Hepatitis E virus genotype 3 is a common finding in liver-transplanted patients undergoing liver biopsy for elevated liver enzymes with a low De Ritis ratio and suspected acute rejection: A real-world cohort.

BACKGROUND: Hepatitis E virus (HEV) infection is a potential reason for elevated liver enzymes after liver transplantation (LT). Our aim was to analyze a real-world cohort of LT patients, who underwent liver biopsy for elevated transaminases and suspected acute rejection, to evaluate frequency of post-transplant HEV infection. PATIENTS: Data from 160 liver biopsies were analyzed. Seventy-one patients were biopsied on schedule after LT without elevated liver enzymes. A subgroup of 25 patients with elevated liver enzymes and suspected rejection was chosen for further analysis. Patient demographics and data were retrieved from a clinical database, patients' charts, and reports. RESULTS: Hepatitis E virus infection was diagnosed in five of 25 patients with suspected acute rejection (20%). HEV genotype 3 was detected in three of the five HEV-infected patients. Patients with HEV infection showed higher ALT levels (P = 0.014), lower De Ritis ratio (P = 0.021), and more frequent glucocorticoid therapy (P = 0.012) compared to HEV-negative patients. CONCLUSION: We found a rate of 20% HEV infections in LT patients undergoing liver biopsy for elevated liver enzymes and suspected acute rejection. These data indicate the necessity for HEV testing in all LT patients with elevated liver enzymes and suspected acute rejection.

Therapeutic platelet transfusion versus routine prophylactic transfusion in patients with haematological malignancies: an open-label, multicentre, randomised study.

BACKGROUND: Routine prophylactic platelet transfusion is the standard of care for patients with severe thrombocytopenia. We assessed the effect of a new strategy of therapeutic platelet transfusion on the number of transfusions and safety in patients with hypoproliferative thrombocytopenia. METHODS: We did a multicentre, open-label, randomised parallel-group trial at eight haematology centres in Germany. Patients aged 16-80 years, who were undergoing intensive chemotherapy for acute myeloid leukaemia or autologous haemopoietic stem-cell transplantation for haematological cancers, were randomly assigned via a computer-generated randomisation sequence to receive either platelet transfusion when bleeding occurred (therapeutic strategy) or when morning platelet counts were 10×10(9) per L or lower (prophylactic strategy). Investigators undertaking interventions were not masked to group assignment. The primary endpoint was the number of platelet transfusions. Analysis was by intention to treat. This trial is registered, NCT00521664. FINDINGS: 197 patients were assigned the prophylactic strategy and 199 the therapeutic strategy. Of 391 patients analysed, the therapeutic strategy reduced the mean number of platelet transfusions by 33·5% (95% CI 22·2-43·1; p<0·0001) in all patients (2·44 [2·22-2·67] in prophylactic group vs 1·63 [1·42-1·83] in therapeutic group), 31·6% (18·6-42·6; p<0·0001) in those with acute myeloid leukaemia (2·68 [2·35-3·01] vs 1·83 [1·58-2·10]), and 34·2% (6·6-53·7; p=0·0193) in those who had had autologous transplantation (1·80 [1·45-2·15] vs 1·18 [0·82-1·55]. We noted no increased risk of major haemorrhage in patients who had undergone autologous transplantation. In those with acute myeloid leukaemia, risk of non-fatal grade 4 (mostly CNS) bleeding was increased. We recorded 15 cases of non-fatal haemorrhage: four retinal in each transfusion group, and one vaginal and six cerebral in the therapeutic group. 12 patients died in the study: two from fatal cerebral haemorrhages in the therapeutic group, and ten (five in each treatment group) unrelated to major bleeding. INTERPRETATION: The therapeutic strategy could become a new standard of care after autologous stem-cell transplantation; however, prophylactic platelet transfusion should remain the standard for patients with acute myeloid leukaemia. The new strategy should be used by some haematology centres only if the staff are well educated and experienced in the new approach and can react in a timely way to first signs of CNS bleeding. FUNDING: Deutsche Krebshilfe eV (German Cancer Aid).

