Induction of lymphocytic inflammatory changes in lung interstitium by human T lymphotropic virus type I.

Human T lymphotropic virus type I (HTLV-I) is the etiological agent of adult T cell leukemia, and reports suggest that several other clinical conditions are associated with HTLV-I infection, including myelopathy and inflammatory pulmonary diseases. However, the clinical entity of HTLV-I-associated lung disease remains unsubstantiated more than 10 years after its description. In the present study, we conducted a histopathological analysis of lung tissues of transgenic mice that expressed gene segments of HTLV-I p40(tax) regions. The aim of the study was to examine the relationship between expression of viral components and development of lung disorders. In these mice, inflammatory changes with infiltration of lymphocytes in peribronchial and perivascular areas and in alveolar septa developed at 11 wk of age and increased in incidence during the observation period (26 wk). There was a significant correlation between the pulmonary pathological changes and the level of expression of p40(tax) mRNA in the lungs. Our results provided for the first time strong evidence of a direct relationship between HTLV-I and development of bronchopulmonary infection.