In line with the potential production and secretion of complement proteins by immune cells residing in meningeal TLTs, a recent proteomic CSF profiling in early MS patients showed that among 227 proteins differentially expressed between the patients with high vs. low cortical lesion load, 30% were related to the complement cascade, suggesting, that in addition to other soluble mediators, complement positively correlates with cortical damage at early disease stages (Magliozzi et al., 2019), possibly by diffusing through a disrupted glial limitans into the subpial cortex causing injury. The gene discussed is VTN; the disease is myeloid sarcoma.