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Chimeric antigen receptor T-cell (CAR-T) therapy yields durable responses in patients with relapsed/refractory diffuse large B-cell lymphoma (r/r DLBCL). Cytokine release syndrome (CRS) is a CAR-T therapy-related adverse event. To date, clinical trials of different CAR-T products have not been aligned on CRS grading scales and management algorithms. We assessed concordance between the Penn, Lee, and American Society for Transplantation and Cellular Therapy (ASTCT) grading systems by retrospectively regrading CRS events in the JULIET (A Phase 2, Single Arm, Multicenter Trial to Determine the Efficacy and Safety of CTL019 in Adult Patients With Relapsed or Refractory DLBCL) trial. Four medical experts with experience treating patients with 3 different CAR-T products independently regraded individual patient-level CRS events from the phase 2, global, pivotal JULIET trial (#NCT02445248). As of 8 December 2017, a total of 111 patients with r/r DLBCL underwent infusion with tisagenlecleucel. Sixty-four patients had CRS events graded per the Penn scale; on retrospective review, 63 and 61 patients had CRS events regraded per the Lee and ASTCT criteria, respectively. The Lee scale yielded concordance for 39, lower grade for 20, and higher grade for 5 events compared with the Penn scale. The ASTCT criteria provided concordance for 37, lower grade for 23, and higher grade for 4 events compared with the Penn scale. Sixteen (14%) of 111 patients in the JULIET trial received tocilizumab, all for severe events (Penn grade 3/4 CRS). This study is the first to assess concordance between 3 CRS grading scales using the same patient data set and to compare tocilizumab use according to the Lee scale in the JULIET trial and the ZUMA-1 (Long-Term Safety and Activity of Axicabtagene Ciloleucel in Refractory Large B-Cell Lymphoma) trial. This analysis describes key differences between grading scales and may inform CRS management practices., (© 2020 by The American Society of Hematology.)

Chimeric antigen receptor-T (CAR-T) cell therapy achieves durable responses in patients with relapsed/refractory diffuse large B-cell lymphoma (r/r DLBCL), but may be associated with neurological toxicity (NT). We retrospectively assessed differences and concordance among 3 available grading scales (the National Cancer Institute Common Terminology Criteria for Adverse Events v4.03 [CTCAE], modified CAR-T Related Encephalopathy Syndrome [mCRES], and American Society for Transplantation and Cellular Therapy [ASTCT] scales) applied to the same set of NT data from the JULIET (A Phase 2, Single Arm, Multicenter Trial to Determine the Efficacy and Safety of CTL019 in Adult Patients With Relapsed or Refractory DLBCL) trial. Individual patient-level NT data from the phase 2, single-group, global, pivotal JULIET trial (NCT02445248) were retrospectively and independently graded, using CTCAE, ASTCT, and mCRES, by 4 medical experts with experience managing patients with 3 different CD19-targeted CAR constructs. According to the US Food and Drug Administration definition of NT using CTCAE, 62 of 106 patients infused with tisagenlecleucel had NT as of September 2017. Among 111 patients infused with tisagenlecleucel (as of December 2017), the 4 experts identified 50 patients (45%) who had any-grade NT per CTCAE, 19 (17%) per mCRES, and 19 (17%) per ASTCT. Reevaluation according to the mCRES/ASTCT criteria downgraded 31 events deemed NT by CTCAE to grade 0. This is the first study to retrospectively apply CTCAE, mCRES, and ASTCT criteria to the same patient data set. We conclude that CTCAE v4.03 was not designed for, and is suboptimal for, grading CAR-T cell therapy-associated NT. The CRES and ASTCT scales, which measure immune effector cell-associated neurotoxicity syndrome, offer more accurate assessments of NT after CAR-T cell therapy., (© 2020 by The American Society of Hematology.)

Pyramidal cells in the superficial layers of the neocortex provide a major excitatory projection to layer 5, which contains the pyramidal cells that project to subcortical motor-related targets. Both structurally and functionally rather little is known about this interlaminar pathway, especially in higher mammals. Here, we made sparse ultrastructural reconstructions of the projection to layer 5 of three pyramidal neurons from layer 3 in cat V1 whose morphology, physiology, and synaptic connections with layers 2 and 3 were known. The dominant targets of the 74 identified synapses in layer 5 were the dendritic spines of pyramidal cells. The fractions of target spiny dendrites were 59, 61, and 84% for the three cells, with the remaining targets being dendrites of smooth neurons. These fractions were similar to the distribution of targets of unlabeled asymmetric synapses in the surrounding neuropil. Serial section reconstructions revealed that the target dendrites were heterogenous in morphology, indicating that different cell types are innervated. This new evidence indicates that the descending projection from the superficial layer pyramidal cells does not simply drive the output pyramidal cells that project to cortical and subcortical targets, but participates in the complex circuitry of the deep cortical layers.

Pyramidal cells in the superficial layers of neocortex of higher mammals form a lateral network of axon clusters known as the 'daisy' network. The role of these axon clusters remains speculative and we still lack a comprehensive quantitative description of the single neurons forming the daisy or their heterogeneity. We filled intracellularly 50 superficial layer pyramidal neurons in the cat primary visual cortex and reconstructed the axonal tree and their synaptic boutons in 3D. Individual bouton clusters were identified using an objective mean-shift algorithm. By parameterizing the morphology of these 50 axonal trees and the 217 bouton clusters they formed, we were able to extract one set of relatively constant parameters and another set of variable parameters. Both sets combined allowed us to outline a comprehensive biological blueprint of superficial layer pyramidal neurons. Overall, our detailed analysis supports the hypothesis that pyramidal neurons use their lateral clusters to combine differential contextual cues, required for context-dependent processing of natural scenes.

The present study is the first to describe quantitatively the patterns of synaptic connections made by the patchy network of pyramidal cell axons in the superficial layers of cat V1 in relation to the orientation map. Intrinsic signal imaging of the orientation map was combined with 3D morphological reconstructions of physiologically-characterized neurons at light and electron microscope levels. A Similarity Index (SI) expressed the similarity of the orientation domain of a given bouton cluster to that of its parent dendritic tree. Six pyramidal cells whose axons had a wide range of SIs were examined. Boutons were sampled from five local and five distal clusters, and from the linear segments that link the clusters. The synaptic targets were reconstructed by serial section electron microscopy. Of the 233 synapses examined, 182 synapses were formed with spiny neurons, the remainder with smooth neurons. The proportion of smooth neurons that were synaptic targets varied greatly (from 0 to 50%) between the cluster samples, but was not correlated with the SI. The postsynaptic density sizes were similar for synapses in local and distal clusters, regardless of their SI. This heterogeneity in the synaptic targets of single cells within the superficial layers is a network feature well-suited for context-dependent processing.

The axons of pyramidal neurons in the superficial layers of the neocortex of higher mammals form lateral networks of discrete clusters of synaptic boutons. In primary visual cortex the clusters are reported to link domains that share the same orientation preferences, but how individual neurons contribute to this network is unknown. Here we performed optical imaging to record the intrinsic signal, which is an indirect measure of neuronal firing, and determined the global map of orientation preferences in the cat primary visual system. In the same experiment, single cells were recorded and labelled intracellularly. We found that individual axons arborise within the retinotopic representation of the classical receptive field, but their bouton clusters were not aligned along their preferred axis of orientation along the retinotopic map. Axon clusters formed in a variety of different orientation domains, not just the like-orientation domains. This topography and heterogeneity of single-cell connectivity provides circuits for normalization and context-dependent feature processing of visual scenes.