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Acquired pure red cell aplasia (PRCA) is anemia associated with the absence of erythroblasts and is characterized by persistent and easy recurrence. However, the underlying mechanisms of acquired PRCA remain obscure, and the role of gene mutations in the pathogenesis of acquired PRCA is not fully characterized. In the present study, we detected thirty newly diagnosed patients with acquired PRCA using whole exome sequencing, and a potential role for STK10 in acquired PRCA was uncovered. The mRNA levels of STK10 in three patients with STK10 mutations were decreased. These three patients had a poor response to immunosuppressive therapy and two died in the follow-up period. Here we report that knockdown of STK10 inhibits erythroid differentiation and promotes apoptosis of K562 cells. We show that knockdown of STK10 resulted in inhibition of ribosome biogenesis and reduced ribosome levels in K562 cells. We also show that the p53 signaling pathway is activated by knockdown of STK10. Our results imply that ribosome biogenesis downregulation together with pathological p53 activation prevents normal erythropoiesis. Our study uncovers a new pathophysiological mechanism leading to acquired PRCA driven by STK10 mutations., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Treatment of anemia in patients with chronic kidney disease (CKD) with recombinant human erythropoietin (rHuEPO) can be disrupted by a severe complication, anti-rHuEPO-induced pure red cell aplasia (PRCA). Specific HLA genotypes may have played a role in the high incidence of PRCA in Thai patients (1.7/1,000 patient years vs. 0.03/10,000 patient years in Caucasians). We conducted a case-control study in 157 CKD patients with anti-rHuEPO-induced PRCA and 56 controls. The HLA typing was determined by sequencing using a highly accurate multiplex single-molecule, real-time, long-read sequencing platform. Four analytical models were deployed: Model 1 (additive: accounts for the number of alleles), Model 2 (dominant: accounts for only the presence or absence of alleles), Model 3 (adjusted additive with rHuEPO types) and Model 4 (adjusted dominant with rHuEPO types). HLA-B*46:01:01:01 and DRB1*09:01:02:01 were found to be independent risk markers for anti-rHuEPO-induced PRCA in all models [OR (95%CI), p-values for B*46:01:01:01: 4.58 (1.55-13.51), 0.006; 4.63 (1.56-13.75), 0.006; 5.72 (1.67-19.67), 0.006; and 5.81 (1.68-20.09), 0.005; for DRB1*09:01:02:01: 3.99 (1.28-12.49), 0.017, 4.50 (1.32-15.40), 0.016, 3.42 (1.09-10.74), 0.035, and 3.75 (1.08-13.07), 0.038, in Models 1-4, respectively. HLA-B*46:01:01:01 and DRB1*09:01:02:01 are susceptible alleles for anti-rHuEPO-induced PRCA. These findings support the role of HLA genotyping in helping to monitor patients receiving rHuEPO treatment., (© 2023. The Author(s).)

T-cell large granular lymphocyte leukemia (T-LGL) is often accompanied by pure red cell aplasia (PRCA). A high depth of next generation sequencing (NGS) was used for detection of the mutational profiles in T-LGL alone (n = 25) and T-LGL combined with PRCA (n = 16). Beside STAT3 mutation (41.5%), the frequently mutated genes included KMT2D (17.1%), TERT (12.2%), SUZ12 (9.8%), BCOR (7.3%), DNMT3A (7.3%), and RUNX1 (7.3%). Mutations of the TERT promoter showed a good response to treatment. 3 of 41 (7.3%) T-LGL patients with diverse gene mutations were revealed as T-LGL combined with myelodysplastic syndrome (MDS) after review of bone marrow slide. T-LGL combined with PRCA showed unique features (low VAF level of STAT3 mutation, low lymphocyte count, old age). Low ANC was detected in a STAT3 mutant with a low level of VAF, suggesting that even the low mutational burden of STAT3 is sufficient for reduction of ANC. In retrospective analysis of 591 patients without T-LGL, one MDS patient with STAT3 mutation was revealed to have subclinical T-LGL. T-LGL combined with PRCA may be classified as unique subtype of T-LGL. High depth NGS can enable sensitive detection of concomitant MDS in T-LGL. Mutation of the TERT promoter may indicate good response to treatment of T-LGL, thus, its addition to an NGS panel may be recommended., (© 2023. The Author(s).)

Pure red-cell aplasia (PRCA) is a syndrome associated with reduced erythroid precursors. This report presents the case of an elderly PRCA patient with significantly proliferated γδT cells and clonal T-cell receptor (TCR) gene rearrangement. The cause of this patient's PRCA was confirmed to be an autoimmune disorder rather than malignancy on the basis of flow cytometry, TCR gene rearrangement, and positron emission tomography/computed tomography (PET/CT) findings. Moreover, the γδT cell group identified in this case was captured for the first time under the microscope; this CD4+/CD8- (extremely high CD4/CD8 ratio) population is rare in PRCA patients. Our patient with a monoclonal and polyclonal hybrid of TCR gene rearrangement was sensitive to cyclosporin A (CsA), despite previous reports suggesting that patients with TCR clonal rearrangement may respond poorly to this drug. Overall, this case presents valuable clinical findings for the future diagnosis and management of PRCA caused by autoimmune conditions and further research on γδT cells' autoimmune pathophysiology and gene rearrangement., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2023 Li, Zhu, Zhang and Wang.)

