TCF1-LEF1 co-expression identifies a multipotent progenitor cell (TH2-MPP) across human allergic diseases.

Repetitive exposure to antigen in chronic infection and cancer drives T cell exhaustion, limiting adaptive immunity. In contrast, aberrant, sustained T cell responses can persist over decades in human allergic disease. To understand these divergent outcomes, we employed bioinformatic, immunophenotyping and functional approaches with human diseased tissues, identifying an abundant population of type 2 helper T (TH2) cells with co-expression of TCF7 and LEF1, and features of chronic activation. These cells, which we termed TH2-multipotent progenitors (TH2-MPP) could self-renew and differentiate into cytokine-producing effector cells, regulatory T (Treg) cells and follicular helper T (TFH) cells. Single-cell T-cell-receptor lineage tracing confirmed lineage relationships between TH2-MPP, TH2 effectors, Treg cells and TFH cells. TH2-MPP persisted despite in vivo IL-4 receptor blockade, while thymic stromal lymphopoietin (TSLP) drove selective expansion of progenitor cells and rendered them insensitive to glucocorticoid-induced apoptosis in vitro. Together, our data identify TH2-MPP as an aberrant T cell population with the potential to sustain type 2 inflammation and support the paradigm that chronic T cell responses can be coordinated over time by progenitor cells.

Augmented Reality Microscopy in the Management of Cerebellopontine Lesions and Microvascular Decompression: A Pilot Study.

Objective: To evaluate whether augmented reality microscopy surgical fluorescence technology, already Food and Drug Administration approved for vascular neurosurgery, can aid in lateral skull base surgery during cerebellopontine (CPA) tumor resection and microvascular decompression. Study Design: Pilot prospective uncontrolled observational cohort study. Setting: An academic tertiary care hospital. Patients: Those who underwent retrosigmoid craniotomy for CPA tumor resection or microvascular decompression for hemifacial spasm, trigeminal neuralgia or pulsatile tinnitus. 11 patients were recruited: 4 underwent CPA tumor resection and 7 underwent microvascular decompression. Interventions: Augmented reality microscopy with fluorescence imaging was utilized to visualize vascular flow intraoperatively. A postoperative surgeon questionnaire was administered to assess the intraoperative efficacy of this technology. Main Outcome Measures: Efficacy of technology in aiding with CPA tumor resection and microvascular decompression. Results: For all 7 microvascular decompression cases, surgeons agreed that the technology aided in identifying areas where disease was affecting tissues with no cases of vascular occlusion identified. In 3 of the 4 CPA tumor resection cases, surgeons agreed that the technology identified areas of vascular flow within the CPA and the tumor. Vascular patency of the sigmoid-transverse sinus was also confirmed. No significant adverse effects were noted except 1 instance of severe-to-profound sensorineural hearing loss. Conclusions: Our study shows that the augmented reality fluorescence technology works during lateral skull base surgery as it can confirm intraoperative vascular integrity. Our data also suggest that this technology may improve visualization of ambiguous vasculature and blood flow to diseased tissue.