The effect of erythropoietin and blood transfusions on highly sensitized patients on a single cadaver renal allograft waiting list

Effect of red cell transfusions on future kidney transplantation

Red cell transfusions, erythropoiesis-stimulating agents (ESAs), and intravenous iron therapy all have a place in the treatment of anemia associated with CKD. Their relative merits and uses are subject to many clinical and nonclinical factors. New concerns associated with the use of ESA therapy make it likely that the use of blood transfusions will increase, refueling previous debates about their associated risks. Data on whether red cell transfusions increase sensitization to HLA antigens, rendering subsequent transplantation more problematic, are mainly derived from older literature. Older data suggested that women were more at risk of HLA sensitization than men, particularly those with previous multiple pregnancies, although recent U.S. Renal Data System data have challenged this. HLA sensitization prolongs the waiting time for transplantation and reduces graft survival. Leukocyte depletion of red cells does not appear to reduce the risk of HLA sensitization. This review summarizes much of the data on these issues, as well as highlighting the need for further research on the potential risks for blood transfusion in patients with CKD.

Red blood cell transfusions in children awaiting heart transplantation

In children awaiting heart transplantation, the benefits of RBC transfusion must be weighed against the potential risks of allosensitization. We sought to describe the use of RBC transfusion and erythropoietin in children with heart failure, as well as assess the impact of these measures on allosensitization. Hospitalized patients listed for heart transplantation between 1/03 and 12/10 were included in the analysis. We excluded patients supported by mechanical support or those highly sensitized prior to listing. Sixty-seven subjects (median age of 6.2 yr) met inclusion criteria. The mean waitlist time was 19.5 days. The majority of subjects, 50 (75%), received at least one RBC transfusion while listed. For those who were transfused, the median number of RBC transfusion events was 3, range: 1-8. Erythropoietin was given to 37 (55%) of subjects. Erythropoietin administration was not associated with subsequent need for transfusion (p = 0.61). Of the 50 subjects who received RBC transfusion, none developed significant elevation of serum PRA by the time of transplant. RBC transfusion may be commonly undertaken in hospitalized children awaiting transplantation. The likelihood of allosensitization following leukoreduced RBC transfusion is extremely low. The benefits of routine erythropoietin administration to reduce the need for transfusion remain to be determined.

Antibodies in alloimmunized uraemic patients treated with recombinant erythropoietin

We have retrospectively analysed sera from 52 already sensitized uraemic patients collected over 1 year and compared erythropoietin (EPO)-treated with non-EPO-treated patients. Significantly fewer (P<0.01) patients (33%) on dialysis because of the rejection of their kidney grafts received EPO than patients on dialysis because of underlying kidney disease (71%). EPO treatment reduced the number of additional blood transfusions, since 3/28 EPO-treated but 12/24 non-EPO-treated patients were given blood (P<0.05). Among the EPO-treated patients, 64% showed a loss of panel-reactive antibodies (PRA), as measured by the micro-lymphocytotoxic technique, while only 12.5% of the non-treated patients showed a loss of PRA (P<0.01). In the subgroup of transplanted patients, PRA loss was only found among the EPO-treated patients, but their number was small (P<0.05). The class, subclass and specificities of the antibodies, as determined by FACS (flow cytometry) analyses, showed no distinct differences between EPO- and non-EPO-treated patients. The differences were significant between transfused and previously transplanted patients.

Prospective analysis of the factors influencing the antibody response to hepatitis B vaccine in hemodialysis patients

Hepatitis B vaccine is effective in producing protection against hepatitis B virus (HBV) infection in hemodialysis (HD) patients, but the antibody response is variable. To identify those factors implicated in the vaccine response, in a prospective study over a 24-month period, we vaccinated 80 seronegative patients on HD (group A) and monitored clinical, biochemical, and immunologic parameters. The protective immunity acquired by vaccination was compared with that developed through HBV infection in 22 age-matched HD patients (group B). The anti-HBs antibody-seronegative patients followed a four-dose vaccination schedule (0, 1, 2, and 6 months) with 40 microg DNA-recombinant hepatitis B vaccine. One month after vaccination, 77.5% of the patients had seroconverted, and 72.5% achieved high antibody response, whereas 22.5% were nonresponders. Patients aged younger than 40 years seroconverted 100%; those aged 40 to 60 years, 75% (P < 0.01); and patients older than 60 years, 74% (P < 0.001). No differences between responders and nonresponders concerning sex, time on HD, HD dose, nutritional status, hemoglobin level, HD membrane, iPTH level, calcitriol treatment, or number of transfusions during vaccination were found. The presence of other factors, such as recombinant human erythropoietin (rHuEPO) therapy or hepatitis C virus (HCV) infection, did not significantly influence antibody responses to hepatitis B immunization. A greater frequency of DR3 (53.8% v 25.7%, P < 0.05), DR7 (53.8% v 18.6%, P < 0.01), and DQ2 (76.9% v 44.1%, P < 0.05), and a lesser frequency of A2 (7.7% v 37.2%, P < 0.05) were found in nonresponders compared with responders. Eighteen months after vaccination, the analysis showed similar antibody titers but lower seroconversion rates in group A as compared with group B. In conclusion, unresponsiveness to hepatitis B vaccine in HD patients was related to factors such as older age, the presence of DR3, DR7, and DQ2, and the absence of A2 alleles. Although the seroprotection produced by the vaccine was less than that achieved through natural HBV infection, our protocol of vaccination was sufficiently immunogenic and provided lasting protection.

