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Quarmyne MO, Ross D, Sinha C, Bakshi N, Boudreaux J, Krishnamurti L. Decision-making about gene therapy in transfusion dependent thalassemia. BMC Pediatr 2022; 22:536. [PMID: 36085025 PMCID: PMC9461218 DOI: 10.1186/s12887-022-03598-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/07/2022] [Accepted: 09/01/2022] [Indexed: 01/19/2023] Open
Abstract
BACKGROUND Hematopoietic stem cell transplantation (HSCT) is a treatment option with curative intent for patients with transfusion dependent thalassemia (TDT) but its application is limited by the lack of suitable donors and acceptability due to the related morbidity/mortality. Transplantation of autologous genetically modified hematopoietic cells, gene therapy (GT) is emerging as a promising treatment option for TDT as it eliminates graft versus host disease (GVHD) and need for immunosuppression. Early results of GT suggest that many, but not all patients achieve transfusion independence after the procedure. There is little information about the acceptability of GT in patients with TDT. We sought to examine patient/family knowledge about GT in TDT and to examine factors that influence decision-making about this therapy. METHODS Parents of children with TDT and adults with TDT were who provided informed consent underwent semi-structured interviews to understand patient/family knowledge and decision-making regarding GT in TDT. Transcribed interviews were coded and the data was examined for emerging themes using a combination of thematic and content analysis. RESULTS Twenty-five study participants with mean age of 38Y (17-52Y) including eight adults living with TDT, and 17 parents of children with TDT underwent semi-structured qualitative interviews. Participant responses coalesced around broad themes related to knowledge of GT, motivating/deterring factors and outcomes. Study participants expressed a desire for 'cure' from thalassemia including transfusion independence, chelation reduction and improved quality of life as motivators for considering GT. Insufficient knowledge about the process, long-term outcomes, safety, and side effects as well as the potential for death/failure of the procedure were deterrents for the consideration GT. Reduction in frequency of transfusions, even without elimination of transfusions was an acceptable outcome of GT for most participants. Participant choice for preferred treatment modality was split between indefinitely continuing transfusions which was familiar to them versus GT which was unfamiliar, and with an uncertain outcome. None of the participants had a matched sibling donor; alternate donor HSCT was the least preferred option in this group. CONCLUSION There is tempered excitement about GT in patients/families with TDT with a general willingness to accept transfusions reduction as the outcome.
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Affiliation(s)
- Maa-Ohui Quarmyne
- Center for Cancer and Blood Disorder, Phoenix Children's Hospital, 1919 E Thomas Road, Phoenix, AZ, 85286, USA.
- Aflac Cancer and Blood Disorders Center, Department of Pediatrics, Emory University, 1405 Clifton Road NE, Atlanta, GA, 30322, USA.
| | - Diana Ross
- Aflac Cancer and Blood Disorders Center, Department of Pediatrics, Emory University, 1405 Clifton Road NE, Atlanta, GA, 30322, USA
| | - Cynthia Sinha
- Aflac Cancer and Blood Disorders Center, Department of Pediatrics, Emory University, 1405 Clifton Road NE, Atlanta, GA, 30322, USA
| | - Nitya Bakshi
- Aflac Cancer and Blood Disorders Center, Department of Pediatrics, Emory University, 1405 Clifton Road NE, Atlanta, GA, 30322, USA
- Aflac Cancer and Blood Disorders Center, Children's Healthcare of Atlanta, 1405 Clifton Road NE, Atlanta, GA, 30322, USA
| | - Jeanne Boudreaux
- Aflac Cancer and Blood Disorders Center, Department of Pediatrics, Emory University, 1405 Clifton Road NE, Atlanta, GA, 30322, USA
- Aflac Cancer and Blood Disorders Center, Children's Healthcare of Atlanta, 1405 Clifton Road NE, Atlanta, GA, 30322, USA
| | - Lakshmanan Krishnamurti
- Yale Pediatric Hematology Oncology and Bone Marrow Transplant, Yale School of Medicine, Yale University, 35 Park Street, CT, 06511, New Haven, USA
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Kracht MJ, Stein A, Knoll C, Badia Alonso P, Gomez E, Quarmyne MO, Shah S, Gendreau J. A proposed algorithm for evaluation and management of pediatric hemophilia patients who present to the emergency department with head trauma. Pediatr Blood Cancer 2022; 69:e29811. [PMID: 35709337 DOI: 10.1002/pbc.29811] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/12/2021] [Revised: 05/01/2022] [Accepted: 05/11/2022] [Indexed: 11/11/2022]
Abstract
Hemophilia is the deficiency of plasma clotting factor VIII (hemophilia A) or IX (hemophilia B) where management focuses on the prevention and treatment of acute bleeding symptoms and their sequelae. The most concerning risk is for life-threatening bleeding, including intracranial hemorrhage (ICH), which is caused by head trauma. Guidelines exist for the evaluation and management of pediatric head trauma, including the Pediatric Emergency Care Applied Research Network (PECARN) protocol, but limited evidence exists for when hemophilia patients present to the emergency department (ED), specifically with head trauma. Literature is limited regarding ICH and hemophilia, which further supports the culture of uncertainty among providers. The objective of this study is to conduct a retrospective chart review to determine the prevalence and clinical characteristics of ICH, and to describe computed tomography (CT) scan use in hemophilia patients who present to Phoenix Children's Hospital (PCH) ED with head trauma from January 1, 2007 to June 1, 2019. A total of 89 ED visits and 43 patients met inclusion criteria, and prevalence of ICH was determined to be 4% with the patients presenting with varied clinical characteristics and few commonalities. Using these data, we propose a new algorithm to aid clinicians in determining the need for CT scan in pediatric hemophilia patients who present to the ED with head trauma.
