Regulatory T Cells Restrain Interleukin-2- and Blimp-1-Dependent Acquisition of Cytotoxic Function by CD4+ T Cells.

In addition to helper and regulatory potential, CD4+ T cells also acquire cytotoxic activity marked by granzyme B (GzmB) expression and the ability to promote rejection of established tumors. Here, we examined the molecular and cellular mechanisms underpinning the differentiation of cytotoxic CD4+ T cells following immunotherapy. CD4+ transfer into lymphodepleted animals or regulatory T (Treg) cell depletion promoted GzmB expression by tumor-infiltrating CD4+, and this was prevented by interleukin-2 (IL-2) neutralization. Transcriptional analysis revealed a polyfunctional helper and cytotoxic phenotype characterized by the expression of the transcription factors T-bet and Blimp-1. While T-bet ablation restricted interferon-γ (IFN-γ) production, loss of Blimp-1 prevented GzmB expression in response to IL-2, suggesting two independent programs required for polyfunctionality of tumor-reactive CD4+ T cells. Our findings underscore the role of Treg cells, IL-2, and Blimp-1 in controlling the differentiation of cytotoxic CD4+ T cells and offer a pathway to enhancement of anti-tumor activity through their manipulation.

Fc-Optimized Anti-CD25 Depletes Tumor-Infiltrating Regulatory T Cells and Synergizes with PD-1 Blockade to Eradicate Established Tumors.

CD25 is expressed at high levels on regulatory T (Treg) cells and was initially proposed as a target for cancer immunotherapy. However, anti-CD25 antibodies have displayed limited activity against established tumors. We demonstrated that CD25 expression is largely restricted to tumor-infiltrating Treg cells in mice and humans. While existing anti-CD25 antibodies were observed to deplete Treg cells in the periphery, upregulation of the inhibitory Fc gamma receptor (FcγR) IIb at the tumor site prevented intra-tumoral Treg cell depletion, which may underlie the lack of anti-tumor activity previously observed in pre-clinical models. Use of an anti-CD25 antibody with enhanced binding to activating FcγRs led to effective depletion of tumor-infiltrating Treg cells, increased effector to Treg cell ratios, and improved control of established tumors. Combination with anti-programmed cell death protein-1 antibodies promoted complete tumor rejection, demonstrating the relevance of CD25 as a therapeutic target and promising substrate for future combination approaches in immune-oncology.

TGF-ß signalling is required for CD4⁺ T cell homeostasis but dispensable for regulatory T cell function.

TGF-ß is widely held to be critical for the maintenance and function of regulatory T (T(reg)) cells and thus peripheral tolerance. This is highlighted by constitutive ablation of TGF-ß receptor (TR) during thymic development in mice, which leads to a lethal autoimmune syndrome. Here we describe that TGF-ß-driven peripheral tolerance is not regulated by TGF-ß signalling on mature CD4⁺ T cells. Inducible TR2 ablation specifically on CD4⁺ T cells did not result in a lethal autoinflammation. Transfer of these TR2-deficient CD4⁺ T cells to lymphopenic recipients resulted in colitis, but not overt autoimmunity. In contrast, thymic ablation of TR2 in combination with lymphopenia led to lethal multi-organ inflammation. Interestingly, deletion of TR2 on mature CD4⁺ T cells does not result in the collapse of the T(reg) cell population as observed in constitutive models. Instead, a pronounced enlargement of both regulatory and effector memory T cell pools was observed. This expansion is cell-intrinsic and seems to be caused by increased T cell receptor sensitivity independently of common gamma chain-dependent cytokine signals. The expression of Foxp3 and other regulatory T cells markers was not dependent on TGF-ß signalling and the TR2-deficient T(reg) cells retained their suppressive function both in vitro and in vivo. In summary, absence of TGF-ß signalling on mature CD4⁺ T cells is not responsible for breakdown of peripheral tolerance, but rather controls homeostasis of mature T cells in adult mice.

External bone marrow cytological examination quality assurance (EQAhem)--summary after 6 years in Poland.

