First, we demonstrated that TNFα and IL-1β, two of the proinflammatory cytokines that have been implicated in mediating hypomyelination in PVL (Pang et al. 2003; Huleihel et al. 2004), significantly impaired myelination in the spinal cord derived culture. The gene discussed is IL1B; the disease is periventricular leukomalacia.