Different reconstitution of peripheral blood lymphocytes and dendritic cells in liver and kidney transplant patients

T cells and dendritic cells are responsible for immune alloreactivity or tolerance after transplantation. In this study, we compared the levels of circulating T, B, and NK lymphocytes, as well as monocytes, plasmacytoid dendritic cells, and myeloid dendritic cells, in adult patients undergoing a liver transplant or kidney transplant. Our findings show that candidates for liver transplant had significantly lower levels of circulating T, B, and dendritic cells than candidates for kidney transplant. Nevertheless, liver transplant patients showed a greater T-cell recovery, despite the use of thymoglobulin, as compared with kidney transplant patients who were induced with Daclizumab. In four kidney transplant patients with allograft rejection we observed a dramatic drop of circulating T and dendritic cells at the time of rejection, and while myeloid dendritic cells and CD4⁺ and CD8 ⁺ cells rapidly recovered after 1 month, plasmacytoid dendritic cells and CD4⁺CD25⁺ T-cell numbers remained significantly lower than in patients without rejection. Future studies will evaluate the monitoring of circulating CD4⁺CD25⁺ T cells and myeloid dendritic cell:plasmacytoid dendritic cell ratio as potential biomarkers for rejection or, alternatively, for withdrawal of immune suppression.