Evidence that treatment of ESRD patients with recombinant human erythropoietin induces immunosuppression without affecting the distribution of peripheral blood mononuclear cell subpopulations.

Fifteen patients with end-stage renal disease (ESRD) were blood sampled before and 1-, 2-, 3-, and 6 months after institution of recombinant human erythropoietin (r-HuEPO) therapy. Subpopulations of immunocompetent peripheral blood mononuclear cells (PBMC) were analyzed by flow cytometry using monoclonal antibodies against various T-lymphocyte antigens, B-lymphocytes, natural killer (NK)-cells, monocytes, and macrophages, and finally bone marrow progenitor cells. Functional properties of peripheral T-lymphocytes were analyzed by proliferation assays with mitogens, alloantigens and microbiological antigens. All patients but 3 responded with sufficient correction of the anaemia. The absolute number of leucocytes and lymphocytes remained unchanged during the study. Likewise, a remarkable intraindividual months to month constancy in the relative distribution of all PBMC subsets analyzed was recorded during the observation period, although some interindividual variability was observed. In contrast, the T-lymphocyte responsiveness decreased significantly except for 2 out of 11. We conclude, that treatment of renal anemia with r-HuEPO seems to induce immunosuppression in ESRD patients without affecting the distribution of various PBMC subsets.