HLA-DR-positive NK cells, found in both healthy individuals and patients with different inflammatory diseases, are characterized as activated cells. However, data on their capacity for IFNγ production or cytotoxic response vary between studies. Thus, more precise investigation is needed of the mechanisms related to the induction of HLA-DR expression in NK cells, their associations with NK cell differentiation stage, and functional or metabolic state. In this work, HLA-DR-expressing NK cell subsets were investigated using transcriptomic analysis, metabolic activity assays, and analysis of intercellular signaling cascades. We demonstrated that HLA-DR⁺CD56^bright NK cells were characterized by a proliferative phenotype, while HLA-DR⁺CD56^dim NK cells exhibited features of adaptive cells and loss of inhibitory receptors with increased expression of MHC class II trans-activator CIITA. The activated state of HLA-DR-expressing NK cells was confirmed by higher levels of ATP and mitochondrial mass observed in this subset compared to HLA-DR⁻ cells, both ex vivo and after stimulation in culture. We showed that HLA-DR expression in NK cells in vitro can be induced both through stimulation by exogenous IL-2 and IL-21, as well as through auto-stimulation by NK-cell-produced IFNγ. At the intracellular level, HLA-DR expression depended on the activation of STAT3- and ERK1/2-mediated pathways, with subsequent activation of isoform 3 of the transcription factor CIITA. The obtained results broaden the knowledge about HLA-DR-positive NK cell appearance, diversity, and functions, which might be useful in terms of understanding the role of this subset in innate immunity and assessing their possible implications in NK cell-based therapy.

The aim of the study was to evaluate the relationship between tumor blood flow (TBF) measured by the pseudo-continuous arterial spin labeling (PCASL) method and IDH1 mutation status of gliomas as well as Ki-67 proliferative index. Methods. The study included 116 patients with newly diagnosed gliomas of various grades. They received no chemotherapy or radiotherapy before MRI. IDH1 status assessment was performed after tumor removal in 106 cases—48 patients were diagnosed with wildtype gliomas (Grade 1–2—6 patients, Grade 3–4—42 patients) and 58 patients were diagnosed with mutant forms of gliomas (Grade 1–2—28 patients, Grade 3–4—30 patients). In 64 cases out of 116 Ki-67 index was measured. Absolute and normalized tumor blood flow values were measured on 3D PCASL maps. Results. TBF and normalized TBF (nTBF) in wildtype gliomas were significantly higher than in IDH1-mutant gliomas (p < 0.001). ASL perfusion showed high values of sensitivity and specificity in the differential diagnosis of gliomas with distinct IDH1 status (for TBF: specificity 75%, sensitivity 77.6%, AUC 0.783, cutoff 80.57 mL/100 g/min, for nTBF: specificity 77.1%, sensitivity 79.3%, AUC 0.791, cutoff 4.7). TBF and nTBF in wildtype high-grade gliomas (HGG) were significantly higher than in mutant forms (p < 0.001). ASL perfusion showed the following values of sensitivity and specificity in the diagnosis of mutant HGG and wildtype HGG (for TBF: specificity 83.3%, sensitivity 60%, AUC 0.719, cutoff 84.18 mL/100 g/min, for nTBF: specificity 88.1%, sensitivity 60%, AUC 0.729, cutoff 4.7). There was a significant positive correlation between tumor blood flow and Ki-67 (for TBF Rs = 0.63, for nTBF Rs = 0.61). Conclusion. ASL perfusion may be an informative factor in determining the IDH1 status in brain gliomas preoperative and tumor proliferative activity.

The aim of this work is to evaluate the universality of non-contrast MR perfusion (PCASL) in determining the rate of cerebral blood flow (CBF) of brain gliomas using magnetic resonance scanners with different magnetic field strengths. The maximum and normalized CBF values, which received on 1.5 and 3.0 T MRI in the same patients with histologically verified high grade gliomas (III, IV grade), were compared with each other. The data obtained by us are reliably comparable, which allows us to consider pCASL as a universal technique for scanners with different magnetic strengths.

Aim: to present a new method for assessing glucose catabolism in brain tissues of healthy volunteers and neurooncology patients. This method is MR spectroscopy with resonance frequency of deuterium (hydrogen isotope) called deuterium metabolic imaging - DMI. Material and methods. We searched scientific papers in PubMed and Google Scholar indexing systems for 2017–2022 publicatioin years. Keywords used: deuterium spectroscopy, DMI, DMV, PET, non-proton spectroscopy, brain tumor metabolism, Warburg effect in brain tumor, glucose/glucolytic flux/metabolism. Results. 474 articles were analyzed, 21 of which were used for this review. The references list additionaly includes 9 articles for 1924–2014 pyublication years. The review covers the history of proton and multinuclear MR spectroscopy (phosphorus, carbon, deuterium) development of and PET diagnostics. We described DMI applicability in visual and quantitative assessment of tissue metabolism disorders in brain tumors and discussed its future use in clinical practice. Conclusion. Compared to fluorodeoxyglucose (FDG) PET, the DMI method provides additional information on metabolic disorders during anaerobic glycolysis in a tumor. DMI can be implemented and performed on clinical MRI scanners.