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- Berglund, David, 1984-
(författare)
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Preparatory Studies to Introduce Regulatory T Cells in Clinical Transplantation
- 2014
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Solid organ transplantation has evolved from being an experimental procedure to a life-saving treatment for patients with end-stage organ failure. The risk of losing a transplant due to acute rejection is very low with the use of modern immunosuppressive protocols and the short-term results are impressive. However, long-term outcomes are suboptimal and transplant recipients are at increased risks for severe complications such as cancers, opportunistic infections and cardiovascular events. The previous struggle to achieve short-term survival has turned into a search for new strategies to improve patient and transplant longevity.Regulatory T cells (TRegs), a subset of T cells, occur naturally in the immune system and have the capacity to down regulate immune responses. Under normal conditions they maintain self-tolerance and prevent excessive immune activation. Functional TReg defects lead to a massive autoimmune response and are not compatible with life. Preclinical data support that TRegs can be used as a cell therapy to prevent transplant rejection, with the potential to minimize the need for traditional immunosuppression and improve the long-term outcome.This thesis aims to enhance the translation of TReg cell therapy to clinical organ transplantation. In particular, strategies for isolation and expansion of TRegs from uremic patients awaiting kidney transplantation have been assessed. A non-invasive imaging technique to study T cell products after intravenous administration was developed, for use in future clinical trials. The performance of a novel cell purification technique was investigated to potentially improve the clinical production of TRegs.The thesis demonstrates that TRegs can be isolated and expanded from uremic patients to display potent suppressive properties in vitro. The mode of isolation and expansion affect the functional characteristics, where cells purified with cytometry based techniques and expanded with mature dendritic cells were the most advantageous. T cells can be labeled using the radioactive tracer [111In]oxine with preserved viability and subsequently followed in vivo with SPECT/CT for more than 1 week after intravenous administration. The use of microfluidic switch technology offers a novel way of purifying TRegs at high speed, purity and viability, under conditions compatible with clinical use.
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- Berglund, David, et al.
(författare)
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Screening of mortality in transplant patients using an assay for immune function
- 2011
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Ingår i: Transplant Immunology. - : Elsevier BV. - 0966-3274 .- 1878-5492. ; 24:4, s. 246-250
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: So far, the ImmuKnow Immune Cell Function Assay (Cylex, Inc., Columbia, MD, USA) has been used to assess risks of infection and rejection in transplant patients. We hypothesized that the ImmuKnow assay might be used for mortality screening in transplant patients overall. METHODS: In the period of February 2007 to December 2009, at the Uppsala University Hospital, 362 patients who received either kidney, kidney+pancreas, kidney+islet cells, liver or liver+kidney allografts were randomly screened using the ImmuKnow assay. All causes of mortality were compared between two groups: patients with at least one ImmuKnow assay below 175ng/mL and patients with all ImmuKnow assays from 175ng/mL and above. Subsequently, the frequency of rejection within thirty days of the ImmuKnow assay was compared between these two groups. RESULTS: The study included 1031 ImmuKnow assays obtained from the 362 patients. A total of 111 patients had at least one ImmuKnow below 175ng/mL and 251 patients had all their ImmuKnow assays from 175ng/mL and above. By January 31st 2010, 16 of 111 patients (14.4%) with at least one ImmuKnow assay below 175ng/mL were deceased, compared to 13 of 251 patients (5.2%) with all ImmuKnow assays from 175ng/mL and above (p=0.0053, Fisher's exact test). There was no difference in the frequency of rejection between the two groups (19.8% versus 17.5%, p=0.66). CONCLUSIONS: In addition to assessing relative risks of infection and rejection in transplant patients, the ImmuKnow assay may be used to identify patients with increased risk of short-term mortality. Transplant patients being highly overimmunosuppressed as assessed by the ImmuKnow assay do not seem to have a lower risk of short-term rejection.
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- Berglund, Erik, et al.
