Bone Blood Research Articles

Catalytic antibodies in the bone marrow and other organs of Th mice during spontaneous development of experimental autoimmune encephalomyelitis associated with cell differentiation

Exact mechanisms of autoimmune disease development are still yet unknown. However, it is known that the development of autoimmune diseases is associated with defects in the immune system, namely, the violation of the bone marrow hematopoietic stem cells (HSCs) differentiation profiles. Different characteristics of autoimmune reaction development in experimental autoimmune encephalomyelitis (EAE) prone Th mice characterizing T-lymphocytes response were analyzed using standard approaches. Profiles of several HSCs differentiation of bone marrow (BFU-E, CFU-E, CFU-GM, CFU-GEMM, T- and B-lymphocytes) of Th male and female mice during spontaneous development of EAE were noticeably different. Patterns of total lymphocytes, B- and T-cells proliferation in several different organs (bone marrow, blood, spleen, thymus, and lymph nodes) were also remarkably different. In addition, there were in time noticeable differences in their changes for some organs of male and female mice. Characters of changes in the profiles of CD4 and CD8 cells proliferation in some organs not always coincide with those for total T lymphocytes. The changes in the differentiation profiles of HSCs and the level of lymphocytes proliferation in the bone marrow and other organs were associated with the increase in the concentration of antibodies against DNA, myelin basic protein, and myelin oligodendrocyte glycoprotein, and catalytic antibodies hydrolyzing these substrates. Despite some differences in changes in the analyzed parameters, in general, the spontaneous development of EAE in male and female mice occurs to some extent in a comparable way.

Low-Grade B Cell Lymphoproliferative Disorder Masquerading as Chronic Rhinosinusitis

Chronic rhinosinusitis (CRS) is one of the most common persistent disorders of the developed world, requiring input from various specialists including primary care physicians, otolaryngologists, respiratory physicians, and allergologists. B-cell lymphoproliferative disorders (BLPDs) are a heterogenous group of malignant conditions defined by an accumulation of mature B lymphocytes in the bone marrow, blood, and lymphoid tissues. We present a case report of an elderly man with rhinosinusitis-like symptoms and atypical features prompting further investigations that culminated in a diagnosis of BLPD.

Central Nervous System Infiltration in Acute Lymphoblastic Leukemia in a Dog

Background: Acute lymphoblastic leukemia (ALL) is a malignant neoplasia in which there is proliferation of lymphoid progenitor cells in the bone marrow, blood, and extramedullary sites. This disorder has a fast and progressive development; in dogs, cases of infiltration of ALL cells in the central nervous system (CNS) are uncommon and rare. Diagnosis can be achieved with the help of the clinical history and physical, radiographic, hematological, myelographic, and cerebrospinal fluid (CSF) tests in patients with or without neurological clinical signs. The present report aims to describe a case of ALL and the presence of lymphoblasts in the CSF of a dog with neurological clinical signs.Case: An 8-year-old Lhasa Apso dog was examined at the Veterinary Hospital of Universidade Federal do Paraná, Curitiba campus. At the physical examination, the animal exhibited apathy and paralysis of pelvic limbs, which progressed to tetraplegia. Abdominal palpation revealed presence of hepatosplenomegaly and absence of lymphadenomegaly. No alterations were observed in radiographs of the cervical, thoracic or lumbar spine. A complete blood count revealed presence of non-regenerative anemia (hematocrit = 22%), extreme lymphocytosis (185,229 cells/µL), lymphoblasts at a level of 72% (133,364 cells/µL), and thrombocytopenia (66,000 platelets/µL). The biochemical tests revealed increased alkaline phosphatase (859 IU/L). The levels of alanine aminotransferase, creatinine, urea, total protein, albumin, and globulin were normal. The diagnosis of ALL was achieved with the help of a myelogram. The myelogram findings included 39% of mature lymphocytes and 59% of lymphoblasts exhibiting large size, spherical shape, poorly delimited borders, with a high nucleus/cytoplasm ratio, marked cytoplasmic basophilia, and 2 to 3 evident nucleoli; metarubricytes (1%) and promyelocytes (0.6%) were also observed. The CSF contained an increased number of nucleated cells (27 cells/µL) comprising lymphocytes (43%), macrophages (33%), and segmented neutrophils (24%). Of the 11.6 lymphocytes per µL of CSF, 8.1 were lymphoblasts, which indicates infiltration of ALL cells in the CNS. The animal died one day after collection of bone barrow and CSF. Discussion: Relevant alterations observed in this case included the neurological signs caused by the infiltration of neoplastic cells in the CNS, severe leukocytosis and lymphocytosis, with large amounts of lymphoblasts in the blood and predominance of lymphoblasts in the bone marrow, which are alterations typically found in ALL. The animal also exhibited non-regenerative anemia and thrombocytopenia, which were secondary to infiltration of leukemic cells in the bone marrow. The CSF exhibited pleocytosis (27 cells/ µL), and 30% of the cells observed were lymphoblasts. Lymphoblast infiltration in the CNS of leukemic dogs is rare, and other studies have reported absence of neurological signs or neurological signs different from those observed in the present study. CSF analysis in indicated in cases of leukemia to assess leukemic cell infiltration in the CNS. In the case reported here, the plasma level of alkaline phosphatase was increased (859 IU/L) as a consequence of hepatomegaly and hepatic cholestasis. ALL is a very aggressive, proliferative neoplasia, and the resulting lymphoblasts infiltrated the CNS of the animal. In cases of ALL, performing complete blood count, myelogram, and CSF analysis is indicated whether the patients exhibit neurological signs or not.

