Epidemiology of human T‐Cell leukemia/lymphoma virus type 1 (HTLV‐1) infections in a subpopulation of Afro‐Caribbean origin in England

Epidemiological studies on neurological diseases in residents of Afro‐Caribbean origin in the West Midlands region of England have identified eight patients with tropical spastic paraparesis (TSP), all of whom were found to be infected with human T‐cell leukemia/lymphoma virus type 1 (HTLV‐1). The husband of one of the patients with TSP was also infected with HTLV‐1 and had a T‐cell lymphoma. In addition, six asymptomatic HTLV‐1‐infected first‐degree relatives of the TSP patients have been found. By anonymous testing of over 700 sera obtained from individuals of Afro‐Caribbean, African, or Asian ethnic origin, seven HTLV‐1‐infected individuals were detected, who were all immigrants from the Caribbean. Overall, these numbers yielded a seroprevalence of HTLV‐1 infections of 3.4% among the immigrant population of Afro‐Caribbean origin, which is comparable with the prevalence of HTLV‐1 in Jamaica in an equivalent age and sex cohort. Sera were tested for HTLV‐1 antibody by means of three different procedures: passive particle agglutination test (Serodia), indirect enzyme‐labeled immunosorbent assay (ELISA; Dupont), and indirect immunofluorescence test (in‐house, using HTLV‐1‐infected MT2 cells). The results of all three tests correlated very well with each other. HTLV‐1 antibody titres in TSP patients were on the whole significantly higher than those of asymptomatic carriers, but some of the apparently healthy firstdegree relatives and one anonymously tested individual had titres as high as most of the TSP patients.