While there was clear PCR reactivity in both CSF cells and PBMC specimens from patient NIH00261 (Fig. 3a), unexpectedly, the fluorescence amplitude of tax sequence was lower in patient NIH00261 compared to a typical HAM/TSP patient NIH00565 (HTLV-1 proviral load; 17.55 %) (Fig. 3a). This evidence concerns the gene CNTN2 and tropical spastic paraparesis.