High-Specificity CRISPR-Mediated Genome Engineering in Anti-BCMA Allogeneic CAR T Cells Suppresses Allograft Rejection in Preclinical Models.

Allogeneic chimeric antigen receptor (CAR) T cell therapies hold the potential to overcome many of the challenges associated with patient-derived (autologous) CAR T cells. Key considerations in the development of allogeneic CAR T cell therapies include prevention of graft-vs-host disease (GvHD) and suppression of allograft rejection. Here, we describe preclinical data supporting the ongoing first-in-human clinical study, the CaMMouflage trial (NCT05722418), evaluating CB-011 in patients with relapsed/refractory multiple myeloma. CB-011 is a hypoimmunogenic, allogeneic anti-B-cell maturation antigen (BCMA) CAR T cell therapy candidate. CB-011 cells feature 4 genomic alterations and were engineered from healthy donor-derived T cells using a Cas12a CRISPR hybrid RNA-DNA (chRDNA) genome-editing technology platform. To address allograft rejection, CAR T cells were engineered to prevent endogenous HLA class I complex expression and overexpress a single-chain polyprotein complex composed of beta-2 microglobulin (B2M) tethered to HLA-E. In addition, T-cell receptor (TCR) expression was disrupted at the TCR alpha constant locus in combination with the site-specific insertion of a humanized BCMA-specific CAR. CB-011 cells exhibited robust plasmablast cytotoxicity in vitro in a mixed lymphocyte reaction in cell cocultures derived from patients with multiple myeloma. In addition, CB-011 cells demonstrated suppressed recognition by and cytotoxicity from HLA-mismatched T cells. CB-011 cells were protected from natural killer cell-mediated cytotoxicity in vitro and in vivo due to endogenous promoter-driven expression of B2M-HLA-E. Potent antitumor efficacy, when combined with an immune-cloaking armoring strategy to dampen allograft rejection, offers optimized therapeutic potential in multiple myeloma. See related Spotlight by Caimi and Melenhorst, p. 385.

Impairment of Endothelial Function by Aerosol From Marijuana Leaf Vaporizers.

BACKGROUND: Marijuana leaf vaporizers, which heat plant material and sublimate Δ-9-tetrahydrocannabinol without combustion, are popular alternatives to smoking cannabis that are generally perceived to be less harmful. We have shown that smoke from tobacco and marijuana, as well as aerosol from e-cigarettes and heated tobacco products, impair vascular endothelial function in rats measured as arterial flow-mediated dilation (FMD). METHODS AND RESULTS: We exposed 8 rats per group to aerosol generated by 2 vaporizer systems (Volcano and handheld Yocan) using marijuana with varying Δ-9-tetrahydrocannabinol levels, in a single pulsatile exposure session of 2 s/min over 5 minutes, and measured changes in FMD. To model secondhand exposure, we exposed rats for 1 minute to diluted aerosol approximating release of uninhaled Volcano aerosol into typical residential rooms. Exposure to aerosol from marijuana with and without cannabinoids impaired FMD by ≈50%. FMD was similarly impaired by aerosols from Yocan (237 °C), and from Volcano at both its standard temperature (185 °C) and the minimum sublimation temperature of Δ-9-tetrahydrocannabinol (157 °C), although the low-temperature aerosol condition did not effectively deliver Δ-9-tetrahydrocannabinol to the circulation. Modeled secondhand exposure based on diluted Volcano aerosol also impaired FMD. FMD was not affected in rats exposed to clean air or water vapor passed through the Volcano system. CONCLUSIONS: Acute direct exposure and modeled secondhand exposure to marijuana leaf vaporizer aerosol, regardless of cannabinoid concentration or aerosol generation temperature, impair endothelial function in rats comparably to marijuana smoke. Our findings indicate that use of leaf vaporizers is unlikely to reduce the vascular risk burden of smoking marijuana.

All-epiphyseal versus trans-epiphyseal screw fixation for tillaux fractures: Does it matter?

BACKGROUND: Tillaux fractures occur primarily in adolescents due to the pattern of physeal closure and are classified as Salter-Harris type III physeal fractures. Operative management with screw fixation is recommended for more than 2 mm of displacement or more than 1 mm of translation. However, the efficacy and complications of trans-physeal vs all-physeal screw fixation have not been investigated extensively. AIM: To compare the clinical and functional outcomes of trans-physeal (oblique) and all-epiphyseal (parallel) screw fixation in management of Tillaux fractures among pediatric patients. METHODS: This was an ethics board approved retrospective review of pediatric patients who presented to our tertiary children's care facility with Tillaux fractures. We included patients who had surgical fixation of a Tillaux fracture over a 10 year period. Data analysis included demographics, mode of injury, management protocols, and functional outcomes. The patients were divided into group 1 (oblique fixation) and group 2 (parallel fixation). Baseline patient characteristics and functional outcomes were compared between groups. Statistical tests to evaluate differences included Fisher's Exact or Chi-squared and independent samples t or Mann Whitney tests for categorical and continuous variables, respectively. RESULTS: A total of 42 patients (28 females and 14 males) were included. There were no significant differences in body mass index, sex, age, or time to surgery between the groups [IK2]. Sports injuries accounted for 61.9% of the cases, particularly non-contact (57.1%) and skating (28.6%) injuries. Computed Tomography (CT) scan was ordered for 28 patients (66.7%), leading to diagnosis confirmation in 17 patients and change in management plan in 11 patients. [GRC3] Groups 1 and 2 consisted of 17 and 25 patients, respectively. For mid to long-term functional outcomes, there were 14 and 10 patients in groups 1 and 2, respectively. Statistical analysis revealed no significant differences in the functional outcomes, pain scores, or satisfaction between groups. No infections, non-unions, physeal arrest, or post-operative ankle deformities were reported. Two (4.8%) patients had difficulty returning to sports post-surgery due to pain. One was a dancer, and the other patient had pain while running, which led to hardware removal. Both patients had parallel fixation. Hardware removal for groups 1 and 2 were 4 (23.5%) and 5 (20.0%) patients, respectively. The reasons for removal was pain in 2 patients, and parental preference in the remaining. CONCLUSION: This is the largest reported series of pediatric patients with Tillaux fractures comparing functional outcomes of different methods of screw fixation orientation to the physis, which showed no difference regarding functional outcomes.

Triquetral Fractures Overview.

PURPOSE OF REVIEW: The triquetrum is the second most commonly fractured carpal bone, comprising 15-18% of all carpal bone fractures. This review summarizes the current knowledge of triquetral fractures, including the anatomy and pathophysiology, evaluation and diagnosis, treatment and management, post-treatment outcomes, and complications. RECENT FINDINGS: Triquetral fractures are frequently caused by impaction of the ulnar wrist after a fall on an outstretched hand or by avulsion of attached ligaments. There are three main types of triquetral fractures: dorsal cortical fractures, triquetral body fractures, and volar cortical fractures. Dorsal cortical fractures are the most common and are usually benign, while volar cortical fractures are the least common and can be problematic. Nonsurgical management is indicated for most triquetral fractures, which usually results in good outcomes. Surgical treatment is indicated for fractures with significant displacement or evidence of instability. Complications of triquetral fractures include non-union, triangular fibrocartilage complex injury, and pisotriquetral arthritis. While less common than scaphoid fractures, triquetral fractures should remain in the differential diagnosis for patients with ulnar-sided wrist pain after falling on an outstretched hand. Most triquetral fractures can be treated with immobilization, though they should be thoroughly evaluated due to their potential to result in instability, loss of motion, and arthrosis. Further research is needed to determine the best method of surgical treatment.