l l l LYMPHOID NEOPLASIA Comment on Tezuka et al, page 346 Of mice, men, and HTLV-1

In this issue of Blood, Tezuka et al report the establishment of humanized mice infected by human T-cell leukemia virus type 1 (HTLV-1) that recapitulate adult T-cell leukemia (ATL)-like leukemic symptoms and display HTLV-1–specific adaptive immune responses.1 HTLV-1 is a deltaretrovirus that isetiologically linked to ATL, an aggressive malignancy characterized by the monoclonal expansion of leukemic CD251CD41 T cells (with atypical multilobulated nuclei) in the peripheral blood. ATL, which is mainly observed in a small percentage of individuals infected during the neonatal period, has a poor prognosis when it reaches an acute state.2 The observations reported by Tezuka et al present an interesting and original contribution of mouse models for biomedical research.