Bone marrow macroscopic examination remains one of the most difficult and subjective laboratory assessments in hematology. Only a few external quality assurance programs in the field are present worldwide. We have developed an external quality assurance program EQAhem that allows assessment of the whole process of bone marrow examination. The program participants assess blood and bone marrow smears from the patient, identify selected cells from photographs provided to them, and interpret the microscopic results. In this article, the results of the EQAhem program in Poland from 6 years are summarized. During this time, 62 labs were assessed in total, and positive results were achieved by 89.25 % labs, taking into account all tests. Correct responses with respect to the percentage of cell count were provided by ca. 77.5 % labs. Slightly worse results were obtained when megakaryocyte count and cell identification from photographs were tested. The worst results were obtained in case of dysplasia assessment and clinical interpretation of microscopic examination (54.1 and 58.6 % correct responses, respectively). EQAhem delivers precise information about the quality of bone marrow examinations performed in Poland and has a substantial educational value. We believe that after 6 years, EQAhem has significantly improved the quality of bone marrow microscopic examinations performed in Poland.

Endothelial overexpression of LOX-1 increases plaque formation and promotes atherosclerosis in vivo.

AIMS: Lectin-like oxLDL receptor-1 (LOX-1) mediates the uptake of oxidized low-density lipoprotein (oxLDL) in endothelial cells and macrophages. However, the different atherogenic potential of LOX-1-mediated endothelial and macrophage oxLDL uptake remains unclear. The present study was designed to investigate the in vivo role of endothelial LOX-1 in atherogenesis. METHODS AND RESULTS: Endothelial-specific LOX-1 transgenic mice were generated using the Tie2 promoter (LOX-1TG). Oxidized low-density lipoprotein uptake was enhanced in cultured endothelial cells, but not in macrophages of LOX-1TG mice. Six-week-old male LOX-1TG and wild-type (WT) mice were fed a high-cholesterol diet (HCD) for 30 weeks. Increased reactive oxygen species production, impaired endothelial nitric oxide synthase activity and endothelial dysfunction were observed in LOX-1TG mice as compared with WT littermates. LOX-1 overexpression led to p38 phosphorylation, increased nuclear factor κB activity and subsequent up-regulation of vascular cell adhesion molecule-1, thereby favouring macrophage accumulation and aortic fatty streaks. Consistently, HCD-fed double-mutant LOX-1TG/ApoE(-/-) displayed oxidative stress and vascular inflammation with higher aortic plaques than ApoE(-/-) controls. Finally, bone marrow transplantation experiments showed that endothelial LOX-1 was sufficient for atherosclerosis development in vivo. CONCLUSIONS: Endothelial-specific LOX-1 overexpression enhanced aortic oxLDL levels, thereby favouring endothelial dysfunction, vascular inflammation and plaque formation. Thus, LOX-1 may serve as a novel therapeutic target for atherosclerosis.

[Sensitivity for antibiotics among the E. coli strains isolated from patients with different clinical stage of infection]. / Antybiotykowrazliwosc szczepów E. coli wyizolowanych z lozyska krwionosnego pacjentów w róznym stopniu zaawansowania klinicznego zakazenia krwi.

Enteric rods are the microorganisms most commonly isolated from blood of hospitalized patients. Bloodstream infections caused by them are associated with significant patient mortality. The aim of the study was analysis of clinical course and evaluation of clinical response on bloodstream infection caused by Escherichia coli. Microorganisms were evaluated for sensibility for antibacterial drugs. For that reason MIC (Minimal Inhibitory Concentration) of antibiotics from different groups was determined for E. coli strains isolated from patients with different clinical stage of infection. No significant differences were shown in sensitivity for antibiotics and MIC among the E. coli strains in correlation with clinical condition of studied patients.

The effect of Cistus incanus herbal tea supplementation on oxidative stress markers and lipid profile in healthy adults.

BACKGROUND: Oxidative stress and dyslipidemia play a critical role in the development of cardiovascular disease (CVD). Regular intake of polyphenol-rich diets is associated with a reduced risk of CVDs. METHODS: The present study was a pilot study with 24 healthy volunteers and was designed to determine if a 12-week administration of Cistus incanus herbal tea, containing phenolic acids and flavonoids, reduces cardiovascular risk factors including oxidative stress and dyslipidemia in healthy adults. Phenolic compounds profile and antibacterial activity of Cistus incanus infusion were also measured. RESULTS: Herbal infusion led to improvement in lipid profile by increase (D4%, p = 0.033) high-density lipoprotein cholesterol concentration and decrease triglyceride (D14%, p = 0.013) concentrations. In addition, the Cistus incanus diet was associated with decreased serum concentrations of malondialdehyde (D16%, p < 0.01) and advanced oxidation protein products (D18%, p < 0.001). CONCLUSIONS: Cistus incanus administration decreases cardiovascular risk factors including oxidative stress and dyslipidemia and this action supports the idea of using Cistus incanus tea on a daily basis as an effective dietary component for prevention of atherosclerotic CVD.

