Iron Deficiency Caused by Intestinal Iron Loss—Novel Candidate Genes for Severe Anemia

The adult human body contains about 4 g of iron. About 1–2 mg of iron is absorbed every day, and in healthy individuals, the same amount is excreted. We describe a patient who presents with severe iron deficiency anemia with hemoglobin levels below 6 g/dL and ferritin levels below 30 ng/mL. Although red blood cell concentrates and intravenous iron have been substituted every month for years, body iron stores remain depleted. Diagnostics have included several esophago-gastro-duodenoscopies, colonoscopies, MRI of the liver, repetitive bone marrow biopsies, psychological analysis, application of radioactive iron to determine intact erythropoiesis, and measurement of iron excretion in urine and feces. Typically, gastrointestinal bleeding is a major cause of iron loss. Surprisingly, intestinal iron excretion in stool in the patient was repetitively increased, without gastrointestinal bleeding. Furthermore, whole exome sequencing was performed in the patient and additional family members to identify potential causative genetic variants that may cause intestinal iron loss. Under different inheritance models, several rare mutations were identified, two of which (in CISD1 and KRI1) are likely to be functionally relevant. Intestinal iron loss in the current form has not yet been described and is, with high probability, the cause of the severe iron deficiency anemia in this patient.

Hi-C detects genomic structural variants in peripheral blood of pediatric leukemia patients

B-cell acute lymphoblastic leukemia (B-ALL) is often driven by chromosome translocations that result in recurrent and well-studied gene fusions. Currently, fluorescent in-situ hybridization probes are employed to detect candidate translocations in bone marrow samples from B-ALL patients. Recently Hi-C, a sequencing-based technique originally designed to reconstruct the three-dimensional architecture of the nuclear genome, was shown to effectively recognize structural variants. Here, we demonstrate that Hi-C can be used as a genome-wide assay to detect translocations and other structural variants of potential clinical interest. Structural variants were identified in both bone marrow and peripheral blood samples, including an ETV6-RUNX1 translocation present in one pediatric B-ALL patient. Our report provides proof-of-principle that Hi-C could be an effective strategy to globally detect driver structural variants in B-ALL peripheral blood specimens, reducing the need for invasive bone marrow biopsies and candidate-based clinical tests.

Molecular Progression of Myeloproliferative and Myelodysplastic/Myeloproliferative Neoplasms: A Study on Sequential Bone Marrow Biopsies

Myeloproliferative neoplasms (MPN) and myelodysplastic/myeloproliferative neoplasms (MDS/MPN) both harbor the potential to undergo myelodysplastic progression or acceleration and can transform into blast-phase MPN or MDS/MPN, a form of secondary acute myeloid leukemia (AML). Although the initiating transforming events are yet to be determined, current concepts suggest a stepwise acquisition of (additional) somatic mutations—apart from the initial driver mutations—that trigger disease evolution. In this study we molecularly analyzed paired bone marrow samples of MPN and MDS/MPN patients with known progression and compared them to a control cohort of patients with stable disease course. Cases with progression displayed from the very beginning a higher number of mutations compared to stable ones, of which mutations in five (ASXL1, DNMT3A, NRAS, SRSF2 and TP53) strongly correlated with progression and/or transformation, even if only one of these genes was mutated, and this particularly applied to MPN. TET2 mutations were found to have a higher allelic frequency than the putative driver mutation in three progressing cases (“TET2-first”), whereas two stable cases displayed a TET2-positive subclone (“TET2-second”), supporting the hypothesis that not only the sum of mutations but also their order of appearance matters in the course of disease. Our data emphasize the importance of genetic testing in MPN and MDS/MPN patients in terms of risk stratification and identification of imminent disease progression.