HLA-DQ and HLA-DRB1 alleles associated with Henoch-Sch\xf6nlein purpura nephritis in Finnish pediatric population: a genome-wide association study

BackgroundThe pathophysiology of Henoch-Schönlein purpura (HSP) is still unclear, but several findings suggest that genetic factors may influence disease susceptibility. We aimed to perform a genome-wide association study (GWAS) in pediatric HSP patients with an emphasis on severe HSP nephritis.MethodsThe study included 46 HSP patients, 42 of whom had undergone kidney biopsy. Forty-nine pediatric patients with an inflammatory bowel disease (IBD) served as an autoimmune disease control group while Finnish bone marrow and blood donors represented the general reference population (n = 18,757). GWAS was performed for HSP and IBD samples in a case-control manner against the reference population. The analysis also included imputation of human leukocyte antigen (HLA) alleles.ResultsGWAS analysis in HSP revealed several polymorphisms from the HLA region that surpassed the genome-wide significance level. Three HLA class II alleles were also significantly more frequent in HSP than in the reference population: DQA1*01:01, DQB1*05:01, and DRB1*01:01. Haplotype DQA1*01:01/DQB1*05:01/DRB1*01:01 occurred in 43.5% of HSP patients, whereas its frequency was 8.2% in IBD patients and 15.0% in the reference population. HSP patients with this haplotype showed similar baseline clinical findings and outcome as HSP patients negative for the haplotype. In IBD patients, no polymorphism or HLA allele appeared significant at the genome-wide level.ConclusionsOur results suggest that haplotype DQA1*01:01/DQB1*05:01/DRB1*01:01 is associated with susceptibility to HSP, but not with the severity of the kidney involvement. These HLA associations did not occur in IBD patients, suggesting that they are specific to HSP and not related to susceptibility to autoimmune diseases in general.Graphical abstract

Impact of an angiotensin II receptor antagonist and antioxidant on count of stem cells and on morphofunctional parameters in animals

Now pathology of cardiovascular system is the major cause of cardiac morbidity and mortality in many countries. It is necessary to develop new methods of diagnosis and treatment of cardiovascular diseases. Studying new properties of drugs and substances to treat pathology of cardiovascular system is very important. Candesartan cilexetil is an angiotensin II receptor antagonist. This drug has a number of side effects. Resveratrol is the natural antioxidant, which has pleiotropic health beneficial effects. Effect of new combination of candesartan cilexetil with resveratrol on mobilization of stem cells was studied in the experiment. Goal. To investigate the effect of candesartan cilexetil and resveratrol at different doses on the number of stem cells, morphofunctional parameters in animals. Methods. Male Balb/C mice were used for the experiment. Animals were received intragastrically candesartan cilexetil and resveratrol at different doses for 7 weeks after physical strain. Evaluation of the effects of substances on mobilization of CD117+ stem cells from bone marrow to blood, morphofunctional parameters were detected by flow cytometry. Results. It was found that candesartan cilexetil at 3 mg/kg dose stimulated mobilization of CD117+ stem cells but was cytotoxic. Candesartan cilexetil at 1.5 mg/kg dose did not increased the number of CD117+ stem cells in bone marrow. The combination of candesartan cilexetil and resveratrol increased the amount of CD117+ stem cells in bone marrow and blood and was safe for cells. Conclusions. New combination of candesartan cilexetil and resveratrol was effective in increasing of the number of CD117+ stem cells and was safer than candesartan cilexetil alone.

