Anti-CD19 chimeric antigen receptor (CAR) T-cell therapy has shown remarkable clinical efficacy in B-cell cancers. However, CAR T cells can induce substantial toxic effects, and the manufacture of the cells is complex. Natural killer (NK) cells that have been modified to express an anti-CD19 CAR have the potential to overcome these limitations. In this phase 1 and 2 trial, we administered HLA-mismatched anti-CD19 CAR-NK cells derived from cord blood to 11 patients with relapsed or refractory CD19-positive cancers (non-Hodgkin’s lymphoma or chronic lymphocytic leukemia [CLL]). NK cells were transduced with a retroviral vector expressing genes that encode anti-CD19 CAR, interleukin-15, and inducible caspase 9 as a safety switch. The cells were expanded ex vivo and administered in a single infusion at one of three doses (1×10⁵, 1×10⁶, or 1×10⁷ CAR-NK cells per kilogram of body weight) after lymphodepleting chemotherapy. The administration of CAR-NK cells was not associated with the development of cytokine release syndrome, neurotoxicity, or graft-versus-host disease, and there was no increase in the levels of inflammatory cytokines, including interleukin-6, over baseline. The maximum tolerated dose was not reached. Of the 11 patients who were treated, 8 (73%) had a response; of these patients, 7 (4 with lymphoma and 3 with CLL) had a complete remission, and 1 had remission of the Richter’s transformation component but had persistent CLL. Responses were rapid and seen within 30 days after infusion at all dose levels. The infused CAR-NK cells expanded and persisted at low levels for at least 12 months. Among 11 patients with relapsed or refractory CD19-positive cancers, a majority had a response to treatment with CAR-NK cells without the development of major toxic effects. (Funded by the M.D. Anderson Cancer Center CLL and Lymphoma Moonshot and the National Institutes of Health; ClinicalTrials.gov number, NCT03056339.)

Glioblastoma multiforme (GBM), the most aggressive brain cancer, recurs because glioblastoma stem cells (GSCs) are resistant to all standard therapies. We showed that GSCs, but not normal astrocytes, are sensitive to lysis by healthy allogeneic natural killer (NK) cells in vitro. Mass cytometry and single-cell RNA sequencing of primary tumor samples revealed that GBM tumor–infiltrating NK cells acquired an altered phenotype associated with impaired lytic function relative to matched peripheral blood NK cells from patients with GBM or healthy donors. We attributed this immune evasion tactic to direct cell-to-cell contact between GSCs and NK cells via αv integrin–mediated TGF-β activation. Treatment of GSC-engrafted mice with allogeneic NK cells in combination with inhibitors of integrin or TGF-β signaling or with TGFBR2 gene–edited allogeneic NK cells prevented GSC-induced NK cell dysfunction and tumor growth. These findings reveal an important mechanism of NK cell immune evasion by GSCs and suggest the αv integrin/TGF-β axis as a potentially useful therapeutic target in GBM.

Multiple factors in the design of a chimeric antigen receptor (CAR) influence CAR T-cell activity, with costimulatory signals being a key component. Yet, the impact of costimulatory domains on the downstream signaling and subsequent functionality of CAR-engineered natural killer (NK) cells remains largely unexplored. Here, we evaluated the impact of various costimulatory domains on CAR-NK cell activity, using a CD70-targeting CAR. We found that CD28, a costimulatory molecule not inherently present in mature NK cells, significantly enhanced the antitumor efficacy and long-term cytotoxicity of CAR-NK cells both in vitro and in multiple xenograft models of hematologic and solid tumors. Mechanistically, we showed that CD28 linked to CD3ζ creates a platform that recruits critical kinases, such as lymphocyte-specific protein tyrosine kinase (LCK) and zeta-chain-associated protein kinase 70 (ZAP70), initiating a signaling cascade that enhances CAR-NK cell function. Our study provides insights into how CD28 costimulation enhances CAR-NK cell function and supports its incorporation in NK-based CARs for cancer immunotherapy. Significance: We demonstrated that incorporation of the T-cell–centric costimulatory molecule CD28, which is normally absent in mature natural killer (NK) cells, into the chimeric antigen receptor (CAR) construct recruits key kinases including lymphocyte-specific protein tyrosine kinase and zeta-chain-associated protein kinase 70 and results in enhanced CAR-NK cell persistence and sustained antitumor cytotoxicity.

