Short-term administration of recombinant human erythropoietin decreases B cell number in human peripheral blood

There are conflicting results on the influence of recombinant human erythropoietin (rHuEPO) administration to lymphocytes, especially to B cells.

We analyzed peripheral white blood cell (WBC) subsets in patients who received one bolus administration of rHuEPO. 119 autologous blood donors were enrolled in this study. Fourty-nine out of them were treated with rHuEPO. Blood samples were obtained before the first phlebotomy and one week later before the second one. By flow cytometry, we measured the numbers of WBC, lymphocytes, dendritic cells, CD4+ T cells, CD8+ T cells, natural killer (NK) cells, B cells, monocytes, and neutrophils, further details of B cell subsets.

In the EPO-treatment group, absolute numbers of lymphocytes, especially CD8+ T cells, NK cells, and B cells, significantly decreased after rHuEPO administration. In B cell subsets, absolute numbers of naïve B cells and IgD^-CD27^- B cells significantly decreased. Other B cell subsets, such as transitional B cells, memory B cells, and marginal zone B cells, also showed a decreasing trend.

These findings suggest that a single administration of rHuEPO can influence human immune system via reduction of B cell number in peripheral blood.