Induction Therapy Modulates the Proportions of CD14+CD16+ and CD14+CD163+ Monocytes in Kidney Allograft Recipients.

Peripheral blood monocytes represent highly efficient effector cells of innate immunity subdivided into different subpopulations by the expression level of membrane antigens. A pro-inflammatory (intermediate/nonclassical) subpopulation of monocytes is defined by expression of CD16 while CD163 seems to be preferentially expressed by immunosuppressive monocytes. The aim of our prospective observational study was to monitore changes of peripheral monocyte subpopulations in early phases of kidney allograft transplantation with regard to different modes of induction immunosuppressive therapy. In total, 20 healthy controls and 71 patients who underwent renal transplantation from a deceased donor were enrolled in the study. The phenotype of peripheral blood monocytes was evaluated by flow cytometry in defined time points. In order to assess the direct effect of immunosuppressives, the proportions of monocyte subpopulations CD14+CD16+ and CD14+CD163+ were evaluated in cultured PBMC exposed to rATG, basiliximab, and methylprednisolone. The proportions of peripheral CD14+CD16+ monocytes were downregulated immediately after the kidney transplantation and basiliximab treatment partially attenuated this trend. The transient downregulation of the CD14+CD16+ subpopulation was adjusted to basal values in two months. The proportions of CD14+CD163+ monocytes were transiently upregulated early after the kidney transplantation and remained higher during the first month in most patients. In ATG treated patients, the expansion of CD14+CD163+ monocytes was delayed but their upregulation lasted longer. In vitro data showed the direct effect of ATG and methylprednisolone on expression of CD16 and CD163 molecules while basiliximab did not affect the phenotype of cultured monocytes. We assume from our data that kidney allograft transplantation is associated with modulation of monocyte subpopulations (CD14+CD16+ and CD14+CD163+) partially affected by an immunosuppressive regime used. Supported by the Grant Agency of the Czech Republic No.: P301/11/1568