This activity may contribute to tissue injury responses to infection and to the pathogenesis of autoimmune diseases such as lupus, inflammatory bowel disease, and rheumatoid arthritis.2–4 In addition, neutrophils have been implicated in both the development of atherosclerosis and amplification of cardiac injury post–myocardial infarction, with neutrophil count (NEUT) and serum MPO concentration correlating with adverse clinical outcomes.5–7. This evidence concerns the gene MPO and infection.