Immunomodulatory action of human recombinant erythropoietin in man

Extensive viral mimicry of 22 AIDS-related autoantigens by HIV-1 proteins and pathway analysis of 561 viral/human homologues suggest an initial treatable autoimmune component of AIDS

HIV-1 viral proteins, particularly the env protein, are homologous to 22 AIDS autoantigens, suggesting their creation by antiviral antibodies subsequently targeting human homologues. They include antibodies to T-cell receptors, CD4 and CD95, complement components, IgG, TNF and other immune-related proteins. Autoantibodies may compromise the immune system via knockdown of these key proteins, and autoimmune attack on the immune system itself, as supported by immune activation in early stages of infection and during the transition to AIDS. Over 500 human proteins contain pentapeptides or longer consensi, identical to viral peptides. Such homology explains the extensive viral/human interactome, likely related to the ability of viral homologues to compete with human counterparts as binding partners. Pathway analysis of these homologous proteins revealed their involvement in immune-related networks (e.g. natural killer cell toxicity/toll, T-cell/B-cell receptor signalling/antigen processing) and viral and bacterial entry and defence pathways (phagosome/lysosome pathways, DNA sensing/NOD/RIG-1 pathways) relevant to AIDS pathogenesis. At its inception, AIDS may have an autoimmune component selectively targeting the immune system. Immunosuppressive therapy or antibody removal, which has already achieved some success, might be therapeutically beneficial, particularly if targeted at removal of the culpable antibodies, via affinity dialysis.

Absence of hematological side effects in acute and subacute nasal dosing of erythropoietin with a low content of sialic acid

The use of human recombinant erythropoietin (EPO) as a neuroprotective agent is limited due to its hematological side effects. An erythropoietin along with a low content of sialic acid (rhEPOb), similar to that produced in the brain during hypoxia, may be used as a neuroprotective agent without risk of thrombotic events. The objective of this investigation was to assess the toxicological potential of a nasal formulation with rhEPOb in acute, subacute and nasal irritation assays in rats. Healthy Wistar rats (Cenp:Wistar) were used for the assays. In an irritation test, animals received 15 μl of rhEPOb into the right nostril. Rats were sacrificed after 24 h and slides of the nasal mucosa tissues were examined. Control and treated groups showed signs of a minimal irritation consisting of week edema and vascular congestion in all animals. In the acute toxicity test, the dose of 47,143 UI/kg was administered by nasal route. Hematological patterns, body weight, relative organ weight, and organ integrity were not affected by single dosing with rhEPOb. In the subacute toxicity test, Wistar rats of both sexes received 6,600 UI/kg/day for 14 days. The toxicological endpoints examined included animal body weight, food consumption, hematological and biochemical patterns, selected tissue weights, and histopathological examinations. An increase of lymphocytes was observed in males that was considered to reflect an immune response to treatment. Histopathological examination of organs and tissues did not reveal treatment-induced changes. The administration of rhEPOb at daily doses of 6,600 UI/kg during 14 days did not produce hematological side effects. These results suggest that rhEPOb could offer the same neuroprotection as EPO, without hematological side effects.

The use of pretransplant erythropoietin to normalize hemoglobin levels has no deleterious effects on renal transplantation outcome

BACKGROUND

The aim of this study was to establish the outcome of renal transplantation in patients given pretransplant erythropoietin (EPO) treatment targeted at reaching a normal hemoglobin concentration (Hb), compared to those given EPO-treatment aimed at maintaining subnormal Hb.

METHODS

A total of 416 patients from Scandinavian countries and with renal anaemia were enrolled to examine the effects of increasing Hb from a subnormal level (90-120 g/liter) to a normal level (135-160 g/liter) by EPO treatment. Half of the patients were randomized to have their Hb increased, with the other half randomized to maintain a subnormal Hb. Thirty-two patients from the normal Hb group and 24 patients from the subnormal group received a renal graft during the study period. The outcomes of these transplantations were examined prospectively for 6 months.

RESULTS

Preoperative Hb levels were 143+/-17 and 121+/-14 g/liter in the two groups, respectively (P<0.0001). The Hb remained higher in the normal Hb group during the first 2 weeks after transplantation. The percentage of patients requiring postoperative blood transfusions in the normal Hb group was 16%, compared with 50% in the subnormal group (P<0.01). No statistically significant difference in the proportion of functioning grafts or in the serum creatinine levels could be detected. No correlation between EPO treatment and creatinine levels after transplantation was found. The frequency of adverse events was similar in the two groups.

CONCLUSIONS

EPO treatment aimed at reaching a normal Hb in renal transplant recipients reduces the postoperative requirement for blood transfusions and has no deleterious effects on kidney graft function.

