Malignant diseases and mortality in blood donors infected with human T-lymphotropic virus type 1 in Israel

Objectives: The natural history of blood donors infected with human T-lymphotropic virus type 1 (HTLV-1) in Israel has never been assessed. The aim of this study was to evaluate the prevalence of malignant disorders and mortality among a cohort of Israelis diagnosed as HTLV-1 carriers during routine blood unit screening. Methods: This was an observational retrospective cohort study. All HTLV-1 cases among Israeli blood donors between 1995 and 2009 were included. Data regarding malignant diseases were extracted from the Israel National Cancer Registry. Mortality data were extracted from the Israel Population Registry. Results: Between January 9, 1995 and December 31, 2009, 1. 574. 497 blood donors were screened for HTLV-1 in the central blood bank services. Of these, 90 were found to be HTLV-1 carriers. This cohort of HTLV-1-infected blood donors was followed for an average of 9.2 ± 6 years. Among them six (6.7%) were diagnosed as having malignant diseases, four of them with adult T-cell leukemia/lymphoma (ATLL). The incidence of ATLL was 0.37 (95% confidence interval 0.13-1.08)/100 HTLV-1 carrier-years. Conclusions: We found a high rate of malignant diseases among HTLV-1-infected blood donors.