There was no significant difference in the proportion of healthy vs asthmatic donors who expressed NOX4, DUOX1, or DUOX 2, and their relative expression was not significantly different between cells from patients with asthma vs healthy control subjects (NOX4, 1.6-fold [0.79-3.1]; DUOX1, 0.87-fold [0.46-1.63]; and DUOX2, 1.12-fold [0.38-3.3]). Here, NOX4 is linked to asthma.