Similar results were obtained by the testing of a number of additional HTLV-1+ T cell lines, including T cell lines spontaneously established from a HTLV-1-infected patient with adult T cell leukemia (ILT-H2) and a HTLV-1-associated myelopathy (HAM/TSP) patient (ILT-M1), and various in vitro-HTLV-1-immortalized CD4+ or CD8+ T cell lines from different healthy donors (such as YT/cM1, RT/cH2 cells) (Figure 1). This evidence concerns the gene CD4 and tropical spastic paraparesis.