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We report a case series of two patients with chronic kidney disease (CKD) who developed erythropoietin-induced pure red cell aplasia following a change in erythropoietin preparation. Both patients responded well to immunosuppressive treatments, but unfortunately developed severe infections as a result of being immunosuppressed., Competing Interests: Declaration of competing interest None., (Copyright © 2024 The Author(s). Published by Elsevier Ltd.. All rights reserved.)

Background/aim: Immune checkpoint inhibitors can induce immune-related adverse events in various organs, thus careful observation is required., Case Report: A 69-year-old man was diagnosed with advanced lung adenocarcinoma and treated with combined therapy of carboplatin plus pemetrexed plus pembrolizumab. After two cycles of treatment, anemia was noted. Myelosuppression due to cytotoxic anticancer agents was suspected and the cytotoxic agents were discontinued, followed by three courses of pembrolizumab monotherapy. However, the anemia persisted, requiring red blood cell transfusions. A bone marrow biopsy revealed erythroblast hypoplasia and chromosomal abnormalities, resulting in a diagnosis of pure red cell aplasia. These adverse events were considered immune-related because of the treatment history with an immune checkpoint inhibitor, and 60 mg/day (1 mg/kg/day) of prednisolone was initiated. Anemia improved, and it did not recur during the tapering of prednisolone., Conclusion: Immune-related pure red cell aplasia should be considered for patients presenting anemia during treatment with immune checkpoint inhibitors., (Copyright © 2024, International Institute of Anticancer Research (Dr. George J. Delinasios), All rights reserved.)

Introduction: Niraparib, a strong poly(adenosine diphosphate-ribose) polymerase (PARP) inhibitor, contributed significantly to progression-free survival as a maintenance therapy in the platinum-sensitive period in both first-line and recurrent ovarian cancer, regardless of the BRCA mutation. Grade 3-4 anemia, which has a manageable side effect profile, especially hematological, is seen in almost 1 out of every 4 patients. To the best of our knowledge, there has been no reported case of pure red cell aplasia (PRCA) induced by niraparib treatment., Case Report: A 65-year-old woman diagnosed with stage 3 serous carcinoma of the tuba received niraparib front-line maintenance treatment had grade 4 anemia after 3 months of niraparib treatment. She underwent bone marrow aspiration and biopsy because of refractory anemia, which needs red blood cell (RBC) transfusions despite interruption of treatment., Management and Outcome: The patient was treated with 1 mg/kg methyl prednisolone, after histopathological assessment was consistent with PRCA. The hemoglobin count returned to the normal range with steroid treatment., Discussion: In daily practice, it should be kept in mind that in the case of refractory anemia induced by niraparib, the underlying cause might be PRCA and can be improved with steroid administration., Competing Interests: Declaration of conflicting interestsThe authors declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Introduction: Chronic lymphocytic leukemia (CLL) has long been known for its complications related to immune deregulation, of which autoimmune cytopenias (AIC) were frequently reported. Ibrutinib has dramatically changed the overall prognosis of patients with CLL. However, whether ibrutinib can induce or aggravate AIC in CLL patients is still disputable. Here we report a CLL patient with pure red cell aplasia (PRCA) occurring during ibrutinib treatment and review available data to discuss the possible role of ibrutinib in developing AIC., Case Report: A 70-year-old female was diagnosed with CLL with indications to initiate ibrutinib treatment given progressive bulky disease. She was admitted for advanced fatigue on the 14th day of ibrutinib monotherapy. A complete blood count revealed severe anemia of hemoglobin (Hb) 37 g/L and a meager reticulocyte count. After excluding other conditions that could cause anemia, PRCA was diagnosed as a complication of CLL., Management and Outcome: Ibrutinib was discontinued on the day of admission. At the same time, the patient received prednisone and intravenous immunoglobulin (IVIg). Five days later, the Hb did not improve. Cyclosporine A (CsA) was added; IVIg was discontinued, and prednisone was tapered. Ten days later, the Hb had risen to 92 g/L with a high reticulocyte count of 0.279 × 10 12 /L. The CLL treatment restarted with Zanbrutinib in combination with a low dose of prednisone and CsA. Her CLL was in partial remission by the latest follow-up with an average Hb count., Discussion: Our case demonstrates a need to evaluate the risk of developing AIC before initiating ibrutinib. For patients with high-risk factors for AIC episodes, the transient addition of other immunosuppressive therapies should be taken into consideration., Competing Interests: Declaration of conflicting interestsThe author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Immune checkpoint inhibitor(ICI)combination therapy is the first-line of treatment for unresectable or recurrent esophageal cancer. The frequency and mechanism of immune-related adverse events(irAEs)associated with ICI are still unclear and may require differentiation from other diseases. The present study examined a patient with unresectable, advanced esophageal cancer treated with cisplatin plus 5-fluorouracil(CF)plus nivolumab as the first-line treatment. CF therapy was discontinued after 1 course owing to adverse events. Nivolumab was continued, but progressive anemia stemming from pure red cell aplasia(PRCA), an irAE of nivolumab administration, was observed. Nivolumab was discontinued, but later, interstitial pneumonia also developed, and pulse steroid therapy was begun. After steroid tapering, both the PRCA and interstitial pneumonia improved. At present, about 6 months have elapsed since the last nivolumab administration without any PRCA recurrence or evidence of tumor progression.