CD25-Treg-depleting antibodies preserving IL-2 signaling on effector T cells enhance effector activation and antitumor immunity.

Intratumoral regulatory T cell (Treg) abundance associates with diminished anti-tumor immunity and poor prognosis in human cancers. Recent work demonstrates that CD25, the high affinity receptor subunit for IL-2, is a selective target for Treg depletion in mouse and human malignancies; however, anti-human CD25 antibodies have failed to deliver clinical responses against solid tumors due to bystander IL-2 receptor signaling blockade on effector T cells, which limits their anti-tumor activity. Here we demonstrate potent single-agent activity of anti-CD25 antibodies optimized to deplete Tregs whilst preserving IL-2-STAT5 signaling on effector T cells, and demonstrate synergy with immune checkpoint blockade in vivo. Pre-clinical evaluation of an anti-human CD25 (RG6292) antibody with equivalent features demonstrates, in both non-human primates and humanized mouse models, efficient Treg depletion with no overt immune-related toxicities. Our data supports the clinical development of RG6292 and evaluation of novel combination therapies incorporating non-IL-2 blocking anti-CD25 antibodies in clinical studies.

[Study of genetic diversity of nontypeable Haemophilus influenzae strains isolated from healthy children and patients with infection symptoms]. / Genetyczna zmiennosc bezotoczkowych szczepów Haemophilus influenzae izolowanych od nosicieli i chorych dzieci z objawami zakazen.

In the study the usefulness of genotyping methods for genetic variability examinations of non-typeable H. influenzae strains circulating in population as well as level the variability of NTHi strains isolated from healthy children and from symptomatic infection cases have been evaluated. Among genotyping methods evaluated, AFLP method of the MfeI/BglII set has been found most useful to study level of genetic variability of NTHi strains population. It has been shown that NTHi strains colonizing nasopharyngeal of healthy children present higher polymorphism level than strains isolated from patient with clinical symptoms of NTHi infection.

[Estimation of the frequency of occurrence of microorganisms isolated from blood cultures of hospitalized patients in the Hospital of Medical University in Gdansk in 2000-2002]. / Ocena czestosci wystepowania drobnoustrojów izolowanych z krwi pacjentów hospitalizowanych w Szpitalu Klinicznym Akademii Medycznej w Gdansku w latach 2000-2002.

The aim of present study was retrospective analysis of the frequencies of occurrence of the most common microorganisms isolated from blood cultures in the Medical University in Gdansk from 2000 to 2002. The blood patterns were taken from adult patients with symptoms suggesting bacteriemia. During the 3 year study period 31788 blood samples were obtained, of which 5520 (17.37%) were positive. The number of Gram-positive bacteria isolated from blood increased and the rate of Gram-negative bacteria decreased over the study period. In addition the increase of frequency of Candida, VRE and Escherichia coli was noted. The number of infections caused by MRSA and Gram-negative ESbetaL+ diminished during time of observation. Acquaintance on the most frequently isolated organisms from blood patterns and they antimicrobial susceptibility should guide the choice of empiric antimicrobial regimens for patients with bacteriemia.

A new assay based on terminal restriction fragment length polymorphism of homocitrate synthase gene fragments for Candida species identification.

Candida sp. have been responsible for an increasing number of infections, especially in patients with immunodeficiency. Species-specific differentiation of Candida sp. is difficult in routine diagnosis. This identification can have a highly significant association in therapy and prophylaxis. This work has shown a new application of the terminal restriction fragment length polymorphism (t-RFLP) method in the molecular identification of six species of Candida, which are the most common causes of fungal infections. Specific for fungi homocitrate synthase gene was chosen as a molecular target for amplification. The use of three restriction enzymes, DraI, RsaI, and BglII, for amplicon digestion can generate species-specific fluorescence labeled DNA fragment profiles, which can be used to determine the diagnostic algorithm. The designed method can be a cost-efficient high-throughput molecular technique for the identification of six clinically important Candida species.

Recurrent bowel-blood translocations of Escherichia coli with the unique virulence characteristics over three-year period in the patient with acute myeloid leukaemia - case report.

