Prevalence of Pure Red Cell Aplasia Following Major ABO-Incompatible Hematopoietic Stem Cell Transplantation

Background

Pure red cell aplasia (PRCA) is one of the important complications in major ABO-incompatible allogeneic hematopoietic stem cell transplantation (HSCT). The established pathogenic factor of PRCA is the persistence of high anti-donor isohemagglutinins. As previously verified, the conditioning regimen and donor type were the factors associated with the development of PRCA in the small-sized studies. Currently, the prevalence, risk factors, and prognosis of PRCA are still worth studying to provide evidence.

Methods

We conducted a prospective nested case-control study to determine the prevalence, donor-related factors, and the outcomes of PRCA following major ABO-incompatible transplantation. A total of 469 patients who underwent ABO-incompatible grafts were observed.

Results

None of the patients were diagnosed with PRCA with minor or bidirectional ABO-incompatible HSCT. Thirteen of the187 patients (7%; 95% confidence interval [CI], 3.9%–11.9%) developed PRCA following major ABO-incompatible HSCT. Eleven of the 13 patients with PRCA recovered entirely. Donor type was an independent factor associated with post-HSCT PRCA (odds ratio [OR]=0.030; 95% CI, 0.003–0.321; P=0.004). The cumulative incidence rates of post-HSCT PRCA in the context of major ABO-incompatible HSCT were 0.8%, 13.1%, and 27.2% for the haploidentical donor (HID), unrelated donor, and matched related donor, respectively. No significant influence of PRCA on transplantation outcomes was observed.

In conclusion, post-HSCT PRCA is a rare and less threatening complication in major ABO-incompatible HSCT. The majority of patients with PRCA could recover. Additionally, HIDs for recipients may have a low risk of post-HSCT PRCA. This trial was registered at www.chictr.org.cn (#ChiCTR2000041412).

A Concise Review of Autoimmune Cytopenias in Chronic Lymphocytic Leukemia

Chronic lymphocytic leukemia (CLL) is frequently associated with autoimmune complications such as autoimmune hemolytic anemia, immune thrombocytopenia, pure red cell aplasia, and autoimmune granulocytopenia. It is critical to diagnose cytopenias from these secondary complications of CLL accurately, since prognosis and therapy are substantially different from patients who have cytopenias due to extensive bone marrow infiltration by CLL. The pathogenesis of autoimmune cytopenias in CLL is complex; and it involves antigen presentation by CLL cells to polyclonal B cells resulting in production of autoantibody, and alteration of the T cell milieu tilting the balance in favor of an autoimmune response. Traditional therapy of autoimmune complications in CLL consists of immunosuppression with corticosteroids and/or anti-CD20 monoclonal antibodies. In patients who have a suboptimal response, treating the underlying CLL is generally effective in ameliorating secondary cytopenias. Although novel oral therapies such as ibrutinib, idelalisib, and venetoclax have been shown to be extremely effective in the management of CLL, prospective data from larger numbers of patients with longer follow-up are needed prior to recommending their routine use in the management of autoimmune cytopenias in CLL.

Clinical features and risk factors of pure red cell aplasia following major ABO-incompatible allogeneic hematopoietic stem cell transplantation

The objective of this paper was to study the incidence, risk factors, clinical outcome, management and prevention of pure red cell aplasia (PRCA) following major ABO-incompatible allogeneic hematopoietic stem cell transplantation (allo-HSCT). We retrospectively analyzed 11 cases of PRCA from a series of 42 patients undergoing major ABO-incompatible allo-HSCT from April 1997 to December 2005. Eleven out of the 42 patients developed PRCA (26.1%). All the 11 cases of PRCA were in blood group O recipients of grafts from blood group A donor (n = 9) or blood group B donor (n = 2). The following factors were associated with an increased risk of PRCA: (1) blood group O recipient; (2) blood group A donor; and (3) blood group O/A in recipient/donor pair. Only blood group O/A in recipient/donor pair was identified as being significantly associated with the occurrence of PRCA by multivariate analysis. Six patients who received donor-type plasma exchange did not develop PRCA and among them 5 cases were the blood group O recipients. Eight patients obtained spontaneous remission and in the remaining 3 patients 2 with long-lasting PRCA were successfully treated with plasma exchange with donor-type plasma replacement and the other one who was also complicated by EBV-associated lymphoproliferative disorder (EBV-PTLD) responded rapidly to anti-CD20 monoclonal antibody and achieved complete resolution of clinical finding and symptom of both EBV-PTLD and PRCA. We conclude that blood group A/O in donor/recipient pair is identified as being significantly associated with the occurrence of PRCA by multivariate analysis. Donor-type plasma exchange and anti-CD20 monoclonal antibody is an effective approach for the treatment of PRCA. PRCA could be prevented by plasma exchange prior to transplantation.

[Pure red cell aplasia (PRCA) induced by anti-EPO antibodies: epidemiology, diagnosis and treatment]

Pure red-cell aplasia (PRCA) is a serious, life threatening rare condition of multifactorial causes manifested as severe anemia with absence of erythroid precursors in the bone marrow. PRCA may be a consequence of antibody production against applied recombinant human erythropoietin (EPO). The first description of PRCA in the course of EPO therapy was performed in a patient receiving subcutaneously Eprex and in the next years after therapy with other erythropoiesis stimulating agents like erythropoietin beta, omega or darbepoetin. In the paper we describe epidemiology and diagnostic criteria of PRCA. The current treatment possibilities of this complication were described with special attention dedicated to different immunosuppressive agents and effectiveness of kidney transplantation with subsequent immunosuppression.

Autoimmune cytopenia in chronic lymphocytic leukemia/small lymphocytic lymphoma: changes in clinical presentation and prognosis

Improved medical care could have altered the clinical presentation and survival of patients with chronic lymphocytic leukemia/small lymphocytic lymphoma (CLL/SLL) complicated by autoimmune disease cytopenia (AID cytopenia). We reviewed the clinical characteristics, treatment, and outcome of AID cytopenia that was diagnosed in 75 (4.3%) of 1750 patients with CLL seen at a single institution over 10 years. When compared with the historical reported data, our study shows a lower rate of autoimmune hemolytic anemia (2.3%), and similar rates of immune thrombocytopenia (2.0%), and pure red blood cell aplasia (0.5%). AID cytopenia occurred at all stages of CLL, responded well to treatment, did not alter overall survival, and contributed to death in only 6 (12%) patients. We propose that more sensitive and accurate diagnostic methods for CLL have decreased the perceived prevalence of AID cytopenia and that improvements in management could have increased the survival of these patients.

