HTLV-1 Uveitis

Indirect immunofluorescence of certain human sera demonstrated an antigen(s) in the cytoplasm of 1--5% of the cells of a T-cell line, MT-1, from a patient with adult T-cell leukemia (ATL), which is endemic in southwestern Japan. The antigen was not detected in other human lymphoid cell lines, including six T-cell lines, seven B-cell lines, and four non-T non-B cell lines. The antigen did not show cross antigenicity with that of herpesviruses, including Epstein--Barr virus, herpes simplex virus, cytomegalovirus, varicella-zoster virus, herpesvirus saimiri, and Marek disease virus. The proportion of antigen-bearing cells was increased by a factor of approximately 5 on culture in the presence of 5-iodo-2'-deoxyuridine. Antibodies against the antigen in MT-1 cells were found in all 44 patients with ATL examined and in 32 of 40 patients with malignant T-cell lymphomas (most of them had diseases similar to ATL except that leukemic cells were not found in the peripheral blood). The antibodies were also detected in 26% of the healthy adults examined from ATL-endemic areas but in only a few of those examined from ATL-non-endemic areas. On electron microscopy, extracellular type C virus particles were detected in pelleted MT-1 cells cultured in the presence of 5-iodo-2'-deoxyuridine.

To study the epidemiology of human T-cell lymphotropic virus type I (HTLV-I)-associated myelopathy/tropical spastic paraparesis (HAM/TSP) in Japan, we conducted two nationwide surveys between October 1986 and March 1989. A total of 710 patients with HAM (definite HAM, 589; probable HAM, 121) were reported. Of the 589 patients with definite HAM, 69% were residents of the areas with the highest prevalence HTLV-I in Japan. To determine the importance of blood transfusion in the pathogenesis of HAM/TSP, we performed a case-control study in the Kagoshima district in southern Japan. Significantly more patients with HAM reported a history of blood transfusion (26/129, or 20%) than did subjects in a health survey of the general population (41/1,290, or 3%; odds ratio = 7.7, p less than 0.001) or than did hospitalized neurological patients (6/119, or 5%; odds ratio = 4.8, p less than 0.001). Furthermore, the cumulative percentages of the intervals between blood transfusion and the onset of the symptoms of HAM fit a lognormal curve, suggesting that transfusion was an important common exposure. Blood transfusion probably transmitted HTLV-I to the patients with transfusion-associated HAM because there was a significant decrease in the number of patients with the transfusion-associated HAM who received blood after implementation of nationwide screening of blood donors in 1986 (p = 0.004). In the first 2 years, screening the blood supply in Japan appears to have decreased the number of reported patients with HAM by 16%.