The influence of recombinant human erythropoietin on tumor necrosis factor alpha and interleukin-10 production by whole blood cell cultures in hemodialysis patients

Impaired immunological response in hemodialysis (HD) patients, which leads to inappropriate cytokine production, is partially caused by the hyperstimulation of both T lymphocytes and monocytes/macrophages. Recent data suggest that human recombinant erythropoietin (rhEPO) may have an immunological action. The goal of our study was to estimate the influence of rhEPO treatment on the production of the inflammatory cytokine tumor necrosis factor alpha (TNFalpha) and antiinflammatory cytokin interleukin-10 (IL-10) in 10 HD patients receiving rhEPO for 6 months. The levels of cytokines were measured in the in vitro cultures of whole blood. The level of IL-10 increased in all treated patients during the therapy, and it was accompanied by a transitory decrease of TNFalpha. The results of our studies suggest that rhEPO may reduce the inflammatory process by decreasing production of TNFalpha and increasing production of IL-10.

The acute effect of intravenously administered recombinant human erythropoietin on the immune response of uremic patients maintained on regular hemodialysis

The uremic patient on regular hemodialysis (RHD) is subjected to a wide range of immune modulators including the uremic state per se, multiple transfusions and exposure to bioincompatible materials and endotoxins. Erythropoietin (EPO) therapy may raise concern about its potential influence on this complex scenario. To envisage this issue, 15 adequately selected patients, stable on RHD, were randomly assigned in a 2:1 ratio into EPO and placebo groups. After initial assessment and determination of baseline values, they received, in a double-blind manner, either EPO or normal saline as an intravenous bolus immediately after termination of dialysis for 30 successive sessions. Thirty minutes later, following sessions 1, 10, 20, and 30, samples were obtained for determination of blood counts, red cell indices, peripheral lymphocyte counts (PLC), CD4/CD8 ratios, blood EPO levels, and serum concentrations of interleukins (IL) IL-2r, IL-3, and IL-6, tumor necrosis factor (TNFs and TNFalpha), and neopterin (NPT). Blood EPO levels displayed the predicted rise in the EPO group, which correlated with partial improvement of red cell parameters. The mean total leukocyte count and PLCs was significantly increased in the EPO group (p < 0.05) but not in the placebo group. CD4/CD8 ratios were not significantly changed in either group. The serum concentrations of IL-2r, IL-3, and NPT remained fairly stable while that of IL-6 was widely variable in both study groups. The mean serum concentrations of TNF and particularly TNFalpha showed a steady and statistically significant increment in the EPO group from 6 to 41 pg/ml (p < 0.05) and 93 to 128 pg/ml (p < 0.03), respectively. No significant change was noticed in the control group. It is concluded that intravenous administration of EPO under the conditions of this study may have an immune stimulating effect. This is shown by the release of TNFs, which in turn may be responsible, through different potential mechanisms, for the increase in the mean peripheral neutrophil count and the blunting of erythroid responsiveness to EPO therapy.

Effect of recombinant human erythropoietin on lymphocyte phenotyping and phagocyte activity in hemodialysis patients

The effect of recombinant human erythropoietin (rHmEPO) on lymphocytic phenotyping as well as on the phagocyte activity of polymorphonuclear cells and monocytes was evaluated in 16 patients on maintenance hemodialysis. The mean age of the patients was 38.2 +/- 16.2 years. There were seven men and nine women. All patients were started on 50 U/kg of rHmEPO intravenously three times per week, and the dosage was increased gradually to achieve target haemoglobin of 12 g/dL. Predialysis blood samples were taken monthly for 3 months, and phagocyte respiratory burst as well as lymphocyte subsets were studied. Healthy blood donors were taken as controls. By 3 months of rHmEPO treatment, there was no significant increase in total T and B cells, but there was a significant increase in both CD4 (P < 0.001) and CD8 (P < 0.005): however, there was no significant change in the CD4/CD8 ratio. There was significant reduction in the natural killer cells (P < 0.005). The phagocyte activity studies showed a significant increase in the respiratory burst in whole blood (P < 0.001) and opsonized zymosan (P < 0.001) as well as improvement in the suppressed polymorphonuclear cell and monocyte activity by uremia. Phagocytosis studied by yeast uptake showed significant improvement from the pretreatment suppressed phagocytes to normal activity posttreatment. In conclusion, treatment with rHmEPO increases CD4 and CD8 cell counts without affecting the CD4/CD8 ratio, decreases the natural killer cells, and improves the impaired phagocyte activity in hemodialysis patients.

