Effect of chronic human recombinant erythropoietin therapy on antibody responses to immunization in chronic hemodialysis patients

Vaccination practices in dialysis patients: A narrative review

In a period of turmoil concerning vaccination practices, there is a serious conflict between scientifically reasonable, evidence-based guidelines and the far-fetched rumors or misconceptions concerning the vaccination practices in the general population. When a significant portion of the medical and paramedical personnel may be deliberately unvaccinated against common biological agents, achieving effective vaccination rates in the dialysis population may be complicated. Vaccination rates are unacceptably low in dialysis patients and seroconversion rates are even lower; further, serological follow-up is generally poor. The particularly anergic immune system of the advanced chronic kidney disease patients is partly a cause of both high rates of infection and low rates of seroconversions. This narrative review is an effort to summarize current knowledge concerning the vaccination practices in dialysis patients with some specific recommendations based on these facts. Of particular interest is a new vaccine, the Zoster Recombinant, Adjuvanted Vaccine (Shingrix), which we will include in our discussion.

Lower Long-term Efficiency of Intradermal Hepatitis b Vaccine Compared to the Intramuscular Route in Hemodialysis Patients

Intramuscular (IM) and Intradermal (ID) vaccination against hepatitis B (HB) are efficient in hemodialysis patients. We retrospectively analysed the response of 32 patients during 48 consecutive months and compared the results of the two vaccination routes using the recombinant vaccine (Engerix, SKB).

Thirteen patients were vaccinated with 5 mcg ID every 2 weeks (total 8 doses), plus an IM dose on month (M) 12 (group A). Nineteen patients (group B) were vaccinated with 4 IM doses of 20 mcg each, on months M0, 1, 2 and 12.

HB antibodies were measured on M5, M11, M13, M24, M36 and M48. An additional 20 mcg IM dose was given with titers below 10 mIU/ml. Seroconversion, seroprotection and antibody levels were equivalent in both groups up to M13; with the exception of seroconversion rates, a significantly different response was observed afterwards (A/B, in mIU/ml): M5: 399 ± 107 vs 342 ± 69, M13: 536 ± 118 vs 673 ± 61, M24: 278 ± 94 vs 595 ± 81, P=0.02, and M48: 68 ± 29 vs 565 ± 92, P=0.003. Early HBSAB levels did not correlate with those found four years later in both groups. An additional booster dose was given 8 times in 4 group A patients (1–3 doses/patient) and 3 times in 1 group B patient.

Immune response to HB vaccine in hemodialysis patients is initially equivalent by both immunization routes. Late antibody titers were found significantly lower in ID immunization with more frequent booster doses needed.

The pleiotropic effects of erythropoietin in infection and inflammation

Erythropoietin (EPO) is a multi-functional cytokine, which exerts erythropoietic effects but also carries anti-apoptotic and immune-modulatory activities upon binding to two distinct receptors which are expressed on erythroid, parenchymal and immune cells, respectively. Whereas EPO ameliorates hemolytic anemia in malaria or trypanosomiasis and improves the course of autoimmune diseases such as inflammatory bowel disease or autoimmune encephalomyelitis, it deleteriously inhibits macrophage functions in Salmonella infection in animal models. Thus, the specific modulation of extra-erythropoietic EPO activity forms an attractive therapeutic target in infection and inflammation.

Immune alterations in untreated and treated myelodysplastic syndrome

INTRODUCTION

Current literature suggests a variety of immune abnormalities are present in myelodysplastic syndrome (MDS) patients. However, they have not been comprehensively characterized or systematized to date. As a result, their clinical implications remain largely unknown. In addition, an increased incidence of various autoimmune conditions has been documented in MDS patients.

AREAS COVERED

The authors offer a comprehensive review of the existing literature on immune mechanisms involved in the pathogenesis of MDS, various immune abnormalities documented in its course, their link with the clonal evolution of MDS as well as immune alterations induced by the existing MDS therapies.

EXPERT OPINION

The course of MDS is accompanied by complex immune alterations, including T-cell and NK-cell defects, decreased functional abilities of neutrophils and antigen-presenting cells, altered antibody and cytokine production. While contemporary MDS therapies are shown to possess some immunomodulatory properties, authentic autoimmune conditions have also been documented with lenalidomide and recombinant erythropoietin. Caution should be exerted with the use of these agents in MDS patients with evidence of autoimmune disorders, as exacerbation of autoimmune phenomena can be anticipated. While the heterogeneity of MDS represents an inherent limitation, integration of emerging information from molecular biology, genetics, immunology research and clinical practice could translate into improved outcomes of this disease spectrum.

Effects of erythropoietin treatment on cell-mediated immune responses in predialysis patients

OBJECTIVE

The effects of erythropoietin (EPO) treatment on the immune functions of dialysis patients have been shown to be controversial and there are only limited data concerning predialysis patients.

