EXPRESSION OF HUMAN T-LYMPHOTROPIC VIRUS TYPE-1 (HTLV-1) TAX REX GENEIN FRESH BRONCHOALVEOLAR LAVAGE CELLS OF HTLV-1-INFECTED INDIVIDUALS/

Accumulating evidence has suggested the involvement of HTLV-1 in the i nflammatory lesions of various organs, including the lung. However, th e causal relationship between HTLV-1 and inflammatory responses in the organs remains to be elucidated. In order to evaluate the expression of HTLV-1 and its effects in the lung, we examined the expression of m RNA for the HTLV-1 tax/rex gene in fresh bronchoalveolar lavage cells (BALC) and peripheral blood mononuclear cells (PBMC) of 23 seropositiv e individuals, including six patients with HTLV-1-associated myelopath y/tropical spastic paraparesis (HAM/TSP), by use of an improved method of reverse transcription-polymerase chain reaction (RT-PCR). The tax/ rex mRNA was more frequently detected in BALC than in PBMC. All the HA M/TSP patients and eight of 17 carriers without neurological symptoms showed the expression of tax/rex mRNA in the BALC. IgM class antibodie s to HTLV-1 were preferentially detected in sera of the tax/rex mRNA-p ositive individuals. The detection of tax/rex mRNA correlated closely with the presence of lymphocytosis accompanied by an elevated proporti on ofIL-2 receptor-bearing T cells in the BALC. Our findings indicate the crucial role of viral expression in the inflammatory response in t he lung in HTLV-1-infected individuals.