Intra-tumoral T cells in pediatric brain tumors display clonal expansion and effector properties.

Brain tumors in children are a devastating disease in a high proportion of patients. Owing to inconsistent results in clinical trials in unstratified patients, the role of immunotherapy remains unclear. We performed an in-depth survey of the single-cell transcriptomes and clonal relationship of intra-tumoral T cells from children with brain tumors. Our results demonstrate that a large fraction of T cells in the tumor tissue are clonally expanded with the potential to recognize tumor antigens. Such clonally expanded T cells display enrichment of transcripts linked to effector function, tissue residency, immune checkpoints and signatures of neoantigen-specific T cells and immunotherapy response. We identify neoantigens in pediatric brain tumors and show that neoantigen-specific T cell gene signatures are linked to better survival outcomes. Notably, among the patients in our cohort, we observe substantial heterogeneity in the degree of clonal expansion and magnitude of T cell response. Our findings suggest that characterization of intra-tumoral T cell responses may enable selection of patients for immunotherapy, an approach that requires prospective validation in clinical trials.

A pilot study of genomic-guided induction therapy followed by immunotherapy with difluoromethylornithine maintenance for high-risk neuroblastoma.

BACKGROUND: Survival for patients with high-risk neuroblastoma (HRNB) remains poor despite aggressive multimodal therapies. AIMS: To study the feasibility and safety of incorporating a genomic-based targeted agent to induction therapy for HRNB as well as the feasibility and safety of adding difluoromethylornithine (DFMO) to anti-GD2 immunotherapy. METHODS: Twenty newly diagnosed HRNB patients were treated on this multicenter pilot trial. Molecular tumor boards selected one of six targeted agents based on tumor-normal whole exome sequencing and tumor RNA-sequencing results. Treatment followed standard upfront HRNB chemotherapy with the addition of the selected targeted agent to cycles 3-6 of induction. Following consolidation, DFMO (750 mg/m2 twice daily) was added to maintenance with dinutuximab and isotretinoin, followed by continuation of DFMO alone for 2 years. DNA methylation analysis was performed retrospectively and compared to RNA expression. RESULTS: Of the 20 subjects enrolled, 19 started targeted therapy during cycle 3 and 1 started during cycle 5. Eighty-five percent of subjects met feasibility criteria (receiving 75% of targeted agent doses). Addition of targeted agents did not result in toxicities requiring dose reduction of chemotherapy or permanent discontinuation of targeted agent. Following standard consolidation, 15 subjects continued onto immunotherapy with DFMO. This combination was well-tolerated and resulted in no unexpected adverse events related to DFMO. CONCLUSION: This study demonstrates the safety and feasibility of adding targeted agents to standard induction therapy and adding DFMO to immunotherapy for HRNB. This treatment regimen has been expanded to a Phase II trial to evaluate efficacy.

Dexmedetomidine for conscious sedation in difficult awake fiberoptic intubation cases.

Currently used methods of sedation for fiberoptic intubation such as benzodiazepines, propofol, or opioids have their limitations. Dexmedetomidine (DEX) is a selective alpha-2 adrenergic agonist that has been used clinically for its sympatholytic, analgesic, and sedative properties. We report on 4 patients with particularly difficult airways who underwent successful awake fiberoptic intubation with DEX. Dexmedetomidine was used to provide a moderate level of conscious sedation without causing respiratory distress or hemodynamic instability during fiberoptic intubation.

Methemoglobinemia associated with dapsone therapy in a child with pneumonia and chronic immune thrombocytopenic purpura.

This report describes a case of methemoglobinemia in association with dapsone therapy. The patient, an immunocompromised child with chronic immune thrombocytopenic purpura, presented with fever, cough, perioral cyanosis, bilateral lower lobe rales, and low O2 saturation by pulse oximetry (89%). His medications included prednisone and rituximab for chronic immune thrombocytopenic purpura, and dapsone for Pneumocystis carinii pneumonia prophylaxis. Because of his lack of dyspnea and tachypnea, and the temporal association of his perioral cyanosis with the initiation of dapsone therapy, a methemoglobin (MetHb) level was obtained and found to be elevated at 9.6%. The authors discuss the mechanism and treatment of methemoglobinemia secondary to dapsone. They also stress the importance of monitoring for signs and symptoms of methemoglobinemia in immunocompromised patients on dapsone therapy for P. carinii pneumonia prophylaxis.

Thrombocytopenia and severe hyperbilirubinemia in the neonatal period secondary to congenital thrombotic thrombocytopenic purpura and ADAMTS13 deficiency.

Congenital thrombotic thrombocytopenic purpura (TTP) is an inherited form of TTP due to the deficiency of von Willebrand factor (vWF) cleaving protease ADAMTS13. The authors describe two children with congenital TTP who presented with thrombocytopenia, hemolytic anemia, elevated LDH levels, and schistocytes on peripheral blood smear. In both children, the diagnosis of the disease was delayed despite neonatal histories significant for thrombocytopenia, anemia, and severe hyperbilirubinemia. Severely decreased ADAMTS13 activity (<0.1 U/mL), the absence of an inhibitor to the protease, and partial deficiency found in the parents confirmed the diagnosis of congenital TTP. The authors suggest that congenital TTP should be considered in the differential diagnosis for newborns presenting with severe hyperbilirubinemia, anemia, and thrombocytopenia.