Abstract IA40: Defining precursors in low-grade lymphomas that seed second lymphomas

Abstract Most patients with low-grade lymphoma will achieve a clinical remission (CR) with standard chemoimmunotherapy. Yet, relapse from minimal residual disease (MRD), either as low-grade or high-grade disease, remains the leading cause of death. Several studies have provided consistent evidence showing the strong prognostic value of measurable MRD using flow cytometry, PCR, next-generation sequencing, or other approaches. While MRD includes the malignant cells that remain in a patient who achieves CR, not all MRD cells may have the functional capability to proliferate into relapse. We recently introduced a nomenclature to more precisely distinguish cells included within MRD. In this nomenclature, M-REC (Minimal-RElapsable Cancer) denotes fully transformed cells capable of driving a relapse; MN-REC (Minimal Non-RElapsable Cancer) denotes fully-transformed cells incapable of driving a relapse; and MRP (Minimal Residual Precursors) denotes residual cells that harbor somatic and/or phenotypic alterations but are not fully malignant, such as those causing a dysplastic “field-effect” in cancers like those of the bladder, head and neck, or esophagus. Studies that defined the genetic phylogeny of lymphoma using diagnostic, relapsed, and transformed B-cell lymphomas from the same patients have identified examples where MRPs repeatedly evolve into clinical lymphomas. This conflicts with the traditional model of cancer evolution, in which “relapses” result from M-RECs that persist after therapy. There are two immediate implications to this paradigm-shifting concept: 1) Many “relapses” are actually second lymphomas, and 2) defining and targeting the vulnerabilities of MRPs may be essential for improving lymphoma-free survival among patients who achieve a CR. It is important to note that the vulnerabilities of MRD may differ within the bone marrow, blood, lymph node, and other sites, so sampling of each is essential. To make this possible, we have advanced two strategies. First, we have established xenografts of human follicular lymphoma explants within immunocompromised mice that capture both malignant and nonmalignant cellular components, as well as predictable transformation to large-cell lymphoma in vivo. Second, we have initiated rapid autopsies of patients with disseminated lymphoma to obtain specimens from multiple organs and thereby define the heterogeneity of environmental niches that support the persistence of MRD. Citation Format: Abner Louissaint, David Weinstock. Defining precursors in low-grade lymphomas that seed second lymphomas [abstract]. In: Proceedings of the AACR Virtual Meeting: Advances in Malignant Lymphoma; 2020 Aug 17-19. Philadelphia (PA): AACR; Blood Cancer Discov 2020;1(3_Suppl):Abstract nr IA40.

Ocorrência de Histoplasma capsulatum isolado no período de 2016 a 2019 em um Laboratório Estadual de Saúde Pública do Centro-Oeste Brasileiro

Objetivo: Analisar a ocorrência de Histoplasma capsulatum nas culturas para fungos que deram entrada em um Laboratório Estadual de Saúde Pública do Centro-Oeste brasileiro no período de 2016 a 2019. Metodologia: Trata-se de um estudo transversal, constituído por culturas para pesquisa de fungos que deram entrada no referido laboratório e provenientes de Hospitais de Referência do Estado. As variáveis analisadas foram gênero, faixa etária, número de positividade e negatividade das culturas para Histoplasma capsulatum e espécime clínico utilizado para análise. Resultados: No período analisado, foi dada entrada de um total de 12.476 culturas para fungos, 2.262 foram positivas, das quais 313 identificou-se a presença do Histoplasma capsulatum. A prevalência percentual desse agente entre as amostras positivas correspondeu a 13,84, nas faixas etárias de 31 a 40 anos (19,28), de 41 - 50 anos (16,83) e de 51 a 60 anos (14,60), com maior prevalência no gênero masculino e quanto aos espécimes clínicos oriundas de medula óssea (85,00), linfonodo (64,29), líquido ascítico (42,86), sangue (39,96) e abscesso (33,33). Ao analisar a razão de prevalência verificou possível associação de histoplasmose em amostras de pacientes, cujas principais matrizes biológicas foram o sangue 6,28 (6,04 – 11,89), medula óssea 5,72 (4,52 – 68,12) e linfonodo (3,15 – 28,48). Conclusão: Nota-se frente à prevalência encontrada a relevância da notificação compulsória dessa micose a nível nacional, a fim de melhorar o monitoramento para subsidiar medidas que facilitem o diagnóstico precoce e o tratamento adequado.

