Hu14.18K.322A Causes Direct Cell Cytotoxicity and Synergizes with Induction Chemotherapy in High-Risk Neuroblastoma.

The disialoganglioside, GD2, is a promising therapeutic target due to its overexpression in certain tumors, particularly neuroblastoma (NB), with limited expression in normal tissues. Despite progress, the intricate mechanisms of action and the full spectrum of the direct cellular responses to anti-GD2 antibodies remain incompletely understood. In this study, we examined the direct cytotoxic effects of the humanized anti-GD2 antibody hu14.18K322A (hu14) on NB cell lines, by exploring the associated cell-death pathways. Additionally, we assessed the synergy between hu14 and conventional induction chemotherapy drugs. Our results revealed that hu14 treatment induced direct cytotoxic effects in CHLA15 and SK-N-BE1 cell lines, with a pronounced impact on proliferation and colony formation. Apoptosis emerged as the predominant cell-death pathway triggered by hu14. Furthermore, we saw a reduction in GD2 surface expression in response to hu14 treatment. Hu14 demonstrated synergy with induction chemotherapy drugs with alterations in GD2 expression. Our comprehensive investigation provides valuable insights into the multifaceted effects of hu14 on NB cells, shedding light on its direct cytotoxicity, cell-death pathways, and interactions with induction chemotherapy drugs. This study contributes to the evolving understanding of anti-GD2 antibody therapy and its potential synergies with conventional treatments in the context of NB.

Impact of a Regional Pediatric Hematology/Oncology Fellowship Program in Guatemala.

PURPOSE: This study aimed to describe and assess the regional experience of a pediatric hematology/oncology fellowship program based in Guatemala. METHODS: The Unidad Nacional de Oncología Pediátrica (UNOP) in Guatemala City, Guatemala, is the only hospital in Central America dedicated exclusively to childhood and adolescent cancer. To address the regional need for specialists, a fellowship program in pediatric hematology/oncology was launched in 2003. The UNOP fellowship program comprises 3 years of training. Although the program is based at UNOP, it also includes rotations locally and internationally to enhance clinical exposure. The curriculum is based on international standards to cover clinical expertise, research, professionalism, communication, and health advocacy. Trainees are selected according to country or facility-level need for pediatric hematologists/oncologists, with a plan for them to be hired immediately after completing their training. RESULTS: Forty physicians from 10 countries in Latin America have completed training. In addition, there are currently 13 fellows from five countries in training. Of the graduates, 39 (98%) are now practicing in pediatric hematology/oncology in Latin America. Moreover, many of them have leadership positions within their institutions and participate in research, advocacy, and policy making. Graduates from the UNOP program contribute to institutions by providing care for an increasing number of patients with pediatric cancer. The UNOP program is the first pediatric hematology/oncology fellowship program in the world to be accredited by Accreditation Council for Graduate Medical Education-International, an international body accrediting clinical training programs. CONCLUSION: The UNOP program has trained specialists to increase the available care for children with cancer in Latin America. This regional approach to specialist training can maximize resources and serve as a model for other programs and regions.

Late cognitive and adaptive outcomes of patients with neuroblastoma-associated opsoclonus-myoclonus-ataxia-syndrome: A report from the Children's Oncology Group.

BACKGROUND: Opsoclonus-myoclonus-ataxia syndrome (OMAS) is a rare autoimmune disorder of the nervous system presenting with abnormal eye and limb movements, altered gait, and increased irritability. Two to four percent of children diagnosed with neuroblastoma have neuroblastoma-associated OMAS (NA-OMAS). These children typically present with non-high-risk neuroblastoma that is cured with surgery, with or without chemotherapy. Despite excellent overall survival, patients with NA-OMAS can have significant persistent neurological and developmental issues. OBJECTIVE: This study aimed to describe long-term neurocognitive and adaptive functioning of patients with NA-OMAS treated with multimodal therapy, including intravenous immunoglobulin (IVIG) on Children's Oncology Group (COG) protocol ANBL00P3. METHODS: Of 53 children enrolled on ANBL00P3, 25 submitted evaluable neurocognitive data at diagnosis and at least one additional time point within 2 years and were included in the analyses. Adaptive development was assessed via the Vineland Adaptive Behavior Scale, and validated, age-appropriate measures of intellectual function were also administered. RESULTS: Twenty-one of the 25 patients in this cohort ultimately received IVIG. Descriptive spaghetti plots suggest that this cohort demonstrated stable long-term cognitive functioning and adaptive development over time. This cohort also demonstrated decreased OMAS scores over time consistent with improved OMAS symptoms. CONCLUSIONS: While statistical significance is limited by small sample size and loss to follow-up over 10 years, findings suggest stable long-term cognitive and adaptive functioning over time in this treated cohort.

