CD99 and myeloid sarcoma: Interestingly, other immunological markers in CSF and blood also show sex-specific differences in MS, e.g., serum levels of macrophage-derived chemokine (MDC), epithe-lial-derived neutrophil-activating protein 78 (ENA-78), Eotaxin-2, a proliferation-inducing ligand (APRIL), TNF-related apoptosis-inducing ligand (TRAIL), and interleukin-20 (IL-20) [37,38], CSF levels of tumor necrosis factor-like weak inducer of apoptosis (TWEAK) [38], CD99 expression on CD4 T cells in the CSF [39], and circulating levels of neutrophil extracellular traps in serum [40].