HTLV-I-associated myelopathy.
HTLV-I was first described as a pathogenic human retrovirus that causes adult T-cell leukemia (ATL). Soon after the discovery of HTLV-I, an association of this virus with a slowly progressive neurological disorder was found independently in Japan and Caribbean islands, and this new clinical entity (HTLV-I-associated myelopathy with tropical spastic paraparesis) was named HAM/TSP. Autopsy findings clarified the chronic inflammatory nature of the disease. Detailed neuropathological analysis demonstrated: (i) T-cell-dominant mononuclear cell infiltration; (ii) diffuse and symmetrical degeneration of the anterolateral and inner portion of the posterior columns involving both myelin and axons; (iii) the presence of cytotoxic T cells and apoptosis of helper/inducer T cells; (iv) in vivo localization of HTLV-I provirus in the perivascular infiltrated T cells; and (v) accentuation of inflammatory lesions at the site with slow blood flow. From these findings it is suggested that a T-cell-mediated chronic inflammatory process targeting the HTLV-I-infected T cells is the primary pathogenic mechanism of HAM/TSP.
Izumo
S
S
Molecular Pathology and Genetic Epidemiology, Center for Chronic Viral Diseases, Kagoshima University, Japan.
Umehara
F
F
Osame
M
M
D001158:Arteries / Q000276:immunology / Q000473:pathology / Q000821:virology; D015368:Human T-lymphotropic virus 1 / Q000235:genetics / Q000276:immunology; D006801:Humans; D007249:Inflammation / Q000276:immunology / Q000473:pathology / Q000503:physiopathology; D007564:Japan; D015493:Paraparesis, Tropical Spastic / Q000276:immunology / Q000473:pathology* / Q000821:virology*; D013116:Spinal Cord / Q000098:blood supply / Q000473:pathology / Q000821:virology; D006377:T-Lymphocytes, Helper-Inducer / Q000473:pathology / Q000821:virology