Chemokine levels and proportions of peripheral immune cells in kidney allograft recipients

RATIONALE: Kidney transplantation is associated with a recruitment of immune cells into the allograft mediated by release of multiple chemokines from parenchymal cells, endothelium and immune cells.The aim of this study was to correlate serum levels of selected chemokines with proportions of immune cells in the peripheral blood of kidney allograft recipients.

METHODS: Fifty seven patients who underwent renal allograft transplantation were monitored for one year. Serum concentrations of CXCL8/IL-8, CXCL5/ENA-78, CCL2/MCP-1, CCL4/MIP-1β and CCL5/RANTES were measured by Luminex, immunophenotyping of immune cells was performed by flow cytometry.

RESULTS: Serum levels of CCL2, CCL4 and CCL5 were downregulated during the first week after the kidney transplantation. During the first months, CCL2/MCP-1 serum levels negatively correlated with the absolute numbers of lymphocytes (day 7, day 14, day 21, 1 month) and monocytes (day 7, day 14, day 21, 1 month, 2 months, 3 months). Serum concentrations of CCL4/ MIP-1β and CCL5/RANTES showed rather unconsistent relationships to peripheral leukocyte numbers and for both two CXCL chemokines attracting neutrophils, no correlation was found. With respect to proportions of immune cells, downregulation of proinflammatory CD14+CD16+ monocytes associated with upregulation of CD14+CD163 monocytes (related to M2 macrophages) was observed immediately after the kidney transplantation independently on chemokine serum levels.

CONCLUSIONS: We conclude from our data that CCL2/MCP-1 levels in peripheral blood of kidney allograft recipients might reflect the recruitment of lymphocytes and monocytes into the graft. Dynamic changres in monocytic CD14+CD16+ and CD14+163+ subpopulations after the transplantation are not significantly related to chemokine serum levels.