AHR and asthma: PAD-4-deficient mouse neutrophils fail to release NETs in response to LPS and TNF stimulation.[99] Simvastatin inhibits NETosis neutrophilic inflammation and AHR by reducing PAD-4 expression in a mouse model of severe asthma.[100] In addition, H3cit has been suggested as a possible novel and specific biomarker for this process.[101] The clinical relevance of increased serum H3cit to the mechanism of asthma progression and risk of exacerbation remains to be determined, and no effective biological agents are available.