CRMO patients with active disease are characterized by elevated pro-inflammatory cytokines [tumor necrosis factor (TNF)-α, IL-1β, IL-6 and IL-8] in the serum (Hofmann et al., 2016a), and reduced IL-10 production in peripheral blood monocytes (Hofmann et al., 2011). This evidence concerns the gene IL1B and chronic recurrent multifocal osteomyelitis.