Lookback study of HTLV-1 and 2 seropositive donors and their recipients in Belo Horizonte, Brazil.

The objective of this study was to perform lookback study in recipients of blood components from human T-lymphotropic virus (HTLV) seropositive donors. HTLV-1/2 may be transmitted by blood transfusion. Brazil is an endemic area for the virus and its screening in blood donors is mandatory since 1993. Hemominas Foundation (HF) is the public transfusion centre in Minas Gerais, Brazil. Data on HTLV-1/2 seropositive donors and recipients from 1993 to 2004 were obtained at HF and 24 contracting hospitals. From 1993 to 2004, HTLV-1/2 enzyme immunoassay (EIA) was performed in 918 678 donations of approximately 422 600 blood donor candidates. Of these, 456 donors (0.1%) were reactive and confirmed by Western blot (WB): 449 HTLV-1 and 7 HTLV-2. Sixty-six (14.5%) were repeat donors and had 194 blood cellular components produced from their previous donations. Of the distributed components, 119/146 (81.5%) had the recipient traced, with a total of 114 individuals. Of these, only 13 recipients were tested: six (46%) were HTLV-1 positive (four recipients of red cell units, two of platelets) and seven (54%) were negative (six of red cell units and one of platelets). Eleven did not respond and 62/114 (54.0%) were deceased. Another 28/114 (25.0%) could not be located. All six seropositive HTLV-1 recipients identified had no symptoms suggestive of HTLV-1-associated diseases. Acellular components, when used alone, were not associated with HTLV seropositivity. HTLV-1 transmission by cellular blood components occurred before screening for the virus was introduced. Haemovigilance was difficult to perform due to unavailability of computer systems before 1999 and to inadequate medical records at hospitals.