Elevated serum osteopontin level is associated with blood eosinophilia and asthma comorbidity in patients with allergic rhinitis

The detection limit for OPN, IL-5, and ECP was 312.5 pg/mL, 3.9 pg/mL, and 2.0 ng/mL, respectively. [...]EOS number in venous blood was measured and counted with a standard automated cell counter. In agreement with OPN production, blood EOS number and serum ECP and IL-5 levels in the asthma+ group were significantly higher than those in the asthma- group (P < .05) (Fig 1, E, F, and G). [...]our finding provided the clue that elevated serum OPN level in patients with AR might contribute to asthma comorbidity through promoting systemic response initiated by EOS migration and activation.