Moreover, we evaluated Fas, FasL, perforin, granzyme, granulysin, bax, Bad, BH3-family, BCL2 and caspase8 gene expression changes between the AC and HAM/TSP groups, and a molecular signalling network is presented for the pathogenesis of HTLV-1 based on the target genes. This evidence concerns the gene FAS and tropical spastic paraparesis.