BACKGROUND Immunotherapy is a novel treatment offering an alternative to traditional chemotherapeutic agents for different malignancies. Hematologic adverse reactions (HARs) related to immune checkpoint inhibitors (ICIs) are uncommon. Pure red cell aplasia (PRCA) is a rare hematologic complication of ICI therapy in metastatic melanoma with significant mortality risk despite treatment with steroids or immunosuppressive therapy. For unexplained acute anemia after exclusion of other causes, performing bone marrow biopsy is imperative to diagnose PRCA and rule out involvement of bone marrow by primary tumor. HARs can occur during ICI therapy or even after ICI therapy is stopped. ICI rechallenge, even after the development of HARs, is considered in some patients with good response to treatment of HARs from ICIs. Recurrence of HARs with the same or different type of reaction is seen in some patients. CASE REPORT Two cases of ICI-induced PRCA were confirmed on bone marrow biopsy after dual ICI treatment with nivolumab and ipilimumab in metastatic melanoma. In case 2, PRCA was successfully treated with steroids and later rechallenged with single-agent nivolumab, causing mild ICI-induced immune thrombocytopenia, which did not require treatment with steroids. CONCLUSIONS It is crucial to increase clinician awareness of the possibility of PRCA development not only during treatment with ICI but also after finishing treatment with ICI; there is high mortality associated with missing an opportunity to diagnose and treat PRCA on time with favorable results. ICI rechallenge can be considered in patients who showed response to immunotherapy, especially those with limited alternative therapeutic options.

Although several agents showed some clinical activity in patients with recurrent thymoma, there is no standard treatment option. Here, we report a late relapse thymoma and pure red cell aplasia case, responsive to everolimus with over 5 years of clinical benefit following multiple lines of treatment. Everolimus controlled the rapidly progressive disease in our patient without significant toxicity., (Copyright © 2022 Wolters Kluwer Health, Inc. All rights reserved.)

Predominantly autoimmune in origin, severe normochromic, normocytic anemia with reticulocytopenia in the setting of the normal production of leukocytes and megakaryocytic lineages is known as pure red cell aplasia (PRCA), which is unlike aplastic anemia in which all lineages are affected due to a stem cell defect. PRCA can be primary (such as autoimmune) or acquired, which can be an acute self-limited illness or a chronic disease that may be induced by medications, including immunotherapy such as monoclonal antibodies (mAbs). Daratumumab is a mAb directed against CD38 used for the treatment of multiple myeloma and systemic amyloid light-chain amyloidosis. The intravenous formulation of daratumumab received initial FDA approval, and later approval was received for the subcutaneous formulation daratumumab and hyaluronidase-fihj. The subcutaneous version increases patient convenience and has become the preferred route of administration since its approval. We herein present the case of a patient with multiple myeloma who developed acquired DNMT3A-positive PRCA while transitioning to daratumumab/hyaluronidase after initial treatment with daratumumab.

