HTLV-I/II associated disease in England and Wales, 1993-7: retrospective review of serology requests.

Apart from HIV two exogenous retroviruses (human T cell leukaemia viruses type I (HTLV-I) and type II (HTLV-II)) infect humans. HTLV-I infection is endemic in Japan, the Caribbean, Africa, and Melanesia and is found among immigrants from these regions in Europe. HTLV-I infection is associated with a 1-5% lifetime risk of adult T cell leukaemia/lymphoma, a 0.25% lifetime risk of HTLV-I associated myelopathy, and other inflammatory conditions (uveitis, alveolitis, and arthritis). HTLV-II infection is endemic in some native American and African peoples and among injecting drug users and has been associated with neurological disease. Between 1986 and 1992, 100 cases of HTLV-I associated myelopathy and 44 cases of adult T cell leukaemia/ lymphoma were diagnosed in the United Kingdom. Adult T cell leukaemia/lymphoma was first described in 1977 and patients with it have a mean life expectancy of only six months, so most of the 44 cases were probably incident cases. However, HTLV-I associated myelopathy causes prolonged morbidity and was not recognised as a clinical entity until 1985; thus the 1986-92 data may include many prevalent cases. We therefore sought to determine the incidence of HTLV-I/II related diseases in England and Wales since 1992.