Pathogenetic significance of HTLV-I infection and immune surveillance in HAM

Kazuo Fujihara

Research output: Contribution to journalArticlepeer-review

2 Citations (Scopus)


HTLV-I proviral DNA load is significantly increased in HTLV-I associated myelopathy (HAM) compared with asymptomatic HTLV-I seropositive carriers (SPC), and this spread of HTLV-I infection seems to be critically important in the pathogenesis of HAM. Thus, in this report, cellular immune surveillance against HTLV-I was reviewed. (1) MHC class I-restricted cytotoxic T lymphocytes (CTL) activities are detected in peripheral blood mononuclear cells (PBMC) of HAM. CTL release various proinflammatory and cytotoxic cytokines, chemokines, and proteases. Since CTL are also found in the spinal lesions of HAM, CTL may contribute to the tissue damage. In spontaneous proliferation of PBMC in HAM, CD4/CD8 is decreased due to the proliferation of CD 8 + CTL. CD4/CD8 is inversely correlated with the clinical severity of HAM. Collectively, CTL may be involved in the pathogenesis of HAM. (2) Activity and subsets of natural killer (NK) cells are lower in HTLV-I-seropositive individuals. Moreover, NK have only a weak cytotoxicity against HTLV-I infected cells. (3) Antibody-dependent cell- mediated cytotoxicity (ADCC) are impaired in HAM compared with SPC due to the suppressed effector cell activity. Since ADCC effectively lyse HTLV-I infected cells in vitro, the impaired ADCC may in part allow the spread of HTLV-I infection in HAM, and potentiation of ADCC may have an anti-HTLV-I therapeutic effect.

Original languageEnglish
Pages (from-to)21-23
Number of pages3
JournalClinical Neurology
Issue number1
Publication statusPublished - 1999


  • Antibody-dependent cell-mediated cytotoxicity (ADCC)
  • Cytotoxic T lymphocytes (CTL)
  • HTLV-I associated myelopathy (HAM)
  • Immune surveillance
  • Natural killer (NK) cells

ASJC Scopus subject areas

  • Clinical Neurology


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