Inherited autosomal dominant gain-of-function (GOF) mutations of signal transducer and activator of transcription 1 (STAT1) cause a wide range of symptoms affecting multiple systems, including chronic mucocutaneous candidiasis (CMC), infections, and autoimmune disorders. We describe a rare case of STAT1 mutation with recurrent CMC, lung infections, and anemia. According to the whole-exome sequencing (WES), the patient was genetically mutated in STAT1 GOF (c.854A>G, p.Q285R), and bone marrow biopsy suggested pure red cell aplasia (PRCA). As a functional verification, STAT1 levels and phosphorylation (p-STAT1) of peripheral blood mononuclear cells (PBMCs) following IFN-γ stimulation in STAT1 GOF patient was higher than in the healthy control. Combination therapy of blood transfusion, antimicrobials, intravenous immunoglobulin, methylprednisolone, and the Janus Kinase (JAK) specific inhibitor ruxolitinib was used during treatment of patients. The patient also received a hematopoietic stem cell transplant (HSCT) to help with infections and anemia. This is the first reported case of STAT1 GOF disease complicated with PRCA. This complication might be attributed to immune disorders caused by STAT1 GOF. Furthermore, ruxolitinib may be a viable therapeutic option before HSCT to improve disease management., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Xie, Shao, Lei, Huang, Fan and Yu.)

Acquired pure red cell aplasia (PRCA) is a syndrome characterized by anemia and a marked reduction of erythroid progenitor cells with various etiologies. The 3 major subtypes of PRCA are idiopathic PRCA, large granular lymphocytic leukemia-associated PRCA and thymoma-associated PRCA, which are thought to be caused by a T-cell-mediated mechanism. In these 3 subtypes, an expansion of clonal cytotoxic T cells is often detected. In addition, those T cells recurrently harbor somatic mutations of STAT3, a gene coding one of the important signal transducers in the JAK/STAT system. Somatic mutations of clonal hematopoiesis (CH)-related genes, including epigenetic modifying genes, have also been reported, however, the data are still not mature enough upon which to draw conclusion, Somatic mutations of STAT3 and CH-related genes may be unique characteristics of acquired PRCA. However, their involvement in dyserythropoiesis or clinical relevance to the clinical course of those somatic mutations. Mutational landscapes, their involvements in dyserythropoiesis and clinical relevance in acquired PRCA remains unclear, and further investigation is needed., (Copyright © 2022 Elsevier Inc. All rights reserved.)

Acquired chronic pure red cell aplasia (PRCA) develops idiopathically or in association with other medical conditions, including T cell large granular lymphocytic leukemia (T-LGLL) and thymoma. T cell dysregulation is considered a cardinal pathogenesis of PRCA, but genetic-phenotypic associations in T cell abnormalities are largely unclear. We evaluated an extended cohort of 90 patients with acquired PRCA, including 26 with idiopathic, 36 with T-LGLL-associated and 15 with thymoma-associated PRCA, for their T cell immuno-phenotypes, clonalities and STAT3 mutations. TCR repertoire skewing of CD8 + T cells was detected in 37.5% of idiopathic, 66.7% of T-LGLL-associated and 25% of thymoma-associated PRCA patients, and restriction to Vβ1 was most prominent (41%). Clonalities of TCRβ or γ chain and STAT3 mutational status were statistically associated (P = 0.0398), and they were detected in all three subtypes. The overall response rate to cyclosporin A was 73.9%, without significant difference by subtypes nor STAT3 mutational status. The T cell dysregulations, such as TCR repertoire skewing with predominant Vβ1 usage, clonality and STAT3 mutations, were frequently found across the subtypes, and the close associations between them suggest that these T cell derangements reflect a common pathophysiological mechanism among these PRCA subtypes., (© 2022. Japanese Society of Hematology.)

Pure red cell aplasia (PRCA) is a rare disorder mainly affecting the erythroid precursor cells. It presents with severe isolated reticulocytopenia with relatively normal counts in the myeloid and megakaryocytic lineages. It has been attributed to numerous congenital and acquired causes. DNA Methyl Transferase 3 Alpha (DNMT3A) mutation has been typically associated with myeloid and lymphoid malignancies. There is a scarcity of data regarding the association of DNMT3A mutation with PRCA. We report a case of a 73-year-old man who initially presented with anemia and reticulocytopenia. After a thorough evaluation and eventual bone marrow biopsy, he was diagnosed with PRCA. Further genetic testing identified a DNMT3A mutation. We are reporting this rare case to highlight the fact that DNMT3A mutation can also present as isolated PRCA in and of itself without the co-occurrence of leukemia, lymphoma, or myelodysplastic syndrome (MDS).

Idiopathic pure red cell aplasia (PRCA) and secondary PRCA associated with thymoma and large granular lymphocyte leukemia are generally considered to be immune-mediated. The PRCA2004/2006 study showed that poor responses to immunosuppression and anemia relapse were associated with death. PRCA may represent the prodrome to MDS. Thus, clonal hematopoiesis may be responsible for treatment failure. We investigated gene mutations in myeloid neoplasm-associated genes in acquired PRCA. We identified 21 mutations affecting amino acid sequences in 11 of the 38 adult PRCA patients (28.9%) using stringent filtering of the error-prone sequences and SNPs. Four PRCA patients showed 7 driver mutations in TET2, DNMT3A and KDM6A, and 2 PRCA patients carried multiple mutations in TET2. Five PRCA patients had mutations with high VAFs exceeding 0.3. These results suggest that clonal hematopoiesis by stem/progenitor cells might be related to the pathophysiology of chronic PRCA in certain adult patients.

Background: Pure red cell aplasia (PRCA) and large granular lymphocytic leukaemia (LGLL) are very rare complications of autoimmune polyendocrine syndrome type 1 (APS1). Here, we report a case of APS1 with PRCA and LGLL. Previous cases were reviewed, and possible mechanisms are discussed., Case Presentation: A 31-year-old female presented with anaemia and was diagnosed with PRCA in our centre. She also had hypoparathyroidism for 24 years, premature ovarian failure for 10 years, osteoporosis for 5 years, recurrent pneumonia with bronchiectasis for 4 years and chronic diarrhoea for 1 year. Boosted whole-exome analysis showed AIRE heterozygous mutations, confirming the diagnosis as APS1. LGLL was diagnosed during follow-up. The PRCA responded well to glucocorticoid. treatment CONCLUSION: AIRE is causally related to the development of LGLL and consequent PRCA, which may be due to some immunological mechanisms.