Background: Hypoproliferative anemia is a frequently encountered adverse event in cancer patients receiving immune checkpoint inhibitors (ICI). Secondary pure red cell aplasia (PRCA) is a rare but recognized immune related adverse event. With the burgeoning use of ICIs, the association of secondary PRCA with an underlying lymphoproliferative disorder is often overlooked., Case Presentation: We report a case of a 67-year-old non-Hispanic Caucasian male with metastatic castrate resistant prostate cancer, who developed severe transfusion dependent anemia with reticulocytopenia while receiving treatment with olaparib and pembrolizumab. His bone marrow findings demonstrated erythroid hypoplasia, in addition to a CD5-negative, CD10-negative monotypic B-cell population and a somatic MYD88L265P mutation. With a presence of an IgM-paraprotein, he was diagnosed with Waldenström macroglobulinemia (WM) with secondary PRCA and treated with 6 cycles of bendamustine and rituximab. He achieved a complete response with this regimen and was transfusion independent., Conclusion: In this case, underlying WM was uncovered through systematic investigation of anemia caused by ICI therapy. This report highlights the possibility of a lymphoproliferative disorder in patients with concerns for PRCA with prior ICI exposure. If identified, treating the underlying lymphoproliferative disorder is highly efficacious in the management of the secondary PRCA., (© 2023. The Author(s).)

Pure red cell aplasia is a relatively rare disease characterized by suppression or absence of erythroid precursors while other cell lineages are normal in the bone marrow. The disease could be secondary to other diseases or an adverse side effect of certain drugs. Tacrolimus is widely used as an immunosuppressive agent in solid-organ transplant without significant myelosuppressive effects. However, several tacrolimus-related pure red cell aplasia cases have been reported to date. Here, we report a case of a renal transplant recipient who developed tacrolimus-associated pure red cell aplasia in the posttransplant period and recovered dramatically after switching from tacrolimus to cyclosporine. Early diagnosis of pure red cell aplasia, which generally requires multiple blood transfusions, is very important because an increased number of blood transfusions can cause immunogenic effects and increased risk for allograft survival. Tacrolimus is a prominent drug for immunosuppression and is suspected to cause pure red cell aplasia during the posttransplant period; therefore, clinicians should consider a switch from tacrolimus to another immunosuppressive agent.

Pure red cell aplasia (PRCA) associated with erythropoiesis-stimulating agents (ESAs), which were first reported in 1998, usually occurs with subcutaneous administration of epoetin alfa (Eprex ® ). Improvements in ESA storage, handling, and administration methods have reduced the PRCA incidence. Continuous erythropoietin receptor activator (CERA) is a third-generation ESA that is rarely reported to induce PRCA. We herein report a case of CERA-induced PRCA presenting with positive anti-erythropoietin (EPO) and anti-CERA antibodies, which was successfully treated with prednisolone. Clinicians should be aware of the possibility of antibody-mediated PRCA induced by an ESA in CKD patients with anemia with reticulocytopenia and low serum EPO levels.

We report on the presentation and outcome of a 28-year-old female who developed red cell aplasia following alemtuzumab therapy for relapsing remitting multiple sclerosis. The patient also developed synchronous immune thrombocytopenia and immune neutropenia, but not aplastic anemia. This patient received high dose steroids, intravenous immunoglobulin (iv.Ig), rituximab, red cell transfusions, vincristine, G-CSF, cyclosporin and mycophenolate to treat the combination of cytopenias over a period of 6 months with subsequent improvement in bone marrow function. While alemtuzumab has several recognized autoimmune complications, little is known about the potential hematological side effects. The combination of red cell aplasia, immune thrombocytic purpura and autoimmune neutropenia has not previously been described in the literature following alemtuzumab immunotherapy and highlights the importance of monthly blood monitoring post alemtuzumab administration.

We herein report a 64-year-old man who was treated with pembrolizumab for relapsed Hodgkin lymphoma. After the third administration of pembrolizumab, he showed acute anemia with a positive direct anti-globulin test. Because of the markedly erythroid hypoplasia, he was diagnosed with pure red cell aplasia (PRCA) caused by pembrolizumab. He was initially treated with prednisolone, but the reticulocytes decreased after tapering prednisolone. He then received high-dose intravenous immunoglobulin (IVIG) with prednisolone, and PRCA was successfully treated. Although the pathogenesis of PRCA caused by immune checkpoint inhibitors (CPIs) remains unclear, IVIG treatment may be effective for some steroid-refractory CPI-induced PRCA cases.

