Airway Hyperresponsiveness in Asthma

*AHR tests are not commonly performed in clinical practice, as they are not necessary for asthma diagnosis and are not readily available in primary care.7 †AHR tests done with direct stimuli, such as the methacholine challenge test, may induce adverse effects, including severe bronchospasm.⁸
AHR, airway hyperresponsiveness; ASM, airway smooth muscle.
*PD20 and PC20 values are common endpoints of tests for airway hyperresponsiveness.^1,3
FEV1, forced expiratory volume in 1 second; PC20, provocative concentration that causes a 20% fall in FEV1; PD20, provocative dose that causes a 20% fall in FEV1.
*AHR is a multifaceted process that is not yet fully understood and includes components in addition to those shown here.1 †Failure of NO to exert bronchodilatory and anti-inflammatory effects may also contribute to AHR.²⁹
AHR, airway hyperresponsiveness; ASM, airway smooth muscle; EOS, eosinophil; IL, interleukin; ILC2, group 2 innate lymphoid cell; NO, nitric oxide; RNS, reactive nitrogen species; Th2, T helper type 2; TNF, tumor necrosis factor; TSLP, thymic stromal lymphopoietin.
*AHR is a multifaceted process that is not yet fully understood and includes components in addition to those shown here.¹
†In a murine allergic airway disease mouse model for human asthma.²¹
AHR, airway hyperresponsiveness; ASM, airway smooth muscle; EOS, eosinophil; IL, interleukin; R, receptor; TNF, tumor necrosis factor; TSLP, thymic stromal lymphopoietin.
*AHR is a multifaceted process that is not yet fully understood and includes components in addition to those shown here.¹
†Failure of NO to exert bronchodilatory and anti-inflammatory effects may also contribute to AHR.²⁹
AHR, airway hyperresponsiveness; ASM, airway smooth muscle; FeNO, fractional exhaled nitric oxide; IL, interleukin; ILC2, group 2 innate lymphoid cell; NO, nitric oxide; ONOO-, peroxynitrite; Th2, T helper type 2; TSLP, thymic stromal lymphopoietin.
*AHR is a multifaceted process that is not yet fully understood and includes components in addition to those shown here.¹
AHR, airway hyperresponsiveness; ASM, airway smooth muscle; IL, interleukin; TNF, tumor necrosis factor; TSLP, thymic stromal lymphopoietin.
*AHR is a multifaceted process that is not yet fully understood and includes components in addition to those shown here.¹
AHR, airway hyperresponsiveness; ASM, airway smooth muscle; EOS, eosinophil; IL, interleukin; ILC2, group 2 innate lymphoid cell; R, receptor; Th2, T helper type 2.

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