Epoetin-associated pure red cell aplasia: past, present, and future considerations

BACKGROUND

Since 1988, millions of patients have received epoetin products intravenously (IV) and subcutaneously. In 1998, epoetin-associated pure red cell aplasia (PRCA) was first reported and causation was attributed to formulations without human serum albumin (HSA), subcutaneous administration, and uncoated rubber stoppers.

STUDY DESIGN AND METHODS

Data on erythropoietin (EPO)-associated PRCA were obtained from the Food and Drug Administration (FDA), regulatory authorities in other countries, and the manufacturers of epoetin alfa, epoetin beta, and darbepoetin. The data included information on numbers of PRCA cases and estimated exposure-adjusted incidence rates by EPO product, anemia etiology, administration route, country of PRCA identification, and date reported.

RESULTS

In 1999, academicians in Paris identified 12 EPO-treated patients with antibody-mediated PRCA; 11 of these patients were on hemodialysis and had received subcutaneous Eprex (Johnson & Johnson). In 2002, authorities in Europe, Australia, Singapore, and Canada mandated Eprex by IV route to hemodialysis patients, and the relevant manufacturers added Teflon coating to prefilled syringes of Eprex; PRCA cases subsequently decreased by 90 percent. By 2003, 180 Eprex-associated PRCA cases were identified in Europe, Canada, Australia, and Asia, despite improvements in handling. Since 2002, FDA safety databases include information on 59 new cases of antibody-associated PRCA, primarily associated with subcutaneous epoetin alfa and darbepoetin that does not contain HSA.

CONCLUSION

Independent actions by regulatory authorities, manufacturers, and academic researchers identified significant numbers of PRCA cases between 1998 and 2003 and characterized the probable etiology. Today, antibody-mediated PRCA is an infrequent class toxicity occurring among some hemodialysis patients on EPOs.

Red cell aplasia and autoimmune hemolytic anemia following immunosuppression with alemtuzumab, mycophenolate, and daclizumab in pancreas transplant recipients

BACKGROUND AND OBJECTIVES

Acquired red cell aplasia (RCA) is a rare disorder and can be either idiopathic or associated with certain diseases, pregnancy, or drugs. In exceptionally rare cases, it has been reported to co-exist with other autoimmune cytopenias. We report a high incidence of RCA and autoimmune hemolytic anemia (AIHA) in pancreas transplant recipients on alemtuzumab-based maintenance therapy.

DESIGN AND METHODS

Between February 2003 and July 2005, 357 pancreas transplant recipients were treated with immunosuppressive regimens containing the lymphocyte-depleting antibody alemtuzumab, the T-cell activation inhibitor daclizumab, and the anti-metabolite mycophenolate mofetil (MMF). We retrospectively reviewed medical records, blood bank data and bone marrow biopsy specimens of patients with a Transplant Information Services database diagnosis of RCA and AIHA from February 2003 to November 2005.

RESULTS

Severe RCA, AIHA, and idiopathic thrombocytopenic purpura (ITP) occurred independently or in combination, in 20 out of 357 (5.6%) pancreas transplant recipients, 12 to 24 months following the initiation of the aforementioned immunosuppressive regimens. Severe opportunistic infections developed late in 14/20 (70%) of these patients. Atypical morphologic features, including variable dysgranulopoiesis, variable megakaryocytic hyperplasia with normal or low peripheral platelet counts, and atypical lymphoid aggregates were found in bone marrow trephine sections of 11 patients in whom the diagnosis of RCA was made.

INTERPRETATION AND CONCLUSIONS

We hypothesize that the combination of alemtuzumab, daclizumab and MMF can result in immune dysregulation thereby permitting autoantibody formation. Because the use of these three immune suppressants is becoming increasingly common, it is important to recognize the severe hematologic complications that can arise.

Impact of ABO incompatibility on engraftment and transfusion requirement after unrelated cord blood transplantation: a single institute experience in Japan

The impact of ABO incompatibility between donor and recipient on engraftment and transfusion requirement was studied in 95 adults who underwent unrelated cord blood transplantation (CBT). The patients included 27 ABO-identical, 29 minor, 21 major and 18 bidirectional ABO-incompatible recipients. Neutrophil engraftment did not differ between ABO-identical/minor ABO-incompatible and major/bidirectional ABO-incompatible recipients (hazard ratio (HR) 1.17, P=0.48). Cumulative incidence of platelet engraftment in ABO-identical/minor ABO-incompatible recipients was higher than in major/bidirectional ABO-incompatible recipients (HR 1.88, P=0.013). In addition, fewer platelet transfusions were required during the first 60 days after CBT in ABO-identical/minor ABO-incompatible recipients (HR 0.80, P=0.040). RBC engraftment did not differ between the two groups (HR 1.25, P=0.33). However, fewer RBC transfusions were required in ABO-identical/minor ABO-incompatible recipients than in major/bidirectional ABO-incompatible recipients (HR 0.74, P<0.005). No patients developed pure red-cell aplasia after CBT. These results indicate that ABO incompatibility affected platelet engraftment and transfusion requirement of RBC and platelet in CBT recipients. Further studies including larger patient numbers are required to elucidate the impact of ABO incompatibility on the clinical outcome of CBT.

Pure red-cell aplasia "epidemic"--mystery completely revealed?

