In MS, microglial/macrophage protein expression (total, i.e., Iba1+, and activated, i.e., CD68+) positively correlated with neuronal density (Iba1+: r = 0.548, p < 0.001, CD68+: r = 0.498, p = 0.001). The gene discussed is AIF1; the disease is myeloid sarcoma.