CXCR3+ Monocytes Increase Significantly in Graft Blood Compared to Peripheral Blood in Patients With Stable Kidney Graft Function.

INTRODUCTION: We have recently reported that some lymphocyte populations do not maintain the same proportion in kidney graft blood as in peripheral blood, despite a stable function of the transplanted kidney. These results suggest that a comparative study between leukocyte cells from graft blood and those obtained from peripheral blood could provide information about the inflammatory state of the transplanted organ. In this work we selected the population of CD4+ lymphocytes and monocytes expressing CXCR3 to test this hypothesis. MATERIAL AND METHODS: The study was performed by flow cytometry during month 3, 6, and 12 after transplantation in 58 patients who received an isolated kidney transplant and the same immunosuppressive regimen. The peripheral blood sample was obtained by venipuncture and the graft blood by fine needle aspiration. RESULTS: We found a significant percentage decrease in CXCR3+ monocytes throughout the first year of transplantation in peripheral blood (15.9 ± 20.7 vs. 12.6 ± 12.4 vs. 6.3 ± 9.0, at 3, 6, and 12 months, respectively; P = .001), whereas the percentage of CXCR3+ monocytes in graft blood did not change over this period. This situation resulted in a significant percentage difference between the CXCR3+ monocytes from the graft blood and those from the peripheral blood at the sixth (15.8 ± 8.1 vs. 12.6 ± 12.4, respectively; P = .008) and 12th months (12.9 ± 8.1 vs. 6.3 ± 9.0, respectively; P < .001). CONCLUSIONS: Therefore, we can conclude that the significant percentage increase of CXCR3+ monocytes in graft blood with respect to peripheral blood suggests the presence of inflammatory activity despite renal function being stable during the second half of the first year post-transplantation.