Effect of pretransplant erythropoietin therapy on renal allograft outcome

Erythropoietin (EPO) is widely used among patients with end-stage renal disease awaiting transplantation. Data suggest that EPO therapy may be immunomodulatory. The purpose of this study was to assess the effects of pretransplant EPO therapy on renal allograft outcome. We evaluated 120 consecutive renal transplant recipients to assess the effect of EPO on graft outcome following renal transplantation. Among the study population, 58 patients were receiving EPO before transplantation (EPO group) and 62 patients were not treated with EPO (non-EPO group). Twenty-four of 58 EPO-treated patients (41%) experienced delayed graft function after transplantation, compared with 11 of 62 (18%) non-EPO-treated patients (P<0.05). The incidence of acute rejection, time to first rejection, and 1-year graft survival rate did not differ between the two groups. In conclusion, pretransplant EPO therapy does not appear to adversely impact on the incidence of acute rejection or 1 year graft survival rate. However, EPO-treated patients may be predisposed to the development of delayed graft function.

The effect of erythropoietin administration on murine bone marrow chimeras

All patients develop anemia after autologous or allogeneic bone marrow transplantation and red blood cell transfusion is almost always required in the post-transplant period. Recently Epo therapy has been employed in the setting of bone marrow transplantation. As bone marrow transplant patients typically suffer from malignancies and are immunocompromised, further immunosuppression should be avoided. Recent reports have suggested that Epo may modulate immune response. We have studied the effects of Epo on immune response in murine bone marrow chimeras. Epo administration resulted in an increase in hematocrit. There was no significant alteration in lymphocyte numbers, although a shift in lymphocytes toward T cell predominance was observed. Epo administration resulted in enhanced cell proliferation in response to T and B cell mitogens, although no alteration in cytotoxicity or natural killer cell activity was observed. No example of Epo-induced impaired immunity was observed.

Long-term therapy with recombinant human erythropoietin (rHu-EPO) in progressing multiple myeloma

Recombinant human erythropoietin (rHu-EPO) is an effective growth factor for erythroid progenitor cells in anemia provoked by several conditions, including bone marrow tumors such as multiple myeloma (MM). We studied a group of 54 patients with MM undergoing second-induction chemotherapy. Thirty of them were randomly assigned to receive rHu-EPO at an initial dosage of 150 units/kg body weight three times a week, increased to 300 units/kg from the sixth week to the end of the 24-week study. Hemoglobin (Hb) levels increased in 77.7% of these patients by the eighth week. In addition, five transfusion-dependent patients in treatment with the VMCP protocol completed the trial without requiring blood supplement after the third month, whereas seven control patients required frequent supplements. Monthly assessment of hematologic parameters demonstrated the ability of rHu-EPO to increase reticulocyte counts, whereas five patients became resistant to the second-induction chemotherapy in apparent concurrence with their rHu-EPO therapy. The response to rHu-EPO in four of the five MM patients receiving cytotoxic protocols combined with alpha-interferon (alpha-IFN) included an increase of serum IgM after the third month. This effect was not demonstrable in any other group, including three rHu-EPO-untreated patients undergoing alpha-IFN + VMCP combined therapy, as well as rHu-EPO-treated patients not receiving alpha-IFN. Our data suggest that alpha-IFN plus rHu-EPO treatment in MM patients is effective in restoring normal B cell function. These results may reflect in vivo the modulation of normal human B cells and lymphoblasts by rHu-EPO observed in vitro.

Immunomodulation of T and B cell functions in multiple myeloma patients treated with combined erythropoietin and alpha-interferon therapy

T and B lymphocyte functions were investigated in the course of a long-term trial of recombinant human erythropoietin in patients with progressing multiple myeloma. Peripheral mononuclear cell as well as T and B lymphocyte cultures were established at the 1st, 13th, and last week of the 24-week protocol from 16 treated and 15 untreated patients. Control cultures from healthy individuals were also obtained. A suppression of phytohemagglutinin-induced proliferation of T cells was noted in all 1st-week cultures, whereas a variable increase of 3H-thymidine uptake was noted at the end of the trial in the cultures from erythropoietin-treated patients. A significant increase was observed, however, in cultures from 5 erythropoietin-treated patients who also received alpha-interferon when their cells were grown in the presence of the hormone. In contrast, the pokeweed mitogen-driven in vitro synthesis of immunoglobulins was not significantly influenced by the duration of erythropoietin treatment, nor by addition of the hormone. IgG secretion by Epstein-Barr virus-transformed B cells in cultures from 9 erythropoietin-treated and 6 untreated patients was enhanced in the presence of both recombinant human erythropoietin and alpha-interferon. These data suggest that synergy between the two cytokines may variably modulate certain immune functions in vitro. This effect might account for the increase of serum IgM levels noted in some patients who received alpha-interferon.