MATERIAL AND METHODS

Twenty-four predialysis patients with renal anemia were assigned to subcutaneous EPO treatment, and those in need (n=19) were additionally treated with i.v. iron every other week. We analyzed the effect of the start of EPO treatment on (i) lymphocyte and lymphocyte subclass counts, (ii) lymphocyte stimulation functions and (iii) persisting IgG-class antibody levels to the viral antigens of Epstein-Barr virus and cytomegalovirus.

RESULTS

Our main findings were a decrease in the absolute lymphocyte count, combined with decreases in all the main lymphocyte subclass counts. The absolute number of cells with activation and memory markers remained constant, and therefore their proportion slightly increased. The proliferation responses to phytohemagglutinin, tuberculin and tetanus declined significantly, while the amount of IgG-class viral antibodies remained unchanged, meaning that the humoral side of immunity was not affected by the start of the EPO treatment. Similarly, the proliferation response to pokeweed mitogen, a B-cell mitogen, was unchanged.

CONCLUSIONS

EPO treatment has a suppressive effect on cellular immune functions of predialysis patients. This suppression does not correlate with erythropoiesis, kidney function or iron status.

Intravenous iron attenuates postvaccination anti-HBsAg titres after quadruple hepatitis B vaccination in dialysis patients with erythropoietin therapy

BACKGROUND

Anaemia in patients with end-stage renal disease (ESRD) is commonly treated with recombinant human erythropoietin (rHuEPO), often in combination with an adjuvant iron supplement. There is much evidence that rHuEPO can influence the immune response by its effect on lymphocytes. Also, iron catalyses the formation of radicals and increases the risk of major infections by negatively affecting the immune system. The relationship between antibodies to hepatitis B surface antigen (anti-HBsAg) responsiveness after hepatitis B vaccination and rHuEPO/adjuvant iron supplementation has not been reported before.

AIM

To determine the effects of subcutaneous erythropoietin and intravenous (i.v.) iron therapy on the responsiveness of anti-HBsAg after quadruple hepatitis B vaccination among ESRD patients.

METHODS

Retrospective medical records were reviewed in a hospital with a tertiary teaching facility. Eighty-three ESRD patients, including 51 who underwent haemodialysis and 32 who underwent peritoneal dialysis therapy, received a quadruple recombinant hepatitis B vaccine. We investigated anti-HBsAg titres in those patients who either received rHuEPO alone (n = 50) or rHuEPO in combination with i.v. iron (n = 33).

RESULTS

We found that the postvaccination anti-HBsAg titre was significantly lower in the rHuEPO plus i.v. iron group when compared with the group with rHuEPO alone (p < 0.05). The increment of anti-HBsAg between the initial month and the seventh month was positively correlated with therapeutic rHuEPO dosages in the group with rHuEPO alone (r = 0.303, p = 0.033). This relationship was not present in the rHuEPO with i.v. iron group (r = -0.289, p = 0.229).

CONCLUSIONS

The levels of anti-HBsAg after hepatitis B vaccination are positively correlated with the dose of rHuEPO treatment during the vaccinated period among ESRD patients without i.v. iron supplementation. Also, i.v. iron negatively impacts the responsiveness of anti-HBsAg titre after hepatitis B vaccination in ESRD patients who have undergone rHuEPO therapy.

Disturbances of acquired immunity in hemodialysis patients

Acquired immunity disturbances in hemodialysis (HD) patients are many and diverse. They are caused by uremia per se, the HD procedure, chronic renal failure complications, and therapeutic interventions for their treatment. Current data suggest that acquired immunity disturbances in HD patients concern mainly the T-lymphocyte and the antigen-presenting cell (APC). The T-lymphocyte-dependent immune response is deficient, predisposing to infections and inadequate response to vaccinations. In addition, APCs are preactivated, which seems to be responsible for the malnutrition-inflammation-atherosclerosis syndrome, and also affects T-lymphocyte function. At the molecular level it is assumed that the interaction between the APC and the T-lymphocyte is impaired. This disturbance is likely to concern the signal that results from the interaction between the major histocompatibility complex:peptide complex on APC surfaces and T-cell receptors on T-lymphocyte surfaces, or the signal that results from the interaction among the co-receptors of these two cells. The aim of the present review was to collect and classify the available clinical and experimental data in this area. Although many pieces are still missing from the puzzle, a better understanding of the responsible molecular mechanisms, will potentially lead to increased survival and a better quality of life in HD patients.