Folic Acid Supplementation Role on Bone Marrow and Blood Cells Morphology during Methotrexate Treatment

Folic Acid Supplementation Role on Bone Marrow and Blood Cells Morphology during Methotrexate Treatment

Cardioprotective myeloid cells

Inflammation Acute ischemic injury to the heart precipitates a strong inflammatory response, including influx of myeloid cells expressing type I interferon–stimulated genes (ISGs). Calcagno et al. used single-cell RNA sequencing to probe the origin, evolution, and heterogeneity of this response in the first 4 days after myocardial infarction using human and mouse myeloid cells. Induction of ISGs in myeloid cells was initially observed in bone marrow and blood. Postinfarct cardiac tissue in mice contained myeloid subsets with and without ISG expression and a steady-state macrophage population with anti-inflammatory activity dependent on Nrf2, a cytoprotective transcriptional regulator. On the basis of their findings, the authors developed an ISG score as a potential biomarker to assess how the vigor of type I interferon signaling influences clinical outcomes after a heart attack. Sci. Immunol 5 , eaaz1974 (2020).

Disseminated Bacillus Calmette\u2013Gu\xe9rin (BCG) infection and acute exacerbation of interstitial pneumonitis: an autopsy case report and literature review

BackgroundIntravesical administration of Bacillus Calmette–Guérin (BCG) has proven useful for treatment and prevention of recurrence of superficial bladder cancer and in situ carcinoma. However, fatal side effects such as disseminated infections may occur. Early diagnosis and accurate therapy for interstitial pneumonitis (IP) are important because exacerbation of IP triggered by infections is the major cause of death. Although some fatality reports have suggested newly appeared IP after intravesical BCG treatment, to our knowledge, there are no reports which have demonstrated acute exacerbation of existing IP. Moreover, autopsy is lacking in previous reports. We report the case of a patient with fatal IP exacerbation after BCG instillation and the pathological findings of the autopsy.Case presentationA 77-year-old man with a medical history of IP was referred to our hospital because of fever and malaise. He had received an intravesical injection of BCG 1 day before the admission. His fever reduced after the use of antituberculosis drugs, so he was discharged home. He was referred to our hospital again because of a high fever 7 days after discharge. On hospitalisation, he showed high fever and systemic exanthema. Hepatosplenomegaly and myelosuppression were also observed. Biopsies revealed multiple epithelioid cell granulomas with Langhans giant cells of the liver and bone marrow. Biopsy DNA analyses of Mycobacterium bovis in the bone marrow, sputum, and blood were negative. His oxygen demand worsened drastically, and the ground-glass shadow expanded on the computed tomography scan. He was diagnosed with acute exacerbation of existing IP. We recommenced the antituberculosis drugs with steroid pulse therapy, but he died on day 35 because of respiratory failure. The autopsy revealed a diffuse appearance of multiple epithelioid cell granulomas with Langhans giant cells in multiple organs, although BCG was not evident.ConclusionsWe report the first case of acute exacerbation of chronic IP by BCG infection. This is also the first case of autopsy of a patient with acute exacerbation of existing IP induced by intravesical BCG treatment. Whether the trigger of acute IP exacerbation is infection or hypersensitivity to BCG is still controversial, because pathological evidence confirming BCG infection is lacking. Physicians who administer BCG against bladder cancer should be vigilant for acute exacerbation of IP.

Wilms tumor 1 gene expression in acute myeloid leukemia: Prognostic significance and usefulness in minimal residual disease monitoring.

Acute myeloid leukemia (AML) is a cancer of the myeloid line of blood cells, characterized by the rapid growth of abnormal cells that build up in the bone marrow and blood and interfere with normal blood cells. (3) Diagnosis is usually made on a bone marrow aspirate sample. Nevertheless, a trephine bone marrow biopsy may be needed if the sample is hypocellular, dilute or inaspirable.(4)Even though Acute leukemia is considered a rare disease, it causes a disproportionally large effect on cancer survival statistics. (5) AML is the most common type of leukemia in adults but still carries the lowest survival rate out of all leukemia’s. Although the prognosis has improved remarkably in the younger age group, it still continues to be poor in older patients. (6,7)Several studies have examined the associated epidemiological risks with AML but its etiology remains unclear. Studies have been hampered by inconsistent diagnosis leading to a change in classification standards.