Clozapine, an atypical antipsychotic, can cause potentially life-threating side effects such as agranulocytosis. Our case presents a picture of severe anemia without any depression of the white cells or platelet lines. A 36-year-old man with treatment-resistant schizophrenia was admitted to the Psychiatric Unit for therapy assessment. After admission, he was gradually switched to clozapine treatment, 400 mg/d. General laboratory test results were normal, with a hemoglobin (Hb) level of 15.2 g/dL. The Hb level gradually decreased to 7.1 g/dL 10 weeks after switching to clozapine, when the patient underwent blood transfusion and clozapine therapy was stopped. No evidence of bleeding was noted. The reticulocyte count was less than 60.000/µL. Other anemia causes were excluded. Bone marrow aspiration performed at 10 weeks revealed red cell hypocellularity, while myelopoietic and megakaryocytic cell lines were normal. All these findings confirmed the diagnosis of pure red cell aplasia. The Hb level gradually increased to 13.3 g/dL 4 weeks after clozapine discontinuation, and the patient was discharged with olanzapine 5 mg/d. Clozapine has been reported to cause hematological abnormalities. In our patient, the diagnosis of pure red cell aplasia was made on the basis of severe and selective anemia, reticulocytopenia, and erythroid aplasia. The pathogenesis of hematologic abnormalities due to clozapine treatment is not known. Suggested mechanisms include a direct toxic effect of clozapine, or its metabolite, on the erythroid precursor cells, or formation of a drug-antibody complex. These aspects call for further and deeper research and reports of clinical observations.

Relapse remains the most common cause of treatment failure after hematopoietic cell transplantation for acute myeloid leukemia. Inability to achieve hematologic complete remission has been a barrier to transplant for patients with refractory disease. We describe six children with refractory myeloid disease undergoing transplant in chemotherapy-induced aplasia, as a strategy to facilitate curative therapy in refractory patients. Clofarabine- or high-dose cytarabine-based chemotherapy regimens were used to achieve marrow aplasia, followed by reduced-intensity conditioning and allogeneic transplant before hematologic recovery. Long-term disease control was achieved in five, with one transplant-related mortality, suggesting the feasibility of this approach., (© 2018 Wiley Periodicals, Inc.)

Background: Unexpected serious adverse drug reactions (sADRs) affecting patients with chronic kidney disease (CKD) who received erythropoiesis-stimulating agents were identified by study co-authors. These included pure red cell aplasia (PRCA) after administration of the Eprex formulation of epoetin or the epoetin biosimilar HX575 and fatal anaphylaxis associated with peginesatide, an erythropoietin receptor agonist. We developed and applied a structured framework to describe these sADRs, including root cause analyses and eradication efforts., Methods: A 10-step framework termed "ANTICIPATE," focusing on signal identification, incidence, causality, and eradication guided our evaluations., Results: Initial cases were identified by a hematologist (Eprex), clinical study monitors (HX575), and 4 nurses (peginesatide). The number of persons with individual ADRs was 13 PRCA cases for epoetin, 2 antibody-mediated PRCA cases for HX575, and 5 fatal anaphylaxis cases for peginesatide. Initial incidence estimates per 1000 treated persons were 0.27 for Eprex-associated PRCA, 11 for HX575-associated PRCA, and 0.38 for peginesatide fatalities. Likely causes were subcutaneous administration of epoetin formulated with polysorbate 80 (Eprex), tungsten leaching from pins included in product syringes (HX575), and inclusion of a phenol stabilizer (peginesatide). Eradication strategies included restricting Eprex administration to the intravenous route, excluding tungsten from HX575 syringes, and for peginesatide, proposed eradication was to return to single-dose vials without preservatives., Conclusion: Although the number of cases of each sADR was small, eradication was successful for 2 sADRs, and a proposed eradication was developed for a third sADR. The structured framework used to describe the above 3 sADRs in patients with CKD can also be used in other clinical settings.