Erythropoietin enhances immune responses in mice

Erythropoietin (Epo) is the main erythropoietic hormone. Recombinant human Epo (rHuEpo) is thus used in clinical practice for the treatment of anemia. Accumulating data reveals that Epo exerts pleiotropic activities. We have previously shown an anti-neoplastic activity of Epo in murine multiple myeloma (MM) models, and in MM patients. Our findings that this anti-neoplastic effect operates via CD8+ T lymphocytes led us to hypothesize that Epo possesses a wider range of immunomodulatory functions. Here we demonstrate the effect of Epo on B lymphocyte responses, focusing on three experimental models: (i) tumor-bearing mice, (5T2 MM mouse); (ii) antigen-injected healthy mice; and (iii) antigen-injected transgenic mice (tg6), overexpressing human Epo. In the MM model, despite bone marrow dysfunction, Epo-treated mice retained higher levels of endogenous polyclonal immunoglobulins, compared to their untreated controls. In both Epo-treated wild type and tg6 mice, Epo effect was manifested in the higher levels of splenocyte proliferative response induced in vitro by lipopolysaccharide. Furthermore, these mice had increased in vivo production of anti-dinitrophenyl (DNP) antibodies following immunization with DNP-keyhole limpet hemocyanin. Epo-treated mice showed an enhanced immune response also to the clinically relevant hepatitis B surface antigen. These findings suggest a potential novel use of rHuEpo as an immunomodulator.

Erythropoietin treatment in advanced multiple myeloma is associated with improved immunological functions: could it be beneficial in early disease?

Erythropoietin (Epo) is the main growth regulator of red blood cells, and recombinant human erythropoietin (rHuEpo) is thus used in clinical practice for the treatment of anaemia, primarily in kidney disease and cancer. rHuEpo treatment was found to be associated with prolonged survival of multiple myeloma (MM) patients. This clinical observation was then supported by studies on murine myeloma models. It thus appeared that rHuEpo had an anti-myeloma effect, causally related to an immunomodulatory function of rHuEpo. The present study investigated whether rHuEpo-treated MM patients acquire improved immunological functions. Treatment with rHuEpo, prescribed for anaemia that occurs in advanced disease, was associated with effects on a variety of immunological parameters and functions. This was expressed in an actual normalisation of the CD4:CD8 cell ratio, enhanced T cell phytohaemagglutinin-mediated activation and proliferation potential, T cell expression of the costimulatory CD28 and inhibitory CTLA-4 molecules, as well as reduced interleukin-6 serum values to normal levels. Furthermore, it was demonstrated that immunological abnormalities manifest in patients even in the early stages of MM. Our findings thus suggest that rHuEpo treatment might be effective in the early stages of MM, before anaemia develops. It is expected that this would boost the immune system, consequently achieving an anti-myeloma function; affecting disease progression and improving the prognosis.

Immunologic defects and vaccination in patients with chronic renal failure

Patients with chronic renal failure suffer from defective host defenses which are directly the result of the renal impairment, in addition to those dependent on the primary illness leading to the renal failure. The mechanisms underlying the defective responses in phagocytic cells, lymphocytes and antigen processing are likely due to either failure to adequately eliminate suppressive compounds by the defective kidneys or to improper metabolic processing of the factors by the damaged renal parynchema. That some of the defects are reversed by transplantation and not dialysis suggests that renal parenchymal metabolic activities may be involved, although it is also possible that functioning glomerular cells are capable of filtering substances that membranes are not currently capable of eliminating. The current strategy for dealing with the immunodeficiency appears to be totally based on developing means to circumvent the defective function. The other approach, correction of the impaired function, cannot be even considered until the mechanisms underlying the defective function of the cells involved in defenses are better delineated. It seems possible that one or a few compounds are pivotal in altering the function of all the affected cell lines, since, with only a small amount of effort, it is possible to relate the dysfunction to abnormal cell membrane functions in phagocytic cells, dendritic cells and lymphocytes. Until the biochemical basis of the dysfunction of all the cell types affected are better defined, such exercises cannot be translated into better management of patients with chronic renal failure. Proper function of host defenses requires that appropriate cells can properly respond to threats to host viability. For the cells of the immune system (phagocytes and lymphocytes) this means that their response to regulatory molecules be appropriate, that their mobility be normal, that their adherence to substrates be preserved, and that they can generate the appropriate response to the challenge. For neutrophils, for example, it is necessary that they recognize and mobilize appropriately to chemotactic stimuli, that they be able to adhere to and migrate through endothelial lining, that their phagocytic activity be sufficient, and that they can kill and degrade endocytosed particles and generate appropriate secretions. Similar lists of requirements for good function can be generated for any cell type in the immune defense system. Uremia, as well as currently available treatments for uremia, directly or indirectly alters the function of all phases of appropriate immune cell function. Defective host responses in uremia have been recognized for decades and there has been considerable effort in the past decade to better define the extent and mechanisms of impaired defenses. Despite the multitude of major defects in humoral, cellular, and inflammatory processes, uremic patients who are cared for today, although they remain at higher risk of serious infectious complications, can and do maintain a good quality of life, with most remaining free of major infections for years and decades.