Heterogeneity of Clinical Presentations and Paraclinical Explorations to Diagnose Disseminated Histoplasmosis in Patients with Advanced HIV: 34 Years of Experience in French Guiana.

We aimed to describe the ways patients with disseminated histoplasmosis—a multifaceted and often lethal disease—present themselves and are explored. A retrospective, observational, multicentric study spanned the period between 1 January 1981 and 1 October 2014. Principal component analysis was performed for the sampling sites and for the clinical signs and symptoms. The factor loadings of the principal components were selected for eigenvalues > 1. The most frequent signs and symptoms were an alteration of the WHO general performance status, fever, digestive tract, respiratory signs and symptoms and lymphadenopathies. The most common sites sampled were bone marrow, respiratory tract, blood, lymph node and liver biopsies, with significant variations in the number of sites from which samples were taken to try to identify the pathogen. The principal component analysis clinical signs and symptoms leading to the diagnosis showed four main lines of variation. The factor loadings of the four main components were compatible with four broad types of clinical presentations and four types of exploration strategies. Extracting simple algorithms was difficult, emphasizing the importance of clinical expertise when diagnosis depends on obtaining a sample where Histoplasma can be seen or grown. Histoplasma antigen detection tests will help simplifying the algorithms.

Vagal \u03b17nAChR signaling regulates \u03b17nAChR+Sca1+ cells during lung injury repair

BackgroundThe distal airways of the lung and bone marrow are innervated by the vagus nerve. Vagal α7nAChR signaling plays a key role in regulating lung infection and inflammation; however, whether this pathway regulates α7nAChR+Sca1+ cells during lung injury repair remains unknown. We hypothesized that vagal α7nAChR signaling controls α7nAChR+Sca1+ cells, which contribute to the resolution of lung injury.MethodsPneumonia was induced by intratracheal challenge with E. coli. The bone marrow mononuclear cells (BM-MNCs) were isolated from the bone marrow of pneumonia mice for immunofluorescence. The bone marrow, blood, BAL, and lung cells were isolated for flow cytometric analysis by labeling with anti-Sca1, VE-cadherin, p-Akt1, or Flk1 antibodies. Immunofluorescence was also used to examine the coexpression of α7nAChR, VE-cadherin, and p-Akt1. Sham, vagotomized, α7nAChR knockout, and Akt1 knockout mice were infected with E. coli to study the regulatory role of vagal α7nAChR signaling and Akt1 in Sca1+ cells.ResultsDuring pneumonia, BM-MNCs were enriched with α7nAChR+Sca1+ cells, and this cell population proliferated. Transplantation of pneumonia BM-MNCs could mitigate lung injury and increase engraftment in recipient pneumonia lungs. Activation of α7nAChR by its agonist could boost α7nAChR+Sca1+ cells in the bone marrow, peripheral blood, and bronchoalveolar lavage (BAL) in pneumonia. Immunofluorescence revealed that α7nAChR, VE-cadherin, and p-Akt1 were coexpressed in the bone marrow cells. Vagotomy could reduce α7nAChR+VE-cadherin+ and VE-cadherin+p-Akt1+ cells in the bone marrow in pneumonia. Knockout of α7nAChR reduced VE-cadherin+ cells and p-Akt1+ cells in the bone marrow. Deletion of Akt1 reduced Sca1+ cells in the bone marrow and BAL. More importantly, 91.3 ± 4.9% bone marrow and 77.8 ± 4.9% lung α7nAChR+Sca1+VE-cadherin+ cells expressed Flk1, which is a key marker of endothelial progenitor cells (EPCs). Vagotomy reduced α7nAChR+Sca1+VE-cadherin+p-Akt1+ cells in the bone marrow and lung from pneumonia mice. Treatment with cultured EPCs reduced ELW compared to PBS treatment in E. coli pneumonia mice at 48 h. The ELW was further reduced by treatment with EPCs combining with α7nAChR agonist-PHA568487 compared to EPC treatments only.ConclusionsVagal α7nAChR signaling regulates α7nAChR+Sca1+VE-cadherin+ EPCs via phosphorylation of Akt1 during lung injury repair in pneumonia.

