CXCL13 and neuromyelitis optica: In addition, since CXCL13 may function as an available biomarker of GC activity in human vaccine trial and advanced stage disease (e.g. neuromyelitis optica spectrum disorders and chronic lymphocytic leukemia) (30, 49, 50), our findings suggest that plasma CXCL13 may act as another prognostic marker in patients with thrombocytopenia.