Elevated levels of seven proteins (TLR4, UBP25, CBR1, Rac GTPase‐activating protein 1 [RGAP1], IL‐21, MICB, and PDE4D) and decreased levels of three proteins (GSTO1, LIRB4 and PIGF) were associated with an increased risk of childhood asthma. Here, IL21 is linked to childhood onset asthma.