Whether the CX3CR1/CX3CL1 axis is involved in muscle healing through the recruitment of circulating monocytes or the activation of macrophages, and whether its relation to the CCL2/CCR2 axis is unequivocal, as in atherosclerosis18, 34, or ambiguous, as in age-related macular degeneration (AMD)35, remains to be understood. The gene discussed is CX3CR1; the disease is age-related macular degeneration.