Session Time: 5:30pm-7:30pm
Presentation Time: 5:30pm-7:30pm
Location: Exhibit Hall E
Introduction: Monocytes compose a neglected immune cell type in transplantation despite their contribution to antibody mediated rejection. We aimed to define the phenotypic and functional profiles of circulating monocytes in kidney transplant recipients during rejection and non-rejection stable status.
Methods: Using flowcytometry, immunophenotype, activation status and cytokine production capacity of monocytes were determined in a cohort of 33 healthy individuals and in 30 stable patients over time. We performed a case-control study comparing 8 recipients who developed rejection to 8 non-rejecting stable control patients using timely matched blood samples prior to and at rejection or non-rejection.
Results: We documented high frequencies of CD16+ monocytes at all-time points in stable recipients compared to healthy individuals. Monocytes retain their high potential to produce pro-inflammatory cytokines TNF-α, IFN-γ, IL-1β and IL-6 post-transplant despite immunosuppressive drugs and recovered kidney function. Importantly, the percentage of IL10 producing monocytes was even significantly increased post-transplant suggestive of a different monocyte polarization in stable patients. At rejection, balance in the monocyte subset composition was skewed towards a significant decrease in the percentage of circulating CD14++CD16+ monocytes, while the percentage of CD14++CD16- monocytes was increased. Significantly increased expression of HLA-DR, CD40, ICAM-I and CCR2 by CD16+ monocytes was found at the time of rejection pointing towards enhanced antigen presentation and migration capacity. Significantly increased percentages of CD14++CD16+ and CD14+CD16++ monocytes were observed in rejection group at the time of Tx compared with non-rejection group, suggesting an important baseline difference possibly distinguishing those developing a rejection episode from non-rejecting patients.
Conclusion: Altogether, our data refer to the monocyte as an active immune cell type interfering with alloimmune response towards the graft. The frequency of circulating CD16+ monocytes before transplantation seems to predict occurrence of acute rejection.
To cite this abstract in AMA style:Bosch Tvanden, Hilbrands L, Kraaij M, Vereyken E, Leenen P, Hesselink D, Baan C, Rowshani A. Increased Precentage of Circulating CD16+ Monocytes Before Transplantation Are Associated With the Occurence of Acute Rejection [abstract]. Am J Transplant. 2015; 15 (suppl 3). https://atcmeetingabstracts.com/abstract/increased-precentage-of-circulating-cd16-monocytes-before-transplantation-are-associated-with-the-occurence-of-acute-rejection/. Accessed June 24, 2019.
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