HDAC9 and susceptibility to pneumonia measurement: NETs play a central role in pathogen containment and immune‐mediated inflammatory diseases, and studies have found that the class I HDAC (HDAC1/2/3/8) and class IIB HDAC (HDAC6/10) inhibitor ricolinostat can inhibit the production of NETs and proinflammatory cells by inhibiting the release of citrullinated histone H3 (cith3) to reduce the incidence rate of pneumonia and septic shock in mice and further improve lung function [51].