CNTN2 and tropical spastic paraparesis: While Tax+ exosome detection was apparent in HAM/TSP CSF (12/20), we could not find evidence of Tax+ exosomes in a small group of asymptomatic carrier (AC) CSF samples (data not shown) (and, as expected, there were none detected from HTLV-1 negative patients (0/5, Fig. 5b, c).