Aggressive NK cell leukaemia after splenectomy: association with CD95-resistant memory T-cell proliferation and recalcitrant clinical course of haemophagocytic syndrome
We describe a 44-yr-old Japanese woman with persistent polyclonal T-cell proliferation and recalcitrant clinical course of haemophagocytic syndrome (HPS). T cells bearing αβ T-cell receptors (TCR) expressed increased amounts of CD95 and of CD45RO, which are phenotypically memory T cells. The TCR repertoire was broad and diverse. Regardless of CD95 expression, these cells were resistant to CD95-mediated apoptosis. Aggressive natural killer cell leukaemia (ANKL) without an association with Epstein–Barr virus was detected 1 month after therapeutic splenectomy that followed 3 yr of immunosuppressive therapy against HPS. The immunophenotype of these leukaemia cells was CD56, CD16dim, CD7, CD45RA and they expressed some CD2, CD8 and HLA-DR. Moreover, hyperdiploid clones with complex chromosomal abnormalities were also detected. Latent NK-cell malignancy seemed to cause the CD95-resistant memory T-cell proliferation and splenectomy resulted in overt ANKL progression. There should be careful consideration of the risks versus benefits of splenectomy in HPS, in light of the possibility of fatal leukaemia/lymphoma progression.
Document Type: Research Article
Affiliations: 1: Imamura Bun-in Hospital, Kagoshima, Japan 2: Division of Oncology, Hematology and Infectious Disease, Department of Internal Medicine Fukuoka University, Fukuoka, Japan 3: Division of Host Response, Center for Chronic Viral Diseases, Kagoshima University Graduate School of Medical and Dental Sciences, Kagoshima, Japan 4: Department of Haematology and Immunology, Kagoshima University Hospital, Kagoshima, Japan
Publication date: September 1, 2008