Spurious High Platelet Count without PLT Flag(S) in a Patient with Severe Aplastic Anaemia.

BACKGROUND: Platelet (PLT) count is one of the most important parameters of automated hematology, as spurious PLT reports could affect medical judgement and bring significant risks. In most cases, spurious PLT will not be reported for review criteria, which will be triggered by abnormal PLT histograms and PLT flag(s). Here, we present a case of severe aplastic anemia after hematopoietic stem cell transplantation with spurious high platelet count with normal histogram and no PLT flag(s). METHODS: The electrical impedance channel (PLT-I) and the fluorescence channel (PLT-F) of Sysmex XN-series hematology analyzer was used to obtain PLT results. Then, the sample was retested by another hematology analyzer MINDRAY BC-7500 [NR] CRP, and incubation was performed to rule out cryoglobulin interference. Furthermore, a microscope was used to estimate the PLT count by the ratio of platelets to red blood cells and observe the morphology of cells. RESULTS: Both PLT-I and PLT-F test results were spuriously high, and microscopically assessed platelet counts were relatively reliable. The observed spiny cells and ghost cells caused by hemolysis may have contributed to the inaccuracy of instrumental counting in this case. CONCLUSIONS: For special hematologic patients, PLT-I with flags may not be sufficient for screening purposes and PLT-F is not always accurate. Multiple testing methods including manual microscopy are needed.

Pancytopenia with aplastic anemia in systemic lupus erythematosus: case series and literature review.

Aplastic anemia (AA) is a rare, potentially catastrophic hematopoiesis failure manifested by pancytopenia and bone marrow aplasia. AA occurrence in Systemic Lupus Erythematosus (SLE) patients is extremely rare. The diagnosis may be delayed due to other possible pancytopenia etiologies. Confirmation of peripheral cytopenias diagnosis necessitates a bone marrow aspiration. The management of AA is challenging, and the literature reported using glucocorticoids, danazol, plasmapheresis, cyclophosphamide, intravenous immunoglobulin, and cyclosporine. We report two cases of SLE patients who presented with pancytopenia, with bone marrow biopsy confirmed AA. One case was treated with cyclophosphamide but unfortunately succumbed to Acute Respiratory Distress Syndrome (ARDS), while the other case was managed with rituximab with a good response. Interestingly, both patients were on azathioprine before the diagnosis of AA. A comprehensive search for reported cases of AA in PubMed, Scopus, and the Directory of Open Access Journals databases was performed to enhance the understanding of the diagnostic and management challenges associated with AA in SLE, facilitating ongoing exploration and research in this field. The decision to do a BM aspiration and biopsy is recommended for SLE patients with an abrupt decline in blood counts and previously stable blood counts.

Aplastic anemia: history and recent developments in diagnosis and treatment.

Acquired aplastic anemia is an immune-mediated disease that targets hematopoietic stem cells, which is diagnosed by findings of peripheral blood pancytopenia and hypocellular bone marrow. Although the diagnostic definition is simple, differential diagnosis from other overlapping hematopoietic disorders such as hypoplastic myelodysplastic syndrome and inherited bone marrow failure syndrome is not easy. Immune suppressive therapy and allogeneic hematopoietic stem cell transplantation are important treatment approaches for aplastic anemia, and both have advanced in recent years. This issue of Progress in Hematology covers four topics related to aplastic anemia: (1) laboratory markers to identify immune pathophysiology and their role on differential diagnosis and prognosis, (2) the path to combination therapy with horse anti-thymocyte globulin, cyclosporine A, and eltrombopag, (3) more than 60 years of history and recent trends in allogeneic HSCT, and (4) genetic testing for differential diagnosis from IBMFS and novel approaches to transplantation for children including fludarabine/melphalan-based conditioning.

Comparison of telomere length in patients with bone marrow failure syndromes and healthy controls.

