GIMAP5 deficiency reveals a mammalian ceramide-driven longevity assurance pathway.

Preserving cells in a functional, non-senescent state is a major goal for extending human healthspans. Model organisms reveal that longevity and senescence are genetically controlled, but how genes control longevity in different mammalian tissues is unknown. Here, we report a new human genetic disease that causes cell senescence, liver and immune dysfunction, and early mortality that results from deficiency of GIMAP5, an evolutionarily conserved GTPase selectively expressed in lymphocytes and endothelial cells. We show that GIMAP5 restricts the pathological accumulation of long-chain ceramides (CERs), thereby regulating longevity. GIMAP5 controls CER abundance by interacting with protein kinase CK2 (CK2), attenuating its ability to activate CER synthases. Inhibition of CK2 and CER synthase rescues GIMAP5-deficient T cells by preventing CER overaccumulation and cell deterioration. Thus, GIMAP5 controls longevity assurance pathways crucial for immune function and healthspan in mammals.

Host metabolome predicts the severity and onset of acute toxicities induced by CAR T-cell therapy.

Anti-CD19 chimeric antigen receptor (CAR) T-cell therapy is a highly effective treatment option for patients with relapsed/refractory large B-cell lymphoma. However, widespread use is deterred by the development of clinically significant acute inflammatory toxicities, including cytokine release syndrome (CRS) and immune effector cell-associated neurotoxicity syndrome (ICANS), that induce significant morbidity and require close monitoring. Identification of host biochemical signatures that predict the severity and time-to-onset of CRS and ICANS may assist patient stratification to enable timely mitigation strategies. Here, we report pretreatment host metabolites that are associated with CRS and ICANS induced by axicabtagene ciloleucel or tisagenlecleucel therapy. Both untargeted metabolomics analysis and validation using targeted assays revealed a significant association between the abundance of specific pretreatment biochemical entities and an increased risk and/or onset of clinically significant CRS (q < .1) and ICANS (q < .25). Higher pretreatment levels of plasma glucose and lower levels of cholesterol and glutamate were associated with a faster onset of CRS. In contrast, low baseline levels of the amino acids proline and glycine and the secondary bile acid isoursodeoxycholate were significantly correlated with clinically significant CRS. Lower concentration of the amino acid hydroxyproline was associated with higher grade and faster onset of ICANS, whereas low glutamine was negatively correlated with faster development of ICANS. Overall, our data indicate that the pretreatment host metabolome has biomarker potential in determining the risk of clinically significant CRS and ICANS, and may be useful in risk stratification of patients before anti-CD19 CAR T-cell therapy.

The impact of race, ethnicity, and obesity on CAR T-cell therapy outcomes.

Cancer outcomes with chemotherapy are inferior in patients of minority racial/ethnic groups and those with obesity. Chimeric antigen receptor (CAR) T-cell therapy has transformed outcomes for relapsed/refractory hematologic malignancies, but whether its benefits extend commensurately to racial/ethnic minorities and patients with obesity is poorly understood. With a primary focus on patients with B-cell acute lymphoblastic leukemia (B-ALL), we retrospectively evaluated the impact of demographics and obesity on CAR T-cell therapy outcomes in adult and pediatric patients with hematologic malignancies treated with CAR T-cell therapy across 5 phase 1 clinical trials at the National Cancer Institute from 2012 to 2021. Among 139 B-ALL CAR T-cell infusions, 28.8% of patients were Hispanic, 3.6% were Black, and 29.5% were overweight/obese. No significant associations were found between race, ethnicity, or body mass index (BMI) and complete remission rates, neurotoxicity, or overall survival. Hispanic patients were more likely to experience severe cytokine release syndrome compared with White non-Hispanic patients even after adjusting for leukemia disease burden and age (odds ratio, 4.5; P = .001). A descriptive analysis of patients with multiple myeloma (n = 24) and non-Hodgkin lymphoma (n = 23) displayed a similar pattern to the B-ALL cohort. Our findings suggest CAR T-cell therapy may provide substantial benefit across a range of demographics characteristics, including for those populations who are at higher risk for chemotherapy resistance and relapse. However, toxicity profiles may vary. Therefore, efforts to improve access to CAR therapy for underrepresented populations and elucidate mechanisms of differential toxicity among demographic groups should be prioritized.

COVID-19 Outcomes in Patients Undergoing B Cell Depletion Therapy and Those with Humoral Immunodeficiency States: A Scoping Review.

BACKGROUND: The role of humoral immunity has been well established in reducing infection risk and facilitating viral clearance in patients with COVID-19. However, the relationship between specific antibody responses and severity of COVID-19 is less well understood. METHODS: To address this question and identify gaps in knowledge, we utilized the methodology of a scoping review to interrogate risk of infection and clinical outcomes of COVID-19 in patients with iatrogenic and inborn humoral immunodeficiency states based on existing literature. RESULTS: Among patients with iatrogenic B-cell depletion, particularly with agents targeting CD20, our analysis found increased risk of severe COVID-19 and death across a range of underlying disease states. Among patients with humoral inborn errors of immunity with COVID-19, our synthesis found that patients with dysregulated humoral immunity, predominantly common variable immunodeficiency (CVID), may be more susceptible to severe COVID-19 than patients with humoral immunodeficiency states due to X-linked agammaglobulinemia and other miscellaneous forms of humoral immunodeficiency. There were insufficient data to appraise the risk of COVID-19 infection in both populations of patients. CONCLUSIONS: Our work identifies potentially significant predictors of COVID-19 severity in patients with humoral immunodeficiency states and highlights the need for larger studies to control for clinical and biologic confounders of disease severity.

HEM1 deficiency disrupts mTORC2 and F-actin control in inherited immunodysregulatory disease.

Immunodeficiency often coincides with hyperactive immune disorders such as autoimmunity, lymphoproliferation, or atopy, but this coincidence is rarely understood on a molecular level. We describe five patients from four families with immunodeficiency coupled with atopy, lymphoproliferation, and cytokine overproduction harboring mutations in NCKAP1L, which encodes the hematopoietic-specific HEM1 protein. These mutations cause the loss of the HEM1 protein and the WAVE regulatory complex (WRC) or disrupt binding to the WRC regulator, Arf1, thereby impairing actin polymerization, synapse formation, and immune cell migration. Diminished cortical actin networks caused by WRC loss led to uncontrolled cytokine release and immune hyperresponsiveness. HEM1 loss also blocked mechanistic target of rapamycin complex 2 (mTORC2)-dependent AKT phosphorylation, T cell proliferation, and selected effector functions, leading to immunodeficiency. Thus, the evolutionarily conserved HEM1 protein simultaneously regulates filamentous actin (F-actin) and mTORC2 signaling to achieve equipoise in immune responses.