The Role of Transitional B cells in Kidney Transplantation Tolerance

Previous studies aimed at identifying biomarkers of tolerance in kidney transplant patients have revealed an expansion of peripheral blood B cells and over- expression of B cell-related genes. In humans, Memory, Naïve and Transitional B cells are the main B cell subsets found in circulation, and it is has been shown that the Transitional subset, defined by its regulatory properties, is expanded in tolerant recipients compared to non-tolerant kidney transplant patients. However, the role this population plays in kidney transplantation tolerance remains unclear. Here, we report three different mechanisms to explain the contribution of B cells in transplantation tolerance.<br/><br/>Kidney transplant patients were divided into five groups; tolerant, stable, monotherapy, patients who lost tolerance and chronic rejector. In addition, this study also included a group of age/gender-matched healthy volunteers. B cells from each group of patients were tested for antigen presentation, antibody production, cytokine production, and co-stimulatory function.<br/><br/>B cells from tolerant patients produced higher levels of IL-10 and lower levels of TNF-α than B cells from chronic rejector after CD40 and CpG activation. Moreover, B lymphocytes from tolerant patients also exhibited a failure in the BCR signalling pathway, suggesting a certain degree of anergy or responsiveness by these cells. Donor- specific assays revealed that B cells from tolerant patients were inefficient to recognise donor-antigens, compared to B cells from chronic rejector. This impairment prevented the triggering of the Th1 response by recipient CD4+ T cells and donor-specific antibody production by Plasma cells. Finally, Transitional B cells were the lowest CD4+ T cell- activating cells, compared to Naïve and Memory B cells. This reduced CD4+ T cell activation was due to low cell viability, reduced CD86 expression and high IL-10 production.<br/><br/>In conclusion, these data suggest that B cells from kidney tolerant recipients contributed to maintaining organ acceptance and graft survival by donor-specific and non-specific regulatory properties exhibited by all their subsets, especially Transitional B cells.<br/>

Name dc:type.qualificationname

Doctor of Philosophy

Level dc:type.qualificationlevel

Doctoral Thesis

Grantor dc:publisher.institution

King's College London

Year dc:date.issued

2014

Author dc:creator

• Nova Lamperti, Estefania

Advisors dc:contributor.advisor

• Lombardi, Giovanna
• Hernandez Fuentes, Maria Puerto

Language dc:language

eng

Identifier

oai:kclpure.kcl.ac.uk:studenttheses/53e3fda4-26d6-4cbb-8c03-e667bab85705

OAI identifier oai:identifier

oai:kclpure.kcl.ac.uk:studenttheses/53e3fda4-26d6-4cbb-8c03-e667bab85705