INTRODUCTION: During normal aging, telomeric DNA is gradually lost in dividing somatic cells, and critically short telomeres lead to replicative senescence, apoptosis, or chromosomal instability. We studied telomere length in bone marrow failure syndromes (BMFS) compared to normal healthy population. METHODS: Peripheral blood was collected from the participants, and genomic DNA was extracted. Relative telomere length was measured using a quantitative polymerase chain reaction. Statistical analysis was performed using SPSS and GraphPad Prism 8.2 software. RESULTS: The median age of normal Indian population was 31 (0-60) years. As expected, telomere length (TL) showed a decline with age and no difference in TL between males and females. The median age of 650 patients with aplastic anemia (AA) was 30 (1-60) years. TL was significantly shorter in patients with AA compared to healthy controls (p < .001). In FA and MDS patients, TL was significantly shorter than age-matched healthy controls (p = .028; p < .001), respectively. There was no difference between the median TL in age-matched AA and FA patients (p = .727). However, patients with MDS had shorter TL than age-matched AA (p = .031). CONCLUSION: TL in BMF syndrome patients was significantly shorter than age-matched healthy controls.

Diagnostic evaluation in bone marrow failure disorders: what have we learnt to help inform the transplant decision in 2024 and beyond?

Aplastic anemia (AA) is the prototypical bone marrow failure syndrome. In the current era of readily available 'molecular annotation', application of comprehensive next-generation sequencing panels has generated novel insights into underlying pathogenetic mechanisms, potentially leading to improvements in personalized therapeutic approaches. New evidence has emerged as to the role of somatic loss of HLA class I allele expression in 'immune-mediated' AA, associated molecular aberrations, and risk of clonal evolution. A deeper understanding has emerged regarding the role of 'myeloid' gene mutations in this context, translating patho-mechanistic insights derived from wider clinical and translational research within the myeloid disorder arena. Here, we review contemporary 'tools' which aid in confirmation of a diagnosis of AA, with an additional focus on their potential in guiding therapeutic options. A specific emphasis is placed upon interpretation and integration of this detailed diagnostic information and how this may inform optimal transplantation strategies.

Recent advances in the diagnosis and treatment of pediatric acquired aplastic anemia.

Acquired aplastic anemia (AA) in children is a rare bone marrow failure that requires several special considerations for its diagnosis and treatment compared with that in adults. The most common issue is the differential diagnosis with refractory cytopenia of childhood and inherited bone marrow failure syndromes, which is crucial for making decisions on the appropriate treatment for pediatric AA. In addition to detailed morphological evaluation, a comprehensive diagnostic work-up that includes genetic analysis using next-generation sequencing will play an increasingly important role in identifying the underlying etiology of pediatric AA. When discussing treatment strategies for children with acquired AA, the long-term sequelae and level of hematopoietic recovery that affect daily or school life should also be considered, although the overall survival rate has reached 90% after immunosuppressive therapy or hematopoietic cell transplantation (HCT). Recent advances in HCT for pediatric patients with acquired AA have been remarkable, with the successful use of upfront bone marrow transplantation from a matched unrelated donor, unrelated cord blood transplantation or haploidentical HCT as salvage treatment, and fludarabine/melphalan-based conditioning regimens. This review discusses current clinical practices in the diagnosis and treatment of acquired AA in children based on the latest data.

Reference guide for the diagnosis of adult primary immune thrombocytopenia, 2023 edition.

