The BCL2 inhibitor venetoclax has complete response rates of up to 50% in chronic lymphocytic leukemia patients, but secondary resistance reflecting acquired mutations in BCL2 can lead to treatment failure. Blombery et al report that an unexpectedly large number of patients carry multiple BCL2 mutations with subclonal variation in their occurrence.

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PURPOSE. Diabetic retinopathy (DR) is a major cause of visual impairment in developed countries. While DR has been described classically as a microvascular disease, recent evidence suggests that changes to retinal microglia are an early feature of retinopathy. In our study, we assessed changes in microglial distribution and morphology in vivo and ex vivo in a mouse model of non-proliferative DR, and further examined effects of age and the absence of the functional chemokine receptor Cx 3 cr1 on the progression of these changes. METHODS.To isolate the effects of the three variables: diabetic status, age, and role of Cx 3 cr1, the Ins2Akita mouse was crossed with Cx 3 cr1-eGFP reporter mice. Eyes were assessed clinically in vivo at 10, 20, 30, and 46 weeks of age, and the retinal structure and arrangement of GFP þ microglia was examined ex vivo using whole mount immunofluorescence staining and confocal microscopy.RESULTS. Clinical examination of the fundus, vasculature, or GFP þ microglial distribution did not reveal any macroscopic changes related to diabetic status: however, ex vivo microscopic analysis revealed alterations in microglial network organization, and evidence of cell shape changes regarded classically as signs of activation, in Ins2Akita mice from 10 weeks of age. These changes were exacerbated in older diabetic mice whose microglia lacked Cx 3 cr1 (Ins2 Akita Cx 3 cr1 gfp/gfp mice). Diabetic status and Cx 3 cr1 deficiency led to accumulations of Iba-1 þ hyalocytes (vitreal macrophages) and subretinal macrophages.CONCLUSIONS. These data showed that changes to murine retinal microglia occur in response to systemic diabetic status in the absence of overt retinopathy and inflammation. These changes are exaggerated in mice lacking Cx 3 cr1, suggesting fractalkineCx 3 cr1 interactions may have a role in early neuronal changes in preproliferative DR. (Invest Ophthalmol Vis Sci.

The BCL2 inhibitor venetoclax has established therapeutic roles in chronic lymphocytic leukemia (CLL) and acute myeloid leukemia. As BCL2 is an important determinant of survival of both myeloid progenitor and B cells, we investigated whether clinical and molecular abnormalities arise in the myeloid compartment during long-term continuous venetoclax treatment for CLL in 89 patients (87 with relapsed/refractory CLL). Over a median follow-up of 75 (range 21-98) months, persistent cytopenias (³ 1 of neutropenia, thrombocytopenia, anemia) lasting ³4 months and unrelated to CLL occurred in 25 patients (28%). Of these patients, 20 (80%) displayed clonal hematopoiesis, including 10 with therapy-related myeloid neoplasms (tMNs). tMNs occurred exclusively in patients previously exposed to fludarabine-alkylator combination therapy with a cumulative 5-year incidence of 10.4% after venetoclax initiation, consistent with rates reported for patients exposed to fludarabine-alkylator combination therapy without venetoclax. To determine whether the altered myelopoiesis reflected acquisition of mutations, we analyzed samples from patients with no or minimal bone marrow CLL burden (n = 41). Mutations in the apoptosis effector BAX were identified in 32% (13/41). In cellular assays, C-terminal BAX mutants abrogated outer mitochondrial membrane localization of BAX and engendered resistance to venetoclax killing. BAX-mutated clonal hematopoiesis occurred independently of prior fludarabine-alkylator combination therapy exposure and was not associated with tMNs. Single cell sequencing revealed clonal co-occurrence of mutations in BAX with DNMT3A or ASXL1. We also observed simultaneous BCL2 mutations within CLL cells and BAX mutations in the myeloid compartment of the same patients, indicating lineage-specific adaptation to venetoclax therapy.

Granulocyte colony-stimulating factor (G-CSF) is a regulator of neutrophil production, function, and survival. Herein, we investigated the role of G-CSF in a murine model of human uveitis-experimental autoimmune uveoretinitis. Experimental autoimmune uveoretinitis was dramatically reduced in G-CSF-deficient mice and in anti-G-CSF monoclonal antibody-treated, wild-type (WT) mice. Flow cytometric analysis of the ocular infiltrate in WT mice with experimental autoimmune uveoretinitis showed a mixed population, comprising neutrophils, macrophages, and T cells. The eyes of G-CSF-deficient and anti-G-CSF monoclonal antibody-treated WT mice had minimal neutrophil infiltrate, but no change in other myeloid-derived inflammatory cells. Antigen-specific T-cell responses were maintained, but the differentiation of pathogenic type 17 helper T cells in experimental autoimmune uveoretinitis was reduced with G-CSF deficiency. We show that G-CSF controls the ocular neutrophil infiltrate by modulating the expression of C-X-C chemokine receptors 2 and 4 on peripheral blood neutrophils, as well as actin polymerization and migration. These data reveal an integral role for G-CSF-driven neutrophil responses in ocular autoimmunity, operating within and outside of the bone marrow, and also identify G-CSF as a potential therapeutic target in the treatment of human uveoretinitis.