Omission of Planning CT Reduces Patient Radiation Exposure during CT-Guided Bone Marrow Biopsy and Aspiration

The purpose of this study is to evaluate the impact of eliminating a preprocedural planning computed tomography during CT-guided bone marrow biopsy on the technical aspects of the procedure, including patient dose, sample quality, procedure time, and CT fluoroscopy usage. Retrospective analysis of 109 patients between 1 June 2018 and 1 January 2021 was performed. Patients were grouped based on whether they received a planning CT scan. Relative radiation exposure was measured using dose-length product (DLP). Secondary metrics included number of CT fluoroscopic acquisitions until target localization, total number of CT fluoroscopic acquisitions, biopsy diagnostic yield, and procedure time. A total of 43 bone marrow biopsies with planning CT scans (Group 1) and 66 bone marrow biopsies without planning CT scans (Group 2) were performed. The average total DLP for Group 1 and Group 2 was 268.73 mGy*cm and 50.92 mGy*cm, respectively. The mean radiation dose reduction between the groups was 81% (p < 0.0001). Significantly more CT fluoroscopy acquisitions were needed for needle localization in Group 2 than Group 1 (p < 0.0001). Total number of CT fluoroscopy acquisitions was four for Group 1 and eight for Group 2 (p = 0.0002). There was no significant difference between the groups in procedure time or diagnostic yield. Patients without a planning CT scan received more fluoroscopic CT acquisitions but overall were exposed to significantly less radiation without an increase in procedure time.

Towards CD177 As a Predictive Biomarker for Hypomethylating Agent Response in Myelodysplastic Syndrome

Background Myelodysplastic syndrome (MDS) represents a heterogenous spectrum of pre-leukemic conditions with a wide range of outcomes. Higher risk MDS as classified by the revised international prognostic scoring system (IPSS-R) score is associated with poor overall survival and up to 30% of patients progressing to acute myeloid leukemia. Hypomethylating agents (HMA) such as azacitadine can improve cytopenias and delay progression to leukemia in about 30% of patients, but these agents may take months to promote response and initially exacerbate cytopenias. Thus treatment related biomarkers that help predict eventual hematologic response are of interest. CD177 is expressed in neutrophils and plays a role in cellular adhesion. In healthy cells, it exhibits bimodal expression by flow cytometry that is stable over time within an individual. The percentage of CD177 positive neutrophils is often decreased in hematopoietic malignancies and myelodysplastic syndromes. Our group has demonstrated that CD177 has diagnostic utility in the identification of myelodysplastic syndromes. As transcription of CD177 is regulated by CpG methylation of its promotor, we hypothesized that treatment with HMAs may improve CD177 expression in clinical responders and potentially guide continuation of HMA therapy. Methods To interrogate the above, we performed a retrospective review of patients with a diagnosed with MDS or MDS/MPN overlap syndromes who received disease modifying therapy with HMA at our institution from 2015 to 2018. Inclusion criteria required documentation of serial bone marrow biopsies with aspirate flow cytometry analysis. CD177 positivity was determined by increase in mean florescence intensity compared to isotype controls. Data was analyzed with using cox multivariate and univariate analysis correlating to treatment response. Results Of the 237 patients, 27 patients met the above criteria. Their average age was 62 (21 to 77) at time of diagnosis with 20 men and 7 women. They exhibited a range of R-IPSS risk stratification with four very high risk, eight high risk, six intermediate risk, and four low risk. Five cases were MDS/MPN overlap. Patients received on average 10 months of HMA treatment with a wide range from 1 month to 42 months of treatment. Median baseline CD177 positivity was 16, 31, 28.5, and 72 percent respectively amongst R-IPSS groups. Of the 27 patients analyzed with repeat bone marrow biopsies, eight patients exhibited 20% or greater increase in CD177(+) neutrophils, ten exhibited a decrease in CD177(+) neutrophils of 20% or greater, and nine exhibited less than a 20% change in CD177(+) neutrophils. with similar distribution of R-IPSS risk stratification amongst groups. (CD177-decreased: 1 very high, 3 high, 1 intermediate, 2 low risk, CD177-stable 1 very high, 2 high, 2 intermediate, and 1 low, Improved-CD177 1 very high, 4 high, 2 intermediate and 1 low). Cox proportional hazard analysis suggests that patients exhibiting a decrease or stable CD177 were less likely to exhibit a treatment response with results trending to significance (OR= 0.13 p=0.099). Conclusion Our initial data suggests that change in CD177 may help predict HMA treatment response. More uniform prospective analysis is indicated to compared CD177 changes over initial treatment. Furthermore, CD177 in peripheral blood and bone marrow samples correlate excellently (R 2=0.95). Prospective studies are underway to correlate CD177 change and initial treatment response utilizing flow analysis of pre-treatment CBCs. Disclosures No relevant conflicts of interest to declare.