Starting in 1998, the number of pure red-cell aplasia (PRCA) cases in patients treated with recombinant human erythropoietin (rHuEPO) increased dramatically. Most cases were observed in patients treated with epoetin alfa produced outside the United States. The peak was observed in 2002; since then, the PRCA incidence has declined. Many factors are likely to have contributed to this up-surge. The molecular structure of the various epoetins and patient characteristics do not seem to play a major role. The route of administration holds some importance, because most PRCA patients received rHuEPO subcutaneously. The peak of PRCA cases overlapped with the removal of human serum albumin from the Eprex formulation (Janssen-Pharmaceutica NV, Beerse, Belgium), for which polysorbate 80 and glycine were substituted. Polysorbate 80 may have increased the immunogenicity of Eprex by eliciting the formation of epoetin-containing micelles or by interacting with leachates released by the uncoated rubber stoppers of prefilled syringes. Compared with the previous formulation, the polysorbate 80 formulation has lower stability, making it more susceptible to stress conditions such as insufficient attention to the cold chain. This situation could facilitate protein denaturation or aggregate formation. Uncoated rubber stoppers were replaced with coated stoppers, and the cold chain was reinforced; the Eprex formulation has remained unchanged. Even though the incidence of PRCA returned to very low levels, discriminating the cause-effect relationship of a single action is difficult, given that all occurred with a similar chronology, and that PRCA develops after a relatively long exposure period. Careful observation of future trends of new PRCA cases is thus mandatory.

Incidence of recombinant erythropoietin (EPO) hyporesponse, EPO-associated antibodies, and pure red cell aplasia in dialysis patients

BACKGROUND

Since 1998, an increase of anti-erythropoietin (anti-EPO) antibody-induced pure red cell aplasia (PRCA) has been reported. As data up to now consisted mostly of spontaneously reported cases the question arose about the frequency of this increase in EPO-induced PRCA. The objectives of this study were to determine the incidence and causes of recombinant EPO hyporesponse, of antibodies to EPO in patients on dialysis, and to relate the detection of anti-EPO antibodies to the presence of PRCA.

METHOD

This multicenter cohort study used existing patient data and serum samples collected at 6-month intervals from 1677 patients with incident end-stage renal disease (ESRD) participating in The Netherlands Cooperative Study on the Adequacy of Dialysis-2 (NECOSAD-2).

RESULTS

Fifty-seven patients had an inadequate EPO response, which resulted in an incidence of 16.7 per 1000 patient-years on EPO while on dialysis. All available sera specimens (N = 232) of these patients were screened for anti-EPO antibodies. The sera specimens of two of these 57 patients tested positive. Of the 57 patients with inadequate EPO response, one had clinical PRCA (incidence 0.29 per 1000 patient-years on EPO and on dialysis). Of the 1346 patients without symptoms of inadequate EPO response, one patient tested borderline positive for anti-EPO antibodies. In total, three patients developed EPO antibodies during follow-up, leading to an estimated incidence of 1.27/1000 (95% CI 0.3 to 3.7/1000) patient-years since the start of dialysis.

CONCLUSION

The incidence of inadequate EPO response in our population of dialysis patients is in concordance with tentative calculations found in the literature. Furthermore, we found the incidence of EPO-induced PRCA and EPO antibodies to be low.

Factors influencing the immunogenicity of therapeutic proteins

Several diseases and disorders are treatable with therapeutic proteins, but some of these products may induce an immune response, especially when administered as multiple doses over prolonged periods. Antibodies are created by classical immune reactions or by the breakdown of immune tolerance; the latter is characteristic of human homologue products. Many factors influence the immunogenicity of proteins, including structural features (sequence variation and glycosylation), storage conditions (denaturation, or aggregation caused by oxidation), contaminants or impurities in the preparation, dose and length of treatment, as well as the route of administration, appropriate formulation and the genetic characteristics of patients. The clinical manifestations of antibodies directed against a given protein may include loss of efficacy, neutralization of the natural counterpart and general immune system effects (including allergy, anaphylaxis or serum sickness). An upsurge in the incidence of antibody-mediated pure red cell aplasia (PRCA) among patients taking one particular formulation of recombinant human erythropoietin (epoetin-alpha, marketed as Eprex(R)/Erypo(R); Johnson & Johnson) in Europe caused widespread concern. The PRCA upsurge coincided with removal of human serum albumin from epoetin-alpha in 1998 and its replacement with glycine and polysorbate 80. Although the immunogenic potential of this particular product may have been enhanced by the way the product was stored, handled and administered, it should be noted that the subcutaneous route of administration does not confer immunogenicity per se. The possible role of micelle (polysorbate 80 plus epoetin-alpha) formation in the PRCA upsurge with Eprex is currently being investigated.

Erythropoietin-induced, antibody-mediated pure red cell aplasia

Pure red cell aplasia (PRCA) is a rare haematological condition that is characterized by severe aregenerative anaemia due to an almost complete cessation of red blood cell production. While antibody-mediated PRCA was extremely rare before 1998, the incidence of this disorder increased sharply after 1998 in patients receiving subcutaneous epoetin alfa produced by Ortho-Biotech and marketed outside the USA. The diagnosis of antibody-mediated PRCA relies mostly on the results of bone marrow biopsy or aspirate, which shows an absence of erythroid precursors and/or red cell maturation arrest while counts of white cell and platelet precursors are normal, and on the identification of circulating anti-erythropoietin antibodies. Retrospective analysis of PRCA cases has shown that immunosuppressive therapy can induce a disappearance of anti-erythropoietin antibodies in most patients. Eur J Clin Invest 2005; 35 (Suppl. 3): 95-99.

Adverse event issue management: what have we learnt from pure red cell aplasia (PRCA)?

After 1998, the number of reported cases of pure red cell aplasia (PRCA) increased dramatically among patients with chronic renal failure treated with exogenous erythropoietin, although the incidence of this condition has now abated. Antibody-positive PRCA has been most commonly associated with use of the Eprex brand of epoetin-alpha. ESA (erythropoiesis-stimulating agent)-associated PRCA remains rare, and suspected cases should undergo a thorough diagnostic work-up before laboratory testing for anti-ESA antibody-positive status. This article provides an overview of the recent history and growing understanding of ESA-associated PRCA together with current approaches to the management of this rare side effect of an otherwise valuable therapy.

