Neutrophils, the body’s first line of defense, respond fast to tissue damage and invading germs by producing vast amounts of reactive oxygen species and releasing granular contents that kill infections.11 Progranulin is highly expressed on neutrophils and is converted into granulin peptides by neutrophil-released elastase.12 After cleavage, granulin peptides stimulate interleukin (IL)-8 expression in epithelial cells to recruit additional neutrophils to the site of inflammation. The gene discussed is GRN; the disease is infection.