It is of interest that HAM/TSP patients have also been reported to develop autoantibodies to neurons that cross-reacted with HTLV-1 Gag and Tax [17, 18], suggesting that increased humoral immune responses including cross- or self-reactive antibodies to CNS antigens for HTLV-1 might alter the risk of CNS inflammation or autoimmune disease. Here, CNTN2 is linked to tropical spastic paraparesis.