Primary immune thrombocytopenia (ITP) is an autoimmune disorder characterized by isolated thrombocytopenia due to accelerated platelet destruction and impaired platelet production. Diagnosis of ITP is still challenging because ITP has been diagnosed by exclusion. Exclusion of thrombocytopenia due to bone marrow failure is especially important in Japan because of high prevalence of aplastic anemia compared to Western countries. Hence, we propose a new diagnostic criteria involving the measurement of plasma thrombopoietin (TPO) levels and percentage of immature platelet fraction (RP% or IPF%); 1) isolated thrombocytopenia with no morphological evidence of dysplasia in any blood cell type in a blood smear, 2) normal or slightly increased plasma TPO level (< cutoff), 3) elevated RP% or IPF% (> upper limit of normal), and 4) absence of other conditions that potentially cause thrombocytopenia including secondary ITP. A diagnosis of ITP is made if conditions 1-4 are all met. Cases in which criterion 2 or 3 is not met or unavailable are defined as "possible ITP," and diagnosis of ITP can be made mainly by typical clinical course. These new criteria enable us to clearly differentiate ITP from aplastic anemia and other forms of hypoplastic thrombocytopenia and can be highly useful in clinical practice for avoiding unnecessary bone marrow examination as well as for appropriate selection of treatments.

Uncovering the Genetic Etiology of Inherited Bone Marrow Failure Syndromes Using a Custom-Designed Next-Generation Sequencing Panel.

Inherited bone marrow failure syndromes (IBMFS) are a group of heterogeneous disorders that account for ∼30% of pediatric cases of bone marrow failure and are often associated with developmental abnormalities and cancer predisposition. This article reports the laboratory validation and clinical utility of a large-scale, custom-designed next-generation sequencing panel, Children's Hospital of Philadelphia (CHOP) IBMFS panel, for the diagnosis of IBMFS in a cohort of pediatric patients. This panel demonstrated excellent analytic accuracy, with 100% sensitivity, ≥99.99% specificity, and 100% reproducibility on validation samples. In 269 patients with suspected IBMFS, this next-generation sequencing panel was used for identifying single-nucleotide variants, small insertions/deletions, and copy number variations in mosaic or nonmosaic status. Sixty-one pathogenic/likely pathogenic variants (54 single-nucleotide variants/insertions/deletions and 7 copy number variations) and 24 hypomorphic variants were identified, resulting in the molecular diagnosis of IBMFS in 21 cases (7.8%) and exclusion of IBMFS with a diagnosis of a blood disorder in 10 cases (3.7%). Secondary findings, including evidence of early hematologic malignancies and other hereditary cancer-predisposition syndromes, were observed in 9 cases (3.3%). The CHOP IBMFS panel was highly sensitive and specific, with a significant increase in the diagnostic yield of IBMFS. These findings suggest that next-generation sequencing-based panel testing should be a part of routine diagnostics in patients with suspected IBMFS.

When to consider inherited marrow failure syndromes in adults.

The inherited bone marrow failure syndromes (IBMFS) are a heterogenous group of disorders caused by germline mutations in related genes and characterized by bone marrow failure (BMF), disease specific organ involvement, and, in most cases, predisposition to malignancy. Their distinction from immune marrow failure can often be challenging, particularly when presentations occur in adulthood or are atypical. A combination of functional (disease specific assays) and genetic testing is optimal in assessing all new BMF patients for an inherited etiology. However, genetic testing is costly and may not be available worldwide due to resource constraints; in such cases, clinical history, standard laboratory testing, and the use of algorithms can guide diagnosis. Interpretation of genetic results can be challenging and must reflect assessment of pathogenicity, inheritance pattern, clinical phenotype, and specimen type used. Due to the progressive use of genomics, new IBMFS continue to be identified, widening the spectrum of these disorders.

Cytogenetics in the management of bone marrow failure syndromes: Guidelines from the Groupe Francophone de Cytogénétique Hématologique (GFCH).