Arginine deficiency leads to impaired cofilin dephosphorylation in activated human T lymphocytes.

The amino acid arginine is fundamentally involved in the regulation of the immune response during infection, inflammatory diseases and tumor growth. Arginine deficiency (e.g. due to the myeloid cell enzyme arginase) inhibits proliferation and effector functions of activated T lymphocytes. Here, we studied intracellular mechanisms mediating this suppression of human T lymphocytes. Our proteomic analysis revealed an impaired dephosphorylation of the actin-binding protein cofilin upon T-cell activation in the absence of arginine. We show that this correlates with alteration of actin polymerization and impaired accumulation of CD2 and CD3 in the evolving immunological synapse in T cell-antigen presenting cells conjugates. In contrast, T-cell cytokine synthesis is differentially regulated in human T lymphocytes in the absence of arginine. While the production of certain cytokines (e.g. IFN-γ) is severely reduced, T lymphocytes produce other cytokines (e.g. IL-2) independent of extracellular arginine. MEK and PI3K activity are reciprocally regulated in association with impaired cofilin dephosphorylation. Finally, we show that impaired cofilin dephosphorylation is also detectable in human T cells activated in a granulocyte-dominated purulent micromilieu due to arginase-mediated arginine depletion. Our novel results identify cofilin as a potential regulator of human T-cell activation under conditions of inflammatory arginine deficiency.

Ischemic-type biliary lesions after liver transplantation: a retrospective analysis of risk factors and outcome.

BACKGROUND: Ischemic-type biliary lesions (ITBL) are the most troublesome complications after liver transplantation. Their cause remains unknown and, although some risk factors have been identified, results from different research groups are often conflicting. The goal of this study was to investigate potential risk factors for ITBL. METHODS: 565 transplantations performed between September 1997 and August 2010 were identified and divided into two cohorts: 77 in which the patient developed ITBL and 488 in which no ITBL occurred. The following factors were analyzed: donor age, patient Child-Pugh score, cold ischemia time, total ischemia time, type of perfusion solution, shipped versus non-shipped organ, ABO-compatibility versus identity between donor and recipient, Rhesus-difference versus identity between donor and recipient, presence versus absence of HLA antibodies in the patient at the time of registration on the transplant waiting list, presence in the donor of at least one HLA-C group 1 allele versus at least one HLA-C group 2 allele. HLA-C is the major inhibitory ligand for killer immunoglobulin-like receptors (KIR) that regulate the cytotoxic activity of natural killer cells. HLA-C alleles can be allocated into two groups, HLA-C1 and HLA-C2, based on their KIR specificity. RESULTS: In a multivariate logistic regression analysis the donor age and patient Child-Pugh score C were found to be independent risk factors for ITBL (p < 0.001 and 0.007, respectively). However, the multivariate Cox regression analysis indicated that neither has an impact on graft survival. CONCLUSIONS: Donor age and patient Child-Pugh score predispose to ITBL, whereas other factors must intervene for their development.

Human Platelet Lysate as Valid Cell Growth Additive to Assess Protein Acetylation.

Experiments with cell cultures are an alternative to animal experiments. One problem, however, is the ethically questionable use of fetal calf serum (FCS, which some authors refer to as fetal bovine serum, FBS). Furthermore, FCS is an undefined variable mixture and a possible source of contaminations. We reported that lysine acetylation was very similar in cells in growth media containing FCS or human platelet lysate (hPL). Here, we explain in detail how to generate and use hPL as a cost-effective substitute for FCS in experiments with mammalian cell cultures. A large panel of cells and conditions can be cultured and tested in media with hPL.

An update on red blood cell transfusion in non-cardiac thoracic surgery.

