A simple method for removing low-density granulocytes to purify T lymphocytes from peripheral blood mononuclear cells

Manufacturing of CD34 + HPC-enriched, high-purity mononuclear cell products from umbilical cord blood

The purpose of this study was to explore methods of selectively enriching CD34 + haematopoietic progenitor cells (HPC) in mononuclear cell (MNC) preparations, and to outline a procedure for cryopreservation and thawing of manufactured material. Density gradient centrifugation of umbilical cord blood was achieved using Ficoll-Paque™ media at 1.077 g/mL and 1.065 g/mL densities and Leucosep preparation tubes. Post-process samples were analysed for CD34 + and MNC content. Finally, MNCs were frozen down at a concentration of 8.5 × 106 cells/mL in CryoStor CS10 using an Asymptote VIAFreeze controlled rate freezer at a rate of - 2 °C per minute, then thawed and analysed for viability and recovery. Processing with 1.065 g/mL media selectively depleted non-HPC cell types, producing an approximately fourfold increase in CD34 + frequency (M ± 1SD = 1.4 ± 1.3%, P < 0.01) relative to the pre-process sample (M ± 1SD = 0.4 ± 0.3%), whereas 1.077 g/mL media produced only a twofold enrichment (0.7 ± 0.6, P < 0.01). This was not accompanied by any significant forfeit of CD34 + recovery (79 ± 32% vs. 78 ± 32% respectively; P = 0.87). The MNCs generated by the 1.065 g/mL procedure were of greater purity (96 ± 2%) than in the 1.077 g/mL procedure (80 ± 7%, P < 0.01). Post-thaw, MNC viability was 95 ± 1% and CD34 + viability was 98 ± 1%. Ultra-pure MNCs rich in CD34 + HPCs can be generated with a simple, inexpensive modification to Ficoll-Paque™ media. These products can be easily cryopreserved using a simple controlled rate freezing procedure.

Indicator of Inflammation and NETosis-Low-Density Granulocytes as a Biomarker of Autoimmune Hepatitis

Introduction. Interest in the potential role of low-density granulocytes (LDGs) in the development of autoimmune diseases has been renewed recently. Due to their pro-inflammatory action, more and more attention is paid to the role of LDGs, including those expressing the enzyme myeloperoxidase (MPO), in the development of autoimmune hepatitis (AIH). LDGs are actively involved in the formation of neutrophil extracellular traps (NETs). This phenomenon may favour the externalization of the autoantigen and lead to damage to internal organs, including the liver. Aim. The main aim of the study was to assess the diagnostic usefulness of the LDG percentage, including the fraction showing MPO expression as markers of systemic inflammation in AIH. Materials and methods. The study included a group of 25 patients with AIH and 20 healthy volunteers. Mononuclear cells, isolated from peripheral blood, were labelled with monoclonal antibodies conjugated to the appropriate fluorochromes (CD15-FITC, CD14-PE, CD10-PE-Cy5, MPO+) and then analyzed on a Navios Flow Cytometer (Beckman Coulter). Results. Patients with AIH had a higher median percentage of LDG (1.2 vs. 0.1; p = 0.0001) and LDG expressing MPO (0.8 vs. 0.3; p = 0.0017) when compared to healthy volunteers. Moreover, the percentage of LDG was characterised by 100% of sensitivity and 55% of specificity (AUC = 0.84; p < 0.0001), while the percentage of LDG expressing MPO was 92% of sensitivity and 55% of specificity (AUC = 0.78; p = 0.0001) in the detection of AIH. Conclusions. Assessment of inflammatory markers, such as the percentage of LDG and the percentage of LDG expressing MPO, may be helpful in assessing the phenomenon of an increased systemic inflammatory response and in assessing liver fibrosis (LC, Liver cirrhosis), which is inherent in liver decompensation. Taking into account the above arguments, the assessment of the percentage of LDG, including LDG expressing MPO, may turn out to be a useful marker in the diagnosis of AIH.

Etiopathogenesis and Diagnostic Strategies in Autoimmune Hepatitis

Autoimmune hepatitis (AIH) is a chronic liver disease with the incidence of 10 to 17 per 100,000 people in Europe. It affects people of any age, but most often occurs in the 40-60 age group. The clinical picture is varied, from asymptomatic to severe acute hepatitis or liver failure. The disease onset is probably associated with the impaired function of T lymphocytes, the development of molecular mimicry, intestinal dysbiosis, or infiltration with low density neutrophils, which, alongside autoantibodies (i.e., ANA, ASMA), implicate the formation of neutrophil extracellular traps (NETs), as a component of the disease process, and mediate the inappropriate immune response. AIH is characterized with an increased activity of aminotransferases, elevated concentration of serum immunoglobulin G, the presence of circulating autoantibodies and liver inflammation. The result of the histological examination of the liver and the presence of autoantibodies, although not pathognomonic, still remain a distinguishing feature. The diagnosis of AIH determines lifelong treatment in most patients. The treatment is implemented to prevent the development of cirrhosis and end-stage liver failure. This work focuses mainly on the etiopathogenesis and diagnosis of AIH.

