All of the Tax1+ cell lines tested, including the IL-2-independent T cell lines (MT-2, HUT102, and MT-1) and IL-2-dependent T cell lines derived from an ATL patient (ATL-026), a HAM/TSP patient (ILT-M1), or a healthy donor whose T cells were transformed in vitro by HTLV-I (YT/cM1), were positive for CD83 (Figure 2a). Here, CD83 is linked to tropical spastic paraparesis.