Safety and impact of donor-type red blood cell transfusion before allogeneic peripheral blood progenitor cell transplantation with major ABO mismatch

BACKGROUND

Changes within the ABO system are regularly observed phenomena in allogeneic bone marrow transplantation (BMT) and peripheral blood progenitor cell transplantation (PBPCT). Major ABO mismatch can lead to different clinical problems including acute hemolysis after infusion of the allograft, delay of red blood cell (RBC) engraftment, or even manifestation of pure red cell aplasia (PRCA).

STUDY DESIGN AND METHODS

This retrospective study demonstrates the safety and the impact of donor-type RBC transfusion before allogeneic PBPCT in major ABO settings as routinely performed at our transplantation unit. This study reports on transfusion of mismatched RBCs at the end of the conditioning period in 35 patients who underwent allogeneic PBPCT, which led to a decrease in isoagglutinin titers in most cases.

RESULTS

A decrease of isoagglutinin titer after donor-type RBC transfusion can significantly reduce the demand of RBC transfusion between transplantation and Day +30 (p = 0.003). Interestingly, patients who developed PRCA were not observed, a complication being regularly documented by other groups.

CONCLUSION

A decrease of isoagglutinin titers by in vivo immunoadsorption before allogeneic PBPCT does not only lack severe complication but also leads to a reduction in demand of RBC transfusion after engraftment and may reduce the incidence of PRCA in these patients.

The increased incidence of pure red cell aplasia with an Eprex formulation in uncoated rubber stopper syringes

BACKGROUND

The incidence of pure red cell aplasia (PRCA) in chronic kidney disease patients treated with epoetins increased substantially in 1998, was shown to be antibody mediated, and was associated predominantly with subcutaneous administration of Eprex. A technical investigation identified organic compounds leached from uncoated rubber stoppers in prefilled syringes containing polysorbate 80 as the most probable cause of the increased immunogenicity.

METHODS

This study investigated whether the incidence of PRCA was higher for exposure to the product form containing leachates than for leachate-free product forms. Antibody-mediated PRCA cases were classified according to indication, product form, and route of administration. Exposure estimates were obtained by country, indication, route of administration, and product form.

RESULTS

For 2001 to 2003, the PRCA incidence rate for patients with subcutaneous exposure to Eprex in prefilled syringes with polysorbate 80 and uncoated rubber stoppers (leachates present) was 4.61/10,000 patient years (95% CI 3.88-5.43) versus 0.26/10,000 patient years (95% CI 0.007-1.44) for syringes with coated stoppers (leachates absent). The rate difference was 4.35/10,000 patient years (95% CI 3.44-5.26; P < 0.0001); the rate ratio was 17 (95% CI 3.14-707). A substantial rate difference remained in sensitivity analyses that adjusted for exposure to multiple product forms.

CONCLUSION

The epidemiologic data, together with the chemical and immunologic data, support the hypothesis that leachates from uncoated rubber syringe stoppers caused the increased incidence of PRCA associated with Eprex. Currently, all Eprex prefilled syringes contain fluoro-resin coated stoppers, which has contributed to decreased incidence of PRCA with continued surveillance.

Antibody-mediated pure red cell aplasia (PRCA): epidemiology, immunogenicity and risks

Although epoetin-induced antibody (Ab)-mediated pure red cell aplasia (PRCA) was very rare prior to 1998, a large increase in the number of global cases was observed from 1999 to 2002 in patients treated with erythropoiesis-stimulating agents (ESAs) for the anaemia associated with chronic kidney disease (CKD). The number of global cases of this immunological form of PRCA has declined precipitously since 2003 following increased awareness of this disorder and changes in the handling and administration of the formulation of epoetin-alpha (EPO) that was associated with the majority of cases. Current recommendations state that patients should stop treatment immediately following a diagnosis of Ab-mediated PRCA and not resume treatment with the same or another ESA. The feasibility of re-treatment following remission from PRCA or during ongoing immunosuppressive therapy is currently under investigation. The immunological mechanism for developing Ab-mediated PRCA is unknown, but a variety of factors may increase the immunogenicity of epoetin or other ESAs. Product-related factors that have the potential to impact on immunogenicity include sequence variations in proteins, the degree and nature of protein glycosylation, the manufacturing process, handling and storage, and components and properties of the product formulation. Patient-related factors associated with developing Ab-mediated PRCA include skin reactions, immune status and treatment history. Increased awareness among physicians of the factors contributing to the development of PRCA and its distinguishing clinical features has coincided with studies aimed at identifying effective therapies for this disorder. A number of immunosuppressive therapies have been shown recently to reconstitute effectively the erythropoietic response in patients with PRCA. However, therapeutic approaches for this serious immunological reaction to recombinant ESAs remain investigative.

Antibody-mediated pure red-cell aplasia (PRCA): the Spanish experience

BACKGROUND

The incidence of antibody (Ab)-mediated pure red-cell aplasia (PRCA) in patients with chronic kidney disease (CKD) has increased between 1998 and 2002. After initially responding to treatment with recombinant human erythropoietic agents for CKD-associated anemia, patients became treatment-refractory and severely anemic. Although most PRCA cases have occurred in Europe, the varying epidemiologies among individual countries have not been well characterized.

METHODS

We investigated Ab-mediated PRCA in 12 Spanish patients treated with epoetin alfa alone or prior to treatment with epoetin beta (n=1) or darbepoetin alfa (n=1). Serum Abs against epoetin alfa were detected by radioimmunoprecipitation (RIP) assay or bioassay. Following diagnosis of PRCA, erythropoietic treatment was stopped and patients received immunosuppressive therapy alone (n=11) or in combination with renal transplant (n=1).

RESULTS

Treatments were administered for 16 months (average) before diagnosis of PRCA in bone marrow aspirates (n=8) or biopsies (n=4). At diagnosis, patients had an average of 0.68% blood reticulocytes and blood hemoglobin (Hb) level of 7.13 g/dL. Eight patients had anti-epoetin Abs detected by RIP, and 5 had neutralizing Abs measured in the bioassay. As of December 2003, 4 patients had died, 3 had no recovery, and 5 had recovered from anemia (blood Hb level, 9.9 g/dL). All 5 recovering patients received corticosteroid therapy alone, and 1 received a renal transplant as well as corticosteroids.

