Agnes Peterfalvi

Invariant Vα7.2-Jα33 TCR is expressed in human kidney and brain tumors indicating infiltration by mucosal-associated invariant T (MAIT) cells

The anti-tumor response of human invariant NKT (NKT) cells is well established. A novel T cell subset, mucosal-associated invariant T (MAIT) cells, possesses similar regulatory properties to NKT cells in autoimmune models and disease. Here, we examined the clonality of four T cell subsets expressing invariant alphaTCR, including Valpha7.2-Jalpha33 of MAIT cells, in 19 kidney and brain tumors. The MAIT clonotype was identified and co-expressed with NKT clonotype in half of the tumors. In contrast, two other invariant T cell clonotypes (Valpha4 and Valpha19) were not present in tumors. Such tumors also expressed Vbeta2 and Vbeta13, the restricted TCRbeta chain of MAIT cells and the antigen-presenting molecule MR1. A high percentage of infiltrating T cells was CD8+ and expressed HLA-DR suggesting activation. Although the MAIT alphaTCR was identified in both peripheral CD56+ and CD56- subsets, infiltrating lymphocytes were CD56 negative. The clonal presence of MAIT cells in tumors correlated with the expression of pro-inflammatory cytokines but no IL-4, IL-5 and IL-10, suggesting that a pro-inflammatory subset of human MAIT cells may exist. Our data imply that a CD56- subset of MAIT cells may participate in tumor immune responses similarly to NKT cells.

Aberrant transcriptional regulatory network in T cells of multiple sclerosis

To identify the molecular network of the genes deregulated in multiple sclerosis (MS), we studied gene expression profile of purified CD3(+) T cells isolated from Hungarian monozygotic MS twins by DNA microarray analysis. By comparing three concordant and one discordant pairs, we identified 20 differentially expressed genes (DEG) between the MS patient and the genetically identical healthy subject. Molecular network of 20 DEG analyzed by KeyMolnet, a comprehensive information platform, indicated the close relationship with transcriptional regulation by the Ets transcription factor family and the nuclear factor NF-kappaB. This novel bioinformatic approach proposes the logical hypothesis that aberrant regulation of the complex transcriptional regulatory network contributes to development of pathogenic T cells in MS.

Impaired Function of Innate T Lymphocytes and NK Cells in the Acute Phase of Ischemic Stroke

Background: Functional alterations of innate lymphocytes, which can mount rapid immune responses and shape subsequent T cell reactions, were examined in the acute phase of ischemic stroke. Methods: Frequencies, intracellular perforin and interferon-γ (IFN-γ) expression of Vδ2 T cells, CD3+ CD56+ natural killer T (NKT)-like and NK cells were examined in the peripheral blood of 20 healthy controls and 28 patients within 6 h of the onset of acute ischemic stroke and after 72 h by flow cytometry. Cytokine production of isolated NKT-like and NK cells following in vitro activation was measured by cytometric bead array. NK cytotoxicity was examined in the peripheral blood mononuclear cells. Results: Percentages of Vδ2, NKT-like and NK cells were constant, and similar to percentages in healthy subjects. In contrast, proinflammatory intracellularIFN-γ expression by Vδ2 T cells, NKT-like cells and NK cells and IFN-γ production by isolated NK cells in culture was low at 6 h and reached the level of healthy subjects by 72 h after stroke. Production of anti-inflammatory cytokines was unaltered. Intracellular perforin expression by Vδ2 T cells, NKT-like cells and NK cells, and NK cytotoxicity was low at 6 h, and reached the level of healthy subjects by 72 h. Increases in IFN-γ and perforin expression by Vδ2 T cells correlated with clinical improvement indicated by decreases in NIHSS scores. Conclusions: Pro-inflammatory and cytotoxic responses of NK, NKT-like and Vδ2 T cells become acutely deficient in ischemic stroke, which may contribute to an increased susceptibility to infections.

Challenges in the evaluation of D-dimer and fibrinogen levels in pregnant women

INTRODUCTION Normal pregnancy is associated with hypercoagulable state. Elevated markers of coagulation and fibrinolytic system activation indicate increased thrombin activity and increased fibrinolysis following fibrin formation throughout pregnancy. These changes exceed the biological variability in most cases. Haemostatic reference intervals are generally based on samples from non-pregnant women. Thus, they may not be relevant to pregnant women, a problem that may hinder accurate diagnosis and treatment of haemostatic disorders during pregnancy. The aim of the study was to follow the changes of haemostatic parameters and to establish gestational age-specific reference intervals during normal pregnancy. MATERIALS AND METHODS Blood samples of 83 pregnant women were collected at gestational weeks 16, 26 and 36. Fibrinogen, D-dimer, and C-Reactive Protein (CRP) were examined. Reference intervals were calculated for fibrinogen, D-dimer tests with two different methods (mean±2 SD or median and 2.5th and 97.5th percentiles with 90% confidence intervals). RESULTS fibrinogen and D-dimer increased progressively throughout pregnancy. Mean fibrinogen levels were higher than the maximum of the conventional reference interval, already in the 16th week of pregnancy. D-dimer levels were at or above the conventional cutoff point (250ng/mL) throughout the pregnancy in 42% of pregnant women, while in the 36th week 98% of them displayed elevated D-dimer levels. CRP did not increase in normal pregnancy. CONCLUSIONS There seems to be an emerging need to reconsider fibrinogen and D-dimer values from a different aspect in pregnancy compared to non-pregnant reference intervals. New reference ranges are suggested to be established in pregnancy.

Deficient leucocyte antisedimentation is related to post-stroke infections and outcome

Background: Patients with stroke are more susceptible to infections, suggesting possible deficiencies of early immune responses, particularly of leucocytes. Aims: To serially examine leucocyte antisedimentation rate (LAR), a simple test to detect activation of leucocytes, and correlate it with S100β, procalcitonin and outcome in patients with acute ischaemic events. Methods: Venous blood samples were taken from 61 healthy volunteers and 49 patients with acute ischaemic events (acute ischaemic stroke (AIS), n = 38; transient ischaemic attack (TIA), n = 11) within 6 hours, at 24 and 72 hours after onset of symptoms. Results: LAR was significantly higher in acute ischaemic events compared to controls within 6 hours after onset of stroke regardless of post-stroke infections. In addition, the increase of LAR was delayed and attenuated in TIA in contrast to AIS. A deficiency in early increase of LAR was associated with post-stroke infections and a poor outcome, measured by the Glasgow Outcome Scale in AIS. There was a positive correlation between LAR and S100β at 72 hours after the onset of ischaemic stroke. Increased levels of S100β at 24 and 72 hours after stroke were associated with poor outcome. Conclusions: An early activation of leucocytes indicated by an increase of LAR is characteristic of acute ischaemic cerebrovascular events. A delayed and ameliorated leucocyte activation represented by LAR is characteristic of TIA in contrast to stroke. Deficient early activation predisposes to post-stroke infections related to poor outcome. In addition, the extent of tissue injury correlates with the magnitude of innate immune responses.