Low-Density Granulocytes Affect T-SPOT.TB Assay by Inhibiting the Production of Interferon-γ in T Cells via PD-L1/PD-1 Pathway

Background

T-SPOT TB (T-SPOT) assay is widely used for detection of Mycobacterium tuberculosis infection that is based on the detection of M. tuberculosis-specific interferon-γ-secreting T cells (ISCs) in peripheral blood mononuclear cells (PBMCs). Recently, high frequencies of low-density granulocytes (LDGs) were found in the PBMCs of tuberculosis patients. Whether these LDGs affect the detection of T-SPOT has not been investigated. The impact of LDGs on T-SPOT assay and related mechanism were investigated in this study.

Methods

The correlations between the frequencies of LDGs and the results of T-SPOT were analyzed. T-SPOT with LDG-removed PBMCs and PBMCs with exogenous addition of LDGs were performed. The possible mechanism was explored by detecting the levels of negative immune regulatory molecules on LDGs. The impact of programmed death ligand 1 (PD-L1) on T-SPOT was evaluated and confirmed by function blocking with neutralizing antibody.

Results

The positive rates of T-SPOT and ISCs in tuberculosis patients with low LDGs frequency (n = 22) were significantly higher than those with high LDGs frequency (n = 39). Removal or exogenous addition of LDGs significantly increased or decreased the ISCs and the positive rate of T-SPOT. The frequencies of interferon-γ-producing T cells were negatively correlated with the frequencies of LDGs. The expression of PD-L1 was significantly elevated on LDGs. Pretreatment of LDGs with anti-PD-L1 antibody significantly counteracted the impact of LDGs on T-SPOT. Treatment of PBMCs with anti-PD-L1 antibody resulted in comparable ISCs with that of LDG removal.

Conclusion

LDGs can inhibit the production of interferon-γ in T cells and decrease the positive rated of T-SPOT assay via highly expressed PD-L1.

Changes in peripheral blood inflammatory factors (TNF-α and IL-6) and intestinal flora in AIDS and HIV-positive individuals

OBJECTIVE

In this study, we investigated the changes in peripheral blood inflammatory factors and intestinal flora in acquired immune deficiency syndrome (AIDS) and human immunodeficiency virus (HIV)-positive individuals (AIDS/HIV patients), and explored the relationships among intestinal flora, peripheral blood inflammatory factors, and CD4+ T lymphocytes.

METHODS

Thirty blood and stool samples from an AIDS group and a control group were collected. The levels of tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6) were determined by enzyme-linked immunosorbent assay (ELISA), and the number of CD4+ T lymphocytes by a FACSCount automated instrument. Quantitative real-time polymerase chain reaction (qRT-PCR) was used to determine the messenger RNA (mRNA) levels of Bifidobacterium, Lactobacillus, Escherichia coli, Enterococcus faecalis, and Enterococcus faecium. Correlations among intestinal flora, inflammatory factor levels, and CD4+ T lymphocyte values were evaluated using the Spearman correlation coefficient.

RESULTS

The levels of TNF-α and IL-6 in the AIDS group were higher than those in the control group, while the number of CD4+ T lymphocytes was lower. The amounts of Bifidobacterium and Lactobacillus in the AIDS group were significantly lower than those in control group, while the amounts of E. coli, E. faecalis, and E. faecium were much higher. The amounts of Bifidobacterium and Lactobacillus were negatively correlated with the content of TNF-α and IL-6 and the CD4+ T lymphocyte count, while those correlations were reversed for E. coli, E. faecalis, and E. faecium.

CONCLUSIONS

The intestinal microbiota of AIDS/HIV patients were disordered, and there was a correlation between the amount of intestinal flora and the number of CD4+ T lymphocytes and the levels of TNF-α and IL-6.

Age-related DNA hydroxymethylation is enriched for gene expression and immune system processes in human peripheral blood

DNA methylation (DNAm) has a well-established association with age in many tissues, including peripheral blood mononuclear cells (PBMCs). Compared to DNAm, the closely related epigenetic modification known as DNA hydroxymethylation (DNAhm) was much more recently discovered in mammals. Preliminary investigations have observed a positive correlation between gene body DNAhm and cis-gene expression. While some of these studies have observed an association between age and global DNAhm, none have investigated region-specific age-related DNAhm in human blood samples. In this study, we investigated DNAhm and gene expression in PBMCs of 10 young and 10 old, healthy female volunteers. Thousands of regions were differentially hydroxymethylated in the old vs. young individuals in gene bodies, exonic regions, enhancers, and promoters. Consistent with previous work, we observed directional consistency between age-related differences in DNAhm and gene expression. Further, age-related DNAhm and genes with high levels of DNAhm were enriched for immune system processes which may support a role of age-related DNAhm in immunosenescence.