CONCLUSIONS

Sudden onset of treatment-refractory anemia in CKD patients suggests a course of treatment cessation followed by diagnostic procedures for Ab-mediated PRCA, and immunosuppressive therapy. This study may serve as a model for a centralized global PRCA registry.

Epoetin-Induced Autoimmune Pure Red Cell Aplasia

During the first 10 yr of therapy with recombinant human erythropoietin ([EPO]), only three cases of antibody-associated pure red cell aplasia have been described in patients who were treated with EPO, whereas several millions of patients have received this treatment. Thus, the possibility for epoetin to induce the formation of anti-EPO antibodies was considered extremely low. However, since 1998, a significant increase in the number of cases of EPO-induced pure red cell aplasia has been found in patients with chronic kidney disease with a peak in 2001 and 2002. The incidence rate seems now to be back to the baseline level. The change in formulation of epoetin a sold outside the United States seems to be the cause of these antibodies.

Antibody-mediated pure red cell aplasia (PRCA): ensuring future progress by collecting data from a registry

The recent emergence of antibody (Ab)-mediated pure red cell aplasia (PRCA) resulting from administration of certain erythropoiesis-stimulating agents (ESAs) has heightened awareness of the potential for this disorder in patients receiving ESAs for anaemia associated with chronic kidney disease (CKD). The Spanish Society of Nephrology sponsored an independent registry for analysis of patients who developed epoetin-induced, Ab-mediated PRCA in Spain. Twelve patients from 11 regional hospitals were included in the Spanish PRCA registry from November 2000 to December 2002 that met the criteria for Ab-mediated PRCA. Patients were reported using a standardized form specifically developed for PRCA, and serum samples were analysed in a central laboratory at Reina Sofia University Hospital in Cordoba, Spain. The characteristics of these patients, their serological and haematological results, and the outcomes of immunosuppressive therapies are presented. The Spanish PRCA registry serves as a model for establishing an independent global PRCA registry sponsored by the various nephrology societies in European Union countries, and elsewhere and coordinated by key investigators from the respective countries.

A cross-sectional immunosurveillance study of anti-EPO antibody levels in CRF patients receiving epoetin alfa in 5 Ontario Renal Centers

BACKGROUND

Epoetin alfa (Eprex*; Johnson & Johnson, Manati, PR) has been used successfully to correct the anemia of chronic renal failure for more than 12 years. Anti-erythropoietin (anti-EPO) antibodies have been reported in a small number of patients, resulting in a blood disorder, pure red cell aplasia (PRCA). To evaluate the utility of a large-scale anti-EPO antibody screening program in patients with chronic kidney disease (CKD) administered epoetin alfa, a study involving 5 large renal centers in southern Ontario, Canada, was conducted.

METHODS

More than 1,500 hemodialysis, peritoneal dialysis, and predialysis patients were screened for the prevalence of anti-EPO antibodies by means of a radioimmunoprecipitation (RIP) assay. Serum samples were drawn and shipped to PPD Development (Richmond, VA) for the immunoprecipitation assay. Serum EPO levels also were measured. All samples that tested positive or borderline for antibodies were sent to MDS Pharma Services (Montreal, Canada) for the neutralization assay.

RESULTS

Of 1,531 samples tested, 1 patient tested low-positive and 3 borderline results were detected by means of RIP. PRCA previously was diagnosed in the patient with the low-positive antibody level; the patient was treated with cyclosporine and currently is being administered epoetin alfa with good response. The 3 patients with borderline antibody results manifested no clinical signs of PRCA. Neutralization assays performed on all 4 serum samples were negative for anti-EPO antibodies.

CONCLUSION

Results from this surveillance study show that the prevalence of antibody to EPO in patients with CKD administered epoetin alfa in 5 Canadian renal centers is low, and the value of a large-scale antibody screening program for PRCA cannot be justified.

Impact of ABO incompatibility on allogeneic peripheral blood progenitor cell transplantation after reduced intensity conditioning

BACKGROUND

Most studies indicate that ABO incompatibility has no effect on the clinical outcome after allogeneic peripheral blood progenitor cell (PBPC) transplantation (allo-PBPCT). However, it carries additional risks of hemolytic reactions, delayed red blood cell (RBC) engraftment, and pure red cell aplasia (PRCA). Data on these events after reduced intensity conditioning (RIC) regimens are limited, but recent studies have suggested a higher transplant-related mortality (TRM) and morbidity in this setting.

STUDY DESIGN AND METHODS

We investigated the impact of ABO-matching on the outcome of 77 patients included in a prospective RIC allo-PBPCT protocol, focusing on engraftment, transfusion requirements, graft-versus-host disease, TRM, and survival.

RESULTS

There were 17 (22%) minor and 8 (10%) major ABO-incompatible transplants. No graft failures were observed. After major ABO-incompatible grafts, RBC engraftment was delayed, longer thrombocytopenia periods were documented, and transfusion requirements increased. A transient mild hemolysis occurred in 10 patients, 7 (41%) minor and 3 (37%) major ABO-mismatched. A PRCA was observed in a O+ patient with a pretransplant anti-Jka, grafted from an A + Jka+ donor. Graft-versus-host disease, disease progression, and TRM were not affected by ABO matching.

CONCLUSION

ABO incompatibility was not associated with clinically relevant hemolysis after the RIC protocol used and did not impair the clinical outcome. PRCA was only observed in one patient, with a non-ABO RBC allo-antibody.

