Immune modulation and monitoring of cell therapy in inflammatory disorders

The immune system consists of a complex network that protects the body from pathogens and cancer. Autoimmune diseases and inflammatory conditions are caused by a disturbed and unbalanced immune system in which the body's own cells are destroyed by immune cells as a result of an inflammatory reaction. In this thesis, I focused on type 1 diabetes as an autoimmune disease to investigate the derailment of the immune system and explored strategies involving cell therapy with tolerogenicdendritic cells to restore immune tolerance. In addition, I studied the application of cell therapy in other inflammatory disorders such as rheumatoid arthritis and graft-versus-host disease.LUMC / Geneeskund

Antioxidant Activities of Extracts of Trengguli Stem Bark (Cassia fistula L.)

This research is conducted to examine the antioxidant activity on the extract of stem bark C.fistula. The antioxidant activities of C.fistula stem bark extract were evaluated with lipid peroxides test using ferric thiosyanat method (FTC) and 2.6-di-t-butyl-4-metilfenol (BHT) as standard equivalent antioxidant capacity. C.fistula stem bark maceration successively used solvent normal heksane (non polar), ethyl acetate (semi-polar) and methanol (polar). The etyl acetate extract (Ea) shows higher antioxidant activity than the n.hexane extract (Hx) and methanol extract (MeOH). Therefore, the sequence of antioxidant activity is as follows ethyl acetate extract > methanol extract > n.hexane extract, with antioxidant activity consecutively at 5 hours: 65.98%, 58.19% and 32.66%. Those amount are equivalent to the standard synthetic antioxidant BHT (100 ppm), which causes 95.7% antioxidant activity (in 5 hours) inhibition of linoleic acid peroxidation. There is a connection between antioxidant activity of an extract with the content of the total phenol in each extract. From the assay of phenolic extracts with the method of Folin-Ciocalteu reagent (FCR) and also using afzelechin standard as a comparision, we find that the ethyl acetate extract has the highest total phenolic where the entire sequences are as follows: Ea> MeOH> Hx. with total phenol content consecutive 177.55, 123.2167, 7.43333

Multidimensional analyses of proinsulin peptide-specific regulatory T cells induced by tolerogenic dendritic cells

Induction of antigen-specific regulatory T cells (Tregs) in vivo is the holy grail of current immune-regulating therapies in autoimmune diseases, such as type 1 diabetes. Tolerogenic dendritic cells (tolDCs) generated from monocytes by a combined treatment with vitamin D and dexamethasone (marked by CD52hi and CD86lo expression) induce antigen-specific Tregs. We evaluated the phenotypes of these Tregs using high-dimensional mass cytometry to identify a surface-based T cell signature of tolerogenic modulation. Naïve CD4+ T cells were stimulated with tolDCs or mature inflammatory DCs pulsed with proinsulin peptide, after which the suppressive capacity, cytokine production and phenotype of stimulated T cells were analysed. TolDCs induced suppressive T cell lines that were dominated by a naïve phenotype (CD45RA+CCR7+). These naïve T cells, however, did not show suppressive capacity, but were arrested in their naïve status. T cell cultures stimulated by tolDC further contained memory-like (CD45RA-CCR7-) T cells expressing regulatory markers Lag-3, CD161 and ICOS. T cells expressing CD25lo or CD25hi were most prominent and suppressed CD4+ proliferation, while CD25hi Tregs also effectively supressed effector CD8+ T cells.We conclude that tolDCs induce antigen-specific Tregs with various phenotypes. This extends our earlier findings pointing to a functionally diverse pool of antigen-induced and specific Tregs and provides the basis for immune-monitoring in clinical trials with tolDC.Nephrolog

GPA33 is expressed on multiple human blood cell types and distinguishes CD4(+) central memory T cells with and without effector function

