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Please use this identifier to cite or link to this item: http://hdl.handle.net/11375/27354
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dc.contributor.advisorNazy, Ishac-
dc.contributor.advisorArnold, Donald-
dc.contributor.advisorKelton, John-
dc.contributor.authorVrbensky, John-
dc.date.accessioned2022-02-03T16:27:20Z-
dc.date.available2022-02-03T16:27:20Z-
dc.date.issued2022-
dc.identifier.urihttp://hdl.handle.net/11375/27354-
dc.description.abstractImmune thrombocytopenia (ITP) is an autoimmune bleeding disorder characterized by a low platelet count (less than 100 x 10^9 platelets/L) and an increased risk of bleeding. ITP is difficult to diagnose and manage due to the deficiencies in our understanding of the pathophysiological mechanisms leading to thrombocytopenia. Anti-platelet autoantibodies are believed to be the primary mechanism of thrombocytopenia in ITP. In this thesis, I demonstrate that autoantibodies can only be detected in half of all ITP patients; therefore, other mechanisms should be investigated. CD8+ T cells have been implicated as a mechanism of disease in ITP, but platelet-specific CD8+ T cells have yet to be identified. I have characterized CD8+ T cells in ITP patients and found that platelet-specific CD8+ T cells can be detected in ITP patients. These platelet-specific CD8+ T cells can also be detected in healthy individuals, so they are not specific to ITP. However, regulatory defects were observed in ITP patients and CD8+ T cell activity was elevated in ITP patients relative to healthy individuals and thrombocytopenic non-ITP patients. Investigating whether platelet-specific CD8+ T cells can actively participate in platelet destruction and underproduction will be an essential step towards better understanding the role of CD8+ T cells as a disease mechanism in ITP, which will lead to improvements in the management of ITP.en_US
dc.language.isoenen_US
dc.subjectimmune thrombocytopeniaen_US
dc.subjectplateletsen_US
dc.subjectcd8+ t cellsen_US
dc.subjectautoimmunityen_US
dc.titleThe Characterization of CD8+ T Cells as a Potential Mechanism of Disease in Immune Thrombocytopeniaen_US
dc.typeThesisen_US
dc.contributor.departmentMedical Sciencesen_US
dc.description.degreetypeThesisen_US
dc.description.degreeDoctor of Philosophy (PhD)en_US
dc.description.layabstractPlatelets are small blood cells that are involved in minimizing blood loss at the site of a wound by forming a plug. In a disease called immune thrombocytopenia (ITP), patients have a low platelet count, which can result in bleeding. The bleeding symptoms of ITP decrease the quality of life for ITP patients and can be life-threatening in rare cases. It is believed that ITP is caused by proteins produced by the immune system called antibodies. I found that the antibodies that cause ITP can only be detected in half of all ITP patients. Therefore, there are probably additional causes of ITP. It is suspected that CD8+ T cells might cause ITP in some patients. CD8+ T cells are part of the immune system and they typically destroy other cells that are cancerous or infected by viruses. CD8+ T cells might also destroy healthy cells, like platelets. My goal was to characterize CD8+ T cells in order to determine their role in ITP. I found that CD8+ T cells from ITP patients can target platelets, and that healthy people have these CD8+ T cells as well. In regard to CD8+ T cells that target platelets, the difference between ITP patients and healthy people appears to be related to immune system regulation and CD8+ T cell activity. In the future, we should focus on understanding how platelet-specific CD8+ T cells can cause a low platelet count in order to improve the clinical management of ITP.en_US
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