IL6 and periventricular leukomalacia: Fas in primary myeloid cells showed no significant difference between SO mice and PVL mice (Fig. 4a), indicating that IL-6 may not promote myeloid cells apoptosis via Fas signaling, which is consistent with our previous research showing that gastric epithelial apoptosis rather than other cells apoptosis plays a specific role in the pathogenesis of PHG.