SARS-CoV-2 vaccination response in pediatric oncology patients.

BACKGROUND: There remains limited knowledge about the immune response to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccination in pediatric oncology patients, which is essential to provide counseling and risk adaptation in this vulnerable population. The goal of this study was to understand immunogenicity after vaccination in pediatric oncology patients, and determine if certain clinical factors impacted response. METHODS: Patients 0-25 years of age with a diagnosis of cancer and actively receiving therapy were enrolled on study. We excluded patients who were completely vaccinated prior to their cancer diagnosis. Blood samples were collected pre-vaccination, as well as 2, 4-6, and 8-12 weeks after vaccination. Healthy children who were fully vaccinated enrolled as controls. Clinical data and complete blood counts around time of vaccination were collected. To study B- and T-cell immunity, we measured neutralizing antibodies by enzyme-linked immunoassay and interferon gamma secretion by enzyme-linked immunospot, respectively. RESULTS: Twenty-six patients enrolled on study, for which 11 were evaluable oncology patients and seven were healthy controls. Adequate B-cell response was seen in 36.4% of patients, and adequate T-cell response in 77.8% of patients. Numbers were too small to detect differences based on malignancy type. There was no differences in immunity based on absolute lymphocyte count (ALC) or intensity of therapy. CONCLUSION: Pediatric oncology patients have a suboptimal immune response to SARS-CoV-2 vaccination. Booster doses will be imperative to provide optimal protection against COVID-19; however, blood counts may not be a useful guide to optimize the time of administration.

Treatment of high-risk Hodgkin lymphoma with a modified Stanford V regimen in the AHOPCA: Substituting chemotherapy agents and hampered outcomes.

BACKGROUND/OBJECTIVES: High-risk Hodgkin lymphoma (HRHL) in children is curable with combined modality therapy. The Association of Pediatric Hematology-Oncology of Central America (AHOPCA) is a consortium of cancer centers from Central America. In 2004, AHOPCA implemented a guideline with a short course of chemotherapy (mStanfordV), strict diagnostics, and radiation guidelines, aimed at reducing abandonment and improving outcomes. METHODS: Newly diagnosed children less than 18 years of age with high-risk HL (Ann Arbor stages: IIB, IIIB, IV) from AHOPCA centers were staged with chest radiography and ultrasound or computed tomography. Therapy was a modified Stanford V (mStanfordV), substituting cyclophosphamide for mechlorethamine and involved field radiation. RESULTS: Of 219 patients with HRHL, 181 patients were eligible and evaluable; 146 (81%) were boys, 22% being less than 6 years; 43 were stage IIB, 84 IIIB, and 54 IV. Thirty-one (17%) abandoned therapy, 28 (15%) progressed, 30 (17%) relapsed, and eight (4%) died of toxicity. Radiation guidelines were not followed. Five-year abandonment-sensitive event-free survival and overall survival (AS-EFS, AS-OS ± SE) for the cohort were 46% ± 4% and 56% ± 4%; 5-year AS-OS for stages IIB, IIIB, and IV was 76% ± 7%, 59% ± 7%, and 35% ± 7% (p = .0006). CONCLUSION: Despite instituting a short treatment guideline, it did not improve the abandonment rate (17%) and did not achieve the reported outcomes of Stanford V. The cyclophosphamide dose used to replace merchlorethamine was inadequate. Despite strict guidelines, the radiation therapy application was inaccurate. Weekly chemotherapy may have adversely affected abandonment of therapy by increasing the burden of travel time. Based on these results, AHOPCA established a new abandonment strategy and a new guideline.

Survey of Spanish hospitals on diabetes care resources.