Bone marrow failure syndromes are rare disorders characterized by bone marrow hypocellularity and resultant peripheral cytopenias. The most frequent form is acquired, so-called aplastic anemia or idiopathic aplastic anemia, an auto-immune disorder frequently associated with paroxysmal nocturnal hemoglobinuria, whereas inherited bone marrow failure syndromes are related to pathogenic germline variants. Among newly identified germline variants, GATA2 deficiency and SAMD9/9L syndromes have a special significance. Other germline variants impacting biological processes, such as DNA repair, telomere biology, and ribosome biogenesis, may cause major syndromes including Fanconi anemia, dyskeratosis congenita, Diamond-Blackfan anemia, and Shwachman-Diamond syndrome. Bone marrow failure syndromes are at risk of secondary progression towards myeloid neoplasms in the form of myelodysplastic neoplasms or acute myeloid leukemia. Acquired clonal cytogenetic abnormalities may be present before or at the onset of progression; some have prognostic value and/or represent somatic rescue mechanisms in inherited syndromes. On the other hand, the differential diagnosis between aplastic anemia and hypoplastic myelodysplastic neoplasm remains challenging. Here we discuss the value of cytogenetic abnormalities in bone marrow failure syndromes and propose recommendations for cytogenetic diagnosis and follow-up.

Deciphering treatment patterns in non-severe/moderate aplastic anemia: an international observational study.

Non-severe aplastic anemia is a rare bone marrow failure disorder characterized by variable degrees and combination of cytopenias, with limited data on management and outcome. We describe a large multicentric series of 259 patients, focusing on clinical and molecular features, treatment, evolution, and survival. The majority required treatment with cyclosporine (CyA) alone (N = 84) or in combination with anti-thymocyte globulin (ATG,44) or eltrombopag (20), eltrombopag alone (10), or others (25) including androgens. Similar outcomes were observed across different strategies, with a 6-month overall response rate of 73% for CyA, 74% for ATG plus CyA, 68% for CyA plus eltrombopag, 87% for eltrombopag, and 79% for others. Notably, 56 patients (39%), mainly receiving CyA plus eltrombopag, achieved a trilineage response (p = 0.02). Progression to myeloid neoplasms was limited (8%) and not related to mutational status. Hemolytic PNH developed in 10% of cases, being predicted by detection of small clones at diagnosis. Survival was negatively impacted by age, male gender, LDH, platelets/erythrocyte transfusion need, and somatic mutations by NGS, and positively by higher neutrophils at diagnosis, PNH clones, and trilineage response at 6 and 12 months. Multivariable analysis confirmed the detrimental role of age and the favorable association with PNH clone and trilineage response at 6 months.

Optimizing diagnostic methods and stem cell transplantation outcomes in pediatric bone marrow failure: a 50-year single center experience.

Peripheral blood cytopenia, a frequent presenting symptom in pediatric patients, can be caused by bone marrow failure (BMF). Timely identification of patients with non-reversible BMF is of crucial importance to reduce the risks of invasive infections and bleeding complications. Most pediatric patients with severe persistent cytopenia, independent of the underlying cause, are offered allogeneic hematopoietic stem cell transplantation (HSCT) as curative therapy. Here we report on our management guidelines and HSCT outcomes of pediatric BMF patients to pinpoint improvements and future challenges. We formulated recommendations based on this 50 years' experience, which were implemented at our center in 2017. By analysis of the HSCT cohort of 2017-2023, the 5-year outcome data is presented and compared to historical outcome data. In addition, outcomes of patients transplanted for identified inherited bone marrow failure syndromes (IBMFS) are compared to severe aplastic anemia (SAA) outcomes to underline the often multiorgan disease in IBMFS with implications for long-term survival. Survival of pediatric patients with irreversible BMF has improved tremendously. SAA patients transplanted after 2017 had a superior 5-year overall (OS) and event-free survival (EFS) of 97% and 85% compared to 68% and 59% in the cohort transplanted before 2017 (p = 0.0011 and p = 0.017). A similar trend was seen for BMF, with an OS and EFS of 89% for those transplanted after 2017 compared to 62% and 59% (p > 0.05). This improvement is mainly related to better survival in the first months after HSCT. The long-term survival after HSCT is lower in IBMFS patients as compared to SAA patients due to secondary malignancies and multiorgan toxicity.   Conclusion: Unbiased protocolized in-depth diagnostic strategies are crucial to increase the frequency of identifiable causes within the heterogeneous group of pediatric BMF. A comprehensive approach to identify the cause of BMF can prevent treatment delay and be useful to tailor treatment and follow-up protocols. What is Known: • Irreversible BMF in pediatric patients can be caused by a wide spectrum of underlying diseases including (pre)malignant disease, IBMFS and AA. Identifying the exact underlying cause of BMF is crucial for tailored therapy, however often challenging and time-consuming. • Frontline allogeneic HSCT is offered to most pediatric patients with severe BMF as curative treatment. What is New: • Protocolized unbiased diagnostics, short time to treatment (< 3 months) and maximal supportive care until curative treatment can prevent complications with a negative effect on survival such as infection and bleeding. • Personalized follow-up protocols for IBMFS patients are essential to prevent a second decline in survival due to long-term treatment toxicity and extra-hematological disease complications.

