Case reports of two patients with complicated outcome of kidney allograft transplantation associated with changes of CD14+CD16+ subpopulation. Patient No.1 is a 56-year old male with delayed graft function and diagnosed acute cellular rejection IIB in early phase following kidney allograft transplantation, treated successfully with thymoglobulin. Patient N. 2 is a 51-year old male with C4d negative humoral rejection (FACSXM positive, presence of MICA antibodies) diagnosed one month after the transplantation. After changing of immunosuppression and subsequent IVIG therapy, the kidney functions became stable. In both cases, the clinical status of patients correlated with proportions of CD14+CD16+ monocytes. TCMR = T cell-mediated rejection, ATN = acute tubular necrosis (absolute numbers of monocyte subpopulations are calculated from the total number of leukocytes and are expressed as number of cells *106/l).