INTRODUCTION: The quality of diabetes care varies from region to region. The objective of this study is to analyze the characteristics of care in different hospitals in Spain through a specific survey assessing different aspects of care for both children and adults. MATERIALS AND METHODS: Cross-sectional observational voluntary survey study, sent to the heads of the Endocrinology and Pediatric Endocrinology Departments or Units in public hospitals with more than 150 beds, during the first semester of 2021. A total of 105 responses were obtained, 55.5% of the 189 requested, which corresponded to a population served of 31,782,409 people, representing almost 80% of the total population served. RESULTS: Patients with diabetes under 15 years of age are cared for by Pediatric Departments, but only 58% of them have a specific Diabetes Education Unit for children, and in 72% of the cases, there is one single nurse dedicated to these tasks, and not always full-time. Those over 15 years of age are attended by specialists in Endocrinology and Nutrition in 94.3 % of hospitals. There are Therapeutic Education Units in Diabetes in practically all hospitals (94.3%). However, Diabetes Day Hospitals exist in only 32 centres and cover 40.3% of the population, since in 22 provinces there are none. Virtual and telematic consultations, as well as retinography, are available in more than 70% of cases, but access to a Diabetic Foot Unit only in 54% of centres. Monographic technological consultations on diabetes have become widespread, but access to mental health specialists with diabetes training remains limited (24% of centres), and interdisciplinary (32%) or interlevel (12%) committees are very scarce. CONCLUSION: Diabetes care in Spain shows great variability from one region to another, and some deficiencies have been detected that affect a large part of the population, such as access to Diabetic Foot Units, as well as mental health specialists with specific training. The presence of multidisciplinary and mixed committees between levels of care remains scarce.

Polyclonal lymphoid expansion drives paraneoplastic autoimmunity in neuroblastoma.

Neuroblastoma is a lethal childhood solid tumor of developing peripheral nerves. Two percent of children with neuroblastoma develop opsoclonus myoclonus ataxia syndrome (OMAS), a paraneoplastic disease characterized by cerebellar and brainstem-directed autoimmunity but typically with outstanding cancer-related outcomes. We compared tumor transcriptomes and tumor-infiltrating T and B cell repertoires from 38 OMAS subjects with neuroblastoma to 26 non-OMAS-associated neuroblastomas. We found greater B and T cell infiltration in OMAS-associated tumors compared to controls and showed that both were polyclonal expansions. Tertiary lymphoid structures (TLSs) were enriched in OMAS-associated tumors. We identified significant enrichment of the major histocompatibility complex (MHC) class II allele HLA-DOB∗01:01 in OMAS patients. OMAS severity scores were associated with the expression of several candidate autoimmune genes. We propose a model in which polyclonal auto-reactive B lymphocytes act as antigen-presenting cells and drive TLS formation, thereby supporting both sustained polyclonal T cell-mediated anti-tumor immunity and paraneoplastic OMAS neuropathology.

Correlation between glucose measurement parameters of continuous flash monitoring and HbA1c. Real life experience in Asturias.

INTRODUCTION: Despite continuous glucose monitoring having been proven useful in patients with type 1 diabetes mellitus, A1C remains the gold standard for assessing disease management. MATERIAL AND METHODS: Descriptive, retrospective study which included 252 patients, 40.5% male, mean age 44.91±14.57 years, mean duration of diabetes 22.21±13.12 years, 88.1% on basal-bolus insulin therapy and 11.9% users of continuous subcutaneous insulin infusion. Glucose measurement, analytical and anthropometric data were obtained. RESULTS: The mean time in range was 60.18±15.60% and was associated with A1C after adjusting for age, gender, duration of diabetes, BMI, insulin regimen, %CV and time below range (ß: -0.548; p<0.01). The glucose management indicator (GMI) was 7.19±0.69% and was also associated with A1C (ß: 0.957; p<0.01) regardless of age, gender, duration of diabetes, BMI, insulin treatment, %CV and time in range. The average difference between A1C and GMI was 0.17±0.65% (-2.70-3.40%), being higher as A1C increased, in a linear and significant manner, without being influenced by the duration of diabetes or CV. CONCLUSIONS: Although we found a positive correlation between continuous glucose monitoring glucose measurement parameters and A1C, there is still not enough evidence to replace one parameter with another.

Second Generation Small Molecule Inhibitors of Gankyrin for the Treatment of Pediatric Liver Cancer.

Background: Gankyrin, a member of the 26S proteasome, is an overexpressed oncoprotein in hepatoblastoma (HBL) and hepatocellular carcinoma (HCC). Cjoc42 was the first small molecule inhibitor of Gankyrin developed; however, the IC50 values of >50 µM made them unattractive for clinical use. Second-generation inhibitors demonstrate a stronger affinity toward Gankyrin and increased cytotoxicity. The aim of this study was to characterize the in vitro effects of three cjoc42 derivatives. Methods: Experiments were performed on the HepG2 (HBL) and Hep3B (pediatric HCC) cell lines. We evaluated the expression of TSPs, cell cycle markers, and stem cell markers by Western blotting and/or real-time quantitative reverse transcription PCR. We also performed apoptotic, synergy, and methylation assays. Results: The treatment with cjoc42 derivatives led to an increase in TSPs and a dose-dependent decrease in the stem cell phenotype in both cell lines. An increase in apoptosis was only seen with AFM-1 and -2 in Hep3B cells. Drug synergy was seen with doxorubicin, and antagonism was seen with cisplatin. In the presence of cjoc42 derivatives, the 20S subunit of the 26S proteasome was more available to transport doxorubicin to the nucleus, leading to synergy. Conclusion: Small-molecule inhibitors for Gankyrin are a promising therapeutic strategy, especially in combination with doxorubicin.