Application of serum Raman spectroscopy in rapid and early discrimination of aplastic anemia and myelodysplastic syndrome.

BACKGROUND: Raman spectroscopy of hematological diseases has gained attention from various researchers. However, serum analysis of bone marrow failure (BMF), represented by aplastic anemia (AA) and myelodysplastic syndromes (MDS) has not been fully investigated. In this study, we aimed at establishing a simple, non-invasive serum detection method for AA and MDS. METHOD: Serum samples from 35 AA patients (N = 35), MDS patients (N = 25), and control volunteers (N = 23) were systematically analyzed via laser Raman spectroscopy, and orthogonal partial least squares discrimination analysis (OPLS-DA). Then, discrimination models between the BMFs and control were constructed and evaluated using the prediction set. RESULTS: Compared to control volunteers, serum spectral data for BMF patients were specific. The intensities of Raman peaks representing nucleic acids (726, 781, 786, 1078, 1190, 1415 cm-1), proteins (1221 cm-1), phospholipid/cholesterol (1285 cm-1), and ß-carotene (1162 cm-1) significantly decreased, while the intensity of lipids (1437 and 1446 cm-1) significantly increased. Intensities of Raman peaks representing nucleic acids (726 cm-1) and collagen (1344 cm-1) in the AA group were significantly lower than in the control group. Intensities of Raman peaks representing nucleic acids (726 and 786 cm-1), proteins (1003 cm-1), and collagen (1344 cm-1) in the MDS group were significantly lower than those of the control group. The intensity of Raman peaks representing lipids (1437 and 1443 cm-1) in the MDS group was significantly higher than in the control group. Patients with AA and MDS exhibited increased serum triglyceride levels and decreased high-density lipoprotein levels. CONCLUSIONS: The relationship between serological test data for patients and typing of AA and MDS provides essential information for rapid and early identification of BMF. This study shows the potential of Raman spectroscopy for non-invasive detection of different BMF types.

Development and validation of early death risk score model for emergency status prediction in very severe aplastic anemia.

This study developed and validated the Early Death Risk Score Model for early identification of emergency patients with very severe aplastic anemia (VSAA). All 377 patients with VSAA receiving first-line immunosuppressive therapy (IST) were categorized into training (n=252) and validation (n=125) cohorts. In the training cohort, age >24 years, absolute neutrophil count ≤0.015×109/L, serum ferritin >900ng/mL and times of fever before IST >1 time were significantly associated with early death. Covariates were assigned scores and categorized as: low (score 0-4), medium (score 5-7) and high (score ≥8) risk. Early death rate was significantly different between risk groups and the validation cohort results were consistent with those of the training cohort. The area under the receiver operating characteristic curve for the model was 0.835 (0.734,0.936) in the training cohort and 0.862 (0.730,0.994) in the validation cohort. The calibration plots showed high agreement, and decision curve analysis showed good benefit in clinical applications. The VSAA Early Death Risk Score Model can help with early identification of emergency VSAA and optimize treatment strategies. Emergency VSAA with high risk is associated with high early death rate, and alternative donor hematopoietic stem cell transplantation could be a better treatment than IST even without HLA-matching.