Background: The aim of this study was to evaluate risk factors for red blood cell (RBC) transfusion in non-cardiac thoracic surgery. Methods: All patients undergoing non-cardiac thoracic surgery in a single tertiary referral center between January and December 2021 were eligible for this study. Data on blood requests and perioperative RBC transfusion were retrospectively analyzed. Results: A total of 379 patients were included, of whom 275 (72.6%) underwent elective surgery. The overall RBC transfusion rate was 7.4% (elective cases: 2.5%, non-elective cases: 20.2%). Patients with lung resections required transfusion in 2.4% of the cases versus 44.7% in patients undergoing surgery for empyema. In multivariable analysis, empyema (P=0.001), open surgery (P<0.001), low preoperative hemoglobin (P=0.001), and old age (P=0.013) were independent risk factors for RBC transfusion. The best predictor of blood transfusion was preoperative hemoglobin with a cut-off value <10.4 g/dL (sensitivity 82.1%, specificity 86.3%, area under the curve 0.882). Conclusions: The rate of RBC transfusion in current non-cardiac thoracic surgery is low, especially in elective lung resections. In urgent cases and open surgery, transfusion rates remain high, particularly in empyema cases. Preoperative requesting of RBC units should be tailored to patient-specific risk factors.

Impact of perioperative red blood cell transfusion, anemia of cancer and global health status on the prognosis of elderly patients with endometrial and ovarian cancer.

Introduction: Perioperative red blood cell (RBC) transfusions have been associated with increased morbidity and worse oncological outcome in some solid neoplasms. In order to elucidate whether RBC transfusions themselves, the preoperative anemia of cancer (AOC), or the impaired global health status might explain this impact on patients with endometrial cancer (EC) or ovarian cancer (OC), we performed a retrospective, single-institution cohort study. Materials and methods: Women older than 60 years with EC or OC were included. The influence of RBC transfusions, AOC, and frailty status determined by the G8 geriatric screening tool (G8 score), as well as the clinical-pathological cancer characteristics on progression-free survival (PFS) and overall survival (OS), was determined by using the Kaplan-Meier method and the Cox regression analyses. Results: In total, 263 patients with EC (n = 152) and OC (n = 111) were included in the study. Patients with EC receiving RBC transfusions were faced with a significantly shorter 5-year PFS (79.8% vs. 26.0%; p < 0.001) and 5-year OS (82.6% vs. 25.7%; p < 0.001). In multivariable analyses, besides established clinical-pathological cancer characteristics, the RBC transfusions remained the only significant prognostic parameter for PFS (HR: 1.76; 95%-CI [1.01-3.07]) and OS (HR: 2.38; 95%-CI [1.50-3.78]). In OC, the G8 score stratified the cohort in terms of PFS rates (G8-non-frail 53.4% vs. G8-frail 16.7%; p = 0.010) and AOC stratified the cohort for 5-year OS estimates (non-anemic: 36.7% vs. anemic: 10.6%; p = 0.008). Multivariable Cox regression analyses determined the G8 score and FIGO stage as independent prognostic factors in terms of PFS (HR: 2.23; 95%-CI [1.16-4.32] and HR: 6.52; 95%-CI [1.51-28.07], respectively). For OS, only the TNM tumor stage retained independent significance (HR: 3.75; 95%-CI [1.87-7.53]). Discussion: The results of this trial demonstrate the negative impact of RBC transfusions on the prognosis of patients with EC. Contrastingly, the prognosis of OC is altered by the preoperative global health status rather than AOC or RBC transfusions. In summary, we suggested a cumulatively restrictive transfusion management in G8-non-frail EC patients and postulated a more moderate transfusion management based on the treatment of symptomatic anemia without survival deficits in OC patients.

A bicistronic vector backbone for rapid seamless cloning and chimerization of αßT-cell receptor sequences.