Anti-Erythropoietin Antibody-Mediated Pure Red Cell Aplasia after Treatment with Recombinant Erythropoietin Products: Recommendations for Minimization of Risk

Since 1998, there has been a marked increase in incidence of pure red cell aplasia secondary to development of anti-erythropoietin antibodies (Ab+ PRCA) in patients who have chronic kidney disease (CKD) and receive recombinant erythropoietin. The relationship between incidence of Ab+ PRCA and specific erythropoietin products has not been examined rigorously. Manufacturers provided data regarding exposure to erythropoietin products and incidence of Ab+ PRCA between January 1998 and March 2003 in patients with CKD. Assuming a Poisson distribution, a maximum likelihood estimate for the Poisson rate parameter was calculated for each product. A test for homogeneity of Poisson rates was conducted to compare likelihood estimates between products. Global incidence of Ab+ PRCA was relatively low. Likelihood estimates were not significantly different for Epogen, Procrit, and Aranesp, independent of their formulation or route of administration. Eprex lacking human serum albumin (HSA) and administered subcutaneously was associated with the greatest risk of Ab+ PRCA. HSA-containing Eprex administered subcutaneously was associated with a lower risk than HSA-free Eprex administered subcutaneously, but this risk exceeded that of intravenous Epogen and intravenous HSA-free Eprex. NeoRecormon administered subcutaneously was associated with less risk than subcutaneous HSA-free Eprex but more risk than intravenous Epogen. HSA-free Eprex should not be administered subcutaneously to patients with CKD due to increased risk of Ab+ PRCA. Although the subcutaneous administration of HSA-containing Eprex is riskier than intravenous Epogen and intravenous HSA-free Eprex, and the use of subcutaneous NeoRecormon is riskier than intravenous Epogen, there is currently no evidence that other products are safer.

Pure red-cell aplasia and epoetin therapy

BACKGROUND

Between 1988 and 1998, antibody-associated pure red-cell aplasia was reported in three patients who had undergone treatment with recombinant human erythropoietin (epoetin). Between 1998 and 2000, 13 such cases were reported from France--12 in patients who had received the Eprex formulation of epoetin alfa and 1 in a patient who had received Neorecormon (a formulation of epoetin beta); both are products that are marketed outside the United States.

METHODS

We obtained reports of epoetin-associated pure red-cell aplasia from the Food and Drug Administration and from the manufacturers of Eprex, Epogen (another formulation of epoetin alfa), and Neorecormon. The numbers of case reports and estimates of exposure-adjusted incidence were analyzed according to the product, the cause of anemia, the route of administration, the country in which pure red-cell aplasia was identified, and the date on which pure red-cell aplasia was reported.

RESULTS

Between January 1998 and April 2004, 175 cases of epoetin-associated pure red-cell aplasia were reported for Eprex, 11 cases for Neorecormon, and 5 cases for Epogen. Over half these cases had occurred in France, Canada, the United Kingdom, and Spain. Between 2001 and 2003, the estimated exposure-adjusted incidence was 18 cases per 100,000 patient-years for the Eprex formulation without human serum albumin, 6 per 100,000 patient-years for the Eprex formulation with human serum albumin, 1 case per 100,000 patient-years for Neorecormon, and 0.2 case per 100,000 patient-years for Epogen. After procedures were adopted to ensure appropriate storage, handling, and administration of Eprex to patients with chronic kidney disease, the exposure-adjusted incidence decreased by 83 percent worldwide.

CONCLUSIONS

After the peak incidence of Eprex-associated pure red-cell aplasia was reached in 2001, interventions designed in response to drug-monitoring programs worldwide resulted in a reduction of more than 80 percent in the incidence of pure red-cell aplasia due to Eprex.

High prevalence in Switzerland of pure red-cell aplasia due to anti-erythropoietin antibodies in chronic dialysis patients: report of five cases

BACKGROUND

Pure red-cell aplasia (PRCA) after erythropoietin (Epo) administration due to the appearance of neutralizing anti-Epo antibodies has been reported in over 200 cases between 1998 and 2002. However, large intercountry disparities were observed in the occurrence of this syndrome.

METHODS

On behalf of the Swiss Society of Nephrology, a survey was conducted in all the dialysis units of Switzerland in order to collect information on the occurrence, diagnostic and evolution data of the cases observed. A questionnaire was send to the nephrologists in charge of each of the 69 dialysis units in January 2003. The clinical and biological data of the suspected cases were analysed and compared with the data provided to health authorities and pharmaceutical companies.

RESULTS

A total of five cases were identified as true PRCA with demonstrated positive anti-Epo antibodies. They occurred between November 1998 and February 2002, were all treated by haemodialysis and had received Epo subcutaneously. The median appearance time of refractory anaemia after Epo initiation was 10 months (range: 7-54 months). Two cases had been treated exclusively with epoietin-alpha, one solely with epoietin-beta and the two others with a combination of both. With five cases out of a total of about 2500 dialysis patients and 2300 Epo-treated dialysis patients or an exposure rate to Epo of 9900 dialysis patient-years during a 4.3 year period, this prevalence is among the highest of those reported in European countries.

CONCLUSIONS

The prevalence of PRCA after Epo administration in dialysis patients appears particularly high in Switzerland. Among the potential explanations, the most plausible are the high percentage of dialysis patients treated with Epo, the almost exclusive subcutaneous administration, the larger market distribution of the epoietin-alpha brand, the eventual disruption of the cold chain and the setting-up of a systematic national survey.

Pure red cell Aplasia in Zaria. A 10- year review

Pure red cell Aplasia (PRCA) is a transfusion dependent condition characterised by anaemia, reticulocytopaenia and a paucity of erythroid precursors in the bone marrow. Records of patients with PRCA seen in Ahmadu Bello University Teaching Hospitals between 1991 and 2001 were reviewed and the outcome of their management was assessed. Fifty per cent of the ten patients had high dose methyl Prednisolone (HDMP) therapy. Seven patients recovered, 2 died and one was lost to follow up. All patients had red cell concentrate transfusion.

Assessment of pure red cell aplasia in US dialysis patients: the limits of the medicare data

BACKGROUND

A report of neutralizing antibodies to recombinant human erythropoietin (rHuEPO) in European dialysis patients raised concerns that US dialysis patients may be at similar risk. We investigated the frequency of diagnosis codes that include pure red cell aplasia (PRCA) in the Medicare end-stage renal disease data.

METHODS

Medicare claims data were used to identify incident dialysis patients from 1995 through 1999 aged 67 years or older who did not have a diagnosis code for aplastic anemia (AA; which includes PRCA) or were not administered rHuEPO before dialysis therapy initiation. Patients were assessed for complicating conditions, rHuEPO dose, hematocrit level, blood transfusion, bone marrow testing, and AA diagnosis (maximal follow-up, 13 months).