Classification of follicular-patterned thyroid lesions using a minimal set of epigenetic biomarkers.

Objective: The minimally invasive fine-needle aspiration cytology (FNAC) is the current gold standard for the diagnosis of thyroid nodule malignancy. However, the correct discrimination of follicular neoplasia often requires more invasive diagnostic techniques. The lack of suitable immunohistochemical markers to distinguish between follicular thyroid carcinoma and other types of follicular-derived lesions complicates diagnosis, and despite most of these tumours being surgically resected, only a small number will test positive for malignancy. As such, the development of new orthogonal diagnostic approaches may improve the accuracy of diagnosing thyroid nodules. Design: This study includes a retrospective, multi-centre training cohort including 54 fresh-frozen follicular-patterned thyroid samples and two independent, multi-centre validation cohorts of 103 snap-frozen biopsies and 33 FNAC samples, respectively. Methods: We performed a genome-wide genetic and epigenetic profiling of 54 fresh-frozen follicular-patterned thyroid samples using exome sequencing and the Illumina Human DNA Methylation EPIC platform. An extensive validation was performed using the bisulfite pyrosequencing technique. Results: Using a random forest approach, we developed a three-CpG marker-based diagnostic model that was subsequently validated using bisulfite pyrosequencing experiments. According to the validation cohort, this cost-effective method discriminates between benign and malignant nodules with a sensitivity and specificity of 97 and 88%, respectively (positive predictive value (PPV): 0.85, negative predictive value (NPV): 0.98). Conclusions: Our classification system based on a minimal set of epigenetic biomarkers can complement the potential of the diagnostic techniques currently available and would prioritize a considerable number of surgical interventions that are often performed due to uncertain cytology. Significance statement: In recent years, there has been a significant increase in the number of people diagnosed with thyroid nodules. The current challenge is their etiological diagnosis to discount malignancy without resorting to thyroidectomy. The method proposed here, based on DNA pyrosequencing assays, has high sensitivity (0.97) and specificity (0.88) for the identification of malignant thyroid nodules. This simple and cost-effective approach can complement expert pathologist evaluation to prioritize the classification of difficult-to-diagnose follicular-patterned thyroid lesions and track tumor evolution, including real-time monitoring of treatment efficacy, thereby stimulating adherence to health promotion programs.

Diagnosis and Management of Opsoclonus-Myoclonus-Ataxia Syndrome in Children: An International Perspective.

BACKGROUND AND OBJECTIVES: Opsoclonus-myoclonus-ataxia syndrome (OMAS) is a rare disorder of the nervous system that classically presents with a combination of characteristic eye movement disorder and myoclonus, in addition to ataxia, irritability, and sleep disturbance. There is good evidence that OMAS is an immune-mediated condition that may be paraneoplastic in the context of neuroblastoma. This syndrome may be associated with long-term cognitive impairment, yet it remains unclear how this is influenced by disease course and treatment. Treatment is largely predicated on immune suppression, but there is limited evidence to indicate an optimal regimen. METHODS: Following an international multiprofessional workshop in 2004, a body of clinicians and scientists comprising the International OMS Study group continued to meet biennially in a joint professionals and family workshop focusing on pediatric OMAS. Seventeen years after publication of the first report, a writing group was convened to provide a clinical update on the definitions and clinical presentation of OMAS, biomarkers and the role of investigations in a child presenting with OMAS, treatment and management strategies including identification and support of long-term sequelae. RESULTS: The clinical criteria for diagnosis were reviewed, with a proposed approach to laboratory and radiologic investigation of a child presenting with possible OMAS. The evidence for an upfront vs escalating treatment regimen was reviewed, and a treatment algorithm proposed to recognize both these approaches. Importantly, recommendations on monitoring of immunotherapy response and longer-term follow-up based on an expert consensus are provided. DISCUSSION: OMAS is a rare neurologic condition that can be associated with poor cognitive outcomes. This report proposes an approach to investigation and treatment of children presenting with OMAS, based on expert international opinion recognizing the limited data available.

