title: HTLV-I infection among relatives of patients with adult T-cell leukemia/lymphoma in Brazil: analysis of infection transmission.
abstract: We examined the presence of HTLV-I infection among 66 family members of 13 patients with well documented ATL to investigate the routes of HLTV-I transmission in a Southeast region of Brazil. HTLV-I infection was screened by an enzyme immunossay (ELISA) test and all repeatedly positive or indeterminate ELISA samples were further tested by a Western-Blot (WB) technique. Indeterminate and inconclusive WB samples were confirmed by a polymerase chain reaction (PCR). ELISA results showed that 40 (60.6%) individuals were not infected; 16 (24.2%) were positive; and 10 (15.2%) were undetermined. Among 16 ELISA positive subjects, 14 (87.5%) were confirmed to be positive by WB while 2 (12.5%) showed inconclusive results. Based on the laboratory data, questionnaire analysis, and family/epidemiological studies, we concluded that HTLV-I vertical transmission occurred in 6 of the 13 families. In 3 of these 6 families, the horizontal transmission also could be demonstrated. An isolated horizontal transmission was detected in one family, and in 6 families we did not find any infected family member. All HTLV-I-infected persons were clinically asymptomatic. The occurrence of an effective HTLV-I vertical transmission detected by the present study suggest that HTLV-I infection is endemic in the Southeast region of Brazil. Consistent with the modes of transmission, the HTLV-I antibody seroprevalence was greater in relatives of ATL patients than in the general blood donor Brazilian population (0.4%). In addition, the present data suggest that HTLV-I carries a high infectivity rate but a low virulence.
authors.affiliation: The Hematology and Transfusion Medicine Service-Universidade Federal de Sao Paulo, Escola Paulista de Medicina, Brazil.
authors.forename: D M
authors.initials: DM
authors.lastname: Borducchi
authors.forename: J S
authors.initials: JS
authors.lastname: Oliveira
authors.forename: J O
authors.initials: JO
authors.lastname: Bordin
authors.forename: J
authors.initials: J
authors.lastname: Kerbauy
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001938:Brazil / Q000453:epidemiology; D002648:Child; D002675:Child, Preschool; D005260:Female; D015490:HTLV-I Infections / Q000453:epidemiology / Q000235:genetics / Q000635:transmission*; D015368:Human T-lymphotropic virus 1 / Q000302:isolation & purification*; D006801:Humans; D015458:Leukemia, T-Cell / Q000235:genetics / Q000821:virology*; D008297:Male; D008875:Middle Aged; D010375:Pedigree