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Introduction: CAR T-cell therapy is highly effective, but also associated with unique toxicities. Because of the origin of T cells in patients who previously underwent allogeneic hematopoietic cell transplantation (alloHCT), graft-versus-host disease (GVHD) in the post-CAR T-cell setting poses a relevant concern but is only scarcely studied. Potential risk factors and mitigation strategies (from CAR T-cell modifications to clinical management) are yet to be determined. Methods: Sharing our retrospective experience and a mini-review of the literature, our aim is to better understand the frequency and risk of the potential occurrence of GVHD after CAR T cells, which are most likely underestimated. Results: Here, we present a cohort of 11 patients with symptoms suggestive of GVHD out of 25 allografted patients treated with CAR T cells, of whom 3 patients (12%) had GVHD most likely triggered by the preceding CAR T-cell treatment. Severe chronic pulmonary GVHD occurred in a patient after CD19-directed CAR T-cell therapy. Extracorporeal photopheresis (ECP) mediated successful long-term control of GVHD without causing relapse of the underlying disease. Discussion/Conclusion: In conclusion, CD19-directed CAR T-cell therapy seems to be feasible in patients after alloHCT but might comprise the potential risk of triggering GVHD, most likely depending on the T-cell source, donor compatibility, and the specific CAR construct used. [ABSTRACT FROM AUTHOR]

Simple Summary: Leukostasis in hyperleukocytotic acute myeloid leukemia (AML) is a medical emergency. The optimal treatment strategy and the potential benefits of incorporating emergency leukapheresis (LA) are still unclear. In our retrospective study, we observed a striking difference in the outcome of FLT3-ITD mutated (mut) AML patients undergoing LA in the early phase of treatment compared to patients with FLT3 wildtype (wt). Knowledge of mutational status might guide treatment decisions in the early phase of hyperleukocytosis. Purpose: We aimed to identify subsets of patients who benefit from emergency LA and to establish a therapeutic algorithm for AML patients with hyperleukocytosis. Methods: In this single-center retrospective cohort study, a total of 20 consecutive patients underwent LA because of their clinical symptoms. Overall survival (OS) analysis was conducted using the Kaplan–Meier plot method. Univariate and multivariate analyses (using multiple logistic regression) were performed. At the time of diagnosis, all patients received a standard diagnostic workup for AML including FLT3-ITD mutational analysis. Results: FLT3-ITD mut AML patients receiving LA had a median OS of 437 days (range 5–2379 days) with a corresponding 14-day survival of 92.3%, while FLT3 wt AML patients displayed a significantly lower median OS of only 5 days (range 1–203 days) with a corresponding 14-day survival of 14.3% (p = 0.0001). Conclusions: Among patients with clinical symptoms of leukostasis, the subset of FLT3-ITD mut AML patients showed a better outcome with lower early mortality after emergency LA. Based on these observations, we established a therapeutic algorithm for AML patients with hyperleukocytosis. [ABSTRACT FROM AUTHOR]

Assessing the amount and subcellular distribution of protein expression is a key component in modern cell biological and medical research. We studied protein kinase Cδ (PKCδ) as a potential regulator of mitochondrial metabolism in astrocytes, and sought to evaluate mitochondrial translocation of PKCδ since this is an important determinant of its function. Apart from visualizing compartment specific localization of mobile proteins such as PKCδ, we also wanted to determine what amount of a cell's total content of a particular protein is located to a specific compartment, or translocated comparing control and experimental condition.We develop a semiquantitative parameter that indicates the relative protein distribution to two subcellular compartments, starting from standard two-channel fluorescence microscopy images. We studied the mitochondrial translocation of PKCδ in astrocytes using double immunofluorescence microscopy and object-oriented image analysis. In one channel, the protein of interest (PKCδ) is labeled, in the other the compartment or organelle of interest (mitochondria, using cytochrome oxidase IV). Both channels were binarized, turned into object populations, and the channel specific values for total area and integrated intensity extracted. From these values, the "intensity density ratio" (IDR) is calculated, a standardized parameter to easily compare distribution patterns in different cells or ROIs. IDR is highly sensitive to changes in localization pattern, and thus easily detects protein translocation in comparison between control and experimental condition. In our study, medium application of glutamate was found to result in partial PKCδ translocation to mitochondria, a statistically highly significant result based only on a limited number of acquired images.