We describe two patients in whom malignant monoclonal T-cell lymphoproliferation developed after administration of chimeric antigen receptor (CAR) T-cell therapy with ciltacabtagene autoleucel (cilta-cel) in the phase 3 CARTITUDE-4 trial. Monoclonal T cells from both patients had detectable CAR transgene expression and integration. The clinicogenomic features of these CAR transgenic T-cell lymphoproliferative neoplasms suggest that multiple potential intrinsic or extrinsic factors (or both) contributed to their pathogenesis, such as transduction of preexisting TET2-mutated T cells, followed by acquisition of further oncogenic genomic variants. Other potential contributors include germline genomic variation, viral infections, and previous treatment for myeloma. In the absence of direct evidence, the contribution of insertional mutagenesis to the development of T-cell lymphoma is currently unclear. (Funded by Johnson & Johnson and Legend Biotech USA; CARTITUDE-4 ClinicalTrials.gov number, NCT04181827.).

Vaccine-induced immune thrombocytopenia and thrombosis (VITT) is associated with antibodies that target platelet factor 4 (PF4) and are heparin-independent. VITT antibodies are implicated in acute, transient prothrombotic disorders that are triggered by adenoviral vector vaccines against coronavirus disease 2019 or by adenovirus infection. We describe chronic prothrombotic disorders featuring anticoagulant-refractory thromboses and intermittent thrombocytopenia that were associated with VITT-like antibodies in five patients (four patients with newly reported cases and the index patient). The patients had low levels of M proteins (median level, 0.14 g per deciliter); in each patient, we found that the M protein was the VITT-like antibody. The antibody clonotype profiles and binding epitopes on PF4 were different from those observed with the acute disorders occurring after vaccination or viral infection, features that reflect distinct immunopathogenesis. Treatment strategies besides anticoagulation alone are needed for the chronic disorders, referred to as VITT-like monoclonal gammopathy of thrombotic significance. (Funded by the Canadian Institutes of Health Research and others.).

Xenotransplantation offers a potential solution to the organ shortage crisis. A 62-year-old hemodialysis-dependent man with long-standing diabetes, advanced vasculopathy, and marked dialysis-access challenges received a gene-edited porcine kidney with 69 genomic edits, including deletion of three glycan antigens, inactivation of porcine endogenous retroviruses, and insertion of seven human transgenes. The xenograft functioned immediately. The patient's creatinine levels decreased promptly and progressively, and dialysis was no longer needed. After a T-cell-mediated rejection episode on day 8, intensified immunosuppression reversed rejection. Despite sustained kidney function, the patient died from unexpected, sudden cardiac causes on day 52; autopsy revealed severe coronary artery disease and ventricular scarring without evident xenograft rejection. (Funded by Massachusetts General Hospital and eGenesis.).

Obinutuzumab, a humanized type II anti-CD20 monoclonal antibody, provided significantly better renal responses than placebo in a phase 2 trial involving patients with lupus nephritis receiving standard therapy.

Whether the large effect size of endovascular thrombectomy (EVT) for stroke due to large-vessel occlusion applies to stroke due to medium-vessel occlusion is unclear.