The Ig superfamily protein glycoprotein A33 (GPA33) has been implicated in immune dysregulation, but little is known about its expression in the immune compartment. Here, we comprehensively determined GPA33 expression patterns on human blood leukocyte subsets, using mass and flow cytometry. We found that GPA33 was expressed on fractions of B, dendritic, natural killer and innate lymphoid cells. Most prominent expression was found in the CD4(+) T cell compartment. Naive and CXCR5(+) regulatory T cells were GPA33(high), and naive conventional CD4(+) T cells expressed intermediate GPA33 levels. The expression pattern of GPA33 identified functional heterogeneity within the CD4(+) central memory T cell (Tcm) population. GPA33(+) CD4(+) Tcm cells were fully undifferentiated, bona fide Tcm cells that lack immediate effector function, whereas GPA33(-) Tcm cells exhibited rapid effector functions and may represent an early stage of differentiation into effector/effector memory T cells before loss of CD62L. Expression of GPA33 in conventional CD4(+) T cells suggests a role in localization and/or preservation of an undifferentiated state. These results form a basis to study the function of GPA33 and show it to be a useful marker to discriminate between different cellular subsets, especially in the CD4(+) T cell lineage.Immunobiology of allogeneic stem cell transplantation and immunotherapy of hematological disease

A unique immune signature in blood separates therapy-refractory from therapy-responsive acute graft-versus-host disease

Acute graft-versus-host disease (aGVHD) is an immune cell-driven, potentially lethal complication of allogeneic hematopoietic stem cell transplantation affecting diverse organs, including the skin, liver, and gastrointestinal (GI) tract. We applied mass cytometry (CyTOF) to dissect circulating myeloid and lymphoid cells in children with severe (grade III-IV) aGVHD treated with immune suppressive drugs alone (first-line therapy) or in combination with mesenchymal stromal cells (MSCs; second-line therapy). These results were compared with CyTOF data generated in children who underwent transplantation with no aGVHD or age-matched healthy control participants. Onset of aGVHD was associated with the appearance of CD11b(+)CD163(+) myeloid cells in the blood and accumulation in the skin and GI tract. Distinct T-cell populations, including TCR gamma delta(+) cells, expressing activation markers and chemokine receptors guiding homing to the skin and GI tract were found in the same blood samples. CXCR3(+) T cells released inflammation-promoting factors after overnight stimulation. These results indicate that lymphoid and myeloid compartments are triggered at aGVHD onset. Immunoglobulin M (IgM) presumably class switched, plasma-blasts, and 2 distinct CD11b(-) dendritic cell subsets were other prominent immune populations found early during the course of aGVHD in patients refractory to both first- and second-line (MSC-based) therapy. In these nonresponding patients, effector and regulatory T cells with skin- or gut-homing receptors also remained proportionally high over time, whereas their frequencies declined in therapy responders. Our results underscore the additive value of high-dimensional immune cell profiling for clinical response evaluation, which may assist timely decision-making in the management of severe aGVHD.Horizon 2020 (H2020)643580Immunobiology of allogeneic stem cell transplantation and immunotherapy of hematological disease

Immune modulation and monitoring of cell therapy in inflammatory disorders

The immune system consists of a complex network that protects the body from pathogens and cancer. Autoimmune diseases and inflammatory conditions are caused by a disturbed and unbalanced immune system in which the body's own cells are destroyed by immune cells as a result of an inflammatory reaction. In this thesis, I focused on type 1 diabetes as an autoimmune disease to investigate the derailment of the immune system and explored strategies involving cell therapy with tolerogenicdendritic cells to restore immune tolerance. In addition, I studied the application of cell therapy in other inflammatory disorders such as rheumatoid arthritis and graft-versus-host disease.</p

Immune modulation and monitoring of cell therapy in inflammatory disorders

The immune system consists of a complex network that protects the body from pathogens and cancer. Autoimmune diseases and inflammatory conditions are caused by a disturbed and unbalanced immune system in which the body's own cells are destroyed by immune cells as a result of an inflammatory reaction. In this thesis, I focused on type 1 diabetes as an autoimmune disease to investigate the derailment of the immune system and explored strategies involving cell therapy with tolerogenicdendritic cells to restore immune tolerance. In addition, I studied the application of cell therapy in other inflammatory disorders such as rheumatoid arthritis and graft-versus-host disease.</p

Translating Mechanism of Regulatory Action of Tolerogenic Dendritic Cells to Monitoring endpoints in Clinical Trials

Transplantation and autoimmunit

Inducing tissue specific tolerance in autoimmune disease with tolerogenic dendritic cells

Pathophysiology and treatment of rheumatic disease