title: Neurologic abnormalities in HTLV-I- and HTLV-II-infected individuals without overt myelopathy.
abstract: BACKGROUND
  Human T-lymphotropic virus (HTLV) type I is the causative agent of HTLV-associated myelopathy (HAM)/tropical spastic paraparesis, and a number of HAM cases with HTLV-II infection have also been reported. However, despite some reports, it is unclear whether HTLV-I or -II infection is associated with other neurologic manifestations.
  
  
  METHODS
  An analysis of medical histories and screening neurologic examinations from a prospective cohort of 153 HTLV-I, 388 HTLV-II, and 810 HTLV-seronegative individuals followed up for means of 11.5, 12.0, and 12.2 years was performed. Participants diagnosed with HAM were excluded. We calculated odds ratios (ORs) and 95% confidence intervals (CIs), adjusting for age, sex, race or ethnicity, income, educational attainment, body mass index, alcohol and cigarette consumption, injection drug use, diabetes, and hepatitis C virus status, using generalized estimating equations for repeated measures.
  
  
  RESULTS
  HTLV-I and -II participants were more likely than seronegative participants to have leg weakness (ORs 1.67 [95% CI 1.28-2.18] and 1.44 [1.16-1.78]), impaired tandem gait (ORs 1.25 [95% CI 1.07-1.47] and 1.45 [1.27-1.64]), Babinski sign (ORs 1.54 [95% CI 1.13-2.08] and 1.51 [1.18-1.93]), impaired vibration sense (ORs 1.16 [95% CI 1.01-1.33] and 1.27 [1.14-1.42]), and urinary incontinence (ORs 1.45 [95% CI 1.23-1.72] and 1.70 [1.50-1.93]). For both HTLV-I and -II participants, higher odds of sensory neuropathy by monofilament examination were no longer significant after adjustment for confounding.
  
  
  CONCLUSIONS
  These results provide strong evidence that human T-lymphotropic virus (HTLV)-I and -II are associated with a spectrum of predominantly motor abnormalities in patients without overt HTLV-associated myelopathy. Further investigation of the clinical course and etiology of these abnormalities is warranted.
authors.affiliation: Blood Systems Research Institute, San Francisco, CA, USA.
authors.forename: H H
authors.initials: HH
authors.lastname: Biswas
authors.forename: J W
authors.initials: JW
authors.lastname: Engstrom
authors.forename: Z
authors.initials: Z
authors.lastname: Kaidarova
authors.forename: G
authors.initials: G
authors.lastname: Garratty
authors.forename: J W
authors.initials: JW
authors.lastname: Gibble
authors.forename: B H
authors.initials: BH
authors.lastname: Newman
authors.forename: J W
authors.initials: JW
authors.lastname: Smith
authors.forename: A
authors.initials: A
authors.lastname: Ziman
authors.forename: J L
authors.initials: JL
authors.lastname: Fridey
authors.forename: R A
authors.initials: RA
authors.lastname: Sacher
authors.forename: E L
authors.initials: EL
authors.lastname: Murphy
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D015331:Cohort Studies; D005260:Female; D005500:Follow-Up Studies; D015490:HTLV-I Infections / Q000175:diagnosis / Q000453:epidemiology*; D015491:HTLV-II Infections / Q000175:diagnosis / Q000453:epidemiology*; D015368:Human T-lymphotropic virus 1 / Q000302:isolation & purification; D015367:Human T-lymphotropic virus 2 / Q000302:isolation & purification; D006801:Humans; D008297:Male; D008875:Middle Aged; D019957:Motor Skills Disorders / Q000175:diagnosis / Q000453:epidemiology / Q000821:virology; D009422:Nervous System Diseases / Q000175:diagnosis / Q000453:epidemiology / Q000821:virology; D015493:Paraparesis, Tropical Spastic / Q000175:diagnosis / Q000453:epidemiology; D011446:Prospective Studies; D055815:Young Adult