Linezolid (LZD) is the first oxazolidinone with excellent safety and efficacy profiles against refractory infections caused by gram-positive organisms. Hematological toxicities such as thrombocytopenia, anemia, and leukocytopenia are common in LZD therapy; however, LZD-induced pure red cell aplasia (PRCA) is rare. An 83-year-old man diagnosed with pleural empyema caused by Staphylococcus aureus received LZD after developing resistance to multiple antibiotics. Although his infection-related symptoms were improved by LZD, progressive anemia was noticed after LZD therapy was initiated. Eight weeks after LZD administration began, his hemoglobin level was 5.7 g/dL and reticulocyte proportion was 0.36%, while his white blood cell and platelet counts remained unchanged since admission. Bone marrow examination revealed markedly decreased erythropoiesis with cytoplasmic vacuolation of erythroblasts. Anemia resolved by 14 days after cessation of LZD. It is important to increase the awareness among clinicians about the potential for the hematological effects associated with LZD, particularly for older patients with pre-existing anemia and treatment courses longer than 14 days. To detect bone marrow suppression, including PRCA, we suggest monitoring the complete blood count and reticulocyte count periodically in patients receiving long-term LZD therapy.

The pure red cell aplasia (PRCA) is an uncommon side effect of isoniazid. We describe a 28-year-old man who developed a severe anaemia caused by PRCA. The patient received antituberculous therapy including isoniazid for his pulmonary tuberculosis. On discontinuation of isoniazid, the anaemia recovered promptly. PRCA should be considered in case of unexplained anaemia during isoniazid treatment., Competing Interests: Competing interests: None declared., (© BMJ Publishing Group Limited 2018. No commercial re-use. See rights and permissions. Published by BMJ.)

Acquired pure red cell aplasia (PRCA) and autoimmune hemolytic anemia (AIHA) are rare complications of immunosuppression in pediatric solid organ transplant patients. We report a 14-month-old female child who developed Coombs positive hemolytic anemia and reticulocytopenia while on tacrolimus after cardiac transplantation. She was successfully treated with rituximab after failing treatment with corticosteroids and intravenous immunoglobulins. Clinicians should consider PRCA differential diagnosis in a patient presenting with reticulocytopenia and hemolysis. In addition, the coexistence of PRCA with AIHA, and the response to therapy with rituximab, supports a common immune-mediated pathogenesis for both disorders., (© 2017 Wiley Periodicals, Inc.)

A 41-year-old woman treated with isoniazid (INH) for latent tuberculosis infection and an oral corticosteroid for sarcoidosis developed severe anemia two months after initiating INH. A bone marrow examination showed erythroblastopenia, and a diagnosis of INH-induced pure red cell aplasia (PRCA) was made. Her reticulocyte count and hemoglobin levels improved two weeks after discontinuation of INH. A literature review of INH-induced PRCA shows that it occurs very rarely in the context of autoimmune disorders. This report describes a case of INH-induced PRCA occurring in a patient with sarcoidosis.

Pure red cell aplasia is a rare condition associated with the use of recombinant human erythropoietin preparations. It has predominantly been associated with the subcutaneous use of a particular epoetin-α product, Eprex, and is rarely associated with intravenous use or with other commercially available products. Only a few cases of pure red cell aplasia secondary to epoetin-β have been reported. On account of its rarity, the condition can often be missed on initial presentation, leading to unnecessary investigations and delayed diagnosis. A high index of suspicion is required for timely diagnosis and proper management. We present a case of severe anaemia secondary to the subcutaneous use of epoetin-β (Recormon) and briefly discuss the pathogenesis, diagnosis and management., (Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/.)

Pure red cell aplasia (PRCA) is a disorder that leads to a nonregenerative anemia that results from erythroid precursors failing to reach maturity in the bone marrow, whereas the numbers of mature myeloid and megakaryocytic cells remain normal. PRCA can be induced by autoimmune processes, infections, drugs, toxins, and radiation, and is diagnosed by a bone marrow cytology examination after excluding the most common causes of nonregenerative anemia. Immunosuppressive therapies are used to treat PRCA, and usually involve the use of glucocorticoids, cyclosporin, or azathioprine. Alternatively, although little studied in veterinary medicine, drugs which stimulate bone marrow (e.g., nandrolone decanoate) have been mentioned as possible therapeutic agents. A case of PRCA that presented at the Veterinary Teaching Hospital of the Faculty of Veterinary Medicine and Animal Science (UNESP)-Botucatu, Brazil showed a good therapeutic response to weekly administration of nandrolone decanoate. Therefore, it was concluded that bone marrow stimulants might improve the quality of life of PRCA patients, provided they are used with caution and under close clinical supervision., (Copyright © 2017 Elsevier Inc. All rights reserved.)

