Impact of host immunity on HTLV-1 pathogenesis: potential of Tax-targeted immunotherapy against ATL

Retrovirology

Table 1 Difference between ATL and HAM/TSP

	ATL	HAM/TSP
Pathology	Malignant lymphoma/leukemia [4]	Chronic inflammation with demyelination [6, 7]
Age of onset	Varies among geographic areas [128,129,130]^a	40–50 years (average) [3]
Sex	Male > female [131]	Male < female [3]
Route of transmission	Mostly vertical [32]	Vertical and horizontal [32, 132]
Tax mRNA (sense)	Low expression [21]	Low expression but higher than ACs [35]
Tax protein	Undetectable in PBMCs but inducible in culture (in about 1/2 cases) [20]	Undetectable in PBMCs but inducible in culture [133]
HBZ mRNA (anti-sense)^b	Constitutively expressed [14]	Constitutively expressed [36]
HBZ protein	Small amount in the nucleus [37]	Small amount in the cytoplasm [37]
Tax-specific CTL response	Impaired [26]	Activated [24]
Cytokines	Elevated IL-10 in the serum [41]	Elevated proinflammatory cytokines in the serum and CXCL10 in the CSF [38,39,40]

ACs asymptomatic HTLV-1 carriers, ATL adult T-cell leukemia, CSF cerebrospinal fluid, CTL cytotoxic T lymphocyte, HAM/TSP HTLV-1 associated myelopathy/tropical spastic paraparesis, PBMC peripheral blood mononuclear cell, y years
^aThe mean ages of ATL onset reported are 43 y in Jamaica [128], 67.5 years in Japan [129], and 52 years in the United States [130]
^bGreater amounts of HBZ mRNA in ATL patients, while not significantly different when standardized by proviral loads [36]

ISSN: 1742-4690