Angiotensin-converting enzyme (CD143) is such a regulatory enzyme essential for the conversion of angiotensin-I (AT-I) to AT-II, a product in the process of proteolytic cleavage of angiotensinogen.7CD143 inhibitors have been shown to decrease the risk to develop pneumonia in elderly individuals and a reduction in mortality rate has been reported in patients who use CD143 inhibitors.8,9 These data indicated that a clearer understanding of the correlation between CD143 and pneumonia will help prevent or survive this disease. The gene discussed is AGT; the disease is susceptibility to pneumonia measurement.