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TheE mu-TCL1transgenic mouse model represents the most widely and extensively used animal model for chronic lymphocytic leukemia (CLL). In this report, we performed a meta-analysis of leukemia progression in over 300 individualE mu-TCL1transgenic mice and discovered a significantly accelerated disease progression in females compared to males. This difference is also reflected in an aggressive CLL mouse model with additional deletion ofTp53besides theTCL1transgene. Moreover, after serial adoptive transplantation of murine CLL cells, female recipients also succumbed to CLL earlier than male recipients. This sex-related disparity in the murine models is markedly contradictory to the human CLL condition. Thus, due to our observation we urge both careful consideration in the experimental design and accurate description of theE mu-TCL1transgenic cohorts in future studies.

CD74 is a surface protein expressed on immune cells, which acts as receptor for the chemokine macrophage migration inhibitory factor (MIF). Signalingviathe MIF/CD74-axis has been reported to be important for the pathogenesis of chronic lymphocytic leukemia (CLL). We wanted to clarify the role of CD74 in MIF-induced signaling/leukemic development. In E mu-TCL1 transgenic mice, occurrence of the leukemic phenotype was associated with increased surface CD74 expression. E mu-TCL1(+/+)Cd74(-/-)mice showed similar kinetics and clinical features of CLL development as E mu-TCL1(+/+)mice. MIF stimulation of leukemic splenocytes led to AKT activation in a CD74-dependent manner. AKT activation was reduced in Cd74-deficient splenocytes in the presence of the oncogenic TCL1-transgene. Tumor cell apoptosis/proliferation were unaffected in E mu-TCL1(+/+)Cd74(-/-)mice. Our data suggest that the need for active CD74 signaling is overcome in the leukemic context of TCL1-driven CLL, and that CD74 may have a dispensable role for CLL pathogenesis in this model.

Survival of chronic lymphocytic leukemia (CLL) cells strictly depends on the support of an appropriate tumor microenvironment. Here, we demonstrate that LYN kinase is essential for CLL progression. Lyn deficiency results in a significantly reduced CLL burden in vivo. Loss of Lyn within leukemic cells reduces B cell receptor (BCR) signaling including BTK phosphorylation, but surprisingly does not affect leukemic cell expansion. Instead, syngeneic CLL transplantation of CLL cells into Lyn- or Btk-deficient recipients results in a strongly delayed leukemic progression and prolonged survival. Moreover, Lyn deficiency in macrophages hinders nursing functions for CLL cells, which is mediated by direct contact rather than secretion of soluble factors. Taken together, LYN and BTK seem essential for the formation of a microenvironment supporting leukemic growth.

To assess the effects of chemoimmunotherapy on post-chemotherapy cognitive impairments (PCCI) in patients with B-cell non-Hodgkin lymphoma (NHL), we used objective and subjective measures of cognitive functions in combination with serum parameters and neuroelectric recordings. Self-perceived status of cognition, fatigue and emotional functioning were reduced in patients (n = 30) compared to healthy controls (n = 10). Cognitive performance was impaired in patients with NHL compared to controls and a norm sample (n = 1179). PCCI was more severe in patients treated with rituximab and bendamustine (BR) than in patients who received R in combination with CHOP (cyclophosphamide, doxorubicin, vincristine, prednisone) polychemotherapy (R-CHOP). Individual alpha peak frequency and serum brain-derived neurotrophic factor (BDNF) levels in patients with NHL correlated with accuracy in the objective cognition test. Higher serum interleukin-6 (IL-6) concentrations were associated with higher fatigue levels. Patients with NHL and especially those who were treated with BR were affected by PCCI. BDNF and IL-6 might be involved in the pathogenesis of PCCI and fatigue.