Acquired pure red cell aplasia (PRCA) is a disorder characterized by normocytic anemia associated with reticulocytopenia and an absence of erythroblasts. The gene mutation profile in acquired PRCA is not defined yet. In this study, we aimed to identify the gene mutation spectrum of patients with acquired PRCA and the correlation between gene mutations and response to immunosuppressive therapy (IST). Thirty newly diagnosed acquired PRCA patients were enrolled in this study, and then whole-exome sequencing were performed among these patients and a panel with 93 candidate genes which associated with other bone marrow failure for the following analysis. Subsequently patients were treated with IST for at least 2 years. When treated with IST, there were thirteen complete response, ten partial response (ORR 76.7%), and seven no response at a medium of 8 (6-10) months. Totally twenty-three mutations in fifteen genes were detected in sixteen patients (53%). The mutated genes were associated with transcription, signal transduction, and epigenetic regulation pathways. The most frequent transitions in the point mutations were C > T. Age, gender, hemoglobin level at diagnosis, and gene mutation or not did not influence the response to IST. However, although patients with BCOR or BCORL1 mutations had a similar response to IST compared with those without mutation (P = 0.235), they had a better response than those with other gene mutations (P = 0.0193). In conclusion, patients with acquired PRCA may have clonal gene mutations. The patients with BCOR and BCORL1 mutations may suggest a better response to IST compared with those with other mutations.

Background: Deficiency of adenosine deaminase 2 (DADA2) is a syndrome with pleiotropic manifestations including vasculitis and hematologic compromise. A systematic definition of the relationship between adenosine deaminase 2 (ADA2) mutations and clinical phenotype remains unavailable., Objective: We sought to test whether the impact of ADA2 mutations on enzyme function correlates with clinical presentation., Methods: Patients with DADA2 with severe hematologic manifestations were compared with vasculitis-predominant patients. Enzymatic activity was assessed using expression constructs reflecting all 53 missense, nonsense, insertion, and deletion genotypes from 152 patients across the DADA2 spectrum., Results: We identified patients with DADA2 presenting with pure red cell aplasia (n = 5) or bone marrow failure (BMF, n = 10) syndrome. Most patients did not exhibit features of vasculitis. Recurrent infection, hepatosplenomegaly, and gingivitis were common in patients with BMF, of whom half died from infection. Unlike patients with DADA2 with vasculitis, patients with pure red cell aplasia and BMF proved largely refractory to TNF inhibitors. ADA2 variants associated with vasculitis predominantly reflected missense mutations with at least 3% residual enzymatic activity. In contrast, pure red cell aplasia and BMF were associated with missense mutations with minimal residual enzyme activity, nonsense variants, and insertions/deletions resulting in complete loss of function., Conclusions: Functional interrogation of ADA2 mutations reveals an association of subtotal function loss with vasculitis, typically responsive to TNF blockade, whereas more extensive loss is observed in hematologic disease, which may be refractory to treatment. These findings establish a genotype-phenotype spectrum in DADA2., (Copyright © 2020 American Academy of Allergy, Asthma & Immunology. Published by Elsevier Inc. All rights reserved.)

GATA1 is an essential regulator of erythroid cell gene expression and maturation. In its absence, erythroid progenitors are arrested in differentiation and undergo apoptosis. Much has been learned about GATA1 function through animal models, which include genetic knockouts as well as ones with decreased levels of expression. However, even greater insights have come from the finding that a number of rare red cell disorders, including Diamond-Blackfan anemia, are associated with GATA1 mutations. These mutations affect the amino-terminal zinc finger (N-ZF) and the amino-terminus of the protein, and in both cases can alter the DNA-binding activity, which is primarily conferred by the third functional domain, the carboxyl-terminal zinc finger (C-ZF). Here we discuss the role of GATA1 in erythropoiesis with an emphasis on the mutations found in human patients with red cell disorders., (© 2019 International Union of Biochemistry and Molecular Biology.)

Acquired pure red cell aplasia and acquired amegakaryocytic thrombocytopenic purpura are rare in children. Similarly, clonal expansion of T-cell large granular lymphocytes is infrequently seen in pediatrics. Lipopolysaccharide-responsive beige-like anchor (LRBA) protein deficiency is a recently described immunodeficiency syndrome that has been associated with inflammatory bowel disease and autoimmune phenomena such as Evans syndrome. Here, we describe a patient with LRBA deficiency who developed acquired pure red cell aplasia and acquired amegakaryocytic thrombocytopenic purpura associated with expansion of clonal T-cell large granular lymphocytes. This has not been described in the literature previously and adds to the knowledge on the spectrum of manifestations of LRBA deficiency.

