GAP43 and clostridium difficile infection: In the group of RRMS patients that switched to fingolimod or alemtuzumab there was a slight trend that those with higher baseline CSF GAP-43 concentration more often achieved clinical disability improvement (CDI; EDSS improvement of ≥1 point for those with an EDSS of ≥ 2 points at baseline, excluding 5 patients as they did not have EDSS ≥ 2 at baseline), but not significant [CDI at follow-up (n = 5): 1930 (1471–2999) pg/mL, no CDI at follow-up (n = 25): 1717 (1354–2398) pg/mL, p = 0.58].