As control, HBZ-specific antibody production was not detected in memory B cell cultures generated from HAM/TSP patients without HBZ-specific antibody response, while memory B cells generated from both HAM/TSP patients with and without HBZ-specific antibody response could produce antibodies specific to HTLV-I Gag, Env or Tax (data not shown). This evidence concerns the gene ERVW-1 and tropical spastic paraparesis.