Infiltration of helper/inducer T lymphocytes heralds central nervous system damage in human T-cell leukemia virus infection.

Cellular infiltrates in new and old lesions in two cases of human T-cell leukemia virus associated myelopathy (HAM) were analyzed with anti-CD3 antibody and OPD4 antibody recognizing CD4 + CD45RO + T lymphocytes. A subset of CD4 lymphocytes with helper/inducer function and labeled with OPD4 constitutes up to 65% of CD3 cells in new lesions in the pons and the cervical cord. In contrast, nonhelper cells and macrophages were dominant in long-standing spinal cord lesions of these HAM cases and inflammatory lesions in two cases of Japanese encephalitis. Thus, unlike in viral infections, the central nervous system (CNS) tissue damage associated with human T-cell leukemia virus (HTLV-1) infection appeared to be heralded by the infiltration of helper/inducer T cells.