In patients with haematological malignancies, the bowel remains the main source of Escherichia coli bloodstream infections. We present the clinical example of recurrent bowel-blood translocations of E. coli with the unique virulence characteristics in a 55-year-old male with the diagnosis of acute myeloid leukaemia. The virulent factors profile of examined strains confirmed that the co-existence of genes papC, sfa, usp and cnf1, encoding virulence factors, predisposes E. coli to translocation from the gastrointestinal tract to the vascular bed. The close cooperation between haematologists and microbiologists is essential to improve the outcome of patients colonised with highly pathogenic strains.

[Study on genetic diversity of genes encoding main adhesins among nontypeable Haemophilus influenzae strains isolated from children in Poland]. / Badania profilu determinant genetycznych kodujacych glówne adhezyny bezotoczkowych szczepów Haemophilus influenzae izolowanych od dzieci w Polsce.

The study was based on hypothesis that in the nontypeable population of H. influenzae strains isolated from children there are some genetically predisposed to induce symptomatic infection in children and that they might be divided into different groups depending on profiles of genes encoding main adhesins synthesis. The work aimed at analysis of distribution of genes encoding adhesins and evaluation of domination possibility of some strains representing particular adhesins genes profiles among NTHi population. Results of the study revealed that among population of NTHi strains, distribution of genes encoding main adhesins are differing. Among children, NTHi strains harbouring genes encoding HA and HMW1/HMW2 adhesins were more prevalent in healthy children and in children with symptomatic infections, respectively. Analysis of strains harbouring main adhesins profiles might be a useful screening method in monitoring strains circulating among children, in order to determine the most invasive NTHi strains.

[Procalcitonin as a diagnostic marker in systemic inflammatory response syndrome (SIRS) and sepsis]. / Prokalcytonina jako marker diagnostyczny Zespolu Uogólnionej Reakcji Zapalnej (SIRS) i posocznicy.

OBJECTIVE: Evaluation the value of procalcitonin as a diagnostic and prognostic marker in septic patients and patients with systemic inflammatory response syndrome (SIRS). MATERIAL AND METHODS: 126 patients were included into the study. The patients were divided into four groups: 1--septic patients with positive blood cultures, 2--septic patients with negative blood cultures, 3--patients with SIRS, 4--patients without sepsis and SIRS. PCT level was measured by imunoluminometric assay (LUMItest) and immunochromatographic assay (PCT-Q). RESULTS: PCT level is higher in patients with sepsis than in patients with SIRS. PCT level is only slightly elevated in patients without sepsis and SIRS. The highest PCT level is found in patients with septic shock. In patients with the clinical improvement the frequency of PCT level increase is approximately twice lower than in patients who died. CONCLUSIONS: Measurement of PCT level on the first, second and third day of hospitalization has no prognostic value. There is no significant difference in PCT level in sepsis caused by Gram positive and Gram negative bacteria. PCT is a useful marker in diagnosis of sepsis but its role in monitoring the severity of sepsis requires more clinical studies.

[Nosocomial bacteremia]. / Bakteriemie szpitalne.

Nosocomial bacteremia according to different authors can be divided in to bacteremia persistent, polymicrobial bacteremia, alternate bacteremia, breakthrough bacteremia, different bacteremia. Developing techniques of microbiological and molecular diagnostics induce us to verify the definition and partition of term "bacteremia".

[Escherichia coli a forgotten pathogen in septicemia]. / Escherichia coli zapomniany patogen posocznic.

The aim of the retrospect study was to analyse the incidence of E. coli bacteremia in eight wards of SPSK 1 ACK AM in Gdansk from 2002 to 2004. We analyzed the incidence of bacteremia, patients outcome, source of infection and antimicrobial susceptibility. During the study period we detected 268 patients with E. coli bacteremia (8,0% of all bacteremic patients). 11,2% of them died within 24-48h after positive blood culture. Incidence of bacteremia was 1,7/1000 patients and the highest level achieved in Hematology Unit--33,2. The main portal of entry was genitourinary tract (24,3%) and gastrointestinal tract (21,8%). The strains (n=263) were least susceptible to ampicillin (33,3%), co-trimoxazole (68,4%), amoxycillin with clavulanic acid (69,3%) and ciprofloxacine (78,9%).

Escherichia coli bacteraemias in intensive care unit patients.

