However, staining of live PLP1-transfected HEKPE7 cells treated with cholesterol yielded enhanced assay sensitivity; both MS patient ON07-7 CSF IgG (100 μg/ml) and MS04-2 CSF displayed a robust and unambiguous positive surface staining of PLP1-transfected cells that was not observed with NMO CSF (Figure 9A). Here, PLP1 is linked to neuromyelitis optica.