Background: Darbepoetin alfa (darbepoetin) is an erythropoiesis-stimulating agent used for the treatment of anemia secondary to chronic kidney disease (CKD) in dogs, but reports describing response are lacking., Hypothesis/objectives: To evaluate the effectiveness of darbepoetin in dogs with anemia secondary to CKD, dosing protocols, and adverse events., Animals: Thirty-three client-owned dogs with naturally occurring CKD, including 26 with comorbidities., Methods: Multi-institutional retrospective study., Results: The median starting dosage and highest dosage of darbepoetin administered were 0.5 and 0.8 μg/kg SC once weekly, respectively. Response to treatment was defined as achieving a packed cell volume (PCV) ≥30% or an increase in PCV ≥10%. Twenty-eight of 33 dogs (85%) achieved a PCV ≥30% and 22 of 33 (67%) dogs achieved an increase in PCV ≥10%. Median time to achieve a PCV ≥30% was 29 days. A higher starting dosage was associated with achieving an increase in PCV ≥10% (P = .01). No dog sustained a response at a dosing interval >q21d. Potential adverse events included increased blood pressure requiring treatment (n = 12), seizures (n = 5), vomiting (n = 3), diarrhea (n = 3), and possible pure red cell aplasia (PRCA) (n = 2)., Conclusions and Clinical Importance: Darbepoetin, when combined with treatment of comorbidities, is an effective treatment for anemia secondary to CKD in dogs. A dosing interval >q21d was ineffective at maintaining a response to treatment. PRCA was a possible adverse event in 2 of 33 dogs (6%)., (Copyright © 2017 The Authors. Journal of Veterinary Internal Medicine published by Wiley Periodicals, Inc. on behalf of the American College of Veterinary Internal Medicine.)

Many processes lead to anemia. This review covers anemias that are less commonly encountered in the United States. These anemias include hemoglobin defects like thalassemia, bone marrow failure syndromes like aplastic anemia and pure red cell aplasia, and hemolytic processes such as paroxysmal nocturnal hemoglobinuria. The pathogenesis, diagnostic workup, and treatment of these rare anemias are reviewed., (Copyright © 2016 Elsevier Inc. All rights reserved.)

Anti-erythropoietin (anti-EPO) antibody-related pure red cell aplasia (PRCA) is a rare but serious complication that can occur during the administration of erythropoiesis-stimulating agents. Treatment with the calcineurin inhibitor cyclosporine has shown benefits in patients with anti-EPO PRCA. The efficacy of tacrolimus, another calcineurin inhibitor, in patients with anti-EPO PRCA has not been determined. The present report is the first our knowledge to describe the successful treatment of a patient with anti-EPO PRCA using tacrolimus. A 73-year-old man was markedly anemic 8 months after starting epoetin beta treatment. He was diagnosed with anti-EPO PRCA. Cyclosporine was started, but he experienced side effects. He was switched from cyclosporine to tacrolimus. No side effects were observed, and his anti-EPO PRCA was improved 6 months later, despite the persistence of anti-EPO antibodies. Tacrolimus was continued until the disappearance of the antibodies. Following the cessation of tacrolimus, PRCA did not relapse. Antibody remained detectable at the time of clinical remission, indicating that immunosuppressive therapy should be continued while monitoring the antibody titer. When the antibody titer decreases to the negative range, cessation of the immunosuppressive therapy does not result in disease relapse.

