The hyperinflammatory syndromes in critically ill patients, including trauma, sepsis, and acute lung injury, are characterized by dysregulated neutrophil responses that contribute to tissue damage and poor outcomes. Using murine models of cytokine storm induced by trauma and lung injury, we identified transforming growth factor β (TGFβ) as a central regulator of immune checkpoint in neutrophils. TGFβ signaling modulates neutrophil activation and upregulates the expression of programmed death-ligand 1 (PDL1). Disruption of TGFβ signaling during hyperinflammation restores the migratory capacity of neutrophils but leads to excessive activation, severe pulmonary tissue damage, and increased susceptibility to spontaneous bacterial infection in the lung. Mechanistically, PDL1 expression alters neutrophil behavior within lung capillaries, promoting intravascular clustering and restricting tissue infiltration. Targeted deletion of PDL1 in neutrophils reverses hyperinflammation-induced clustering, restores effective trafficking to infectious foci, and enhances host-protective immune function while limiting pathological neutrophil hyperactivation. These findings define a TGFβ-PDL1 regulatory axis that restrains the pathogenicity of neutrophils during hyperinflammation, revealing a checkpoint mechanism that balances host defense and tissue integrity.

The use of chimeric antigen receptor (CAR) T-cell therapy is increasing for adult B-cell acute lymphoblastic leukemia (B-ALL), with 3 CD19 CAR T-cell products commercially available. Several key clinical questions related to best practices for CAR T-cell administration in this population exist, and limited prospective randomized trials have been conducted to fill these knowledge gaps. Thus, to help guide clinical practice, we conducted a modified Delphi study to develop and validate consensus recommendations on the administration of commercially available CAR T-cell therapy for adults with B-ALL. Consensus panelists (n = 9) included principal investigators (PIs) from Real World Outcomes Collaborative of CAR T-Cell Therapy in Adult ALL (ROCCA) consortium sites and were selected based on expertise and CAR T-cell center volume. Final panel consensus recommendations were distributed for rating by the remaining PIs from ROCCA consortium sites, which served as the validation group (n = 27). Consensus topics included patient selection, bridging and pre-CAR T-cell leukemia staging, lymphodepletion, and CAR T-cell treatment setting, specific toxicity prevention and management, post-CAR T-cell response assessment and disease monitoring, and the role of consolidation and/or maintenance therapies after CAR T-cell therapy. Initially, 58 recommendation statements were evaluated for consensus. After 2 panel meetings, a total of 34 statements achieved consensus rating among the expert panel. After rating by the validation group, all but 1 recommendation statement continued to meet consensus, for a total of 33 consensus recommendation statements on the administration of CAR T-cell therapy in adult B-ALL.

Driver mutations in T-cell acute leukemia (T-ALL) rarely affect druggable kinases. However, these kinases can be aberrantly activated or repressed as secondary oncogenic events. Thus, integrating unbiased phosphoproteomics with genomic approaches may offer novel opportunities for target discovery and therapeutic interventions. In our study, we identified WNK1 as a potential target in T-ALL by pairing a list of vulnerable kinases with data from a phosphoproteomic screen of T-ALL cell lines. We subsequently validated WNK1 by loss-of-function-based studies and tested WNK inhibitors in several in vitro and in vivo T-ALL models and clinical T-ALL samples. We showed that therapeutic WNK1 repression promotes polyploidy, resulting in cell proliferation arrest, and morphometric changes, such as incomplete cell division or chromosome segregation through altered mitotic spindle assembly and abscission defects. Furthermore, we found that WNK1 is overexpressed in the TAL1/2-related subgroup, but not in normal thymus or lymph nodes, suggesting a potential translational area for clinical exploitation in poor-prognosis T-ALL carrying PTEN mutations and del(6q). Our work also reports a functional contribution of WNK1 in the leukemia establishment and progression. Structurally WNK1 is an atypical serine/threonine kinase that diverge from canonical kinases by lacking the conserved lysine in subdomain II, instead featuring a cysteine in subdomain I, which is critical for ATP-binding. This unusual structural configuration creates a distinct ATP-binding pocket with limited sequence similarity to conventional kinases, offering a unique opportunity to develop highly selective small-molecules. Targeting this atypical ATP-domain could thus provide a therapeutic advantage and broaden the treatment landscape for T-ALL.

