TLR4 and chronic recurrent multifocal osteomyelitis: Indeed, monocytes from CRMO patients fail to express granulocyte monocyte colony-stimulating factor (GM-CSF), and the anti-inflammatory molecules IL-10 and IL-1 receptor antagonist (IL-1RA) under resting conditions and/or in response to TLR4 stimulation with LPS (Fig. 4a).