PREVALENCE OF ANTIBODIES TO HUMAN T-CELL LEUKEMIA-LYMPHOMA VIRUS IN BLOOD-DONORS IN NORTH LONDON

Objectives-To determine the prevalence of antibodies to the human T ce ll leukaemia/lymphoma viruses (HTLV-I and HTLV-II) in blood donors in north London in order to assess the economic impact and the logistic e ffects that routine screening would have on the blood supply. Design-A ll donations collected by the north London blood transfusion centre be tween January 1991 and June 1991 were screened for antibodies to HTLV- I and HTLV-II by modified, improved Fujirebio gel particle agglutinati on test. Positive samples were titrated and retested as necessary. Sub jects-96 720 unpaid volunteers, who gave 105 730 consecutive donations of blood and plasma. Setting-North London blood transfusion centre. M ain outcome measure-Observed numbers of donors confirmed to be seropos itive for HTLV by reference laboratories. Results-Of 2622 (2.5%) initi ally reactive samples, 414 (0.4% of all samples) gave a titre of great er-than-or-equal-to 1 in 16 on the modified agglutination test. Thirty five of the 414 serum samples yielded positive results on one of two enzyme linked immunosorbent assays (ELISA (Cambridge Biotech and Abbot )), and none of these results were confirmed by either reference labor atory. Five samples yielded positive results on both ELISAs and all fi ve of these were confirmed to contain antibodies to HTLV. One of the f ive contained antibodies to HTLV-II and the others antibodies to HTLV- I. Four seropositive donors were white women whose only risk factor fo r infection was sexual contact. The fifth (positive for antibodies to HTLV-II) was an Anglo-Caribbean man who admitted to previous misuse of intravenous drugs. Conclusion-The prevalence of antibodies to HTLV in blood donors in north London was one in 19 344 (0.005%). Up to 100 do nors a year might be identified in the United Kingdom as being infecte d with HTLV, although prevalence in different regions may vary conside rably.