Testing for Other Human Retroviruses: HTLV-I and HTLV-II

The first human retroviruses to be discovered, human T lymphotropic virus type I (HTLV-I) and human T lymphotropic virus type II (HTLV-II) were reported in 1980 and 1982, respectively.1,2 HTLV-I was soon associated with adult T cell leukemia/lymphoma (ATL), a lymphoproliferative illness first reported in Japan in 1977. In 1985 a neurologic illness, now called HTLV-I-associated myelopathy/tropical spastic para-paresis (HAM/TSP), was also associated with HTLV-I. In contrast, HTLV-II, which was initially thought to be associated with hairy cell leukemia, has not been clearly associated with any disease. Screening of volunteer blood donors for HTLV-I began in 1986 in Japan and in 1988 in the United States; screening is also performed in Canada, France, the French West Indies, and Trinidad-Tobago.3