Coordinated Loss and Acquisition of NK Cell Surface Markers Accompanied by Generalized Cytokine Dysregulation in COVID-19.

Coronavirus disease 2019 (COVID-19), caused by the SARS-CoV-2 virus, is accompanied by a dysregulated immune response. In particular, NK cells, involved in the antiviral response, are affected by the infection. This study aimed to investigate circulating NK cells with a focus on their activation, depletion, changes in the surface expression of key receptors, and functional activity during COVID-19, among intensive care unit (ICU) patients, moderately ill patients, and convalescents (CCP). Our data confirmed that NK cell activation in patients with COVID-19 is accompanied by changes in circulating cytokines. The progression of COVID-19 was associated with a coordinated decrease in the proportion of NKG2D+ and CD16+ NK cells, and an increase in PD-1, which indicated their exhaustion. A higher content of NKG2D+ NK cells distinguished surviving patients from non-survivors in the ICU group. NK cell exhaustion in ICU patients was additionally confirmed by a strong negative correlation of PD-1 and natural cytotoxicity levels. In moderately ill patients and convalescents, correlations were found between the levels of CD57, NKG2C, and NKp30, which may indicate the formation of adaptive NK cells. A reduced NKp30 level was observed in patients with a lethal outcome. Altogether, the phenotypic changes in circulating NK cells of COVID-19 patients suggest that the intense activation of NK cells during SARS-CoV-2 infection, most likely induced by cytokines, is accompanied by NK cell exhaustion, the extent of which may be critical for the disease outcome.

Alterations in the CD56- and CD56+ T Cell Subsets during COVID-19.

The effectiveness of the antiviral immune response largely depends on the activation of cytotoxic T cells. The heterogeneous group of functionally active T cells expressing the CD56 molecule (NKT-like cells), that combines the properties of T lymphocytes and NK cells, is poorly studied in COVID-19. This work aimed to analyze the activation and differentiation of both circulating NKT-like cells and CD56- T cells during COVID-19 among intensive care unit (ICU) patients, moderate severity (MS) patients, and convalescents. A decreased proportion of CD56+ T cells was found in ICU patients with fatal outcome. Severe COVID-19 was accompanied by a decrease in the proportion of CD8+ T cells, mainly due to the CD56- cell death, and a redistribution of the NKT-like cell subset composition with a predominance of more differentiated cytotoxic CD8+ T cells. The differentiation process was accompanied by an increase in the proportions of KIR2DL2/3+ and NKp30+ cells in the CD56+ T cell subset of COVID-19 patients and convalescents. Decreased percentages of NKG2D+ and NKG2A+ cells and increased PD-1 and HLA-DR expression levels were found in both CD56- and CD56+ T cells, and can be considered as indicators of COVID-19 progression. In the CD56- T cell fraction, increased CD16 levels were observed in MS patients and in ICU patients with lethal outcome, suggesting a negative role for CD56-CD16+ T cells in COVID-19. Overall, our findings suggest an antiviral role of CD56+ T cells in COVID-19.

Transcranial direct current stimulation improves clinical symptoms in adolescents with attention deficit hyperactivity disorder.

Anodal transcranial direct current stimulation (tDCS) of the prefrontal cortex has repeatedly been shown to improve working memory. As patients with attention deficit hyperactivity disorder (ADHD) are characterized by both underactivation of the prefrontal cortex and deficits in working memory that correlate with clinical symptoms, it is hypothesized that the modulation of prefrontal activity with tDCS in patients with ADHD increases performance in working memory and reduces symptoms of ADHD. To test this hypothesis, fifteen adolescents with ADHD (12-16 years old, three girls and 12 boys) were treated according to the randomized, double-blinded, sham-controlled, crossover design with either 1 mA anodal tDCS over the left dorsolateral prefrontal cortex or with the sham protocol 5 days each with a 2 weeks pause between these conditions. Anodal tDCS caused a significant reduction in clinical symptoms of inattention and impulsivity in adolescents with ADHD compared to sham stimulation. The clinical effects were supported by a significant reduction in inattention and hyperactivity in a standardized working memory test (QbTest). The described effects were more pronounced 7 days after the end of stimulation, a fact which emphasizes the long-lasting clinical and neuropsychological changes after tDCS. This study provides the first evidence that tDCS may reduce symptoms of ADHD and improve neuropsychological functioning in adolescents and points on the potential of tDCS as a form of treatment for ADHD.

Transcranial Direct Current Stimulation Modulates Neuronal Networks in Attention Deficit Hyperactivity Disorder.

