[Epidemiology of HTLV-I carriers in Hirado Island and virological and immunological investigation of HTLV-I associated pulmonary disease].

Adult T-cell leukemia (ATL) is endemic in Kyushu. Our study at Hirado island in Nagasaki prefecture revealed a higher incidence (35.9%) of HTLV-I carriers in villages with fishing than in those without (16.5%). HTLV-I carriers showed a higher incidence of abnormal findings on chest roentgenogram (21.7%) than non-carriers (16.5%), but most were lesions of old pulmonary tuberculosis and pleural thickening. Virological and immunological investigations were performed for 10 HTLV-I carriers, 3 patients with HTLV-I associated myelopathy (HAM), and 3 patients with ATL to determine the presence of HTLV-I associated pulmonary disease. In HAM patients, there were high titers of anti HTLV-I antibody, positive IgA reaction to HTLV-I, and an increase in interleukin-2 receptor (IL-2)-positive T-cells in the peripheral blood; and lymphocytosis and an increase in IL-2-positive T-cells in the bronchoalveolar lavage fluid (BALF). Virological examination showed the presence of pX gene and tax1/rex1 mRNA in the peripheral blood and BALF. Similar immunological and virological findings in 2 of 10 carriers suggested the presence of HTLV-I associated pulmonary disease.