Antibody-mediated pure red cell aplasia is a rare but serious complication in chronic kidney disease patients receiving recombinant human erythropoietin (r-HuEpo). Between April 2012 and May 2013, eight such cases were reported in our institution. Their clinical features were reviewed and their HLA alleles were compared with those of healthy controls. All patients were exposed to epoetin alfa (Eprex ® ) with polysorbate-80 as stabilizer via subcutaneous route with a mean age of 61.9 years and mean exposure of 11.2 months of r-HuEpo before loss of efficacy. 87.5% of the cases were male and Chinese and received immunosuppression as treatment for pure red cell aplasia. All three of the successfully treated patients are alive compared with only 40% of the transfusion-dependent patients. DRB1*12:02 was more frequently expressed among the cases than healthy controls suggesting a plausible molecular link.

Various mechanisms contribute to anemia in inflammatory bowel diseases (IBD), drug-related causes being less frequent. The hematological and other adverse events of azathioprine (AZA) therapy are well documented, but drug-associated pure red cell aplasia (PRCA) is an uncommon event. We hereby describe two cases of AZA-associated PRCA in patients with Crohn's disease. The diagnosis was supported by pathological reports, and prompt hematological recovery was seen with discontinuation of the offending drug. This report highlights the need to consider this rare entity in IBD patients in appropriate settings and for adopting adequate precautionary measures.

A 56-year-old woman was referred to our department for detailed examination of anemia. She was diagnosed with pure red cell aplasia (PRCA) associated with severe reticulocytopenia based on blood testing and severe erythroblastopenia based on bone marrow aspiration. Blood tests revealed severe hypogammaglobulinemia, but monoclonal protein was not detected in either serum or urine by immunoelectrophoresis. Plasma cells were not increased in bone marrow aspirates or the biopsy specimen. Neither osteolytic lesions nor plasmacytoma was detected by computed tomography. We thus ruled out multiple myeloma. She had been treated with various Chinese herbal medicines prescribed at the referring hospital. We suspected PRCA induced by one of the Chinese herbal medicines and completely discontinued all of these herbal preparations. Hematologic testing revealed that the reticulocyte count and hemoglobin concentration began to recover on day 7 and the hemoglobin concentration and IgG levels had reached reference ranges on day 73 after discontinuation of the Chinese herbal medicines. We suspected Sanyaku (Dioscorea rhizome) or Bukuryou (Poria cocos) to have induced PRCA and hypogammaglobulinemia in this patient. To the best of our knowledge, this is the first report of PRCA and hypogammaglobulinemia induced by a Chinese herbal medicine. Clinicians must consider the possibility of drug-induced PRCA and hypogammaglobulinemia in patients taking Chinese herbal preparations.

A 67-year-old woman was diagnosed with chronic lymphocytic leukemia (CLL) in October 2001. In August 2004, she received chemotherapy consisting of fludarabine and cyclophosphamide (FC therapy). After three cycles of FC therapy, the number of tumor cells was markedly decreased. However, anemia progressed. She was diagnosed with pure red cell aplasia (PRCA) by bone marrow examination and was successfully treated with cyclosporin A (CsA). In October 2008, anemia progressed with the exacerbation of CLL and she received three cycles of fludarabine therapy. Although the number of tumor cells diminished, the anemia did not improve. She was diagnosed with PRCA recurrence and was again successfully treated with CsA. PRCA is a rare complication in patients with CLL and has been attributed to T cell-mediated mechanisms. Six cases with PRCA that developed after fludarabine therapy for CLL have already been reported. Fludarabine therapy may be toxic to Treg, resulting in the loss of self-tolerance. It is important to consider the possibility of PRCA in patients with progressive anemia after fludarabine therapy for CLL.

A 79-year-old female diagnosed with T cell/histiocyte-rich large B cell lymphoma in complete remission after six cycles of rituximab-combined chemotherapy developed severe anemia, reticulocytopenia, and bone marrow erythroid hypoplasia. She was diagnosed with pure red cell aplasia (PRCA) accompanied by Coombs-negative autoimmune hemolytic anemia evidenced by a lack of glycophorin-A-positive cells in the bone marrow, haptoglobin under the detection level, and a high titer of RBC-bound IgG. Anti-erythropoietin receptor (EPOR) antibody was detected in the serum, and oligoclonal α/β and γ/δ T cells were also detected in her peripheral blood by Southern blotting analysis. Parvovirus B19 DNA was not detected by PCR. Although the treatment with rituximab had limited efficacy (specifically, only for hemolysis), subsequent cyclosporine therapy led to prompt recovery of erythropoiesis with the disappearance of anti-EPOR antibody and oligoclonal T cells. This is the first case report of anti-EPOR antibody-associated PRCA in a patient with malignant lymphoma treated successfully with cyclosporine.

