TAC1 and susceptibility to pneumonia measurement: Available data implicate that pathogenesis of pneumonia correlates with attenuation of cough reflex,2,3 an important defensive reflex in human body mediated by substance P and an inflammatory peptide bradykinin through evoking sensitization of airway sensory nerves.4,5 A reduced concentration of substance P has been reported in sputum of patients with pneumonia.6 These findings make many groups hypothesize that the enzymes involved in the regulation of substance P and bradykinin may possibly have a causal role in pneumonia.