[Cardiovascular diseases in people with diabetes mellitus in Spain according to the Primary Care Clinical Database (BDCAP) in 2017]. / Enfermedades cardiovasculares en personas con diabetes mellitus en España según la Base de Datos Clínicos de Atención Primaria (BDCAP) en 2017.

INTRODUCTION AND OBJECTIVES: Atherosclerotic cardiovascular disease and heart failure are the leading cause of morbidity and mortality in patients with diabetes. The objective of this work is to know the prevalence of atherosclerotic cardiovascular diseases and heart failure in people diagnosed with diabetes in Spain during 2017 and compare them with those not diagnosed with diabetes according to age and sex. METHODS: Data for diagnoses of diabetes mellitus (DM), acute myocardial infarction (AMI), stroke, peripheral artery disease (PAD) or heart failure (HF) for 2017 were obtained from the National Health System's Primary Care Clinical Database (BDCAP). RESULTS: Comparing people with diabetes and people without diabetes over 35 years of age, the Odds Ratio (OR) for being diagnosed with acute myocardial infarction, stroke, peripheral artery disease or heart failure is about 2 in those over 64 years of age and more than 4 in patients under that age. This OR is superior in females versus males for all diagnoses apart from peripheral artery disease. CONCLUSIONS: This study shows the high cardiovascular comorbidity of patients with diabetes in Spain, with a greater excess of risk in patients under 65 years of age, more pronounced in women. We should offer more intensive treatment for DM2 in women.

Validation of a Methodology for the Detection of Severe Acute Respiratory Syndrome Coronavirus 2 in Saliva by Real-Time Reverse Transcriptase-PCR.

In January 2021, the Chilean city of Concepción experienced a second wave of coronavirus 2019 (COVID-19) while in early April 2021, the entire country faced the same situation. This outbreak generated the need to modify and validate a method for detecting severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in saliva, thereby expanding the capacity and versatility of testing for COVID-19. This study was conducted in February 2021 in the Chilean city of Concepción during which time, the town was under total quarantine. The study participants were mostly symptomatic (87.4%), not hospitalized, and attended care centers because of their health status rather than being asked by the researchers. People coming to the health center in Concepción to be tested for COVID-19 (via reverse transcriptase polymerase chain reaction [RT-PCR]) from a specimen of nasopharyngeal swab (NPS) were then invited to participate in this study. A total of 131 participants agreed to sign an informed consent and to provide saliva and NPS specimens to validate a method in terms of sensitivity, specificity, and statistical analysis of the cycle threshold (Ct) values from the RT-PCR. Calculations pertaining to the 127 participants who were ultimately included in the analysis showed sensitivity and specificity at 94.34% (95% CI: 84.34-98.82%) and 98.65% (95% CI: 92.70-99.97%), respectively. The saliva specimen showed a performance comparable to NPS as demonstrated by the diagnostic parameters. This RT-PCR method from the saliva specimen is a highly sensitive and specific alternative compared to the reference methodology, which uses the NPS specimen. This modified and validated method is intended for use in the in vitro diagnosis of SARS-CoV-2, which provides health authorities in Chile and local laboratories with a real testing alternative to RT-PCR from NPS.

Trade-offs between individual and ensemble forecasts of an emerging infectious disease.

Probabilistic forecasts play an indispensable role in answering questions about the spread of newly emerged pathogens. However, uncertainties about the epidemiology of emerging pathogens can make it difficult to choose among alternative model structures and assumptions. To assess the potential for uncertainties about emerging pathogens to affect forecasts of their spread, we evaluated the performance 16 forecasting models in the context of the 2015-2016 Zika epidemic in Colombia. Each model featured a different combination of assumptions about human mobility, spatiotemporal variation in transmission potential, and the number of virus introductions. We found that which model assumptions had the most ensemble weight changed through time. We additionally identified a trade-off whereby some individual models outperformed ensemble models early in the epidemic, but on average the ensembles outperformed all individual models. Our results suggest that multiple models spanning uncertainty across alternative assumptions are necessary to obtain robust forecasts for emerging infectious diseases.

New Quinone Antibiotics against Methicillin-Resistant S. aureus.

