Human T-cell lymphotropic virus: overview and update on the clinical spectrum - abstract

ABSTRACT

The first human retrovirus, human T-cell lymphotropic virus type 1 (HTLV -1) was isolated in 1980 and was soon identified as the cause of adult T-cell leukemia (ATL), a fatal lymphoproliferative hematologic malignancy first designated as a clinical entity by Takatsuki in Japan. Five years later we discovered that this virus was the causative agent of a chronic myelopathy, first called Jamaican neuropathy by Cruikshank in 1956 and now called tropical spastic paraparesis (TSP). HTLV-1 was soon recognized to be the causative agent of similar neurological disorder (HTLV-1 associated myelopathy (HAM) in southern Japan because by definition all patients had to be HTLV-1 seropositive. Thus in less than a decade, a century of research and speculation was resolved when it was found that this myelopathy, thought only to occur in blacks of poor socioeconomic status in tropical countries, existed in non-blacks in a temperate climate. HTLV-1 causes chronic inflammation but the pathogenesis of HTLV-1 disease is undetermined despite extensive definitive laboratory studies. The two most major diseases, ATL and TSP/HAM are rarely found in the same patient although other manifestations of HTLV-1 infection such as skin involvement, arthropathy and broncho alveolitis are not infrequently seen. We remain uncertain of the definitive factors which precipitate clinical infection and recognize that the absence of HTLV-1 seropositivity by routine laboratory tests does not in itself exclude HTLV-1 disease (AU)