Dysregulation of T-cell-mediated immunity is responsible for acquired pure red cell aplasia (PRCA). Although STAT3 mutations are frequently detected in patients with T-cell large granular lymphocytic leukemia (T-LGLL), which is often complicated by PRCA and which is also reported to be associated with acquired aplastic anemia (AA) and myelodysplastic syndrome (MDS), whether STAT3 -mutated T cells are involved in the pathophysiology of PRCA and other types of bone marrow failure remains unknown. We performed STAT3 mutation analyses of the peripheral blood mononuclear cells from PRCA patients (n = 42), AA (n = 54), AA-paroxysmal nocturnal hemoglobinuria (AA-PNH; n = 7), and MDS (n = 21) using an allele-specific polymerase chain reaction and amplicon sequencing. STAT3 mutations were not detected in any of the 82 patients with AA/PNH/MDS but were detected in 43% of the 42 PRCA patients. In all 7 STAT3 -mutation-positive patients who were studied, the STAT3 mutations were restricted to sorted CD8 + T cells. The prevalence of STAT3 mutation in idiopathic, thymoma-associated, autoimmune disorder-associated, and T-LGLL-associated PRCA was 33% (5 of 15), 29% (2 of 7), 20% (1 of 5), and 77% (10 of 13), respectively. The STAT3 -mutation-positive patients were younger (median age, 63 vs 73 years; P = .026) and less responsive to cyclosporine (46% [6 of 13] vs 100% [8 of 8]; P = .0092) in comparison with STAT3 -mutation-negative patients. The data suggest that STAT3 -mutated CD8 + T cells may be closely involved in the selective inhibition of erythroid progenitors in PRCA patients., (© 2018 by The American Society of Hematology.)

Idiopathic acquired pure red cell aplasia (PRCA) is a rare, autoimmune-related disease. This study aimed to describe the previously unidentified DNA alterations associated with PRCA. Here, next generation sequencing using a panel containing 295 critical genes was applied to detect potentially pathogenic mutations in four patients with PRCA. A total of 529 mutations were identified and further classified into three categories, namely, uncertain (n = 25), likely benign (n = 20) and benign (n = 484) mutations, based on the American College of Medical Genetics and Genomics (ACMG) 2015 guidelines and ClinVar database. The spatial proximity between two loci of the uncertain or benign mutations was evaluated using Hi-C datasets of KBM7 and K562 cell lines, respectively. Significant spatial proximity was observed in uncertain mutation pairs compared with benign mutation pairs. In addition, 17 variants were eventually identified after excluding those with mutant frequencies >0.001, including 7 newly identified variants. FANCF and LRP1B mutations existed twice in patients. FANCF and LRP1B mutations were likely to affect protein stability based on prediction analysis. Taken together, our data may provide valuable information about PRCA. FANCF and LRP1B mutations may be associated with acquired PRCA.

Although T-cell large granular lymphocytic leukemia (T-LGLL) is a clinically indolent disorder, patients with moderate to severe cytopenia require therapeutic intervention. The recent discovery of STAT3 mutations has shed light on the genetic basis of T-LGLL pathogenesis. However, the association of STAT3 mutational status with patients' clinical, histopathologic, and other laboratory features has not been thoroughly evaluated in T-LGLL. In this study, STAT3 mutations were identified in 18 of 36 patients with T-LGLL (50%), including Y640F (12/18, 66.7%), N647I (3/18, 16.7%), E638Q (1/18, 5.6%), I659L (1/18, 5.6%), and K657R (1/18, 5.6%). Interestingly, pure red cell aplasia was seen exclusively in T-LGLL patients without STAT3 mutations (6/15 in the wild-type STAT3 group versus 0/13 in the mutant STAT3 group; P = .02); these patients also were the only responders to T-LGLL therapy (mainly cyclophosphamide) in wild-type STAT3 group. Patients harboring STAT3 mutations were more prone to rheumatoid arthritis (4/13 versus 0/15 in the wild-type STAT3 group; P = .04), frequently requiring therapy for neutropenia/neutropenia-associated infections, and demonstrated good therapeutic responses to methotrexate. No significant differences were seen in complete blood count, flow cytometric immunophenotypic features, T-cell receptor γ V-J rearrangement repertoire, and bone marrow biopsy morphology among the STAT3-mutation and wild-type groups other than significantly larger tumor burden in patients with STAT3 mutations. The distinct disease association and therapeutic responses observed in patients with mutant and wild-type STAT3 warrant further investigation to elucidate the underlying mechanisms. They also highlight the importance of identifying STAT3 mutational status in patients with T-LGLL, which may aid in clinical therapeutic choice., (Copyright © 2017 Elsevier Inc. All rights reserved.)

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.

Objective: To evaluate the significance of T-cell antigen receptor (TCR) gene rearrangement among patients with acquired pure red cell aplastic anemia (A-PRCA)., Methods: For 16 patients with A-PRCA, an immunosuppressive regimen based on cyclosporin A (CsA) was applied. Rearrangement of the TCR gene was detected by PCR, and T lymphocyte subsets in peripheral blood specimens was detected with flow cytometry., Results: Five patients had presented with TCR clonal rearrangement and were positive for both TCR γ and TCR δ. The blood of 13 patients have returned to normal with the treatment, which included 3 cases with bone marrow returning to normal. In 7 cases, the red cell hyperplasia of bone marrow is still down, but has increased with the treatment. Three patients were close to cure, 7 showed remission, 3 were improved, but 3 were ineffective. The rate of effective treatment in those with TCR rearrangement (2/5) was significantly lower than that those without (11/11, chi-square=8.123, P < 0.05). Compared with those without the TCR gene rearrangement, the Th cells and proportion of Th/Ts were significantly lower, while the Ts cell (CD3+CD8+) were significantly higher in those with the rearrangement (P < 0.05)., Conclusion: TCR gene rearrangement may play a role in the pathogenesis of A-PRCA. CsA is effective for the treatment of A-PRCA, but patients presenting clonal TCR gene rearrangement may response poorly to the treatment.

