Interleukin-2 receptor α chain (CD25) is overexpressed in human T-cell leukemia virus 1 associated adult T-cell leukemia/lymphoma (ATL). Daclizumab a humanized monoclonal antibody blocks IL-2 binding by recognizing the interleukin-2 receptor α chain (CD25). We conducted a phase I/II trial of daclizumab in 34 patients with ATL. Saturation of surface CD25 on circulating ATL cells was achieved at all doses; however saturation on ATL cells in lymph nodes required 8 mg/kg. Up to 8 mg/kg of daclizumab administered every 3 weeks was well tolerated. No responses were observed in 18 patients with acute or lymphoma ATL; however, 6 partial responses were observed in 16 chronic and smoldering ATL patients. The pharmacokinetics / pharmacodynamics of daclizumab suggest that high-dose daclizumab would be more effective than low-dose daclizumab in treatment of lymphoid malignancies and autoimmune diseases (e.g., multiple sclerosis) since high-dose daclizumab is required to saturate IL-2R alpha in extravascular sites.

SUMMARY Hodgkin-like cells (HLC) have been described in a variety of non-Hodgkin lymphomas (NHL) including chronic lymphocytic leukemia (CLL) and peripheral T-cell lymphoma (PTCL). There have been rare reports in the Japanese population of human T-cell lymphotrophic virus-1 (HTLV-1)-associated adult T-cell leukemia/lymphoma (ATLL) harboring HLC; however, no similar cases have been described in western patients. We report a 53-year-old African-American man that presented with progressive weakness and lethargy, and was found to have generalized lymphadenopathy and hypercalcemia. A lymph node biopsy showed involvement by ATLL with scattered Epstein-Barr virus (EBV)-positive cells, some of which resembled Hodgkin cells that had a B-cell phenotype, consistent with an Epstein-Barr virus-lymphoproliferative disorder (LPD). The patient had stage 4 disease with bone marrow involvement. In light of the associated B-cell lymphoproliferative process, the patient was treated with six cycles of intensive chemotherapy that targeted both the ATLL and the EBV-LPD that resulted in a complete response. An awareness of the association of EBV-LPD with Hodgkin-like cells in the context of ATLL is necessary to avoid potential misdiagnosis and to aid in therapeutic decisions.