Real-world effectiveness of intensive chemotherapy with 7&3 versus venetoclax and hypomethylating agent in acute myeloid leukemia.

Intensive chemotherapy with cytarabine and anthracycline (7&3) remains the standard therapy for patients medically fit for induction, but the assessment of fitness remains controversial. Venetoclax and hypomethylating agent (ven/HMA) combination therapy has improved outcomes in unfit patients but no prospective study has assessed ven/HMA versus 7&3 as initial therapy in older, fit patients. Given no studies and expectation of ven/HMA use in patients outside of trial criteria, we evaluated retrospective outcomes among newly diagnosed patients. A nationwide electronic health record (EHR)-derived database and the University of Pennsylvania EHR identified 312 patients receiving 7&3 and 488 receiving ven/HMA who were 60-75 years old without history of organ failure. Ven/HMA patients were older and more likely to have secondary AML, adverse cytogenetics, and adverse mutations. Median overall survival (OS) for patients receiving intensive chemotherapy was 22 versus 10 months for ven/HMA (HR 0.53, 95% CI 0.40-0.60). Controlling for measured baseline characteristic imbalances reduced survival advantage by half (HR 0.71, 95% CI 0.53-0.94). A sub-group of patients with equipoise, likelihood at least 30%-70% of receiving either treatment, had similar OS outcomes (HR 1.10, 95% CI 0.75-1.6). Regarding safety outcomes, 60-day mortality was higher for ven/HMA (15% vs. 6% at 60 days) despite higher documented infections and febrile neutropenia for 7&3. In this multicenter real-word dataset, patients selected for intensive chemotherapy had superior OS but a large group had similar outcomes with ven/HMA. Prospective randomized studies, controlling for both measured and unmeasured confounders, must confirm this outcome.

Notch Ligand Delta-like 4 Promotes Regulatory T Cell Identity in Pulmonary Viral Infection.

Regulatory T (Treg) cells establish tolerance, prevent inflammation at mucosal surfaces, and regulate immunopathology during infectious responses. Recent studies have shown that Delta-like ligand 4 (Dll4) was upregulated on APC after respiratory syncytial virus (RSV) infection, and its inhibition leads to exaggerated immunopathology. In the present study, we outline the role of Dll4 in Treg cell differentiation, stability, and function in RSV infection. We found that Dll4 was expressed on CD11b+ pulmonary dendritic cells in the lung and draining lymph nodes in wild-type BALB/c mice after RSV infection. Dll4 neutralization exacerbated RSV-induced disease pathology, mucus production, group 2 innate lymphoid cell infiltration, IL-5 and IL-13 production, as well as IL-17A+ CD4 T cells. Dll4 inhibition decreased the abundance of CD62LhiCD44loFoxp3+ central Treg cells in draining lymph nodes. The RSV-induced disease was accompanied by an increase in Th17-like effector phenotype in Foxp3+ Treg cells and a decrease in granzyme B expression after Dll4 blockade. Finally, Dll4-exposed induced Treg cells maintained the CD62LhiCD44lo central Treg cell phenotype, had increased Foxp3 expression, became more suppressive, and were resistant to Th17 skewing in vitro. These results suggest that Dll4 activation during differentiation sustained Treg cell phenotype and function to control RSV infection.

STAT5-induced lunatic fringe during Th2 development alters delta-like 4-mediated Th2 cytokine production in respiratory syncytial virus-exacerbated airway allergic disease.

Notch activation plays an important role in T cell development and mature T cell differentiation. In this study, we investigated the role of Notch activation in a mouse model of respiratory syncytial virus (RSV)-exacerbated allergic airway disease. During RSV exacerbation, in vivo neutralization of a specific Notch ligand, Delta-like ligand (Dll)-4, significantly decreased airway hyperreactivity, mucus production, and Th2 cytokines. Lunatic Fringe (Lfng), a glycosyltransferase that enhances Notch activation by Dll4, was increased during RSV exacerbation. Lfng loss of function in Th2-skewed cells inhibited Dll4-Notch activation and subsequent IL-4 production. Further knockdown of Lfng in T cells in CD4Cre(+)Lfng(fl/fl) mice showed reduced Th2 response and disease pathology during RSV exacerbation. Finally, we identified STAT5-binding cis-acting regulatory element activation as a critical driver of Lfng transcriptional activation. These data demonstrate that STAT5-dependent amplification of Notch-modifying Lfng augments Th2 response via Dll4 and is critical for amplifying viral exacerbation during allergic airway disease.

Real-world effectiveness of CPX-351 vs venetoclax and azacitidine in acute myeloid leukemia.

CPX-351 and venetoclax and azacitidine (ven/aza) are both indicated as initial therapy for acute myeloid leukemia (AML) in older adults. In the absence of prospective randomized comparisons of these regimens, we used retrospective observational data to evaluate various outcomes for patients with newly diagnosed AML receiving either CPX-351 (n = 217) or ven/aza (n = 439). This study used both a nationwide electronic health record (EHR)-derived de-identified database and the University of Pennsylvania EHR. Our study includes 217 patients who received CPX-351 and 439 who received ven/aza. Paitents receiving ven/aza were older, more likely to be treated in the community, and more likely to have a diagnosis of de novo acute myeloid leukemia. Other baseline covariates were not statistically significantly different between the groups. Median overall survival (OS) for all patients was 12 months and did not differ based on therapy (13 months for CPX-351 vs 11 months for ven/aza; hazard ratio, 0.88; 95% confidence interval, 0.71-1.08; P = .22). OS was similar across multiple sensitivity analyses. Regarding safety outcomes, early mortality was similar (10% vs 13% at 60 days). However, documented infections were higher with CPX-351 as were rates of febrile neutropenia. Hospital length of stay, including any admission before the next cycle of therapy, was more than twice as long for CPX-351. In this large multicenter real-world dataset, there was no statistically significant difference in OS. Prospective randomized studies with careful attention to side effects, quality of life, and impact on transplant outcomes are needed in these populations.