The transcription factor GATA1 has pleiotropic hematopoietic functions, particularly in erythroid and megakaryocytic ontogeny. Although mechanistic investigations have uncovered many facets of GATA1 biology, how GATA1 coregulates divergent cell fates remains incompletely characterized. We previously described that loss of Stag2, a member of the cohesin complex and a recurrent mutational target in myelodysplastic syndrome (MDS) and myeloid leukemia of Down syndrome, results in altered chromatin accessibility, transcription factor function, and cell differentiation. Therefore, we hypothesized that chromatin accessibility determines GATA1 cistrome specificity and lineage fate decisions. To understand the connection between chromatin accessibility and GATA1, we comprehensively studied erythropoiesis in Stag2Δ mice. Defects in Stag2-deficient hematopoiesis included reduced numbers of erythroid progenitors (EryPs), impaired terminal erythroid differentiation, increased number of megakaryocyte progenitors, and increased megakaryocytes. RNA- and assay for transposase-accessible chromatin-sequencing of EryPs revealed altered patterns of Gata1 target gene expression with altered accessibility in conjunction with loss of expression of erythroid targets and gain of megakaryocyte targets. Despite unchanged Gata1 expression, Gata1 occupancy was reprogrammed from erythroid to megakaryocyte targets with Fli1 motifs enriched at Stag2Δ Gata1 binding sites. Functionally, we observed that Stag2-deficient EryPs have a diminished erythroid output and augmented megakaryocyte output in orthogonal differentiation assays, which was partially reversed with Fli1 knockdown. Human models and patients with primary MDS recapitulated the essential phenotypic and molecular features of our in vivo murine MDS model. Collectively, this study establishes chromatin accessibility as a determinant of transcription factor binding specificity, revealing an accessibility-driven Gata1 retargeting mechanism underlying MDS dyserythropoiesis.

Sickle cell disease (SCD) causes brain injury and cognitive disability. Systemic inflammation and endothelial injury are central to SCD pathophysiology, yet the relationship between systemic drivers of blood-brain barrier (BBB) disruption and brain injury remains understudied. This cross-sectional study assessed whole-brain and regional BBB permeability (Ktrans) using dynamic contrast-enhanced magnetic resonance imaging in 37 adults with SCD in steady-state and 37 non-SCD adults. Cerebral oxygen extraction fraction (OEF) and white matter mean diffusivity (MD) measured tissue hypoxia and microstructural injury, respectively. The SCD cohort showed elevated Ktrans compared with controls (3.6 x10-4min-1 vs. 2.58x10-4min-1, 95% CI median difference [0.36, 1.30]x10-4min-1, P< 0.001), indicating BBB disruption. In SCD, white matter Ktrans was associated with MD (β [95% Cl]: 6.25 [1.72, 10.77], P=0.008), independent of OEF (β [95% Cl]: 0.22 [0.09, 0.35]) and silent cerebral infarcts (β [95% Cl]: 0.01 [0.00, 0.02]). The interaction (P=0.037) between Ktrans and OEF on MD suggested a combined, deleterious effect of BBB disruption and hypoxia on microstructural injury. High-throughput plasma proteomics followed by differential expression analysis, and weighted gene correlation network analysis in a subset of 61 participants revealed 79 proteins associated with BBB permeability belonged to iron homeostasis, response to hypoxia, immune dysregulation, extracellular matrix degradation, lipoprotein homeostasis, and arginine-proline metabolism pathways. All pathways were independently associated with microstructural injury. BBB permeability is a mediator of brain injury for all pathways except extracellular matrix degradation. Targeting specific systemic pathways to protect the BBB may represent a therapeutic approach to preserve brain health in SCD.

Sickle cell disease (SCD) is a hereditary hemoglobinopathy characterized by persistent pain. The mechanisms underlying pain in SCD are poorly understood, and opioids remain the primary treatment, despite their severe side effects. Here, we investigated the contribution of lysophosphatidic acid (LPA), an endogenous pronociceptive lipid mediator, to chronic pain in SCD using humanized transgenic homozygous Berkeley mice that express >99% human sickle hemoglobin (HbSS) and control HbAA mice that express normal human hemoglobin A. Hyperalgesia in HbSS mice was associated with an increase in both plasma level of LPA and expression of LPA receptor 1 (LPA1R) mRNA in L1 to L5 dorsal root ganglion (DRG). Blocking LPA synthesis with BI-2545, or blocking LPA1R function with small interfering RNA (siRNA) or the LPA1R antagonist, AM966, reversed mechanical and heat hyperalgesia in HbSS mice. LPA also produced acute mechanical and heat hyperalgesia in HbAA mice, which resulted from the sensitization of C-fiber nociceptors. In HbSS mice, hyperalgesia was associated with sensitization of nociceptive DRG neurons. Nociceptors from hyperalgesic HbSS mice had lower rheobase, more positive resting membrane potential, and higher frequency of action potential. Although no changes were found in the values of inward currents in nociceptors of HbSS mice compared with HbAA mice, outward-inactivating and noninactivating currents were reduced, indicating the importance of potassium channels to sensitization in SCD. All these parameters were normalized by pretreatment of HbSS mice with LPA1R siRNA. Our results suggest that LPA signaling may be a promising target for treating pain in SCD.

