HTLV-1-infected asymptomatic carriers compared to HAM/TSP patients over-express the apoptosis- and cytotoxicity-related molecules

Expression changes of cytotoxicity and apoptosis genes in HTLV-1-associated myelopathy/tropical spastic paraparesis patients from the perspective of system virology

“…HAM/TSP is a chronic neuro-inflammatory infection, which develops slowly but persistently, eventually leading to paralysis [ 14 ]. Multi-organ lymphocyte infiltration, overexpression of T-bet transcription factor, cytokine IFN-γ production and spontaneous proliferation of lymphocytes are among the most important features of this disease [ 5, 15, 16 ]. Based on the available evidence, HTLV-1 initially infects the long-living CD4+CD25+CCR4+ T regulatory cells, and uses these cells as a reservoir.…”

“…Moreover, the virulence factors of HTLV-1, especially Tax , increase Th1 production and consequently increase the inflammation and tissue destruction in the CNS [ 21, 22 ]. Based on previous studies, the rate of Tax transcription is much higher in HAM/TSP patients than in ACs and ATLL patients [ 5, 22 ].…”

“…Based on a review of studies, the process of apoptosis is one of the most important approaches for the treatment of HTLV-1 infection, particularly for the elimination of IL-2-dependent CD4+ T cells in ATLL patients [ 23, 26–28 ]. According to Mohammadi et al ., expression of the genes involved in cell cytotoxicity and apoptosis in HAM/TSP patients is lower than in ACs [ 5 ]. In another study, the effect of curcumin on the increase in cytotoxicity and apoptosis activity of HTLV-1-infected cells was investigated in HAM/TSP patients and ACs, and it was found that subsequent to consuming curcumin, expression of genes in the apoptosis and cytolytic enzymes significantly increased in AC patients [ 29 ].…”

“…The immune system employs a variety of approaches including apoptosis of infected cells, production of granzymes and perforin enzymes, release of nitric oxide radicals, phagocytosis, and antibody production to eliminate infectious agents, especially HTLV-1 [ 5 ]. However, HTLV-1 is one of the most exclusive pathogen viruses of humans, and reduces the immune response by infecting immune cells especially CD4+ T cells [ 5–7 ]. HAM/TSP is a chronic neurodegenerative inflammation.…”

“…Previous studies have shown that HTLV-1-infected cells undergo apoptosis, which is an important mechanism for virus elimination [ 5, 9 ]. However, the mechanism of pathogenesis of HTLV-1 is still not properly known.…”