CD8+ T cells contribute to survival in patients with COVID-19 and hematologic cancer.

Patients with cancer have high mortality from coronavirus disease 2019 (COVID-19), and the immune parameters that dictate clinical outcomes remain unknown. In a cohort of 100 patients with cancer who were hospitalized for COVID-19, patients with hematologic cancer had higher mortality relative to patients with solid cancer. In two additional cohorts, flow cytometric and serologic analyses demonstrated that patients with solid cancer and patients without cancer had a similar immune phenotype during acute COVID-19, whereas patients with hematologic cancer had impairment of B cells and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)-specific antibody responses. Despite the impaired humoral immunity and high mortality in patients with hematologic cancer who also have COVID-19, those with a greater number of CD8 T cells had improved survival, including those treated with anti-CD20 therapy. Furthermore, 77% of patients with hematologic cancer had detectable SARS-CoV-2-specific T cell responses. Thus, CD8 T cells might influence recovery from COVID-19 when humoral immunity is deficient. These observations suggest that CD8 T cell responses to vaccination might provide protection in patients with hematologic cancer even in the setting of limited humoral responses.

CD8 T cells compensate for impaired humoral immunity in COVID-19 patients with hematologic cancer.

Cancer patients have increased morbidity and mortality from Coronavirus Disease 2019 (COVID-19), but the underlying immune mechanisms are unknown. In a cohort of 100 cancer patients hospitalized for COVID-19 at the University of Pennsylvania Health System, we found that patients with hematologic cancers had a significantly higher mortality relative to patients with solid cancers after accounting for confounders including ECOG performance status and active cancer status. We performed flow cytometric and serologic analyses of 106 cancer patients and 113 non-cancer controls from two additional cohorts at Penn and Memorial Sloan Kettering Cancer Center. Patients with solid cancers exhibited an immune phenotype similar to non-cancer patients during acute COVID-19 whereas patients with hematologic cancers had significant impairment of B cells and SARS-CoV-2-specific antibody responses. High dimensional analysis of flow cytometric data revealed 5 distinct immune phenotypes. An immune phenotype characterized by CD8 T cell depletion was associated with a high viral load and the highest mortality of 71%, among all cancer patients. In contrast, despite impaired B cell responses, patients with hematologic cancers and preserved CD8 T cells had a lower viral load and mortality. These data highlight the importance of CD8 T cells in acute COVID-19, particularly in the setting of impaired humoral immunity. Further, depletion of B cells with anti-CD20 therapy resulted in almost complete abrogation of SARS-CoV-2-specific IgG and IgM antibodies, but was not associated with increased mortality compared to other hematologic cancers, when adequate CD8 T cells were present. Finally, higher CD8 T cell counts were associated with improved overall survival in patients with hematologic cancers. Thus, CD8 T cells likely compensate for deficient humoral immunity and influence clinical recovery of COVID-19. These observations have important implications for cancer and COVID-19-directed treatments, immunosuppressive therapies, and for understanding the role of B and T cells in acute COVID-19.

Compartmentalized effects of aging on group 2 innate lymphoid cell development and function.

The effects of aging on innate immunity and the resulting impacts on immunosenescence remain poorly understood. Here, we report that aging induces compartmentalized changes to the development and function of group 2 innate lymphoid cells (ILC2), an ILC subset implicated in pulmonary homeostasis and tissue repair. Aging enhances bone marrow early ILC2 development through Notch signaling, but the newly generated circulating ILC2 are unable to settle in the lungs to replenish the concomitantly declining mature lung ILC2 pool in aged mice. Aged lung ILC2 are transcriptomically heterogeneous and functionally compromised, failing to produce cytokines at homeostasis and during influenza infection. They have reduced expression of Cyp2e1, a cytochrome P450 oxidase required for optimal ILC2 function. Transfer of lung ILC2 from young mice enhances resistance to influenza infection in old mice. These data highlight compartmentalized effects of aging on ILC and indicate that targeting tissue-resident ILCs might unlock therapies to enhance resistance to infections and diseases in the elderly.

Notch ligand Delta-like 4 induces epigenetic regulation of Treg cell differentiation and function in viral infection.

Notch ligand Delta-like ligand 4 (DLL4) has been shown to regulate CD4 T-cell differentiation, including regulatory T cells (Treg). Epigenetic alterations, which include histone modifications, are critical in cell differentiation decisions. Recent genome-wide studies demonstrated that Treg have increased trimethylation on histone H3 at lysine 4 (H3K4me3) around the Treg master transcription factor, Foxp3 loci. Here we report that DLL4 dynamically increased H3K4 methylation around the Foxp3 locus that was dependent upon upregulated SET and MYDN domain containing protein 3 (SMYD3). DLL4 promoted Smyd3 through the canonical Notch pathway in iTreg differentiation. DLL4 inhibition during pulmonary respiratory syncytial virus (RSV) infection decreased Smyd3 expression and Foxp3 expression in Treg leading to increased Il17a. On the other hand, DLL4 supported Il10 expression in vitro and in vivo, which was also partially dependent upon SMYD3. Using genome-wide unbiased mRNA sequencing, novel sets of DLL4- and Smyd3-dependent differentially expressed genes were discovered, including lymphocyte-activation gene 3 (Lag3), a checkpoint inhibitor that has been identified for modulating Th cell activation. Together, our data demonstrate a novel mechanism of DLL4/Notch-induced Smyd3 epigenetic pathways that maintain regulatory CD4 T cells in viral infections.