Abstract 5196: CSFR-1R a potential therapeutic target in 4T1 xenograft breast cancer model

Abstract The 4T1 cell line is a mouse mammary carcinoma which can mimic stage IV breast cancer in humans. When these cells are xenografted into a BALB/c mouse there is an infiltration of macrophages into the spleen, bone marrow and blood which was observed 11 days after engraftment. Increased cell proliferation was also detected in the spleen and blood. We found that 4T1 cells produced high levels of M-CSF in culture. In this study we attempt to neutralize the secreted cytokine from the tumor cells with anti-M-CSF (clone, A10603L) or to block the receptor with anti-M-CFR (CSF-1R) (clone, AFS98). Mice were xenografted with 4T1 cells then given one dose of 100 ug of neutralizing antibodies to either anti-M-CSF or anti-CSF-1R two days post tumor engraftment. Animals were sacrificed at multiple time points between 1-3 weeks. Treatment with one dose of anti-M-CSF showed minimal to no difference compared to the 4T1 xenograft group. Treatment with anti-CSF-1R showed reduced macrophage infiltration in the bone marrow, spleen and blood at day 11. BrdU incorporation levels dropped in the spleen and blood of these animals. Spleen size and total cell numbers were also reduced by 40% compared to the 4T1 xenograft group. Citation Format: Jeanne Elia, Hong Zhang, Chiaokai Wen, Xifeng Yang. CSFR-1R a potential therapeutic target in 4T1 xenograft breast cancer model [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 5196.

Abstract 5709: Disruption of mitochondrial metabolism underlies the efficacy of devimistat in acute myeloid leukemia

Abstract Background: Acute myeloid leukemia (AML) remains an agressive malignancy with poor clinical outcomes, particularly in older patients. Dysregulated metabolism has long presented a promising target for cancer therapeutics; however, the development of clinical-stage therapies targeting cancer cell metabolism has been limited and faces challenges to achieve both efficacy and acceptable toxicity. As an exception, the lipoic acid analogue devimistat has shown positive clinical outcomes in numerous early-phase clinical trials including for relapsed and refractory AML patients. While inhibition of lipoic acid-dependent ketoacid dehydrogenase (KADH) enzymes has been proposed as the mechanism of these antineoplastic effects, the mechanisms underlying the efficacy devimistat and its possible relation to metabolism in patients has not been established. Methods: Samples of bone marrow and blood plasma from patients with relapsed or refractory AML before and after treatment with devimistat were collected. The samples were analyzed using liquid chromatography coupled to high-resolution mass spectrometry (LC-HRMS) methods to profile ~400 polar metabolites. Kinetic flux profiling in cultured cancer cell lines treated with devimistat was also performed. Results: Analysis of blood plasma samples collected following devimistat treatment revealed detectable levels of drug, consistent with clinically therapeutic concentrations. Comprehensive metabolite profiling of pretreatment and posttreatment blood plasma samples revealed distinct metabolic alterations induced by devimistat administration. Devimistat is thought to inhibit ketoacid dehydrogenase (KADH) enzyme, and consistent with this proposed mechanism of action, accumulations of KADH substrates were observed in the posttreatment samples. Local metabolism in the tumor microenvironment was also altered by devimistat therapy, with robust reductions of TCA intermediates measured in bone marrow plasma samples collected after treatment. Interestingly, quantification of these metabolites revealed an association between overall clinical outcomes and changes in concentrations of bone marrow metabolites. Kinetic flux tracing demonstrated an expected reduction of mitochondrial metabolic flux in cultured tumor cells following treatment with devimistat. Conclusions: Comprehensive metabolite profiling reveals that devimistat targets KADH enzymes and reduces mitochondrial metabolism in humans. Furthermore, these metabolic changes are quantitatively associated with clinical outcomes, posing a potential opportunity for biomarker development and precision metabolic therapy. Citation Format: Michael A. Reid, Shree Bose, Zhengtao Xiao, Peter G. Mikhael, Juan Liu, Jason W. Locasale, Timothy S. Pardee. Disruption of mitochondrial metabolism underlies the efficacy of devimistat in acute myeloid leukemia [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 5709.

