CCR2 and diabetes mellitus: Furthermore, Ccr2 null mice have a defect to mobilize monocytes from the bone marrow; thus, even in naive conditions, these animals already have fewer monocytes in the bloodstream.232 Noteworthy, double-blind clinical trials failed to demonstrate the efficacy of a selective and safe CCR2 antagonist in diabetes and posttraumatic neuropathic pain.97,98 Therefore, further preclinical studies and clinical trials are necessary to further confirm the importance of the CCL2/CCR2 axis for neuropathic pain development and also the possible mechanisms underlying.198,199