Anodal transcranial direct current stimulation (tDCS) of the prefrontal cortex has been repeatedly shown to improve working memory (WM). Since patients with attention deficit hyperactivity disorder (ADHD) are characterized by both underactivation of the prefrontal cortex and deficits in WM, the modulation of prefrontal activity with tDCS in ADHD patients may increase their WM performance as well as improve the activation and connectivity of the WM network. In the present study, this hypothesis was tested using a double-blind sham-controlled experimental design. After randomization, sixteen adolescents with ADHD underwent either anodal tDCS over the left dorsolateral prefrontal cortex (DLPFC, 1 mA, 20 min) or sham stimulation with simultaneous fMRI during n-back WM task. Both in one-back and two-back conditions, tDCS led to a greater activation (compared with sham stimulation) of the left DLPFC (under the electrode), left premotor cortex, left supplementary motor cortex, and precuneus. The effects of tDCS were long-lasting and influenced resting state functional connectivity even 20 min after the stimulation, with patterns of strengthened DLPFC connectivity after tDCS outlining the WM network. In summary, anodal tDCS caused increased neuronal activation and connectivity, not only in the brain area under the stimulating electrode (i.e. left DLPFC) but also in other, more remote brain regions. Because of moderate behavioral effects of tDCS, the significance of this technique for ADHD treatment has to be investigated in further studies.

Behavioural treatment increases activity in the cognitive neuronal networks in children with attention deficit/hyperactivity disorder.

Response cost and token approach (RCT) within the scope of a summer camp training is an effective treatment program for attention deficit hyperactivity disorder (ADHD). It is likely that intensive RCT training influences networks responsible for ADHD symptoms. Functional magnetic resonance imaging (fMRI) was carried out in 12 children with ADHD before and after the RCT program and in 12 healthy control children twice. For fMRI, a Go/No-go paradigm was used to investigate the influence of RCT training on attention and impulsivity. The No-go condition revealed only weak activation in the dorsal part of the anterior cingulate cortex (ACC), parietal and dorsolateral prefrontal cortex (DLPFC) before the training in children with ADHD compared to healthy children. However, this activation in these brain regions was significantly more pronounced after the training. This increase in hemodynamic response cannot be attributed merely to repetition of the measurement since the effect was not observed in healthy children. The increase in hemodynamic response in the ACC and right DLPFC was significantly associated with a reduction in response time variability and clinical symptoms in ADHD patients. After the RCT training, the children with ADHD demonstrated more pronounced activation of cortical structures which are typically related to response monitoring and self-control. It seems likely that children with ADHD learned more cognitive control in a continuous performance task as was revealed by both neuropsychological outcome and fMRI.

A refined characterisation of the NeoHepatocyte phenotype necessitates a reappraisal of the transdifferentiation hypothesis.

Under certain culture conditions human peripheral blood monocytes may be induced to express phenotypic markers of non-haematopoietic lineages, including hepatocyte-defining traits. One such example, the NeoHepatocyte, was previously shown to express a broad panel of hepatocyte-like marker antigens and metabolic activities, both in vitro and following engraftment in the liver of immunodeficient mice. In this report, a refined description of NeoHepatocytes, with regard to their expression of xenobiotic-metabolising enzymes, morphology, hepatocyte marker expression and cell surface phenotype, is presented in comparison with human macrophages in defined states of activation. Contrary to prior assertions, it would seem more likely that NeoHepatocytes express particular hepatocyte-defining genes during a normal programme of macrophage differentiation rather than undergoing a process of transdifferentiation to become hepatocyte-like cells.

First-in-human high-cumulative-dose stem cell therapy in idiopathic pulmonary fibrosis with rapid lung function decline.

Previous phase I studies demonstrated safety and some beneficial effects of mesenchymal stem cells (MSCs) in patients with mild to moderate idiopathic pulmonary fibrosis (IPF). The aim of our study was to evaluate the safety, tolerability, and efficacy of a high cumulative dose of bone marrow MSCs in patients with rapid progressive course of severe to moderate IPF. Twenty patients with forced ventilation capacity (FVC) ≥40% and diffusing capacity of the lung for carbon monoxide (DLCO) ≥20% with a decline of both >10% over the previous 12 months were randomized into two groups: one group received two intravenous doses of allogeneic MSCs (2 × 108 cells) every 3 months, and the second group received a placebo. A total amount of 1.6 × 109 MSCs had been administered to each patient after the study completion. There were no significant adverse effects after administration of MSCs in any patients. In the group of MSC therapy, we observed significantly better improvement for the 6-minute walk distance in 13 weeks, for DLCO in 26 weeks, and for FVC in 39 weeks compared with placebo. FVC for 12 months in the MSCs therapy group increased by 7.8% from baseline, whereas it declined by 5.9% in the placebo group. We did not find differences between the groups in mortality (two patients died in each group) or any changes in the high-resolution computed tomography fibrosis score. In patients with IPF and a rapid pulmonary function decline, therapy with high doses of allogeneic MSCs is a safe and promising method to reduce disease progression.

