Tehran University of Medical Sciences Iranian Journal of Allergy, Asthma and Immunology 1735-1502 5 4 2006 12 15 153 166 Houshang Rafatpanah Reza Farid Gelareh Golanbar Farahzad Jabbari Azad 2015 10 01 Although the structure of human T lymphoptropic virus type I (HTLV-I) has been known well, the function of some proteins encoded by HTLV-I PX region is not fully understood. Furthermore, the responses of the immune system to HTLV-I remain still unknown. Most of HTLV-I-infected individuals show a strong and persistently activated cytotoxic T-cell (CTL) response to the virus. The frequency of HTLV-I specific CTL is higher in patients with HTLV-I-associated myelopathy/tropical spastic paraparesis (HAM/TSP) compared with HTLV-I carriers. However, the efficacy of the immune response determines the outcome of HTLV-I-associated diseases. Among the risk factors which contribute to the observed differences between HAM/TSP patients and HTLV-I carriers, the interaction between different genes and/or environmental factors seem to be important. These factors may also involve in outcome of HTLV-I infection in infected-individuals. https://ijaai.tums.ac.ir/index.php/ijaai/article/view/149 https://ijaai.tums.ac.ir/index.php/ijaai/article/download/149/149