The influence of recombinant human erythropoietin on apoptosis and cytokine production of CD4+ lymphocytes from hemodialyzed patients

Erythropoietin induces tumour progression and CD39 expression on immune cells in a preclinical model of triple-negative breast cancer

The adverse effects observed in some cancer patients treated with erythropoiesis-stimulating agents such as erythropoietin (EPO) might be due to the latter's well-known immunosuppressive functions. Here, we used a mouse model of syngeneic triple-negative breast cancer to explore EPO's immunomodulatory role in a tumour setting. Our results showed that EPO treatment promotes tumour growth, exacerbates the 'immune desert', and results in a 'cold tumour'. EPO treatment changed the immune cell distribution in peripheral blood, secondary lymphoid organs, and the tumour microenvironment (TME). Our in-depth analysis showed that EPO mainly impacts CD4 T cells by accelerating their activation in the spleen and thus their subsequent exhaustion in the TME. This process is accompanied by a general elevation of CD39 expression by several immune cells (notably CD4 T cells in the tumour and spleen), which promotes an immunosuppressive TME. Lastly, we identified a highly immunosuppressive CD39+ regulatory T cell population (ICOS+, CTLA4+, Ki67+) as a potential biomarker of the risk of EPO-induced tumour progression. EPO displays pleiotropic immunosuppressive functions and enhances mammary tumour progression in mice.

The influence of a single hemodialysis procedure on human T lymphocytes

At the moment it is unknown to what extent the impaired function of T lymphocytes in ESRD patients depends on uremia, and to what extent on hemodialysis (HD) procedure. Therefore, the purpose of the study was to evaluate percentages of T lymphocyte subpopulations ex vivo, plasma concentrations of IL12p70, TNF, IL-10, IL-6, IL-1β, IL-8 cytokines and selected proliferation parameters of in vitro activated T lymphocytes in HD patients before and after single HD procedure using flow cytometry. We demonstrated that the percentage of CD8⁺ cells ex vivo was decreased while the CD4⁺/CD8⁺ ratio was increased after HD procedure. Also, there was significant decrease in the percentage of CD8⁺HLA-DR⁺, CD8⁺CD69⁺ and CD8⁺CD95⁺ cells after HD. At the same time, an increase in the percentage of CD4⁺CD95⁺ cells was observed after HD. From all analyzed cytokines, only the concentration of IL-8 was significantly decreased after HD procedure. A single HD session enhanced proliferation capacity of CD4⁺ cells but not CD8⁺ cells in vitro by increasing number of cell divisions and percentage of dividing cells. Our results show that a single hemodialysis can have immunomodulatory effect on HD patients and may contribute to the state of immune deficiency observed in patients with ESRD.

Effect of Erythropoietin on Lymphocytes Apoptosis in Experimental Chronic Renal Failure

Recombinant human erythropoietin was injected intraperitoneally in a total dose of 900 U/kg to rats with experimental chronic renal failure. Suspension of lymphocytes from animals with chronic renal failure was used in vitro, erythropoietin was used in concentrations of 30, 15, 7.5, 3.75, and 1.88 U/liter. Intact cells (Annexin-5-FITC(-)/7-AAD(-)), cells with early signs of apoptosis (Annexin-5-FITC(+)/7-AAD(-)), cells with late signs of apoptosis and partially necrotic cells (Annexin-5-FITC(+)/7-AAD(+)), as well as cells with early signs of necrosis (Annexin-5-FITC(-)/7-AAD(+)) were differentiated by fl ow cytometry. It was found that the number of peripheral blood lymphocytes with early and late signs of apoptosis and necrosis increased in chronic renal failure. Erythropoietin at a total dose of 900 U/kg reduced the number of blood lymphocytes with signs of apoptosis and necrosis and thus elevated the number of intact lymphocytes. Erythropoietin in concentrations ranging from 1.88 to 30.0 U/liter dose dependently lowered the number of lymphocytes with early signs of apoptosis and the number of lymphocytes with the signs of late apoptosis and necrosis in vitro.

Changes in the Expression of Transcription Factors Involved in Modulating the Expression of EPO-R in Activated Human CD4-Positive Lymphocytes

We have recently described the presence of the erythropoietin receptor (EPO-R) on CD4⁺ lymphocytes and demonstrated that its expression increases during their activation, reaching a level reported to be typical for erythroid progenitors. This observation suggests that EPO-R expression is modulated during lymphocyte activation, which may be important for the cells’ function. Here we investigated whether the expression of GATA1, GATA3 and Sp1 transcription factors is correlated with the expression of EPO-R in human CD4⁺ lymphocytes stimulated with monoclonal anti-CD3 antibody. The expression of GATA1, GATA3 and Sp1 transcription factors in CD4⁺ cells was estimated before and after stimulation with anti-CD3 antibody by Western Blot and flow cytometry. The expression of EPO-R was measured using real-time PCR and flow cytometry. There was no change in the expression of GATA1 and GATA3 in CD4⁺ lymphocytes after stimulation with anti-CD3 antibody. However, stimulation resulted in the significantly increased expression of the Sp1 factor. CD4⁺ lymphocytes stimulated with anti-CD3 antibody exhibited an increase in both the expression level of EPOR gene and the number of EPO-R molecules on the cells’ surface, the latter being significantly correlated with the increased expression of Sp1. Sp1 is noted to be the single transcription factor among the ones studied whose level changes as a result of CD4⁺ lymphocyte stimulation. It seems that Sp1 may significantly affect the number of EPO-R molecules present on the surface of activated CD4⁺ lymphocytes.