RESULTS

Of 101,782 patients eligible for study, 9,896 patients had diagnosis codes for AA after dialysis therapy initiation, 3,894 patients underwent bone marrow tests (required for PRCA diagnosis), 19 patients had diagnosis codes for AA based on bone marrow examination and no other complicating conditions, and 5 patients were administered blood transfusion in 1 or more months during follow-up, of whom only 1 patient had persistent low hematocrit levels while being administered rHuEPO and blood transfusion. This latter patient was identified from a total of 101,782 patients, or 70,706.75 person-years of rHuEPO exposure.

CONCLUSION

Diagnosis codes in the Medicare data are inadequate for the conclusive study of PRCA in US dialysis patients. Despite limitations of this study, it appears that few cases of rHuEPO-associated PRCA have occurred in US Medicare dialysis patients. Additional investigation is needed to determine whether apparent differences between US complication rates and those elsewhere result from differences in the manufacturing and/or use of erythropoietin products.

[Epidemiological data on anaemia during malignant affections]

FREQUENT IN THE CASE OF CANCER: According to a European multicentre study on 15 000 cancer patients, the percentage of anaemia exceeded 66% during the development of solid tumours and 72% during development of malignant tumours. The lowest levels of haemoglobin were correlated with the lowest performance status, however no treatment had been prescribed for anaemia in the majority of patients. MULTIPLE MYELOMAS AND LYMPHOMAS: The frequency of anaemia appeared just as high during these malignant affections and the correlation between haemoglobin levels and performance status was just as clear. Likewise, around one half of the anaemic patients had not been treated in an adapted or efficient manner. SIGNIFICANCE OF ANEMIA DURING LYMPHOMAS: It appeared that the anaemia of Hodgkin's disease, related to the inflammation, was correlated with shorter survival, whereas the anaemia of non-hodgkin lymphoma, related to medullar infiltration, generally affected the complete rate of response.

Pure red cell aplasia secondary to treatment with erythropoietin

Pure red cell aplasia (PRCA) is a rare condition defined as severe anemia secondary to the virtual absence of red blood cell precursors in the bone marrow. In the setting of patients treated with rHuEPO, the disease is generated by epoetin-induced antibodies that neutralise all the exogenous rHuEPO and cross-react with endogenous erythropoietin. As a result, serum erythropoietin levels are undetectable and erythropoiesis becomes ineffective. Only 4 cases of PRCA associated with rh-EPO have been reported before 1998. Thereafter, a sharp increase in the incidence of this rare condition has been reported, mainly associated with epoetin alpha use outside the United States. A number of possible mechanisms leading to PRCA development have been identified. Among these, modification of drug formulation and down stream processing probably has had a major role. Indeed, in 1998 the formulation of epoetin alpha in Europe was modified because of the fear of the "mad cow" syndrome. However, differences in molecule structure and glycosylation among different epoetins can not be excluded. It should also be underlined that the rise in the incidence of PRCA cases has been coincident with a major shift from intravenous to subcutaneous administration of rHuEPO. The abrupt rise in the incidence of PRCA cases observed in the last few years, deserves particular attention; however, we have to balance its severity, but extreme rarity, with the high number of chronic kidney disease patients who die each year because of cardiovascular disease that could partially be reduced by anemia treatment.

ABO mismatch may affect engraftment in multiple myeloma patients receiving nonmyeloablative conditioning

BACKGROUND

Blood group incompatibility does not appear to affect the overall outcome in patients undergoing myeloablative conditioning before allogeneic BMT. Data on ABO-mismatched transplantation in the nonmyeloablative setting are limited.

STUDY DESIGN AND METHODS

A retrospective analysis of the effects of ABO mismatches in multiple myeloma patients who received a nonmyeloablative conditioning regimen was conducted.

RESULTS

Three of 27 patients received a minor ABO-mismatched graft, all with evidence of hemolysis before converting to donor ABO group on Days 10, 15, and 6. Six patients received a major ABO-mismatched graft; of these, three developed GVHD of more than grade 2 and subsequently converted to the ABO blood group of the donor on Days 38, 33, and 43. Of the three patients without GVHD, one rejected the allograft and had autologous reconstitution. One remained a mixed chimera to Day 100 despite three donor lymphocyte infusions, and one developed pure RBC aplasia. None of the ABO-matched patients rejected the graft, whether they developed GVHD or not. RBC transfusions were significantly higher in the major and minor ABO-mismatched patients than in the ABO-matched patients, with medians of 12 units (range, 2-35), 13 units (range, 5-18), and 4 units (range, 2-15), respectively (p = 0.02). ABO-matched patients had a similar incidence of GVHD, with 5 of 9 ABO-mismatched patients (56%) having more than grade 2 versus 10 of 18 (56%). Four of 9 ABO-mismatched patients (44%) were mixed chimeras up to Day 100 versus 2 of 18 ABO-matched patients (11%), and the difference was significant (p = 0.01).

CONCLUSION

Patients with ABO mismatch had problems with engraftment, including graft rejection, pure RBC aplasia, and mixed-lineage chimerism. RBC transfusions were significantly higher in the ABO-mismatched recipients. GVHD may play a role in engraftment, possibly by facilitating the disappearance of native ABO antibodies via graft-versus-plasma cell effect. A prospective study to evaluate the effects of ABO mismatch on engraftment in the nonmyeloablative setting is needed.

Association of parvovirus B19 infection with idiopathic collapsing glomerulopathy

BACKGROUND

Collapsing glomerulopathy (CG), a disorder with severe glomerular and tubular involvement, occurs either as an idiopathic lesion or in some patients with human immunodeficiency virus (HIV) infection known as HIV-associated nephropathy (HIVAN). We previously reported a renal transplant recipient with de novo CG and red cell aplasia in association with persistent parvovirus B19 (PVB19) infection. This prompted us to look for an association between PVB19 infection and CG.

