Recent work from Werneburg et al. [90] showed that synaptic material is tagged by complement C3 (not by C1q) and is engulfed by microglia in the retinogeniculate system of models of demyelination and in the visual thalamus of MS patients before the onset of clinical disease and before overt signs of demyelination. The gene discussed is C3; the disease is myeloid sarcoma.