CNTN2 and Sezary syndrome: After 24 h co-culture with HTLV-1 donor MT-2 cells >2% of permissive HUT78 cells, a male HTLV-1 negative cell line derived from a lymphoma patient with Sezary syndrome (Bunn and Foss, 1996), started to express detectable HTLV-1 specific Tax protein visualised by the highly specific anti-Tax antibody, clone Lt-4 (Tanaka et al., 1990), using flow cytometry.