title: Results of 1-year screening of donors in The Netherlands for human T-lymphotropic virus (HTLV) type I: significance of Western blot patterns for confirmation of HTLV infection.
abstract: BACKGROUND
  Between January 1993 and January 1994, Dutch blood banks screened approximately 674,000 volunteer donors for the presence of antibodies to human T-lymphotropic virus type I (HTLV-I).
  
  
  METHODS
  Confirmatory testing was performed on samples from 870 different anti-HTLV-I-reactive donors (0.13% of the total tested).
  
  
  RESULTS
  According to the authors' Western blot (WB) interpretation criteria, 15 (0.002%) donors tested HTLV-I-positive in the WB; 201 tested negative, and 654 (75% of donors reacting on enzyme-linked immunosorbent assay) tested indeterminate. Fresh samples from 234 of 870 anti-HTLV-reactive donors were tested for HTLV-I and type II (HTLV-II) DNA by polymerase chain reaction: all 15 WB-positive donors tested positive for HTLV-I DNA; 206 WB-indeterminate and 13 WB-negative donors tested negative for HTLV-I and -II DNA. Application of the manufacturer's (World Health Organization-based) guidelines for WB interpretation would have resulted in the misclassification of 48 (23%) of 206 polymerase chain reaction-negative donors as HTLV-I/II-positive. Risk factors were present in 14 of 15 HTLV-I-infected donors: 8 had a partner from an HTLV-I-endemic area, 4 were from HTLV-I-endemic countries, and 2 had received blood transfusions.
  
  
  CONCLUSIONS
  HTLV-I and -II infection is rare among Dutch blood donors. HTLV screening will prevent few cases of HTLV-related disease, but it will prevent a further spread of the virus by transfusion. In a low-risk population, conservative guidelines for WB interpretation unnecessarily generate an excess of false-positive results.
authors.affiliation: Central Laboratory of the Netherlands, Red Cross Blood Transfusion Service.
authors.forename: H L
authors.initials: HL
authors.lastname: Zaaijer
authors.forename: H T
authors.initials: HT
authors.lastname: Cuypers
authors.forename: C
authors.initials: C
authors.lastname: Dudok de Wit
authors.forename: P N
authors.initials: PN
authors.lastname: Lelie
mesh_terms: D001782:Blood Donors; D015153:Blotting, Western; D004279:DNA, Viral / Q000097:blood; D006800:Deltaretrovirus Infections / Q000097:blood* / Q000517:prevention & control*; D015481:HTLV-I Antibodies / Q000097:blood; D015368:Human T-lymphotropic virus 1 / Q000235:genetics; D015367:Human T-lymphotropic virus 2 / Q000235:genetics; D006801:Humans; D008403:Mass Screening; D009426:Netherlands; D016133:Polymerase Chain Reaction
chemical_list: D004279:DNA, Viral; D015481:HTLV-I Antibodies