Chromosomal breakpoints affecting immunoglobulin loci are recurrent in Hodgkin and Reed-Sternberg cells of classical Hodgkin lymphoma.

Chromosomal breakpoints affecting immunoglobulin (IG) loci are recurrent in many subtypes of B-cell lymphomas. However, despite the predominant B-cell origin of the Hodgkin and Reed-Sternberg (HRS) cells in classical Hodgkin lymphoma (cHL), the presence of chromosomal translocations in IG loci has not yet been systematically explored. Therefore, we have investigated a series of cHL for chromosomal breakpoints in the IGH (n = 230), IGL (n = 139), and IGK (n = 138) loci by interphase cytogenetics. Breakpoints in the IGH, IGL, or IGK locus were observed in the HRS cells of 26 of 149 (17%), 2 of 70, and 1 of 77 evaluable cHLs, respectively. The IG partners could be identified in eight cHLs and involved chromosomal bands 2p16 (REL), 3q27 (BCL6, two cases), 8q24.1 (MYC), 14q24.3, 16p13.1, 17q12, and 19q13.2 (BCL3/RELB). In 65 of 85 (76%) cHLs evaluable for an IGH triple-color probe, the HRS cells showed evidence for a (partial) deletion of the IGH constant region, suggesting the presence of class switch recombination (CSR). Furthermore, analyses with this probe in cases with IGH breakpoints indicated that at least part of them seem to be derived from CSR defects. Our results show that chromosomal breakpoints affecting the IG loci are recurrent in cHL.

A cell-based approach to the minimization of immunosuppression in renal transplantation.

Five renal transplant recipients were preoperatively treated with transplant acceptance-inducing cells (TAICs) in a Phase-I safety study of TAICs as an adjunct immune-conditioning therapy in living-donor kidney transplantation. Initially, patients received anti-thymocyte globulin induction therapy in combination with tacrolimus and steroid immunosuppression. Over the course of 12 weeks, steroids were withdrawn and tacrolimus therapy was minimized. Three of the five patients were able to tolerate low-dose tacrolimus monotherapy and one patient was withdrawn from all immunosuppression for over 8 months. No acute or delayed adverse events were associated with the infusion of TAICs. Monitoring of the recipient anti-donor reactivity of TAIC-treated patients in mixed lymphocyte cultures demonstrated that, during periods of clinically stable graft function, recipient T-cell proliferation and cytokine secretion in response to stimulation with donor alloantigen was relatively suppressed. Therefore, although the TAIC-II trial did not provide conclusive evidence of a beneficial effect of preoperative TAIC treatment, the results were encouraging because they suggest that TAICs promote a state of alloantigen-specific unresponsiveness, which might allow safe minimization of pharmacological immunosuppression.

Loss of expression of LyGDI (ARHGDIB), a rho GDP-dissociation inhibitor, in Hodgkin lymphoma.

The guanosine triphosphatase (GTPase) inhibitor LyGDI (ARHGDIB, Ly/D4-GDI, RhoGDIb or RhoGDI 2) is abundantly expressed in haematopoetic cells and possibly plays a role in the onset of apoptosis. Gene expression profiling of Hodgkin cell lines revealed that LyGDI expression was downregulated in these cell lines. The present study evaluated the expression of LyGDI in Hodgkin cells in vivo and studied the function of LyGDI in Hodgkin cell lines in vitro. Our results showed that virtually all Hodgkin and Reed-Sternberg cells in classical Hodgkin lymphoma lacked LyGDI protein expression. On the other hand, almost all non-Hodgkin lymphomas, except for anaplastic large cell lymphomas, expressed LyGDI protein. Transfection of the classical Hodgkin cell line L428 with a vector containing full-length LyGDI-induced apoptosis in a subset of cells. However, the majority of Hodgkin cells with transgenic expression of LyGDI escaped apoptosis. Our data show that lack of LyGDI expression is a frequent feature of cHL but that it is not of vital importance for the growth and survival of these cells.