Flow cytometric analysis of leukocytes eluted from haemodialysers

The cellular immune system is impaired in uraemic and haemodialysed patients. We describe a method of studying leukocytes eluted from dialysers at the end of the dialysis session, and we have studied five haemodialysers: cuprophane (CU), cellulose acetate (CA), polymethylemethacrylate (PMMA), polyacrylonitrile (PN), and polysulphone (PS). The analysis was performed by flow cytofluorimetry using monoclonal antibodies. The absolute number of eluted leukocytes was rather elevated, ranging from 88 (CU) to 9 (PS) millions of cells. When compared to peripheral blood values, the percentage analysis revealed an increase of PMN and monocytes and a decrease of lymphocytes. A relative increase of B lymphocytes was observed in all filters studied. A trapping of T lymphocytes (PAN) and a minor increase of NK cells (PMMA, PS, CA) were also observed. The elution of leukocytes from dialysers may be helpful in evaluating the biocompatibility of membranes for haemodialysis.