Many chromosomal deletions encompassing the 2q23.1 region have been described ranging from small deletions of 38 kb up to >19 Mb. Most phenotypic features of the 2q23.1 deletion syndrome are due to a MBD5 gene loss independent of the size of the deletion. Here, we describe a male patient harboring a novel interstitial deletion encompassing the 2q22.3 q23.3 chromosomal region. Array-CGH revealed a 7.1 Mb deletion causing haploinsufficiency of several genes including MBD5, ACVR2, KIF5C, and EPC2. This patient presents with additional findings to those already described in individuals who have deletions of MBD5 including toes absence of halluces, pure red cell aplasia, and intestinal aganglionosis. Interestingly, in the deleted region there are previously identified regulatory sequences which are located upstream to ZEB2, which is associated with Hirschsprung disease (HSCR). Several genes have been associated with pure red cell aplasia, but to our knowledge, this is the first time that 2q deletion is associated with this phenotype. These additional findings should be added to the list of manifestations associated with 2q deletion, and provide support for the hypothesis that this individual has a true contiguous gene deletion syndrome., (© 2015 Wiley Periodicals, Inc.)

Large granular lymphocyte leukemia (LGL L) has been morphologically characterized as a group of lymphoproliferative diseases that include T-cell large granular lymphocytic leukemia (T-LGL L) and chronic lymphoproliferative disorders of natural killer cells (CLPD-NK). We investigated mutations in the Src homology 2 (SH2) domain of the signal transducer and activator of transcription 3 (STAT3) gene in Asian cohorts of T-LGL L and CLPD-NK (n = 42 and 11, respectively). Two mutations, Y640F and D661Y, were identified using direct sequencing or allele-specific (AS) PCR. Y640F and D661Y mutations were found in seven and 18 patients, respectively. Two patients were positive for both mutations. Frequencies of STAT3 mutations in T-LGL L and CLPD-NK were 47.6% and 27.2%, respectively. Pure red cell aplasia (PRCA) was associated with the mutations (P = 0.005). The mutations were persistently found at stable levels in some patients after more than 5 years using AS-quantitative PCR. The results of the present study indicate that the SH2 domain of the STAT3 gene is frequently mutated in Asian T-LGL L and CLPD-NK, and that PRCA is closely correlated with the mutations., (© 2013 The Authors. Cancer Science published by Wiley Publishing Asia Pty Ltd on behalf of Japanese Cancer Association.)

An 80-year-old man was referred to our department because of lymphocytosis. His white cell count was 17.1 × 10(3)/μL, with 64% prolymphocytes. He did not exhibit splenomegaly or lymphadenopathy. Prolymphocytes were CD5(+), CD10(-), CD19(+), CD20(+), CD21(+weak), CD22(+), CD23(-), and HLA-DR(+), and expressed μδ/λ cell-surface immunoglobulins. G-banding and fluorescence in situ hybridization using c-MYC and immunoglobulin heavy-chain (IgH) gene probe revealed that leukemia cells carried the t(8;14)(q24;q32)/c-MYC-IgH fusion gene, and breakage and reunion occurred within the non-coding region of c-MYC exon 1 as well as the α switch region of IgH. Nine months after the initial presentation, the patient's hemoglobin level fell to 5.7 g/dL. Coombs' test was positive and marked hypoplasia of erythroid precursors was detected in his bone marrow. The patient was treated with prednisolone followed by 4 weekly doses of rituximab, which led to resolution of the anemia and complete response of the underlying leukemia. The role of t(8;14)(q24;q32)/c-MYC-IgH in the pathogenesis of B-cell prolymphocytic leukemia (B-PLL) may not be identical to that in aggressive lymphoid neoplasms, and, in the present case, autoantibodies targeting both mature red cells and erythroid precursors may have been concurrently produced in the setting of B-PLL.

Adult hematopoiesis occurs primarily in the BM space where hematopoietic cells interact with stromal niche cells. Despite this close association, little is known about the specific roles of osteoblastic lineage cells (OBCs) in maintaining hematopoietic stem cells (HSCs), and how conditions affecting bone formation influence HSC function. Here we use a transgenic mouse model with the ColI(2.3) promoter driving a ligand-independent, constitutively active 5HT4 serotonin receptor (Rs1) to address how the massive increase in trabecular bone formation resulting from increased G(s) signaling in OBCs impacts HSC function and blood production. Rs1 mice display fibrous dysplasia, BM aplasia, progressive loss of HSC numbers, and impaired megakaryocyte/erythrocyte development with defective recovery after hematopoietic injury. These hematopoietic defects develop without compensatory extramedullary hematopoiesis, and the loss of HSCs occurs despite a paradoxical expansion of stromal niche cells with putative HSC-supportive activity (ie, endothelial, mesenchymal, and osteoblastic cells). However, Rs1-expressing OBCs show decreased expression of key HSC-supportive factors and impaired ability to maintain HSCs. Our findings indicate that long-term activation of G(s) signaling in OBCs leads to contextual changes in the BM niche that adversely affect HSC maintenance and blood homeostasis.

Myelodysplastic syndromes (MDS) with pure red cell aplasia (PRCA) have been shown to be a rare form of MDS. A 35-year-old man presented with pancytopenia: hemoglobin 59 g/L, reticulocytes 2 × 10(9)/L, platelets 33 × 10(9)/L, and leukocytes 1.8 × 10(9)/L with 1% blasts. Bone marrow was hypercellular with 50.4% myeloid cells, 0.0% erythroblasts, 25.4% basophils, and 5.6% myeloblasts. Dysplastic changes including pseudo-Pelger-Huët anomaly of neutrophils and mononuclear micromegakaryocytes were found. Immunohistochemistry with glycophorin C confirmed erythroid aplasia. Cytogenetic analysis showed 46,XY,i(17)(q10)[18]/47,XY,+8[2]. Considering two reported cases, these findings indicate that isolated i(17q) may be implicated in the pathogenesis of MDS with PRCA as a recurrent cytogenetic aberration.