There is an urgent need for the development of new antibiotics. Here, we describe the inhibitory activity of new quinone compounds against methicillin-resistant Staphylococcus aureus (ATCC® 43300), methicillin-sensitive S. aureus (ATCC® 29213), and two clinical isolates from Chile (ISP-213 and ISP-214). We observed 99.9% reduction in viability within 2 h of exposure without the cultures exhibiting any post-antibiotic effect, which was twice the kinetics to that observed with vancomycin. These clinical isolates did not acquire resistance to these quinone derivatives during the course of our study. We found that these compounds protected larvae of the greater wax moth, sp. Galleria mellonella, from infection by these MRSA clinical strains as effectively as vancomycin. These quinone derivatives are potential drug candidates worth further development.

Excellent Outcome for Pediatric Patients With High-Risk Hodgkin Lymphoma Treated With Brentuximab Vedotin and Risk-Adapted Residual Node Radiation.

PURPOSE: Brentuximab vedotin, an effective anti-CD30 antibody-drug conjugate approved for use in adults with classical Hodgkin lymphoma (HL), was introduced in this frontline trial to reduce prescribed radiation in children and adolescents with classical HL. METHODS: Open-label, single-arm, multicenter trial for patients (age ≤ 18 years) with stage IIB, IIIB, or IV classical HL was conducted. Brentuximab vedotin replaced each vincristine in the OEPA/COPDac (vincristine, etoposide, prednisone, and doxorubicin/cyclophosphamide, vincristine, prednisone, and dacarbazine) regimen according to GPOH-HD2002 treatment group 3 (TG3); two cycles of AEPA and four cycles of CAPDac. Residual node radiotherapy (25.5 Gy) was given at the end of all chemotherapy only to nodal sites that did not achieve a complete response (CR) at the early response assessment (ERA) after two cycles of therapy. Primary objectives were to evaluate the safety and efficacy (complete remission at ERA) of this combination and the 3-year event-free (EFS) and overall survival (OS). The trials are registered at ClinicalTrials.gov (identifier: NCT01920932). RESULTS: Of the 77 patients enrolled in the study, 27 (35%) achieved complete remission at ERA and were spared radiation. Patients who were irradiated received radiation to individual residual nodal tissue. At a median follow-up of 3.4 years, the 3-year EFS was 97.4% (SE 2.3%) and the OS was 98.7% (SE 1.6%). One irradiated patient experienced disease progression at the end of therapy and now remains disease free more than 6 years following salvage therapy, and one unexpected death occurred. Only 4% of patients experienced grade 3 neuropathy. CONCLUSION: The integration of brentuximab vedotin in the frontline treatment of pediatric high-risk HL is highly tolerable, facilitated significant reduction in radiation exposure, and yielded excellent outcomes.

Evaluation of angiogenic signaling molecules associated with reactive thrombocytosis in an iron-deficient rat model.

BACKGROUND: Iron deficiency anemia (IDA)-induced reactive thrombocytosis can occur in children and adults. The underlying mechanism for this phenomenon is indeterminate. Traditional cytokines such as thrombopoietin (TPO), interleukin-6 (IL-6), and IL-11 involved in megakaryopoiesis have not been shown to be the cause. Recent studies suggest that growth factors and signaling molecules involved with angiogenesis influence the proliferation and differentiation of megakaryocytes. METHODS: We investigated the possible association between angiogenic cytokines with reactive thrombocytosis due to IDA in an iron-deficient (ID) rat model. Complete blood count, iron panels, and TPO levels were measured at baseline and 5 weeks later in both control (C) and ID rats. Angiogenic cytokines were evaluated in the bone marrow in all rats. RESULTS: We successfully induced IDA in our rats by phlebotomy and reduced iron diet. We did not find an increase of TPO in ID rats. A review of the bone marrow showed an increase in the number of megakaryocytes, vascular structures, as well as increased intensity of stain for vascular endothelial growth factor (VEGF), and CXC chemokine receptor 4 (CXCR4) in rats with IDA compared to controls. CONCLUSIONS: Our results of histological bone marrow data suggest an important role for angiogenesis in the development of IDA-induced thrombocytosis. IMPACT: Thrombocytosis is common with IDA in both children and adults, but the mechanism is unclear. We confirmed that TPO is not the major driver of iron deficiency-associated thrombocytosis. We confirmed the increase in the number of megakaryocytes in the bone marrow despite stable TPO levels. We provided evidence supporting an important role of angiogenesis in megakaryocytopoiesis/thrombopoiesis with increased vascular structures and angiogenic cytokines in the bone marrow of iron-deficient rats. The demonstration that angiogenesis may play an important role in secondary thrombocytosis could lead to a new approach in treating symptomatic reactive thrombocytosis by targeting angiogenesis.