Therefore, the ability of P. acnes to induce IL-1β should be demonstrated by monitoring IL-1β levels in NP and AF cell cultures and in vivo models of DDD that have been infected with P. acnes strains isolated from degenerated human discs, and covering different phylogenetic groups that are known to vary in their inflammatory nature as well as other pathogenic characteristics (McDowell et al., 2013). This evidence concerns the gene IL1B and Dowling-Degos disease 1.