Myelodysplastic syndrome and acute myeloid leukemia (AML) belong to a continuous disease spectrum of myeloid malignancies with poor prognosis in the relapsed/refractory setting necessitating novel therapies. Natural killer (NK) cells from patients with myeloid malignancies display global dysfunction with impaired killing capacity, altered metabolism, and an exhausted phenotype at the single-cell transcriptomic and proteomic levels. In this study, we identified that this dysfunction was mediated through a cross-talk between NK cells and myeloid blasts necessitating cell-cell contact. NK cell dysfunction could be prevented by targeting the αvβ-integrin/TGF-β/SMAD pathway but, once established, was persistent because of profound epigenetic reprogramming. We identified BATF as a core transcription factor and the main mediator of this NK cell dysfunction in AML. Mechanistically, we found that BATF was directly regulated and induced by SMAD2/3 and, in turn, bound to key genes related to NK cell exhaustion, such as HAVCR2 , LAG3 , TIGIT , and CTLA4 . BATF deletion enhanced NK cell function against AML in vitro and in vivo. Collectively, our findings reveal a previously unidentified mechanism of NK immune evasion in AML manifested by epigenetic rewiring and inactivation of NK cells by myeloid blasts. This work highlights the importance of using healthy allogeneic NK cells as an adoptive cell therapy to treat patients with myeloid malignancies combined with strategies aimed at preventing the dysfunction by targeting the TGF-β pathway or BATF.

Background: With the goal of achieving immune system reset, autologous hematopoietic stem cell transplantations have been performed in patients with multiple sclerosis (MS). Material and Methods: Two hundred and eighty-six consecutive patients with MS were autografted in a single center using non-frozen peripheral blood stem cells (PBSCs), on an outpatient basis and conditioning with cyclophosphamide and rituximab. The protocol was registered in ClinicalTrials.gov identifier NCT02674217. Results: One hundred and ninety-four females and 92 males were included; the median age was 47. All procedures were started on an outpatient basis and only 8 persons needed to be admitted to the hospital during the procedure. In order to obtain at least 1 × 106/kg viable CD34 cells, 1-4 aphereses were performed (median 1). The total number of viable CD34+ cells infused ranged between 1 and 19.2 × 106/kg (median 4.6). Patients recovered above 0.5 × 109/L absolute granulocytes on median day 8 (range 0-12). Two individuals needed red blood cells but none needed platelet transfusions. There were no transplant-related deaths and the 128-month overall survival of the patients is 100%. In 82 persons followed up for 3 or more months, the Expanded Disability Status Scale diminished from a mean of 5.2-4.9, the best results being obtained in relapsing-remitting and primary progressive MS. Conclusions: It is possible to conduct autotransplants for patients with MS employing non-frozen PBSCs and outpatient conduction. Additional information is needed to assess the efficacy of these procedures in the treatment of patients with MS.

Sticky platelet syndrome (SPS) is an inherited condition that leads to arterial and venous thrombosis. There is scant information about the association between SPS and obstetric complications. This study aimed to assess the relationship between SPS and fetal loss at a single institution. The obstetric histories of all consecutive female patients prospectively studied in a 324-month period at a single institution with a history of thrombosis and a clinical marker of primary thrombophilia were reviewed. Between 1989 and 2016, 268 consecutive patients with a clinical marker of primary thrombophilia and a history of arterial or venous thrombosis were studied; of these, 108 were female patients. Within this subset of thrombophilic females, 77 (71%) had been pregnant at some point. Twenty-eight of these 77 patients (37%) had had a spontaneous abortion and 24 of those (86%) were found to have SPS. On the other hand, in a subset of 73 female patients with SPS who had been pregnant, 32% had miscarriages. These figures are significantly higher than the prevalence of spontaneous abortions in the general Mexican population of pregnant women, which is 12%-13% (chi-square: 7.47; p=0.0063). Accordingly, the relative risk of having a miscarriage is 2.66 times higher in female patients with SPS than in the general population (p=0.0014). In Mexico, female patients with SPS experience significantly more spontaneous abortions than the general population. Since the treatment of SPS is simple and effective and could in turn prevent adverse obstetric outcomes, its investigation in women treated for obstetric complications may be useful and deserves further research.