Clinicopathologic Characteristic and Natural History of Patients with Non Hereditary, Non Polycythemia Vera (NH/NPV) Persistent Polycythemia

Introduction; Polycythemia Vera (PV), is one of the most common Philadelphia chromosome negative myeloproliferative disorders. The identification of Janus Kinase (JAK) 2 mutations and the publication of 2016 revision of WHO classification of myeloid neoplasms has improved diagnostic accuracy of PV. The lower cut-off values of Hemoglobin (Hb) and hematocrit (Hct) used in WHO diagnostic criteria, however, resulted in increased number of adult patients undergoing further evaluation for PV leading to identification of patients with acquired, idiopathic Persistent polycythemia (PP) who not meet WHO criteria for PV despite extensive work up. The clinicopathologic features, disease course, treatment and outcomes of these patients has not been well characterize. This study seeks to described clinicopathologic and molecular profile of cohort of adult patients with Non Hereditary, Non-Polycythemia Vera (NHNPV) Persistent Polycythemia. Methodology; Patients with PP diagnosed and followed up in Fresno community regional medical center/University of San Francisco (UCSF) Fresno, from January 2010 to December 2020 were reviewed. Patients who didn't meet WHO diagnostic criteria for PV after full evaluation including bone marrow biopsies were included in the study. Those with incomplete evaluation, clearly attributable secondary causes of polycythemia or erythropoietin (EPO) level above institutional laboratory reference range (2-18), were excluded from the study. Patients with polycythemia diagnosed at pediatric age were also excluded. The study was approved by institutional review board of UCSF Fresno. Results; 129 subjects with JAK 2 Negative PP were reviewed of which 63 had EPO levels within or below the normal range (2-18). Of 36 patients who met the study inclusion and exclusion criteria, majority were males (70% N= 28) and non-Hispanic (56% N=20) with median age at diagnosis of 48.5 years (range 18-70 years). Half of the patients (N=18) have no identifiable etiology of PP. In patients with associated conditions, the most common is non-oxygen requiring clinical OSA (36%) and tobacco smoking (19.4%). Of note, all these patients have EPO level less than 10 which represents the median value of the local institutional defined normal range for EPO. Four (11%) patients have non-iron overloaded hemochromatosis gene mutation (1 Homozygous H63D HFE gene, 2 heterozygous mutation and one with unspecified mutation type). Average Hb and Hct at diagnosis was (17.26+/- 2.23) and (49.76+/- 6.34) respectively. Mean EPO level 7.05+/-2.75 with less than third of patients 8 (22%) with level less or equal to in 5 units. There is no statistically significance difference between mean diagnostic EPO level between males and females in the study (7.20+/-2.89 vs.6.51+/-2.26) and so is the Hct though males have numerically higher levels. The most common bone marrow morphology includes normocellularity (51.76+/-10.36) with erythroid hyperplasia (25%) or megakaryocyte hyperplasia without dysplasia (17%) and grade 1/3 fibrosis 6/36. Abnormal mutations were identified in 17 patients whose bone marrow biopsies were evaluated with limited or extensive next generation sequencing (NGS). Of those patients with available results, 6 patients (35% out of those with NGS) have identifiable previously well described genetic mutations {FANCA S1311fs*1, HGF R134H, TP53 splice site 97-2A&gt;G, KMT2A (Gain), MLL3 (KMT2C) and AFF4, ASXL1 c.1934dupG/TrpfsX12 (p. Gly646)}. 9 patients had variance of unknown significant (VUS) mutations (Table 1) with average of 6.2 mutation per patient. Only 1 VUS (TSC1 K587R) was reported in 2 different patients (#7, #9) Mild Myeloproliferative neoplasia (MPN) associated symptoms was reported in 22% of patient with Intermittent phlebotomy (72% N= 26) and aspirin (75% N=27) was the treatment for majority of patients. One patient died during the follow up period. No patient progressed to other MPN, myelofibrosis or AML during the study period. Conclusion; With improved diagnostic criteria and accuracy of PV, increased number of patients are diagnosed with NHNPV Persistent polycythemia. None of the mutation or VUS identified from extensive evaluation is recurrent in our cohort of patient. Longer follow up is needed to delineate clinical significance and prognosis of these mutation in patients with NHNPV persistent Polycythemia. Figure 1 Figure 1. Disclosures Abdulhaq: BMS, Alexion, Oncopeptides, Morphosys, Pfizer, Norvartis: Honoraria; Oncopeptides, Alexion, Amgen: Speakers Bureau; Morphosys, BMS, Amgen: Membership on an entity's Board of Directors or advisory committees.

