. We sought to validate EPO by assaying for its concentration using R&D Quantikine ELISA in the original group of asthmatics and non‐asthmatics, and also tested matched samples at age 5, an enlarged group of samples from the same cohort at age 3 and available matched samples collected at birth. Results Mean Log EPO in age 3 plasma was decreased in asthma group (0.757 vs 0.969 IU/L; asthma vs no asthma; p=0.016). Matched samples at age 5 did not differ by group. Upon enlarging the age 3 sample size (asthma n=18; no asthma n=54) EPO concentration remained decreased in asthma group (0.795 vs 0.898 IU/L; p=0.028 [one‐tailed]); subjects from the enlarged group who also had samples at birth (asthma n=17; no asthma n=41) did not show a similar proteomic alteration (1.41 vs 1.45 IU/L; p=0.7). Conclusion Our study validates by a second assay that reduced plasma EPO at age 3 can serve as a candidate biomarker differentiating subjects with asthma from those without. (RC1ES018328)