title: Sibling adult T-cell leukemia/lymphoma and clustering of human T-cell lymphotropic virus type I infection in a Jamaican family.
abstract: BACKGROUND
  Human T-cell lymphotropic virus type I (HTLV-I) infection is endemic in Jamaica, with an estimated crude seroprevalence of 5%. Adult T-cell lymphoma/leukemia (ATL), a disease caused by HTLV-I, has an incidence of 1-2/100,000 in the Jamaican population. Familial ATL has not previously been reported from Jamaica.
  
  
  METHODS
  Hospital records and histologic specimens of the two cases were reviewed. HTLV-I infection was confirmed by antibody testing and by polymerase chain reaction on paraffin-embedded tissue, where serum was unavailable. Family members were identified by the patients' parents. After giving informed consent, family members were asked to complete an interviewer-administered questionnaire and to agree to phlebotomy.
  
  
  RESULTS
  ATL developed 10 years apart in two siblings from a Jamaican family at age 16 and 24 years. A study of 19 members of their extended family, including both parents, 2 grandparents, and 3 siblings, revealed an overall HTLV-I seroprevalence of 17%. This compared with 75% among parents and siblings living in the same household as the patients. HTLV-I antibody-positive (HTLV-I-positive) and negative family members had similar mean age. Three of 3 HTLV-I-positive subjects were breast-fed, compared with 10 of 15 HTLV-I-negative subjects. Intravenous drug abuse, sex with prostitutes, homosexuality, and blood transfusion were not reported. The mean number of sexual partners were similar. Both parents, who were antibody-positive, had polylobated atypical lymphocytes in their peripheral blood.
  
  
  CONCLUSIONS
  The HTLV-I antibody seroprevalence is greater in the family than in the general population, consistent with the modes of transmission. The antibody seronegativity of both grandmothers suggests sexual transmission between parents. The development of ATL at age 16 and 24 years is consistent with maternal-infant transmission and a long latent period, as reported by other authors.
authors.affiliation: Department of Medicine, University of the West Indies, Kingston, Jamaica.
authors.forename: R J
authors.initials: RJ
authors.lastname: Wilks
authors.forename: L
authors.initials: L
authors.lastname: LaGrenade
authors.forename: B
authors.initials: B
authors.lastname: Hanchard
authors.forename: M
authors.initials: M
authors.lastname: Campbell
authors.forename: J
authors.initials: J
authors.lastname: Murphy
authors.forename: B
authors.initials: B
authors.lastname: Cranston
authors.forename: W A
authors.initials: WA
authors.lastname: Blattner
authors.forename: A
authors.initials: A
authors.lastname: Manns
mesh_terms: D000293:Adolescent; D000328:Adult; D005260:Female; D015490:HTLV-I Infections / Q000635:transmission*; D006801:Humans; D007563:Jamaica; D015459:Leukemia-Lymphoma, Adult T-Cell / Q000235:genetics*; D008297:Male; D010375:Pedigree