BACKGROUND: Although bacterial infections are common in critically ill patients, isolation of bacteria from the sample is not always unambiguous. The authors addressed Escherichia coli bacteraemia in patients treated in the Intensive Care Unit in the Teaching Hospital in Gdansk in 2002-2009. METHODS: Using a computer database, the names of Escherichia coli positive patients and dates of blood sampling were found, followed by a retrospective assessment whether positive blood cultures were accompanied by the clinical features of sepsis or asymptomatic bacteraemia. RESULTS: Positive cultures were found in 40 blood samples (36 patients). Bacteraemia was diagnosed in 11, sepsis in 10, severe sepsis in 6 and septic shock in 13 cases. In the bacteraemia group, the condition originated from the gastrointestinal tract - 4 cases; from the lungs - 1; while in 6 cases, the aetiology was not detected. In patients with an infection, the likely source was the gastrointestinal tract - 12 cases; the lungs - 4; and pyothorax - 2. In 11 cases, the aetiology remained unidentified. In 3 patients in the bacteraemia group, cultures of other microorganisms were found to be positive, while there were 4 cases among the septic patients. In the bacteraemia group, 8 patients died in the intensive care unit, without relation to bacteraemia. Amongst septic patients 17 died, including 12 whose death was probably attributable to Escherichia coli infection. CONCLUSIONS: Escherichia coli bacteraemias and infections have been and will remain an everyday problem in hospital wards. The differentiation of asymptomatic bacteraemia from infection is essential for rational antibiotic therapy, which is particularly important considering the increasing resistance of microorganisms.

TALEN-Mediated Inactivation of PD-1 in Tumor-Reactive Lymphocytes Promotes Intratumoral T-cell Persistence and Rejection of Established Tumors.

Despite the promising efficacy of adoptive cell therapies (ACT) in melanoma, complete response rates remain relatively low and outcomes in other cancers are less impressive. The immunosuppressive nature of the tumor microenvironment and the expression of immune-inhibitory ligands, such as PD-L1/CD274 by the tumor and stroma are considered key factors limiting efficacy. The addition of checkpoint inhibitors (CPI) to ACT protocols bypasses some mechanisms of immunosuppression, but associated toxicities remain a significant concern. To overcome PD-L1-mediated immunosuppression and reduce CPI-associated toxicities, we used TALEN technology to render tumor-reactive T cells resistant to PD-1 signaling. Here, we demonstrate that inactivation of the PD-1 gene in melanoma-reactive CD8(+) T cells and in fibrosarcoma-reactive polyclonal T cells enhanced the persistence of PD-1 gene-modified T cells at the tumor site and increased tumor control. These results illustrate the feasibility and potency of approaches incorporating advanced gene-editing technologies into ACT protocols to silence immune checkpoints as a strategy to overcome locally active immune escape pathways. Cancer Res; 76(8); 2087-93. ©2016 AACR.

Negative immune checkpoints on T lymphocytes and their relevance to cancer immunotherapy.

The term 'inhibitory checkpoint' refers to the broad spectrum of co-receptors expressed by T cells that negatively regulate T cell activation thus playing a crucial role in maintaining peripheral self-tolerance. Co-inhibitory receptor ligands are highly expressed by a variety of malignancies allowing evasion of anti-tumour immunity. Recent studies demonstrate that manipulation of these co-inhibitory pathways can remove the immunological brakes that impede endogenous immune responses against tumours. Antibodies that block the interactions between co-inhibitory receptors and their ligands have delivered very promising clinical responses, as has been shown by recent successful trials targeting the CTLA-4 and PD-1 pathways. In this review, we discuss the mechanisms of action and expression pattern of co-inhibitory receptors on different T cells subsets, emphasising differences between CD4(+) and CD8(+) T cells. We also summarise recent clinical findings utilising immune checkpoint blockade.

Manipulation of T cell function and conditional gene targeting in T cells.

Cre-Lox recombination is known as a site-specific recombinase technology, and is widely used to carry out modification at specific sites in the DNA of cells. The system consists of an enzyme, Cre recombinase, that recombines a pair of short target sequences, the lox sites. The Cre-Lox system can be used to activate or repress a gene depending on the placement of the lox sites. Placing the Cre recombinase under the control of a cell-specific promoter allows expression only in specific cells or cellular subsets, thus providing a powerful tool for analysis of gene function at specific developmental or physiological niches. Nowadays almost every aspect of T cell biology can be approached by a specific Cre model. This powerful tool allows scientists to overcome the limitations of gene-deficient animals and target a gene of interest specifically in T cell or T cell subsets by appropriate placement of the lox sites. Here we describe the main Cre lines that enable gene targeting in T helper cells or CD4 T cell subsets, and the most common methods of assessing the recombination efficiency.