These changes could be responsible, at least in part, for neuronal loss and may also induce the demyelination of axons found in CSM and OPLL; however, they could also induce alternative activation by Th2 cytokines (IL-4, -10, and -13) and increase M2 microglia/macrophages, which provide neuroprotection and enhanced phagocytic activity. This evidence concerns the gene IL4 and ossification of the posterior longitudinal ligament of the spine.