Heart transplantation (HTx) is now an established therapy for end-stage cardiac failure not responding to medical treatment. Recent decades have seen improved outcome following HTx due to more effective and targeted immunosuppressive therapy. However, acute and chronic rejection remains a major cause of morbidity and mortality. At the same time, immunosuppressive strategies are associated with significant side effects, including development of tumours. Hence, the induction of immunologic tolerance to alloantigen is considered the “holy grail” of transplant research. T regulatory cells (Tregs) are a subset of T cells that appear to suppresscytotoxic cell and initiate tolerance to foreign tissues. The Tregs suppresscytotoxic cells through specific cytokine pathways and cell-cell contact. In-vivo T reg migration has been a matter of debate in recent years. Treg trafficking is governed by chemokines, which are small secreted proteins, acting via their distinct trans-membrane serpentine receptors. Experimental work has demonstrated an involvement of distinct chemokine pathways in Tregs migration and localization following cardiac transplantation; however, there is paucity of data in humans. I investigated the effects of chemokines on Tregs in heart transplant recipients through a series of observational studies. My study demonstrated that acute rejection following heart transplantation is associated with a significant elevation of peripheral blood Th1 chemokine levels. I hereby further show that peripheral blood Treg counts in stable heart transplant recipients are not affected by immunosuppression but are significantly lower in patients taking statins. I have demonstrated via in-vitro chemotaxis assays a specific pattern of chemotactic response for Tregs and the effector T cells. Using double immunofluorescence staining and immunostaining, I show for the first time that Tregs may migrate to the allograft under the influence of CCL17.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:551313 |
| Date | January 2011 |
| Creators | Khan, Nouman Ullah |
| Contributors | Yonan, Nizar |
| Publisher | University of Manchester |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Source | https://www.research.manchester.ac.uk/portal/en/theses/the-effect-of-chemokines-on-t-regulatory-cellsfollowing-heart-transplantation(6b5b194d-f2fd-4869-9b22-95ce099ac3ed).html |
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