To facilitate preclinical testing of T-cell receptors (TCRs) derived from tumor-reactive T-cell clones it is necessary to develop convenient and rapid cloning strategies for the generation of TCR expression constructs. Herein, we describe a pDONR™221 vector backbone allowing to generate Gateway™ compatible entry clones encoding optimized bicistronic αßTCR constructs. It harbors P2A-linked TCR constant regions and head-to-head-oriented recognition sites of the Type IIS restriction enzymes BsmBI and BsaI for seamless cloning of the TCRα and TCRß V(D)J regions, respectively. Additional well-established TCR optimizations were incorporated to enhance TCR functionality. This included replacing of the human αßTCR constant regions with their codon-optimized murine counterparts for chimerization, addition of a second interchain disulfide bond and arrangement of the TCR chains in the order ß-P2A-α. We exemplified the utility of our vector backbone by cloning and functional testing of three melanoma-reactive TCRs in primary human T cells.

Inhibition of Arginase 1 Liberates Potent T Cell Immunostimulatory Activity of Human Neutrophil Granulocytes.

Myeloid cell arginase-mediated arginine depletion with consecutive inhibition of T cell functions is a key component of tumor immune escape. Both, granulocytic myeloid-derived suppressor cells (G-MDSC) and conventional mature human polymorphonuclear neutrophil granulocytes (PMN) express high levels of arginase 1 and can act as suppressor cells of adaptive anti-cancer immunity. Here we demonstrate that pharmacological inhibition of PMN-derived arginase 1 not only prevents the suppression of T cell functions but rather leads to a strong hyperactivation of T cells. Human PMN were incubated in cell culture medium in the absence or presence of an arginase inhibitor. T cells from healthy donors were then activated either polyclonally or in an antigen-specific manner in the supernatants of the PMN cultures at different PMN-T cell ratios. T cell proliferation was completely suppressed in these supernatants in the absence of an arginase inhibitor. Arginase inhibition led to a strong hyperinduction of T cell proliferation, which exceeded control activation conditions up to 25-fold. The hyperinduction was correlated with higher PMN-T cell ratios and was only apparent when PMN arginase activity was blocked sufficiently. The T cell stimulatory factor was liberated very early by PMN and was present in the < 3 kDa fraction of the PMN supernatants. Increased T cell production of specific proinflammatory cytokines by PMN supernatant in the presence of arginase inhibitor was apparent. Upon arginase inhibition, downregulation of important T cell membrane activation and costimulation proteins was completely prevented or de novo induction accelerated. Antigen-specific T cell cytotoxicity against tumor cells was enhanced by PMN supernatant itself and could be further increased by PMN arginase blockade. Finally, we analyzed anergic T cells from multiple myeloma patients and noticed a complete reversal of anergy and the induction of strong proliferation upon T cell activation in PMN supernatants by arginase inhibition. In summary, we discovered a potent PMN-mediated hyperactivation of human T cells, which is apparent only when PMN arginase-mediated arginine depletion is concurrently inhibited. Our findings are clearly relevant for the analysis and prevention of human tumor immune escape in conjunction with the application of arginase inhibitors already being developed clinically.

Human platelet lysate as validated replacement for animal serum to assess chemosensitivity.

Experiments with cultured mammalian cells represent an in vitro alternative to animal experiments. Fetal calf serum (FCS) is the most commonly used media supplement worldwide. FCS contains a mixture of largely undefined growth factors and cytokines, which support cell proliferation. This undefined nature of FCS is a source of experimental variation, undesired immune responses, possible contaminations, and because of its way of production an ethical concern. Thus, alternative, defined, valid, and reliable media supplements should be characterized in a large number of experiments. Human platelet lysate (hPL) is increasingly appreciated as an alternative to FCS. Since it is unclear whether cells respond differentially to clinically relevant chemotherapeutics inducing replicative stress and DNA damage (Hydroxyurea, Irinotecan), induction of reactive oxygen species (ROS), the tyrosine kinase inhibitor (TKi) Imatinib, and novel epigenetic modifiers belonging to the group of histone deacetylase inhibitors (HDACi), we investigated these issues. Here we show that cancer cells derived from leukemia and colon cancer grow very similarly in culture media with FCS or outdated hPL. Notably, cells have practically identical proteomes under both culture conditions. Moreover, cells grown with FCS or hPL respond equally to all types of drugs and stress conditions that we have tested. In addition, the transfection of blood cells by electroporation can be achieved under both conditions. Furthermore, we reveal that class I HDACs, but not HDAC6, are required for the expression of the pan-leukemic marker WT1 under various culture conditions. Hence, hPL is a moderately priced substitute for FCS in various experimental settings.

