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Title: Immunology of granulomatosis with polyangiitis
Author: Zhao, Yuan
Awarding Body: King's College London (University of London)
Current Institution: King's College London (University of London)
Date of Award: 2013
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Granulomatosis with polyangiitis (GPA, formerly known as Wegener’s granulomatosis) is a rare and sometimes fatal systemic autoimmune disease. Anti-neutrophil cytoplasmic antibodies (ANCAs) specific for proteinase 3 (PR3) are associated with GPA. However, the pathogenesis of GPA is not yet clear. Our aim was to investigate the local autoimmune response, circulating immune modulatory cells and cells expressing the immune suppressor molecules programmed death 1 (PD-1) and its ligands in GPA. In mucosa from GPA patients, activated B cells were observed located alongside PR3 expressing cells and B cell survival factors BAFF and APRIL, which was produced by the granulomas and giant cells. B cells were proliferating and persistent in biopsies. However no evidence of B cell clones from the mucosal biopsies circulating in peripheral blood was observed in GPA. An increased frequency of circulating TFH cells and a reduced frequency of Treg cells was observed in peripheral blood from GPA patients on conventional therapies compared to healthy controls. No such difference was found in GPA patients treated with rituximab. The frequency of circulating TFH and Treg cells was found to be inversely correlated in human peripheral blood. No difference in the relative quantity of mRNA encoding PD-1 in lymphocytes and monocytes was found in GPA patients compared with healthy controls. Lower percentage of CD14+ monocytes expressing PD-1 was observed in GPA patients. Lower relative quantity of mRNA encoding PD-1 ligands PD-L1 and PD-L2 in T cells and monocytes was observed in GPA patients. In conclusion, data in this thesis identifies activated B cells alongside auto-antigens and B cell survival factors in the mucosa in GPA. A negative correlation between TFH and Treg cells is observed that implies the balance between T cell subsets and its B cell dependence are associated with disease activity in GPA. The deficiency of PD-L1 and PD-L2 mRNA in lymphocytes and monocytes may contribute to the pathogenesis of GPA.
Supervisor: Zhao, Yuan Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available