Analysis of Mean Corpuscular Volume and Red Cell Distribution Width in Patients with Aplastic Anemia.

To explore the characteristics of hemogram in patients with aplastic anemia (AA), especially mean corpuscular volume (MCV) and red cell distribution width (RDW). We examined the blood routine of 180 new-onset AA patients and used 166 patients with myelodysplastic syndrome (MDS) as controls. Among the 180 AA patients, 105 (58.3%) were diagnosed with severe AA (SAA), while 75 (41.7%) were diagnosed with non-severe AA (NSAA). Compared to MDS, patients with SAA generally had unfavorable hemogram, including significantly lower white blood cell (WBC), absolute neutrophil count (ANC), hemoglobin (Hb), platelet (PLT) and reticulocyte counts (RET). However, WBC, ANC and lymphocyte counts were higher in the NSAA group than in the MDS group; Hb and Ret were comparable between the two groups. 8.5% of SAA patients and 58.1% of NSAA patients presented with macrocytic anemia, whereas 25.7% of SAA and 64.0% of NSAA had a high RDW. In the MDS group, 54.7% of patients presented with macrocytic anemia, and 84.7% had increased RDW. WBC, ANC, PLT, and Ret in a high-RDW group (25.7% of SAA) were significantly higher than in a normal-RDW group (74.3% of SAA). Overall, most SAA patients exhibited normocytic-normochromic anemia, and their hemograms decreased more significantly; more than half of NSAA patients showed macrocytic-heterogeneous anemia, and their hemograms were similar to those of MDS. Patients with elevated RDW may have better residual bone marrow hematopoietic function than those with normal RDW but with more severe anemia.

Pancytopenia in celiac disease-A case series of 20 children.

Pancytopenia in children with celiac disease (CeD) is postulated to be due to nutritional deficiency such as vitamin B12, folate and copper or an autoimmune process resulting in aplastic anemia with hypoplastic marrow. In the present case series, we report the profile and explore the etiology of pancytopenia among children with CeD. There are only a few case reports of pancytopenia in children with CeD. We enrolled newly diagnosed cases of CeD and pancytopenia presenting in the celiac disease clinic over three years. Detailed evaluation was carried out for the cause of pancytopenia. We followed up on the cases for compliance and response to gluten-free diet at three months, six months and 12 months. Twenty patients were eligible for inclusion. They were divided into two groups: one with aplastic anemia with hypoplastic marrow labeled as Gp CeD-AA and the other with megaloblastic/nutritional anemia labeled as Gp CeD-MA. Patients in Gp CeD-MA presented with classical symptoms of CeD as recurrent diarrhea, abdomen distension, pallor and poor weight gain. They had none or just one transfusion requirement and had an early and complete recovery from pancytopenia. Patients in Gp CeD-AA presented with atypical symptoms such as epistaxis, short stature, fever, pallor and weakness. They had a multiple blood transfusion requirement and had delayed and partial recovery from pancytopenia. Pancytopenia is not a disease in itself but is the presentation of an underlying disease. It can occur due to various coexisting disorders in children with CeD, which can be as simple as nutritional deficiencies to as complex as an autoimmune process or malignancy. CeD should be included in the differential diagnosis of aplastic anemia as CeD and aplastic anemia both have a similar pathological process involving T cell destruction of tissues.

Research progress on the hematopoietic microenvironment in aplastic anemia.

Aplastic anemia (AA) is a disease of bone marrow hematopoietic failure, and the main clinical manifestation is pancytopenia. Its pathogenesis is still unclear. In recent years, more research has been done on its immune abnormalities to explain its pathogenesis and less on the hematopoietic microenvironment, but there are still some advances. This article summarizes the research on the hematopoietic microenvironment of AA in recent years to provide new ideas for the clinical treatment of AA.

Differential diagnosis of bone marrow failure syndromes guided by machine learning.

