No abstract

No abstract

Despite recent advances with monoclonal antibody therapy, chronic lymphocytic leukemia (CLL) remains incurable. Natural killer (NK) cells are potent antitumoral effectors, particularly against hematological malignancies. Defective recognition of B-CLL leukemic cells by NK cells has been previously described. Here, we deciphered the mechanisms that hamper NK cell-mediated clearance of B-CLL and evaluated the potential of NK cells as therapeutic tools for treatment of CLL. First of all, leukemic B cells resemble to normal B cells with a weak expression of ligands for NK receptors. Conversely, NK cells from B-CLL patients were functionally and phenotypically competent, despite a decrease of expression of the activating receptor NKp30. Consequently, resting allogeneic NK cells were unable to kill leukemic B cells in vitro. These data suggest that patients' NK cells cannot initiate a proper immune reaction due to a lack of leukemic cell recognition. We next set up a xenotransplantation mouse model to study NK-CLL cell interactions. Together with our in vitro studies, in vivo data revealed that activation of NK cells is required in order to control B-CLL and that activated NK cells synergize to enhance rituximab effect on tumor load. This study points out the requirements for immune system manipulation for treatment of B-CLL in combination with monoclonal antibody therapy.

SummaryCentral nervous system involvement (CNSi) is a rare and poorly reported complication of chronic lymphocytic leukaemia (CLL). Establishing cause and effect between the CLL and the neurological symptoms remains challenging. We have analysed a retrospective cohort of 30 CLL patients with CNSi, documented by lymphocytic infiltration either by flow cytometry of the cerebrospinal fluid (CSF; n = 29) or CNS biopsy (n = 1). Neurological symptoms were heterogeneous. At the time of CNSi, less than half of the patients had a progressive CLL and 20 had never been treated for CLL. Initial treatment with fludarabine-based immuno-chemotherapy, with or without intra-CSF therapy, led to durable response in eight out of nine untreated patients. In contrast, 50% patients receiving various prior treatments needed additional therapy within a median of 4 months (1-16). Ibrutinib led to complete response in 4/4 heavily pre-treated patients. From CNSi, 5-year overall survival was 72% and 48% for treatment-na€ ıve and previously treated patients respectively (P = 0Á06); 5-year progression-free survival (PFS) was 43% and 0% (P = 0Á125). 17p deletion was significantly associated with poor PFS (P = 0Á006). CNSi may be the only sign of progression of CLL and should be considered an initiation criterion of systemic treatment. Prognosis seemed to be related to CLL characteristics rather than to CNSi itself.

No abstract