Patients Diagnosed with Myelodysplastic Syndromes Display Lower Bone Mass: Assessment Using Bone Marrow Biopsies Manually and with Artificial Intelligence

Background: Murine models of myelodysplastic syndromes (MDS) exhibit lower bone mass (B-Mass), and several reports suggest increased incidence of osteoporosis and fractures in MDS patients. Whether MDS is associated with lower B-Mass is unknown. Aims: 1) to develop a simple method to estimate trabecular B-Mass from bone marrow biopsies (BMB); 2) to compare the trabecular B-Mass of MDS patients at diagnosis and non-MDS controls; 3) to develop an artificial intelligence (AI) algorithm for automated trabecular B-Mass assessment. Methods: In this study we included male patients age ≥ 65 years old with "lower-risk" (LR) MDS, diagnosed at Tel Aviv Sourasky Medical Center, between 2011 and 2019 and age-matched controls undergoing bone marrow (BM) biopsy for either unexplained anemia or as a part of staging work-up for newly diagnosed lymphoma. BM slides (H&E stain) were digitally scanned. The total relevant area (TRA, Figure 1A) was identified and bone trabeculae were manually contoured using Adobe Photoshop software. Bone area (BA, figure 1B) was calculated as the sum of all contoured pixels of bone, and B-Mass = BA/TRA(%). The manually annotated data were used to develop a preliminary AI algorithm to automatically detect the BA as well as BM fat for use in the current and future research in the field. The Sørensen-Dice similarity coefficient (DSC) was used to assess agreement between manual and AI annotations. Results: There were 43 MDS and 36 control patients with mean ages of 80 and 78 years (p&gt;0.05), respectively. Comorbidities in both groups were similar. Notably, trabecular B-Mass of MDS was significantly lower than that of controls: 11.6% [95%CI 9.9-13.3] vs 18.3% [16.6-20.3], respectively (p&lt;0.0001). This represented a 37% relative reduction for MDS patients compared to controls. Next, the manually annotated data used to develop an AI algorithm automatically assessed trabecular B-Mass. The devised algorithm, tested on 17 patient samples, yielded a DSC (Mean ± SEM) of 0.76 ± 0.015 and 0.81 ± 0.02 for bone and fat respectively (Figure 1C and 1D). Conclusions: We have developed a simple technique to estimate trabecular B-Mass based on available BM sections. Importantly, we found that trabecular B-Mass of LR-MDS patients is compromised already at diagnosis. In addition, automated (AI) assessment of B-Mass using available H&E-stained BM slides is feasible and clinically relevant for patients with MDS and other hematological malignancies. Future work will develop the AI technique and expand it to identify all components of the BM, including the cellular compartment. This will enhance our understanding of the osteohematological niche in such patients, and aid in diagnosis as well as treatment planning. This study was supported by a grant from the Dotan Hemato-oncology Fund, the Cancer Biology Research Center, Tel Aviv University to DN, MM and HSO. Figure 1: Bone marrow biopsy (BMB) slide of a representative patient showing (A) the total relevant area, and (B) the bone area - TRA and BA respectively. Demonstrating the artificial intelligence (AI) technique for the same patient, we compare (C) manual annotation to (D) AI-based annotation of both bone (red) and fat (green). Figure 1 Figure 1. Disclosures Mittelman: Janssen · Roche · Novartis · Takeda · Medison / Amgen · Neopharm / Celgene / BMS · Abbvie · Gilead: Research Funding; Novartis · Takeda · Fibrogen · Celgene / BMS · Onconova · Geron: Other: Clini; Onconova · Novartis · Takeda · Silence: Membership on an entity's Board of Directors or advisory committees; MDS HUB: Consultancy; Celgene / BMS · Novartis: Speakers Bureau.