The deficiency of glycosyl-phosphatidylinositol (GPI)-anchored proteins in plasma membranes of PIG-A gene mutated hematopoietic stem cells (HSCs) is so far insufficient to explain the domination of paroxysmal nocturnal hemoglobinuria (PNH) clone over the normal HSC. We attempted to elucidate possible link between MHC and initial severe aplastic anemia (ISAA/PNH) type and non-aplastic (n/PNH) outcome of PNH. In 50 PNH patients assigned as ISAA/PNH (n = 13), n/PNH (n = 33) or nonassigned (n = 4) and 200 ethnically matched controls we analyzed MHC associations. Our data confirmed strong associations of DRB1*15:01 (RR = 3.51, p = 0.0011) and DQB1*06:02 (RR = 7.09, p = 0.000026) alleles, especially with n/PNH subtype. B*18:01 allele was associated with increased risk of ISAA/PNH subtype (RR = 5.25, p = 0.0028). We conclude that both class II and class I MHC alleles are associated with different subsets of PNH. Clonal selection of PIG-A mutated cells with cognate metabolic block is associated with MHC class II alleles DRB1*15:01 and DQB1*06:02 independent from initial severe AA clone selection. MHC class I molecule B*18:01 can additionally influence the domination of PNH clone in PNH subjects with initial severe aplastic anemia.

A 28-year-old man with marked eosinophilia is described. FIP1L1/PDGFRA mRNA showed multiple alternatively-spliced fusion transcripts. Sequencing analysis showed that the deduced DNA breakpoints were intron 10 in the FIP1L1 gene and exon 12 in the PDGFRA gene. Then, a diagnosis of chronic eosinophilic leukemia (CEL) was made. Whereas the response to the treatments with prednisolone and hydroxyurea were unsatisfactory, treatment with imatinib showed a rapid decrease of eosinophils. The hemoglobin level also dropped and bone marrow examination showed pure red cell aplasia. Continued administration of very low dose imatinib (100 mg every 5 days) led to and maintained complete molecular remission, with good tolerability.

Background: Anti-r-HuEpo associated PRCA developed in patients received subcutaneous injection of r-HuEpo for treatment of renal anemia in chronic kidney disease. This adverse immunological effect of r-HuEpo causes sudden loss of r-HuEpo efficacy, low circulating reticulocyte count and bone marrow biopsy shows an absence of erythroid precursor cells with normal cell population of non-erythroid lineage. There are postulation cause of anti-r-HuEpo associated PRCA including genetic factor, immunogenicity factor, storage and handlings factor and formulation of r-HuEpo product. Previous observation of our report showed an aggregation of HLA-DRB1*09 in four anti-r-HuEpo associated PRCA cases. This allele is rare in Caucasian (<1%) but more common in Thai population (8.4-12.5%). This study was aimed to investigate the possible association between HLA-DRB1*09 or other specific HLA and anti-r-HuEpo associated PRCA., Methods: Twenty two cases of proven anti-r-HuEpo associated PRCA were recruited and studied retrospectively based on the incidence report of serious adverse drug reaction. The EDTA bloods were drawn for HLA typing using sequence specific primer polymerase chain reaction (SSP-PCR). The HLA data of 1,800 potential cadaveric kidney transplantation recipients in the waiting list as chronic kidney disease control and 1,500 potential bone marrow stem cell donors in national stem cell registry as healthy population control were retrieved from the database of Thai Red Cross for comparison., Results: The distribution of gene frequency of HLA-A, -B, -DR and -DQ alleles in anti-r-HuEpo associated PRCA cases showed high gene frequency of HLA-A*02, HLA-A*11 and HLA-A*24 for HLA-A loci, HLA-B*18, HLA-B*46, HLA-B*60 and HLA-B*62 for HLA-B loci, and HLA-DRB1*09, HLA-DRB1*12 and HLA-DRB1*15 for HLA-DR loci. There was a significant difference of HLA-DRB1*09 gene frequency (P < 0.001) which associated with HLA-DQB1*0309 between anti-r-HuEpo associated PRCA cases, and potential cadaveric kidney transplantation in the waiting list or potential national stem cell registry donor. The odd ratio of HLA-DRB1*09 allele for anti-r-HuEpo associated PRCA was 2.89 (95% CI: 1.88-4.46; p-value: <0.001)., Conclusions: Our data demonstrated the association of HLA-DRB1*09-DQB1*0309 and anti-r-HuEpo associated PRCA cases. This association may be used in identifying the risk of the patients.

Aims: Antibody (Ab)-positive pure red-cell aplasia (PRCA) is a very rare but serious adverse event associated with recombinant human erythropoietin treatment (4.1 reports per 100,000 patient-years) in which patients produce antibodies to recombinant and endogenous erythropoietin, halting red blood cell production. In a previous case series, four Thai subjects with chronic kidney disease and Ab-positive PRCA were reported to have the HLA-DRB1*9 allele. To confirm a possible association of HLA-DRB1*9 and Ab-positive PRCA, we performed a pharmacogenomic analysis using subjects from an earlier case-control study of risk factors associated with Ab-positive PRCA, which had been performed using subjects from Europe or Canada. The primary goal of the analysis was to test the association between HLA-DRB1*9 and Ab-positive PRCA. A secondary goal was to perform an exploratory analysis in order to identify additional HLA alleles potentially associated with Ab-positive PRCA., Patients & Methods: Subjects were taken from a case-control study of Ab-positive PRCA in chronic kidney disease patients treated in Europe or Canada. Ab-positive PRCA cases (n=24) were matched to controls (n=81) by timing of treatment exposure and, when possible, by location., Results: The allele frequency of HLA-DRB1*9 was 12.5% in cases vs 1.2% in controls (p=0.002). The frequency of the HLA-DRB1*9/other genotype was 25.0% in cases vs 2.5% in controls (p=0.004; OR: 10.8 [95% CI: 2.2-53.7]). Within the exploratory analysis, six additional HLA alleles (HLA-A*25, HLA-B*53, HLA-C*12, HLA-DQB1*3, HLA-DQB1*6 and HLA-DRB1*4) were also found to be associated with Ab-positive PRCA., Conclusion: This study confirmed that HLA-DRB1*9 occurs at a significantly higher frequency in Ab-positive PRCA cases than in controls; however, within this sample set, carrying the *9 allele was neither necessary nor sufficient to cause Ab-positive PRCA.

