When PVL is present at a lower threshold or sublytic concentration, PVL contributes to a number of proinflammatory pathways, including the release of IL-8 and IL-6, which can cause granulosis of polymorphonuclear leukocytes (PMNs) and the release of reactive oxygen species like O2− [25,39]. This evidence concerns the gene IL6 and periventricular leukomalacia.