Histopathologic Characterization of Vexas Syndrome

Introduction: VEXAS syndrome (vacuoles, E1 ubiquitin ligase, X-linked, autoinflammatory, somatic) is a newly recognized inflammatory disorder caused by somatic mutations in the UBA1 gene. Bone marrows from these patients reveal a range of morphological changes in hematopoietic precursor cells. In this study, we aim to assess the laboratory indices and morphologic spectrum of bone marrow pathology in VEXAS syndrome. Methods: We identified 16 cases of VEXAS syndrome. All cases had confirmed UBA1 mutation. We reviewed bone marrow biopsies corresponding to the date of diagnosis. This study was approved by the Mayo Clinic Institutional Review Board. Results: All patients were male with a median age of 73 years - associated autoimmune disorders included Sweet syndrome, inflammatory arthritis, relapsing polychondritis and granulomatosis with polyangiitis. 14/16 patients had anemia with median hemoglobin of 10.4 (Range: 6.7- 14.1 g/dL). 15/16 had macrocytosis with median MCV 110.4 (Range: 94.8- 123.1 /fL). 5/16 had thrombocytopenia with median platelet count 174 (Range: 20- 500 x10^9/L). 7/16 had leukopenia with median WBC 3.65 (Range: 2.4- 11.6 x10^9/ L). The ESR and CRP medians were 61.0 mm/hr and 81.5 mg/L, respectively. Karyotype was performed in 12 patients of which 11 were normal and the remaining case showed a complex karyotype. An NGS panel targeting the most frequent myeloid disorder associated gene mutations was negative in 10/15 cases. GS for myeloid mutations revealed pathogenic mutations in 5 patients, involving genes TET2 (2/5), DNMT3A (2/5), and TP53 (1/5). Conclusions: Bone marrow findings in VEXAS syndrome, in this series of 16 patients, are individually non-specific, yet when taken altogether in the overtly abnormal cases, are very suggestive when the clinical index of suspicion is high. In such scenarios, the combined clinical and bone marrow findings should prompt discussion and consideration for UBA1 mutation testing given the significant clinical implications for patient management and prognosis. Disclosures Patnaik: StemLine: Research Funding; Kura Oncology: Research Funding. Warrington: Eli Lilly: Research Funding; Kiniksa: Research Funding.

Dynamic Stromal Changes in Myelofibrosis Patients Pre/Post JAK Inhibition Is Revealed in Clinically Archived Bone Marrow Biopsies By Smooth Muscle Actin (SMA)-CD34 Dual Immunohistochemistry

