CXCL13 and bacterial infectious disease: In contrast to other viral (e.g., TBE) or bacterial infections, CSF-CXCL13 levels in neuroborreliosis showed a significant decrease only a few days after the start of antibiotic therapy, in contrast to the leucocyte count, CSF/serum albumin ratio, or Bb-specific IgG AI [9,10,13,27,63].