Data on correlation analyses of white blood cell counts and differential cytology are rather heterogeneous with a tendency for a positive correlation between CSF-CXCL13 and leucocyte, lymphocyte, and plasma cell counts in various viral and bacterial CNS infections, multiple sclerosis, neuroinfectious diseases of unknown pathogens, and primary CNS lymphomas, as shown in our study [4,9,10,13,14,15,19,24,26,31,40,44,45,46,47,53,65]. Here, CXCL13 is linked to primary central nervous system lymphoma.