METHODS

DNA from archived biopsies of patients with CG was analyzed for PVB19 by polymerase chain reaction (PCR). Results were compared with HIVAN, idiopathic focal segmental glomerulosclerosis (FSGS), and controls. In situ hybridization (ISH) was done to localize PVB19 in renal biopsies. Peripheral blood specimens of patients with CG, HIV infection, healthy controls, and randomly selected hospitalized patients (sick controls) were also analyzed for PVB19.

RESULTS

PVB19 DNA was detected in renal biopsies of 18 out of 23 (78.3%) patients with CG, 3 out of 19 (15.8%) with HIVAN, 6 out of 27 (22.2%) with FSGS, and 7 out of 27 (25.9%) controls (P < 0.01, CG vs. HIVAN, FSGS, and controls). PVB19 was detected in peripheral blood of 7 out of 8 (87.5%) CG patients, 3 out of 22 (13.6%) with HIV infection, 4 out of 133 (3%) healthy controls, and 2 out of 50 (4%) sick controls (P < 0.001, CG vs. HIV infected, healthy, and sick controls). PVB19 was identified in glomerular parietal and visceral epithelial and tubular cells by ISH.

CONCLUSIONS

The significantly higher prevalence of PVB19 DNA in renal biopsies and peripheral blood of CG patients suggests a specific association between PVB19 infection and CG. In susceptible individuals, renal epithelial cell infection with PVB19 may induce CG.

Regeneration of erythropoiesis after related- and unrelated-donor BMT or peripheral blood HPC transplantation: a major ABO mismatch means problems

BACKGROUND

Blood group incompatibility in allogeneic BMT is common but does not appear to affect the outcome in terms of incidence of graft rejection or delayed engraftment. However, major ABO incompatibility may be associated with prolonged erythroid aplasia.

STUDY DESIGN AND METHODS

In a retrospective analysis of 286 allogeneic transplant recipients, the prevalence of prolonged erythroid aplasia, including pure RBC aplasia, was determined.

RESULTS

Patients receiving major ABO-incompatible grafts showed a significant delay in reticulocyte engraftment (median, 32 days; range, 12-347) from that in patients receiving ABO-identical (20; 10-152) or minor ABO-incompatible (21; 12-47) grafts. Pure RBC aplasia occurred in 7 (3%) of 240 evaluable recipients and was observed only in the major ABO-incompatible group (7/43, 16%). Treatment of pure RBC aplasia consisted of either plasma exchange, which resulted in a response within 16 to 68 days, or immunoadsorption, in which the response occurred between Days 119 and 204 after initiation of treatment.

CONCLUSION

Major ABO incompatibility may lead to delayed reticulocyte engraftment, resulting in prolonged transfusion dependency and increased risks of transmission of infection and iron overload. Therefore, therapeutic strategies should be taken into consideration to allow erythroid reconstitution in these patients.

Pure red cell aplasia associated with large granular lymphocytic leukemia: a rare association in Western countries

The coexistence of large granular lymphocytic leukemia (LGLL) and pure red cell aplasia (PRCA) has been previously described, but is rare in Western countries (7% in a recent series of LGLL cases). We present the clinical features, hematological parameters and immunophenotype of two patients with PRCA associated with CD3+ LGLL.

Acquired pure red cell aplasia in Japan

We reviewed the clinical features of 150 patients with acquired pure red cell aplasia (PRCA) in Japan. There were 35 patients with acute type and 115 with chronic type PRCA. Of the acute PRCA patients, 17 had human parvovirus B19 infection. Drug-induced PRCA was demonstrated in 7 patients. Of the 115 patients with chronic PRCA, 51 patients were classified as primary and 64 cases were associated with miscellaneous diseases such as thymoma, a variety of hematological disorders and collagen diseases. Among the hematological disorders, PRCA was most frequently seen in granular lymphocyte proliferative disorders (GLPD). The erythroid colony growth patterns from bone marrow were variable. The serum erythropoietin level was high in most patients. Various kinds of treatment were tried for the chronic PRCA cases. Cyclosporin A (CyA) was the most effective form of treatment and the response rate was 82% (31/38). Twenty-three of 37 patients (62%) responded to bolus methylprednisolone therapy. The largest number of patients were treated with oral prednisolone, and the therapy was effective in 27 of the 55 (49%). The response rate to cyclophosphamide was only 29% (5/17), but in combination with prednisolone, half of the patients (7/14) responded to the therapy. CyA is recommended as the first-line therapy for acquired chronic PRCA.

A regional experience of red cell aplasia

The incidence and current management of red cell aplasia in children was determined from a retrospective survey of haematologists and paediatricians in the northern health region of England over a 7-year period. Thirty-three children were diagnosed: 4 had Diamond Blackfan anaemia, 22 transient erythroblastopenia of childhood, and 7 parvovirus B19 aplasia, with annual incidences of 1, 5 and 2 per 1,000,000 children respectively. Many were over-investigated. Three with Diamond Blackfan anaemia were steroid responsive. One with transient erythroblastopenia was retrospectively diagnosed because anaemia did not recur after steroids were stopped. Transient erythroblastopenia is the most common single cause of red cell aplasia in immunocompetent children. Time, observation and bone marrow examination before steroid therapy are the ways to distinguish transient erythroblastopenia from Diamond Blackfan anaemia or leukaemia. Interpretation of red cell indices using age-related percentiles may reduce the number of inappropriate investigations of the anaemia, but is often unhelpful in distinguishing the various causes of red cell aplasia.

Pure red cell aplasia

Eleven cases of Pure red cell aplasia (PRCA) in children were encountered in our hospital since 1982. The age range was 4 months to 12 years. There was a male preponderance with M:F ratio as 9:2. There were 4 cases due to viral fever, 1 with bronchopneumonia, 2 of tuberculosis, 1 of enteric, 1 of NHL and 2 were of congenital PRCA. Tuberculosis per-se had given rise to PRCA in the two cases, which is not reported earlier though its association with anti-tubercular therapy is well recorded. Cases of infective etiology other than viral responded very well to specific treatment. Steroid was the drug of choice in PRCA with viral etiology.