Myelodysplastic syndrome (MDS) with erythroid hypoplasia, a rare form of MDS, has not yet been clearly defined. We report here a 20-year-old woman with severe transfusion-dependent anemia and reticulocytopenia. White blood cells and platelet counts were normal. Bone marrow examination showed a low percentage of erythroid precursors (6%) and a marked dyserythropoiesis and dysmegakaryopoiesis. A diagnosis of MDS (refractory anemia according to the FAB classification) with erythroid hypoplasia was made. Cytogenetic analysis of the bone marrow and peripheral blood revealed a 46,XX,t(3;14)(p21.1;q24.1) translocation, which was confirmed by fluorescence in situ hybridization analysis. This translocation was detected in the apparently healthy younger brother, father, and aunt (father's sister) of the patient. Clonality of T cells in the patient was not confirmed by the polymerase chain reaction and heteroduplex temperature-gradient gel electrophoresis. IgM serology for B19 parvovirus was negative. Other conditions known to be associated with erythroid hypoplasia, such as thymoma, were not present. The patient failed to respond to immunosuppressive therapy (antithymocyte globulin and cyclosporin A). Administration of recombinant human erythropoietin improved her anemia. To our knowledge, this balanced translocation, namely t(3;14)(p21.1;q24.1), which is present both in the patient with MDS with erythroid hypoplasia and in the healthy members of the family, has not been defined previously., ((c) 2006 Wiley-Liss, Inc.)

Diamond Blackfan anemia (DBA) is a genetically and clinically heterogeneous disorder characterized by erythroid failure, congenital anomalies, and a predisposition to cancer. Faulty ribosome biogenesis is hypothesized to be the underlying defect, leading to erythroid failure due to accelerated apoptosis in affected erythroid progenitors/precursors. Since first observed in DBA, pro-apoptotic hematopoiesis has been recognized as a common mechanism for hematopoietic failure in virtually all of the inherited bone marrow failure syndromes. Inherited as an autosomal dominant trait, one of what appears to be multiple DBA genes, coding for ribosomal protein RPS19, has been cloned. The discovery of additional genes will no doubt clarify the molecular pathophysiology of this disorder. Even within families, individuals may vary dramatically as to the degree of anemia, treatment response, and the presence of congenital anomalies. The study of DBA has been facilitated by the creation of international patient registries that provide more reliable information regarding clinical presentation, genetics, and outcome, as well as descriptions of congenital malformations and cancer predisposition, than can be culled from the literature. Analysis of registry data has led to improvements in clinical care and provides patients and research specimens for clinical and laboratory investigations.

This study detected clonal T cells in patients with acquired pure red-cell aplasia (PRCA) by Southern blotting and polymerase chain reaction (PCR). Twenty-nine adult patients with acquired PRCA were enrolled in this study. Seventeen patients had primary acquired PRCA, while 12 patients had the secondary form. Twenty-two of 29 (76%) patients demonstrated TCR rearrangement by at least one method. We divided the patients into three groups depending on T-cell clonality. The CD4/8 ratio of patients who were positive on Southern blotting was significantly lower than that of other groups. Except for the CD4/8 ratio, other laboratory findings did not significantly differ among the three groups. The CD4/8 ratio should be a useful surrogate marker to detect T-cell clonality., (Copyright (c) 2005 Wiley-Liss, Inc.)

Aase-Smith syndrome type II is rare in childhood and there are few reported cases. Here, we report an 8-month-old boy with congenital red cell aplasia and triphalangeal thumbs. In addition to thumb anomalies, he presented with growth failure, hypertelorism and novel osseous radiologic abnormalities, large fontanelles and micrognathia as extraordinary. Some clinical symptoms had complete clinical remission with deflazacort treatment.

In our Paediatric Clinic we observed a case of transient aplastic crisis caused by Parvovirus B19 in a child and his mother, both affected by spherocytic haemolytic anemia. Anti-Parvovirus IgM antibody titre and viral search by PCR were positive. Anemia was treated with transfusion of concentrated red blood cells. In case of a family onset of hyperacute anemia it is necessary to consider a bone marrow aplastic crisis of the red series, induced by Parvovirus B19, especially if there is notice of an ongoing outbreak of erythema infectiosum.

We encountered two cases of thymoma accompanied by pure red cell aplasia and demonstrating clonal rearrangement of the T-cell receptor beta-chain gene (TCR-beta) in lymphocytes. Patient 1 was a 55-year-old man and Patient 2 was a 43-year-old woman. Both had severe anemia and mediastinal tumors. Bone marrow aspiration was performed and pure red cell aplasia diagnosed. Thymoma was the presumptive diagnosis for the mediastinal tumors, and extended thymectomy was performed. The post-operative diagnosis was invasive thymoma (spindle-cell type) in Patient 1 and non-invasive thymoma (mixed lympho-epithelial type) in Patient 2. The cell compositions (%) obtained with T-cell surface marker analysis were as follows: [table: see text] Southern blot analysis disclosed clonal rearrangement of TCR-beta genes in thymoma thymocytes from both patients.