(författare)
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Evidence for Ca2+-regulated ATP release in gastrointestinal stromal tumors
- 2013
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Ingår i: Experimental Cell Research. - : Elsevier BV. - 0014-4827 .- 1090-2422. ; 319:8, s. 1229-1238
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Tidskriftsartikel (refereegranskat)abstract
- Gastrointestinal stromal tumors (GISTs) are thought to originate from the electrically active pacemaker cells of the gastrointestinal tract. Despite the presence of synaptic-like vesicles and proteins involved in cell secretion it remains unclear whether GIST cells possess regulated release mechanisms. The GIST tumor cell line GIST882 was used as a model cell system, and stimulus-release coupling was investigated by confocal microscopy of cytoplasmic free Ca2+ concentration ([Ca(2+)1](i)), flow cytometry, and luminometric measurements of extracellular ATP. We demonstrate that GIST cells have an intact intracellular Ca2+-signaling pathway that regulates ATP release. Cell viability and cell membrane integrity was preserved, excluding ATP leakage due to cell death and suggesting active ATP release. The stimulus-secretion signal transduction is at least partly dependent on Ca2+ influx since exclusion of extracellular Ca2+ diminishes the ATP release. We conclude that measurements of ATP release in GISTs may be a useful tool for dissecting the signal transduction pathway, mapping exocytotic components, and possibly for the development and evaluation of drugs. Additionally, release of ATP from GISTs may have importance for tumor tissue homeostasis and immune surveillance escape.
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- Berglund, Erik, et al.
(författare)
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Functional role of the Ca2+-activated Cl- channel DOG1/TMEM16A in gastrointestinal stromal tumor cells
- 2014
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Ingår i: Experimental Cell Research. - : Elsevier BV. - 0014-4827 .- 1090-2422. ; 326:2, s. 315-325
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Tidskriftsartikel (refereegranskat)abstract
- DOG1, a Ca2+-activated Cl- channel (CaCC), was identified in 2004 to be robustly expressed in gastrointestinal stromal tumors (GIST). It was rapidly included as a tumor marker in routine diagnostics, but the functional role remained unknown. CaCCs are important regulators of normal physiological functions, but also implicated in tumorigenesis, cancer progression, metastasis, cell migration, apoptosis, proliferation and viability in several malignancies. We therefore investigated whether DOG1 plays a role in the three latter in GIST by utilizing in vitro cell model systems. Confocal microscopy identified different subcellular localizations of DOG1 in imatinib-sensitive and imatinib-resistant cells. Electrophysiological studies confirmed that DOG1-specific pharmacological agents possess potent activating and inhibiting properties. Proliferation assays showed small effects up to 72 h, and flow cytometric analysis of adherent cells with 7-AAD/Annexin V detected no pharmacological effects on viable GIST cells. However, inhibition of DOG1 conveyed pro-apoptotic effects among early apoptotic imatinib-resistant cells. In conclusion, DOG1 generates Cl- currents in GIST that can be regulated pharmacologically, with small effects on cell viability and proliferation in vitro. Inhibition of DOG1 might act pro-apoptotic on some early apoptotic GIST cell populations. Further studies are warranted to fully illuminate the function of DOG1 and its potential as therapeutic target.
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- Aad, G., et al.
(författare)
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Commissioning of the ATLAS Muon Spectrometer with cosmic rays
- 2010
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Ingår i: European Physical Journal C. Particles and Fields. - : Springer Science and Business Media LLC. - 1434-6044 .- 1434-6052. ; 70:3, s. 875-916
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Tidskriftsartikel (refereegranskat)abstract
- The ATLAS detector at the Large Hadron Collider has collected several hundred million cosmic ray events during 2008 and 2009. These data were used to commission the Muon Spectrometer and to study the performance of the trigger and tracking chambers, their alignment, the detector control system, the data acquisition and the analysis programs. We present the performance in the relevant parameters that determine the quality of the muon measurement. We discuss the single element efficiency, resolution and noise rates, the calibration method of the detector response and of the alignment system, the track reconstruction efficiency and the momentum measurement. The results show that the detector is close to the design performance and that the Muon Spectrometer is ready to detect muons produced in high energy proton-proton collisions.
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