Pulmonary involvement in patients with human T lymphotropic virus type 1-associated myelopathy: the presence of specific IgA antibody in bronchoalveolar lavage fluid.

It has been shown that T lymphocyte alveolitis occurs in patients with human T lymphotropic virus type-1 (HTLV-1)-associated myelopathy/tropical spastic paraparesis (HAM/TSP). To determine whether HTLV-1-specific antibodies were present in bronchoalveolar lavage (BAL) fluid, we investigated 15 patients with HAM/TSP, five HTLV-1 carriers without HAM/TSP, and 10 normal control subjects seronegative for HTLV-1. Studies of BAL showed that 12 of 15 patients with HAM/TSP were associated with bronchoalveolar T lymphocytosis. Such abnormalities of the lung were not found in three other patients with HAM/TSP, non-HAM/TSP carriers, and normal control subjects. Using Western blots, specific IgA antibodies were detected only in BAL fluid from 12 patients with HAM/TSP and with pulmonary involvement. On the other hand, specific IgG antibodies in BAL fluid were positive not only in 12 patients with HAM/TSP and with pulmonary involvement, but also in two of three patients with HAM/TSP and three of five non-HAM/TSP carriers, both of whom showed normal BAL findings. Specific IgM class antibodies in BAL fluid were not detected in any subjects in these three groups. Specific IgA antibodies were found in the sera of 12 patients with HAM/TSP and with BAL lymphocytosis, but not in three patients with HAM/TSP and without BAL lymphocytosis, and five non-HAM/TSP carriers. These results suggest that the production of HTLV-1-specific IgA antibodies is closely related to pulmonary involvement in patients with HAM/TSP.