[Pathogenesis of T-lymphocyte alveolitis associated with HTLV-I infection]

Pulmonary involvement has been demonstrated in patients with spastic myelopathy associated with HTLV-I infection (HAM/TSP). Pulmonary lesions in these patients are characterized by T-lymphocytosis and increased level of soluble IL-2 receptor in bronchoalveolar lavage fluid. T-lymphocytes from peripheral blood and bronchoalveolar lavage fluid proliferated spontaneously and released IL-2 and IL-2 receptor when cultured in vitro. Spontaneous proliferation of T-lymphocytes was also found in HTLV-I carriers without myelopathy, but less intensely than in HAM/TSP patients. Interestingly, HTLV-I-infected cells were markedly increased in bronchoalveolar lavage fluid from HAM/TSP patients compared to HTLV-I carriers without myelopathy. These results suggest that T-lymphocyte activation and increased HTLV-I-infected cells play an important role in the pathogenesis of pulmonary involvement in patients with HAM/TSP.