3054 – MONOCYTE SUBSET PRODUCTION DURING AGING

A growing body of evidence suggests that monocytes are more heterogenous than previously appreciated and that monocyte subsets play distinct roles in both health and disease. We have previously demonstrated that two separate pathways of monocyte production by granulocyte-monocyte progenitors (GMPs) and monocyte-dendritic cell progenitors (MDPs) yield functionally distinct monocyte subsets in mouse bone marrow. GMPs produce classical monocytes with neutrophil-like properties, and MDPs yield classical monocytes that give rise to monocyte-derived DCs (moDCs). We also showed that Toll-like receptor agonists differentially promote production of these monocyte subsets during emergency monopoiesis. Aging induces a myeloid bias leading to increased monocyte output by the bone marrow. However, it is unclear whether the GMP and MDP pathways both contribute to increased monocyte output during aging. We observed myeloid-biased hematopoiesis in the bone marrow of old mice and elevated classical monocytes in the circulation, recapitulating previous reports. Single cell RNA-sequencing revealed an increased proportion of classical monocytes expressing MHC II molecules (H2-A and H2-E genes) and Cd74 in the bone marrow of old mice. We also observed a higher frequency of MHC II-expressing monocytes in the bone marrow and blood of old mice by flow cytometry. Together the data suggest that production of moDCs by MDPs is enhanced during aging. We are also investigating whether infection and acetaminophen-induced liver injury alter the balance of monocyte subsets that promote inflammation and tissue damage versus tissue repair and regeneration.

Epigenome-wide cross-tissue correlation of human bone and blood DNA methylation – can blood be used as a surrogate for bone?

ABSTRACT Difficulty in obtaining bone tissue is an obstacle to studying epigenetics to understand gene–environment interactions, and their role in disease pathogenesis. Blood is an obvious alternative and in this proof of principle study, our aim was to systematically investigate whether blood is a viable surrogate for bone. We measured epigenome-wide DNA methylation at 850 K CpG sites in matched trabecular bone and peripheral blood collected from the same patients at the same time-point (n = 12 women; 66–85y), to investigate the between-tissue correspondence. What constituted a CpG site with corresponding methylation in both tissues was stringently defined. Only sites highly correlated (r2 > 0.74; FDR q-value <0.05) and at least 80% similarity in methylation level (Δβ <0.2) between paired samples were retained. In total, 28,549 CpG sites were similarly methylated in bone and blood. Between 33% and 49% of loci associated with bone phenotypes through GWAS were represented among these sites, and major pathways relevant to bone regulation were enriched. The results from this study indicate that blood can mirror the bone methylome and capture sites related to bone regulation. This study shows that in principal, peripheral blood is a feasible surrogate for bone tissue in DNA methylation investigations. As the first step, this will provide a platform for future studies in bone epigenetics, and possibly for larger-scale epidemiological studies.

Clonal hematopoiesis in the bone marrow and blood of healthy volunteers.

7517 Background: Clonal hematopoiesis of indeterminate potential (CHIP) has been described in blood samples from large series of patients. Its prevalence and consequences remain questioned because sequencing methods vary and because most studies were performed in cohorts of individuals suffering from non-hematological diseases (solid cancers, diabetes, cardiovascular or psychiatric diseases). CHIP has been described as a risk factor for blood cancer. However, the diagnosis of most blood cancers relies on morphologic and genetic examination of the bone marrow, and clonal hematopoiesis has never been evaluated in bone marrow samples from healthy individuals. Hence, it is not clear whether the current definition of CHIP is clinically relevant. To address this issue, we studied clonal hematopoiesis in paired peripheral blood and bone marrow samples from an unprecedented cohort of rigorously selected healthy volunteers. Methods: Here, we investigated the frequency of clonal hematopoiesis in 82 paired bone marrow and blood samples from carefully selected healthy adult volunteers (HEALTHOX clinical trial, ClinicalTrials.gov Identifier: NCT02789839). This study was approved by the ethics committees (CPP Tours and AFSSAPS identifier ID-RCB: 2011-A00262-39; CPP Ile-de-France III: 2753). Forty-one genes known to be mutated in myeloid malignancies were sequenced with a 1% threshold of detection. All variants were checked using IGV software v2.3. Statistical analyses were performed using Mann-Whitney, chi-squared, Fisher’s exact, Wilcoxon matched-pairs tests or Spearman correlation using GraphPad Prism 6. Results: In bone marrow samples, clones were found in almost 40 % of healthy volunteers over 50 years-old (yo). The most frequent mutations were found in DNMT3A (48%) and TET2 (28%) and the other mutations were found in ASXL1 (8%), JAK2 (8%), RAD21 (4%) and SRSF2 (4%) with one individual carrying three variants. Blood parameters and bone marrow smears were normal with the exception of two individuals with mild macrocytosis or thrombocytosis. Clonal hematopoiesis cases differed from others by age (62.8 vs. 38.6 years, P &lt; .0001) and platelet count (294 vs. 241 G/L, P &lt; .0208). Conclusions: These results confirm that clonal hematopoiesis is a very common condition in healthy adults over 50 years old. Consequently, the detection of driver myeloid mutations should be interpreted with caution in the absence of cytologic abnormalities in the blood and/or in the bone marrow.