Reconstitution of T Cell Proliferation under Arginine Limitation: Activated Human T Cells Take Up Citrulline via L-Type Amino Acid Transporter 1 and Use It to Regenerate Arginine after Induction of Argininosuccinate Synthase Expression.

In the tumor microenvironment, arginine is metabolized by arginase-expressing myeloid cells. This arginine depletion profoundly inhibits T cell functions and is crucially involved in tumor-induced immunosuppression. Reconstitution of adaptive immune functions in the context of arginase-mediated tumor immune escape is a promising therapeutic strategy to boost the immunological antitumor response. Arginine can be recycled in certain mammalian tissues from citrulline via argininosuccinate (ASA) in a two-step enzymatic process involving the enzymes argininosuccinate synthase (ASS) and argininosuccinate lyase (ASL). Here, we demonstrate that anti-CD3/anti-CD28-activated human primary CD4+ and CD8+ T cells upregulate ASS expression in response to low extracellular arginine concentrations, while ASL is expressed constitutively. ASS expression peaked under moderate arginine restriction (20 µM), but no relevant induction was detectable in the complete absence of extracellular arginine. The upregulated ASS correlated with a reconstitution of T cell proliferation upon supplementation of citrulline, while the suppressed production of IFN-γ was refractory to citrulline substitution. In contrast, ASA reconstituted proliferation and cytokine synthesis even in the complete absence of arginine. By direct quantification of intracellular metabolites we show that activated primary human T cells import citrulline but only metabolize it further to ASA and arginine when ASS is expressed in the context of low amounts of extracellular arginine. We then clarify that citrulline transport is largely mediated by the L-type amino acid transporter 1 (LAT1), induced upon human T cell activation. Upon siRNA-mediated knockdown of LAT1, activated T cells lost the ability to import citrulline. These data underline the potential of citrulline substitution as a promising pharmacological way to treat immunosuppression in settings of arginine deprivation.

Cytotoxicity of tumor antigen specific human T cells is unimpaired by arginine depletion.

Tumor-growth is often associated with the expansion of myeloid derived suppressor cells that lead to local or systemic arginine depletion via the enzyme arginase. It is generally assumed that this arginine deficiency induces a global shut-down of T cell activation with ensuing tumor immune escape. While the impact of arginine depletion on polyclonal T cell proliferation and cytokine secretion is well documented, its influence on chemotaxis, cytotoxicity and antigen specific activation of human T cells has not been demonstrated so far. We show here that chemotaxis and early calcium signaling of human T cells are unimpaired in the absence of arginine. We then analyzed CD8(+) T cell activation in a tumor peptide as well as a viral peptide antigen specific system: (i) CD8(+) T cells with specificity against the MART-1aa26-35*A27L tumor antigen expanded with in vitro generated dendritic cells, and (ii) clonal CMV pp65aa495-503 specific T cells and T cells retrovirally transduced with a CMV pp65aa495-503 specific T cell receptor were analyzed. Our data demonstrate that human CD8(+) T cell antigen specific cytotoxicity and perforin secretion are completely preserved in the absence of arginine, while antigen specific proliferation as well as IFN-γ and granzyme B secretion are severely compromised. These novel results highlight the complexity of antigen specific T cell activation and demonstrate that human T cells can preserve important activation-induced effector functions in the context of arginine deficiency.