The natural history of BCR-ABL1 negative myeloproliferative neoplasms (MPNs) is progression towards an overt myelofibrotic (MF) phase with variable risk to develop secondary acute myeloid leukemia. Current treatments include Janus kinase inhibitors (JAKi) which can temporarily alleviate MF-related symptoms but are non-curative and most patients eventually progress to a more advanced stage. Given the negative prognostic impact of bone marrow fibrosis in MPNs and generally poor outcome post JAKi failure, it would be important to identify in situ biomarkers that address the initiation, perpetuation and early reversal of the fibrotic reaction. The current clinical standard for bone marrow fibrosis assessment involves reticulin/trichrome stains that detect relatively static extracellular matrix products rather than the fibrosis driving cells directly. To address this, we have developed a smooth muscle actin stromal-vascular (SMA-CD34) dual immunohistochemical (IHC) technique amenable to morphologic scoring and complemented with a CellProfiler image analysis pipeline. SMA was prioritized over other validated stromal IHC markers given work by others in experimental models demonstrating SMA+ myofibroblasts to be the differentiated output of critical fibrosis inducing Gli1+ 'driver' mesenchymal stem/progenitor cells in MPN. Herein, we demonstrate the feasibility of our translational approach using a clinically annotated cohort of MF patients from the Princess Margaret Cancer Centre MPN Registry. After selecting for high quality (&gt;1.0 cm) paired pre and post JAKi biopsies amenable to image and transcriptome-based analysis, the pilot cohort was comprised of 13 cases with 38% high-risk, 54% intermediate-2 and 8% intermediate-1 risk by DIPSS. Driver mutations were JAK2 V617F (77%), CALR (15%) and other (8%). JAKi therapies included ruxolitinib (31%) + pelabresib (23%), momelotinib (15%), itacitinib (15%) and pacritinib (8%). The SMA-CD34 stromal assessment at baseline revealed distinct interstitial myofibroblast patterns and vascular perturbations not captured by conventional clinical hematopathology assessment (e.g. SMA+ dilated sinusoids). A SMA-CD34 scoring system was developed using a 4-point scale representing normal (0 pts), increased vascularity (1 pt), focal interstitial SMA (2 pts), multifocal interstitial SMA (3 pts) and diffuse SMA (4 pts). Scoring was then performed by blinded hematopathologists. A trend towards JAK2 mutated MF cases demonstrating higher SMA grade at baseline was noted. Interestingly, variable trajectories in SMA scores emerged following treatment with JAKi. Specifically, SMA signals had increased in 15%, decreased in 46% and were stable in 38% post-JAKi when using a morphologic SMA grading scheme. When compared to reticulin fibrosis, the severity of SMA signals had diverged in 1/3 of the cases (e.g. SMA grade decreased, reticulin grade stable). To further complement the SMA-CD34 morphologic grading, a CellProfiler image analysis pipeline was developed yielding a non-vessel associated normalized SMA area metric as a supervised correlate of the clinical SMA scoring system (R 2 = 0.68). Additional supervised and unsupervised bioinformatic approaches for clustering of relevant SMA-CD34 features including an algorithm that informs SMA spatial patterns with respect to niche elements such as arterioles (CD34+SMA+), sinusoids (CD34+) and adipocytes is in development. Lastly, Nanostring Fibrosis V2 panel was employed on a subset that met RNA concentration and quality metrics. Exploratory interpretation showed significant differentially expressed genes in pre vs. post JAKi specimens related to lipid metabolism such as ADIPOR1, SCD, ELOVL6 as well as the chemokine CXCL16. This may suggest a link between fatty acid metabolism and inflammatory differentiation along the SMA-vascular axis in the bone marrow modulated by JAKi treatment. SMA-CD34 IHC stratifies MF bone marrow biopsies differentially from standard WHO reticulin/trichome grading providing a practical formalin-fixed paraffin embedded (FFPE) tissue-based biomarker for assessing fibrosis related bone marrow niche elements from archived clinical samples. While our pilot numbers precluded statistical evaluation by JAKi-type, clinical response and NGS mutational profile at this time, further studies are underway to validate the SMA-CD34 signature on a larger MF cohort. Figure 1 Figure 1. Disclosures Gupta: Sierra Oncology: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; AbbVie: Consultancy, Honoraria; Novartis: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; BMS-Celgene: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Roche: Consultancy; Incyte: Honoraria, Research Funding; Constellation Pharma: Consultancy, Honoraria; Pfizer: Consultancy.