Changes in erythron peripheral component during chemotherapy in patients with malignant lymphomas and parvovirus B19 infection.

e20086 Background: The purpose of the study was to analyze changes in the erythron peripheral component during chemotherapy for malignant lymphomas in patients infected with parvovirus B19 (B19V). Methods: The study included 34 patients with lymphomas (48.7±4.3 years). B19V infection was determined by the presence of IgM/IgG antibodies to B19V in blood serum and DNA in blood plasma and bone marrow before chemotherapy (CT). Parameters of the erythron peripheral component - RBC, HGB, MCW, MCH, MCHC, RDW, PLT, RET (#), IRF, LFR, MFR, HFR (%), and myelogram were evaluated before and after CT (Sysmex XE 2100, Japan). Results: 82.5% of patients had IgG to B19V, including IgM in 11.8%. B19V DNA was detected in 23.4% of patients: in the bone marrow and blood in 11.7%, only in the bone marrow in 11.7%. The range of viral load in the bone marrow was 1435-79573 IU/ml, in the blood 2-349 IU/ml. RBC in all patients before CT was within the reference range, with a tendency to decrease in the group with B19V: 4.01±0.06×1012/L with B19V and 4.57±0.08×1012/L without B19V. Levels of HGB before CT were respectively 112±1.26 g/L and 116±1.26 g/L, decreasing after CT by 1.5 and 1.3 times (p &lt; 0.05) depending on the viral load. MCV, MCH and MCHC varied: 78.6 – 84.8 fl, 24.9 – 28.0 pg and 314–330 g/L in the group with B19V, and 89.7–91.3 fl, 29.5–29.8 pg and 324–337 g/L, respectively, in the group without B19V, which indicates the development of hypochromic microcytic anemia. RET levels before CT in the group with B19V were 38.3±3.44×109/L, after CT – 10.6±2.7×109/L, being lower than in the group without B19V by 1.8 and 3.8 times (p &lt; 0.001), respectively. IRF, MFR and HFR in patients with B19V before CT were 10.6±2.23%, 9.5±1.54% and 1.1±0.022%, being lower than in non-infected patients by 1.6, 1.3 and 3.6 times, respectively. After CT, the downward trend in the proportion of young fractions continued. The noted changes in the erythron peripheral unit indicated inhibition of erythropoiesis, more pronounced in patients with B19V, and were consistent with the myelogram data. Conclusions: The development of anemia without the expected increase in RET, and in particular immature forms - IRF, MFR, HFR - in patients with lymphomas and B19V infection indicates inhibition of erythropoiesis. Early manifestation of these changes allows for timely treatment correction.

Experimental Acute Sepsis Reduced Number of Osteocalcin Immunolabeled Cells in Periodontal Ligament.

The aim of this study was to evaluate the effect of acute sepsis in the periodontal ligament, alveolar and furcation bone in absence of periodontitis induction through histological and immunohistochemical analyses. A septic rat model was established by cecal ligation and puncture (CLP). Twelve rats were randomly divided into CLP (n=6) and Sham (n=6) groups. The animals were euthanized at 24 h and hemimandibles were submitted to histomorfometric (bone matrix, collagenous fibers, fibroblasts, osteocytes, inflammatory cells, and blood vessels) and immunohistochemical (BMP-2/4, RANKL and osteocalcin) evaluation in alveolar bone, furcation bone and periodontal ligament. Our results demonstrated that histomorphometric parameters were similar in alveolar bone, furcation bone and periodontal ligament of Sham and CLP rats. Regarding to immunohistochemical analyses, the number of BMP-2/4 and RANKL immunolabeled cells was also similar in both groups. Furthermore, it was detected a reduction in the osteocalcin immunolabeled cells in periodontal ligaments of CLP compared to Sham rats (p=0.0014). In conclusion, the acute sepsis induction resulted in reduced number of osteocalcin labelled cells in periodontal ligament region. Moreover, no significant histological differences were observed in the periodontium of rats under acute sepsis. Considering the role of osteocalcin in bone remodeling, the study contributes to revealing the importance of careful periodontal evaluation in the presence of sepsis.