Considering only MS patients, we found significant positive associations between CSF levels of IL-12p40 (Spearman r = 0.559, p = 0.0002) and CXCL13 (Spearman r = 0.378, p = 0.0149), but not IL-8, with the third measure of CEL on brain MRI. The gene discussed is CXCL13; the disease is myeloid sarcoma.