Recombinant human erythropoietin therapy in children on dialysis

The addition of recombinant human erythropoietin (rHuEPO) to the therapeutic regimen for children with chronic renal failure (CRF) is one of the most important improvements in care in the last 20 years. Anemia had played an important role in the morbidity of chronic dialysis treatment. Before the availability of rHuEPO, repeated erythrocyte transfusions provided incomplete treatment and had significant long-term sequelae. Recombinant erythropoietin treatment resulted in the amelioration of anemia and marked reduction in transfusions. Additional benefits of the correction of anemia with rHuEPO include improvements in exercise tolerance and regression of ventricular hypertrophy. Many rHuEPO-treated patients have had subjective increases in appetite, but there has been no consistent improvement in dietary intake or anthropometric measures. Correction of anemia with rHuEPO has not been shown to improve the growth of children with CRF receiving dialysis. The most significant adverse effects of rHuEPO are the development of iron deficiency and the exacerbation or development de novo of hypertension. RHuEPO treatment has been shown to treat the anemia of CRF in children safely and effectively. In most cases, putative inhibitors of erythropoiesis and blood loss can be overcome. Many of the symptoms previously ascribed to "uremia" have improved with correction of anemia. The full implications of treatment of anemia with rHuEPO will be clearer when the health outcomes for children who never become severely anemic or require transfusions are more completely studied.

Evidence-based recommendations for the clinical use of recombinant human erythropoietin

In an era of increasing scrutiny regarding use of health care resources, it is critical that physicians have rational, evidence-based guidelines for treatment decisions. This review of more than 200 published papers constitutes a comprehensive approach to evaluating the current evidence regarding the clinical use of recombinant human erythropoietin therapy in renal failure patients. After this review, specific recommendations are provided regarding who should receive r-HuEPO; what the target hemoglobin should be; the best route of administration of r-HuEPO; how iron status should be evaluated and managed; and monitoring and follow-up of patients taking r-HuEPO. Throughout the article, areas for important future research are also identified.

Anemia of uremia is associated with reduced in vitro cytokine secretion: immunopotentiating activity of red blood cells

Many in vitro studies demonstrate various stimulatory effects of red blood cells (RBC) on T cell reactivity. Only a few suggest a role for RBC in vivo, such as decreased B and T cell function in iron deficiency anemia. Immune deficiency of uremia is only partially corrected by dialysis treatment. We postulated therefore that this anemia may contribute in part to the immune deficiency of uremia. The aim of our study was to evaluate this postulate and to investigate the role RBC may have in the immune system in vivo. The in vitro secretion of interleukin-2 (IL-2), gamma-interferon (gamma-IFN), tumor necrosis factor (TNF) and colony stimulating factor (CSF) by human peripheral blood mononuclear cells isolated from patients and controls was used as a measure of immune function. The following protocols were carried out: IL-2 secretion was measured in patients with end-stage renal disease (ESRD) and in controls. RBCs were transfused to patients with ESRD and secretion of cytokines was measured before, and 4 hours, 4, 7 and 14 days afterwards; patients with ESRD received recombinant human erythropoietin (rHuEpo) and secretion of cytokines was measured before treatment and two and four months later. Finally, the effect of phlebotomy and transfusion of the autologous blood on cytokine secretion in healthy subjects was measured. Secretion of IL-2 by patients with ESRD was substantially lower than that of healthy subjects. In each group, IL-2 secretion correlated positively with hemoglobin level, r = 0.73, P < 0.01 and r = 0.71, P < 0.01.(ABSTRACT TRUNCATED AT 250 WORDS)

Immunomodulatory action of human recombinant erythropoietin in man

Recent findings suggest that recombinant human erythropoietin (rhEpo) may have an immunomodulating action. We have studied the in vitro and in vivo effects of rhEpo on immune functions in man. Low pharmacological concentrations of the hormone inhibit T-cell activation and proliferation, while higher ones are without that effect. The same Epo concentrations inhibit mitogen- and alloantigen-driven B-cell differentiation and immunoglobulin synthesis and, to a lesser extent, B-cell proliferation. In vivo treatment with rhEpo causes an initial inhibition of T- and B-cell proliferation, but with prolonged administration improved responsiveness is observed. Our data support the notion that rhEpo can regulate immune functions, a fact of potential clinical application.