CD200 and myeloid sarcoma: Mitochondrial dysfunction has been implicated as a contributory factor to the disease pathogenesis in MS with evidence of mitochondrial respiratory chain (MRC) dysfunction being reported in postmortem brain samples of MS patients [2] together with confocal in vivo imaging studies of the spinal cord in experimental autoimmune encephalomyelitis (EAE) mouse models of MS revealing evidence of an aberration of mitochondrial function [3].