A soluble recombinant multimeric anti-Rh(D) single-chain Fv/CR1 molecule restores the immune complex binding ability of CR1-deficient erythrocytes

CR1 (CD35, the C3b/C4b receptor) is a widely distributed membrane glycoprotein with a unique cluster conformation on the surface of erythrocytes (E). CR1 on E is responsible for the transport of immune complexes (IC) to liver and spleen. As a cofactor of the C3b cleavage by factor I, CR1 is also a potent inhibitor of C activation and inflammation. In some diseases (systemic lupus erythematosus, hemolytic anemia, AIDS, etc.) an acquired low level of CR1 on E has been observed, leading to an impaired clearance of IC. The aim of this study was to design a heterofunctional molecule that will bind to E and restore a normal or a supranormal CR1 density on E that could mimic the unique distribution pattern of CR1 on normal E. For that purpose a new multimerizing system based on the properties of the C-terminal part of the alpha-chain of the C4 binding protein (C4bp) was used. We first produced a multimeric soluble CR1 that proved to be a better inhibitor of in vitro C activation than the monomeric form of CR1, then a heteromultimeric molecule made of CR1 and single-chain Fv anti-Rh(D) valences able to attach E and providing E with as much as a 10-fold increase in CR1 density with the same CR1 distribution pattern as native E. CR1/single-chain Fv anti-Rh(D)-treated E were able in vitro to attach as many opsonized IC as native E. These data open the way for future use of multimeric and heteromultimeric forms of soluble recombinant CR1 as therapy of IC diseases.

Defective immune response to tetanus toxoid in hemodialysis patients and its association with diphtheria vaccination

The incidence of infectious diseases is increased in patients with chronic renal failure. This is thought to be due to an impaired T cell stimulation by antigen presenting cells. Immunization programs are of great significance in the prevention of infections in immunocompromised individuals. However, the immune response to various vaccinations is impaired in patients with chronic renal failure. So far only few studies have focused on seroresponse to tetanus toxoid. Therefore we measured the levels of antitetanus toxoid antibodies in 71 hemodialysis patients with unknown vaccination history. The antibody levels were detected prior to and twelve months after a single "Td" or "Td-d-d" vaccination. Initially only 31 (44%) of the patients had a sufficient protection against tetanus. Of the unprotected patients 15 (38%) seroconverted after immunization, while 25 (63%) did not respond. We found a high association (p < 0.04, Fisher's exact test) between the efficacy of vaccination against diphtheria and tetanus. Out of 38 initially unprotected patients 27 (71%) showed a similar response to both vaccines: 9 (24%) individuals seroconverted, while 18 (47%) did not. Our data clearly demonstrate the need for frequent monitoring of antibody levels after immunization against tetanus and diphtheria in hemodialysis patients.

Low efficiency of active immunization against diphtheria in chronic hemodialysis patients

Recent epidemiological studies indicate a low immunity to diphtheria in adults in industrialized countries. In the light of the epidemic increase of diphtheria in countries such as Russia and the Ukraine, systematic vaccination against this disease is recommended. We analyzed the immunity to diphtheria of 228 hemodialysis patients and the efficiency of single versus triple vaccination against diphtheria. Antibodies against diphtheria toxoid were determined by enzyme immunoassay in sera of 228 adult hemodialysis patients. Fifty-four patients were triple vaccinated against diphtheria and were followed for six months; 17 patients were single immunized and antitoxoid titers were determined 1 and 12 months later. The overall protection rate against diphtheria was 22% and equal in male and female patients. After triple immunization, only 35% of the patients developed protective antibody concentration (> 0.1 i.e./ml) six months after the third vaccination. A single vaccination caused protective titres twelve months later in 41% of the patients. There was no difference between responders and non-responders in the duration, intensity or modality of hemodialysis treatment or the response to previous vaccinations against hepatitis-B. We suggest to monitor antibodies against diphtheria toxoid in vaccinated hemodialysis patients at risk for diphtheria since protective titers are often not attained by the standard vaccination protocol.

The alloimmunized patient: monitoring and therapeutics

The sensitization of renal transplant patients in the form of antihuman leukocyte antigen antibodies often constitutes significant risk to allograft function. Testing for these antibodies is done before, at the time of, and after renal transplantation. Correct interpretation of the results necessitates an understanding of the principles of the tests and of the clinical factors in the patients, especially those receiving another transplant. Treatment remains difficult, although preliminary trials with intravenous gamma globulin have shown promising results in some patients.