The choice to postpone treatment while awaiting genetic testing can result in significant delay in definitive therapies in patients with severe pancytopenia. Conversely, the misdiagnosis of inherited bone marrow failure (BMF) can expose patients to ineffectual and expensive therapies, toxic transplant conditioning regimens, and inappropriate use of an affected family member as a stem cell donor. To predict the likelihood of patients having acquired or inherited BMF, we developed a 2-step data-driven machine-learning model using 25 clinical and laboratory variables typically recorded at the initial clinical encounter. For model development, patients were labeled as having acquired or inherited BMF depending on their genomic data. Data sets were unbiasedly clustered, and an ensemble model was trained with cases from the largest cluster of a training cohort (n = 359) and validated with an independent cohort (n = 127). Cluster A, the largest group, was mostly immune or inherited aplastic anemia, whereas cluster B comprised underrepresented BMF phenotypes and was not included in the next step of data modeling because of a small sample size. The ensemble cluster A-specific model was accurate (89%) to predict BMF etiology, correctly predicting inherited and likely immune BMF in 79% and 92% of cases, respectively. Our model represents a practical guide for BMF diagnosis and highlights the importance of clinical and laboratory variables in the initial evaluation, particularly telomere length. Our tool can be potentially used by general hematologists and health care providers not specialized in BMF, and in under-resourced centers, to prioritize patients for genetic testing or for expeditious treatment.

Inherited bone marrow failure syndromes: a review of current practices and potential future research directions.

PURPOSE OF REVIEW: Recent advances in diagnosis and treatment of inherited bone marrow failure syndromes (IBMFS) have significantly improved disease understanding and patient outcomes. Still, IBMFS present clinical challenges that require further progress. This review aims to provide an overview of the current state of diagnosis and treatment modalities of the major IBMFS seen in paediatrics and present areas of prioritization for future research. RECENT FINDINGS: Haematopoietic cell transplantation (HCT) for IBMFS has greatly improved in recent years, shifting the research and clinical focus towards cancer predispositions and adverse effects of treatment. Each year, additional novel genes and pathogenic variants are described, and genotype-phenotype mapping becomes more sophisticated. Moreover, novel therapeutics exploring disease-specific mechanisms show promise to complement HCT and treat patients who cannot undergo current treatment options. SUMMARY: Research on IBMFS should have short-term and long-term goals. Immediate challenges include solidifying diagnostic and treatment guidelines, cancer detection and treatment, and continued optimization of HCT. Long-term goals should emphasize genotype-phenotype mapping, genetic screening tools and gene-targeted therapy.

Bone marrow expression of CD68/CD163 macrophages, IL-17 and FOXP3 cells in aplastic anemia and their relation to prognosis.

OBJECTIVES: The primary mechanism for bone marrow failure in aplastic anemia (AA) is autoimmune hematopoietic stem cell destruction. AA can be cured with antithymocyte globulin (ATG) treatment, and some smaller studies have indicated that the number of regulatory T cells (Tregs) may be predictive of response. Additionally, AA patients appear to have elevated numbers of Th17 cells and bone marrow macrophages, but outcome data are missing. METHODS: We performed immunohistochemistry on bone marrow biopsies from 121 ATG-treated AA patients and 14 healthy controls, using antibodies against FOXP3 (for Tregs), IL-17 (for Th17), CD68 (for pan-macrophages) and CD163 (for M2 type macrophages) to study their possible relation to ATG response and AA prognosis. RESULTS: AA patients had significantly fewer Tregs and Th17 cells but significantly more macrophages compared with controls. Treg, Th17 and pan-macrophage cell numbers were not associated with ATG response or differences in survival. Patients with higher levels of M2 macrophages had improved 5-year overall survival: 79.6% versus 57.4% (p = .017), and this benefit was primarily seen in AA patients with non-severe disease. CONCLUSIONS: We found that Treg and Th17 cell numbers did not predict ATG response or survival, whereas M2 macrophages may be associated with improved survival.