Intensified chemotherapy regimens have improved outcomes in adults with Philadelphia chromosome-negative (Ph-) B-cell acute lymphoblastic leukemia (B-ALL), yet relapse remains a major cause of treatment failure and death. Blinatumomab is a T-cell engager that demonstrated marked activity in relapsed and measurable residual disease-positive (MRD+) B-ALL, as well as in frontline consolidation for MRD- patients. The phase 2 GRAALL-2014/B-QUEST substudy evaluated the integration of blinatumomab into consolidation and maintenance therapy for adults with high-risk (HR) B-ALL. Between 2015 and 2020, 489 adults aged 18 to 59 years with newly diagnosed Ph- B-ALL were enrolled, and among these 259 were classified as HR (presence of KMT2A-r, IKZF1 deletion, or end-of-induction MRD ≥ 10-4). A total of 94 patients with HR were enrolled in the QUEST study (2018-2020) and received up to 5, 28-day cycles of blinatumomab during consolidation and maintenance. In addition, 90 patients with HR who were treated before QUEST activation without blinatumomab served as controls in a post hoc analysis. Baseline characteristics were comparable between groups. Blinatumomab consolidation significantly improved MRD clearance, reduced relapse, and prolonged survival. At 5 years, cumulative incidence of relapse, disease-free survival (DFS), and overall survival were 23%, 68%, and 79% in the blinatumomab group compared with 49% (P = .001), 42% (P = .001), and 60% (P = .03) in controls. Patients eligible for allogeneic hematopoietic stem cell transplantation (alloHSCT) derived overall benefit. However, no clear additional DFS advantage was observed among those who ultimately underwent transplantation. These findings support the frontline integration of blinatumomab and warrant prospective evaluation of transplantation strategies in this setting. This trial was registered at www.clinicaltrials.gov as #NCT03709719.

T cell exhaustion has been shown to be a key resistance mechanism to efficacy of T cell engagers (TCE) in multiple myeloma (MM). Mezigdomide, a potent cereblon E3 ligase modulator that targets IKZF1 and IKZF3 simultaneously for proteasomal degradation, has been shown to modulate T cell activity in MM patients. We explored the possibility that targeting IKZF1/IKZF3 could address T cell exhaustion and restore functionality. We conducted extensive transcriptomic and epigenetic profiling on ex vivo generated exhausted T cells, using their autologous activated T cells as a comparison. Our study reveals that IKZF1 and IKZF3 are critical regulators contributing to the development and maintenance of T cell exhaustion. They regulate transcription by directly binding to promoters and enhancers, both proximal and distal, thereby altering transcriptional potential. Increased IKZF1 binding to exhaustion genes after multiple T cell stimulations results in enhancement of transcription, while binding to cytokine genes results in transcription repression. Mezigdomide treatment in exhausted T cells results in decreased expression of exhaustion-related markers, increased proinflammatory cytokine expression, and enhanced target cell killing with Alnuctamab, a B-cell maturation antigen (BCMA) targeting TCE. This study provides crucial mechanistic insights into the roles of IKZF1/IKZF3 in T cell exhaustion, supporting the rationale for combining mezigdomide with TCEs to enhance therapeutic outcomes in MM.

In the primary analysis of ANDROMEDA, addition of subcutaneous daratumumab to bortezomib/cyclophosphamide/dexamethasone (D-VCd) significantly improved hematologic complete response (CR) rate versus VCd, establishing D-VCd as the only approved therapy for light-chain (AL) amyloidosis. We present results from the preplanned final analysis. In this phase 3 trial, we randomly assigned 388 patients with newly diagnosed AL amyloidosis to six cycles of VCd alone (control group) or with subcutaneous daratumumab (D-VCd) followed by single-agent daratumumab every 4 weeks for up to 24 total cycles. The primary endpoint was hematologic CR. The updated hematologic CR rate was 59.5% for D-VCd versus 19.2% for VCd (odds ratio, 6.03; 95% confidence interval [CI], 3.80-9.58; P<0.0001). Median time to hematologic CR was shorter with D-VCd (67.5 days [range, 8.0-879.0]) versus VCd (85.0 days [range, 14.0-617.0]). With a median follow-up of 61.4 months, significant improvement was observed with D-VCd versus VCd in major organ deterioration-progression-free survival (hazard ratio, 0.44; 95% CI, 0.31-0.63; P<0.0001) and overall survival (hazard ratio, 0.62; 95% CI, 0.42-0.90; P=0.0121). Cardiac and renal response rates were 2-3 times higher with D-VCd versus VCd. Achieving hematologic or cardiac CR was associated with improved major organ deterioration-progression-free survival and overall survival. Adverse events were consistent with the known safety profiles for VCd and daratumumab. Adding daratumumab to VCd resulted in deeper and more rapid hematologic responses and recovery of organ function, translating to statistically significant improvement in both overall survival and major organ deterioration-progression-free survival in newly diagnosed AL amyloidosis. ClinicalTrials.gov NCT03201965.