Acquired primary pure red cell aplasia (PRCA) has frequently been shown to be associated with T cells that inhibit marrow erythropoiesis. A 41-year-old female presented with anemia in December 1985. Bone marrow examination revealed 1.8% erythroid cells. A diagnosis of PRCA was made. She received prednisolone, and her hemoglobin level recovered to 12 g/dl. In February 1995, her hemoglobin level decreased to 5.8 g/dl, and acquired primary PRCA recurred. Surface markers of peripheral blood mononuclear cells demonstrated CD4/8 ratio inversion. The T-cell receptor (TCR)-beta chain gene showed germ line configuration by Southern blot analysis of the mononuclear cells in peripheral blood. However, stepdown polymerase chain reaction analysis revealed that the TCR-beta gene of peripheral blood mononuclear cells was rearranged. With highly sensitive polymerase chain reaction analysis, clonality of T cells was confirmed. We propose that some acquired primary PRCA patients have a T-cell clonal disorder, similar to some PRCA patients with large granular lymphocytes leukemia or thymoma., (Copyright 1999 Wiley-Liss, Inc.)

Morphological characteristics of lymphocytes and the response to cyclosporine treatment have revealed some unique patients with pure red cell aplasia. Lymphocytes from these patients consisted mainly of non-granulated lymphocytes. All of the patients were successfully managed by cyclosporine monotherapy irrespective of prior treatment. A reduction in lymphocyte mass was not a prerequisite for the remission of pure red cell aplasia, and responses occurred within 1 month from the start of therapy. Clonal T-cell proliferation was detected in four patients, which raised the possibility of idiopathic pure red cell aplasia being associated with a clonal proliferation of T cells. An examination of the lymphocytes in patients with pure red cell aplasia could potentially be used to plan better therapeutic modalities and assess prognosis.

Authors reports a rare case of association between two pathologies that, even if apparently very different, are both immunologically determined: celiac disease (CD) and transient erythroblastopenia of childhood (TEC). Such an association may be less rare commonly thought and this may be true for other autoimmune diseases, too. Clinical and pathological observations, together with etio-pathogenetic hypotheses, are discussed.

From 1980 through 1994, we identified 47 adult patients with acquired pure red cell aplasia (median age, 64 years; range, 22 to 84 years). Associated clinical disorders included T-cell large granular lymphocytic (LGL) leukemia, thymoma, chronic lymphocytic leukemia, and non-Hodgkin's lymphoma. Review of bone marrow findings in 40 patients showed absence of erythroid precursors in 14 patients and rare pronormoblasts in 26. None had morphologic evidence of myelodysplasia. T-cell receptor gene rearrangement studies with Southern blot technique in 14 patients showed clonal rearrangements in nine. Karyotypic analyses performed in 28 patients showed clonal abnormalities in four. Overall, 28 of 47 patients (60%) responded to immunosuppressive therapy, but none were the patients with cytogenetic abnormalities. There was a trend toward superior response to immunosuppressive agents in the patients with T-cell LGL leukemia. Cyclophosphamide, with or without corticosteroids, was the most useful treatment agent. Cyclosporine A was effective for refractory disease. Neither the presence of an associated clinical disorder nor the existence of detectable erythroid precursors affected overall survival. We conclude that (1) T-cell LGL leukemia is the disorder most commonly associated with pure red cell aplasia, (2) the presence of clonal cytogenetic abnormality predicts poor response to immunosuppressive therapy, and (3) oral cyclophosphamide and cyclosporine A are effective treatment regimens.

Traditional cytogenetic analysis from bone marrow aspirates is time consuming and frequently suboptimal due to poor viability of cells in culture. Fluorescence in situ hybridization (FISH) with appropriate DNA probes is a potential alternative to routine cytogenetics. Our study examined the reliability of uptake of specific alpha satellite centromere probes from chromosome 18 (D18Z1) and X (DXZ1) and the Yq heterochromatin (pHY3.4) directly from routine hematological bone marrow smears. Altogether 34 separate hybridizations, performed on slides from 20 patients, were scored for fluorescence signals. Cells in interphase were examined with each probe using unstained slides. In addition Giemsa stained slides were destained and then used for interphase FISH. Between 412 and 631 cells were scored for the expected number of signals; 2 for the 18 centromere, 2 for the X centromere in females, one signal for the Yqh in males. The results showed the expected number of signals in 87-97% of cells with the 18 and X probes and 95-97% of cells with the Y probe. Interphase FISH is a reliable, reproducible technique for use on direct bone marrow smears.

Patients and Methods: Seven children of the same family with a possible variant of Diamond-Blackfan anemia (DBA) are reported. Five were male siblings, and the other two were their cousins, one male and one female. All were products of consanguineous marriages of healthy parents. All cases occurred within one generation. Anemia was present at birth or shortly after birth. Hepatosplenomegaly was present in all. Four had short stature. Hematological findings included normochromic, normocytic, or macrocytic anemia, marked reticulocytopenia, with initial normal white blood cell and platelet count, and absent or markedly decreased erythroid precursors on bone marrow examination. All were treated initially with prednisolone; in one patient oxymetholone was added., Results: Three children failed to respond to the initial treatment, and also failed to respond to cyclosporin A and pulse doses of methylprednisolone. Myelofibrosis occurred in two siblings, 9 and 11 years from diagnosis. In two children the disease recurred 9 and 12 years after initial diagnosis., Conclusions: Our cases point to a possible variant of DBA characterized by the presence of normochromic normocytic anemia, hepatosplenomegaly, absent skeletal malformations, and unusual long- term complications.

We report a patient with pure red cell aplasia and type I autoimmune polyglandular syndrome who also had an expansion of suppressor T lymphocytes in the peripheral blood. Southern blotting of DNA from these cells suggest T cell receptor (TCR) gamma gene rearrangement. We confirmed true clonality of this by amplification of the gene rearrangement using the polymerase chain reaction and subsequent analysis of the product by gene cloning and DNA sequencing.