Antibody-mediated pure red cell aplasia (PRCA) is a rare complication of erythropoietin (EPO) therapy. Identification and demonstration of functional activity of EPO antibodies required to diagnose this condition is difficult and only performed in selected laboratories worldwide. In this article we report a recent cluster of three cases of antibody-mediated PRCA over a 16-month period in a single center associated with EPREX use. We also describe the use of a simple low-cost inhibitor assay that can be used to screen for PRCA in local laboratories.

Anti recombinant human erythropoietin (r-HuEpo) associated pure red cell aplasia (PRCA) is an immunologic adverse effect of using subcutaneous r-HuEpo. Immunosuppressive agents have been suggested as treatment of this serious complication. After the reversal of anti-r-HuEpo antibody, the patients continue to have renal anemia and require long-term blood transfusion, albeit less frequently than when the antibody is positive. It is controversial whether re-challenging the patients with r-HuEpo is appropriate because re-challenging may cause the reappearance of the antibody. To balance the risk of antir-HuEpo antibody reappearance and longterm blood transfusion complications, we re-challenged r-HuEpo in five anti-r-HuEpo associated PRCA cases after a successful reversal of antibody using prednisolone in combination with cyclophosphamide. The rechallenge was performed intravenously since there were no reports of anti-r-HuEpo associated PRCA cases using this administration route. The duration after the reversal of antibody was 2.4 months before the re-challenge. Two patients were immediately re-challenged as soon as the antibodies reversed. After rechallenge with intravenous r-HuEpo, all patients responded to r-HuEpo: target level of Hb was maintained, blood transfusion was not required, and anti-r-HuEpo was consistently negative. All patients were followed for at least 6 months after re-challenge. Our data suggest that re-challenge with intravenous r-HuEpo can successfully treat anti- r-HuEpo associated PRCA.

Cases 1 and 2 were 55- and 68-year-old males, respectively. Both were administered deferasirox (DFX) because they received red blood cell transfusions regularly as treatment for myelodysplastic syndrome refractory anemia. DFX administrations were stopped on the 22nd day in case 1 and on the 78th day in case 2 because significantly reduced hemoglobin values and reticulocyte counts were observed. Bone marrow examinations showed pure red cell aplasia in both cases. In case 1, the reticulocyte ratio recovered to the value before drug administration 21 days after drug withdrawal. In case 2, it started increasing on the 14th day, and had recovered to the value before drug administration by the 42nd day after drug withdrawal. Human parvovirus B19 infections were negative in both cases. Both cases were thought to have drug-induced pure red cell aplasia, probably due to DFX. This drug should be used carefully with regular follow-ups of the reticulocyte count.

A 62-year-old woman with hypertension, type 2 diabetes mellitus, hyperlipemia and coronary heart disease started taking clopidogrel, with no addition of any other new drugs. However, with the addition of the drug, the patient was diagnosed as having acquired pure red cell aplasia (PRCA), and no any other inducing factors were detected from the patient. Furthermore, with the withdrawal of clopidogrel from the treatment, the patient recovered from the PRCA and did not recur. Therefore, we report PRCA as a rare side effect of clopidogrel for the first time.

We herein report the case of a patient with human immunodeficiency virus infection and acquired immune deficiency syndrome who was diagnosed with drug-induced pure red cell aplasia consequent to lamivudine treatment. The patient was admitted to our hospital for treatment of increasing shortness of breath following physical effort. Upon admission, routine blood tests revealed a hemoglobin level of 7.6 g/dL and a hematocrit proportion of 21.2%, with normal leukocyte and platelet counts. After stopping the lamivudine treatment, the patient's hemoglobin concentration and hematocrit level returned to normal. A bone marrow examination showed an exclusive reduction in erythrocyte formation. This case indicates that lamivudine can induce severe anemia without the influence of zidovudine.