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Affiliation(s)
- M Jensen Kracht
- University of Arizona College of Medicine Tucson, Tucson, Arizona, USA
| | - Amy Stein
- Midwestern University Arizona College of Osteopathic Medicine, Glendale, Arizona, USA
| | - Christine Knoll
- Center for Cancer & Blood Disorders, Phoenix Children's Hospital, Phoenix, Arizona, USA
| | - Priscila Badia Alonso
- Center for Cancer & Blood Disorders, Phoenix Children's Hospital, Phoenix, Arizona, USA
| | - Esteban Gomez
- Center for Cancer & Blood Disorders, Phoenix Children's Hospital, Phoenix, Arizona, USA
| | - Maa-Ohui Quarmyne
- Center for Cancer & Blood Disorders, Phoenix Children's Hospital, Phoenix, Arizona, USA
| | - Sanjay Shah
- Center for Cancer & Blood Disorders, Phoenix Children's Hospital, Phoenix, Arizona, USA
| | - Joanna Gendreau
- Center for Cancer & Blood Disorders, Phoenix Children's Hospital, Phoenix, Arizona, USA
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Shamriz O, Kumar D, Shim J, Briones M, Quarmyne MO, Chonat S, Lucas L, Edington H, White MH, Mahajan A, Park S, Chandrakasan S. Correction to: T Cell‑Epstein‑Barr Virus-Associated Hemophagocytic Lymphohistiocytosis (HLH) Occurs in Non‑Asians and Is Associated with a T Cell Activation State that Is Comparable to Primary HLH. J Clin Immunol 2021; 41:1979. [PMID: 34378110 PMCID: PMC8895089 DOI: 10.1007/s10875-021-01117-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Oded Shamriz
- Aflac Cancer and Blood Disorders Center, Children's Healthcare of Atlanta and Department of Pediatrics, Emory University School of Medicine, Atlanta, GA, USA.,Allergy and Clinical Immunology Unit, Department of Medicine, Hadassah Medical Organization, Faculty of Medicine, Hebrew University of Jerusalem, Jerusalem, Israel
| | - Deepak Kumar
- Aflac Cancer and Blood Disorders Center, Children's Healthcare of Atlanta and Department of Pediatrics, Emory University School of Medicine, Atlanta, GA, USA
| | - Jenny Shim
- Aflac Cancer and Blood Disorders Center, Children's Healthcare of Atlanta and Department of Pediatrics, Emory University School of Medicine, Atlanta, GA, USA
| | - Michael Briones
- Aflac Cancer and Blood Disorders Center, Children's Healthcare of Atlanta and Department of Pediatrics, Emory University School of Medicine, Atlanta, GA, USA
| | - Maa-Ohui Quarmyne
- Aflac Cancer and Blood Disorders Center, Children's Healthcare of Atlanta and Department of Pediatrics, Emory University School of Medicine, Atlanta, GA, USA.,Center for Cancer and Blood Disorders, Phoenix Children's Hospital, Phoenix, AZ, USA
| | - Satheesh Chonat
- Aflac Cancer and Blood Disorders Center, Children's Healthcare of Atlanta and Department of Pediatrics, Emory University School of Medicine, Atlanta, GA, USA
| | - Laura Lucas
- Aflac Cancer and Blood Disorders Center, Children's Healthcare of Atlanta, Atlanta, GA, USA
| | - Holly Edington
- Aflac Cancer and Blood Disorders Center, Children's Healthcare of Atlanta and Department of Pediatrics, Emory University School of Medicine, Atlanta, GA, USA
| | - Michael H White
- Aflac Cancer and Blood Disorders Center, Children's Healthcare of Atlanta and Department of Pediatrics, Emory University School of Medicine, Atlanta, GA, USA
| | - Advay Mahajan
- Aflac Cancer and Blood Disorders Center, Children's Healthcare of Atlanta and Department of Pediatrics, Emory University School of Medicine, Atlanta, GA, USA
| | - Sunita Park
- Department of Pathology, Children's Healthcare of Atlanta, Atlanta, GA, USA
| | - Shanmuganathan Chandrakasan
- Aflac Cancer and Blood Disorders Center, Children's Healthcare of Atlanta and Department of Pediatrics, Emory University School of Medicine, Atlanta, GA, USA.
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4
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Shamriz O, Kumar D, Shim J, Briones M, Quarmyne MO, Chonat S, Lucas L, Edington H, White MH, Mahajan A, Park S, Chandrakasan S. T Cell-Epstein-Barr Virus-Associated Hemophagocytic Lymphohistiocytosis (HLH) Occurs in Non-Asians and Is Associated with a T Cell Activation State that Is Comparable to Primary HLH. J Clin Immunol 2021; 41:1582-1596. [PMID: 34173902 PMCID: PMC8233186 DOI: 10.1007/s10875-021-01073-9] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2021] [Accepted: 05/20/2021] [Indexed: 12/11/2022]
Abstract
Purpose T cell-Epstein-Barr virus–associated hemophagocytic lymphohistiocytosis (T cell-EBV-HLH) is prevalent in East Asia and has poor prognosis. Understanding of this disease is limited, and literature regarding prevalence in North America is scarce. Herein, we summarize our experience. Methods A retrospective analysis of T cell-EBV-HLH patients admitted to Children’s Healthcare of Atlanta (GA, USA) from 2010 to 2020 was conducted. Additional immune studies were completed in a subset of patients. Results We report 15 patients (10 months–19 years of age) diagnosed with T cell-EBV-HLH. Nine patients were Hispanic, and the majority did not have primary HLH (p-HLH) gene defects. Soluble interleukin-2 receptor levels in T cell-EBV-HLH were significantly higher than other forms of secondary-HLH but comparable to p-HLH, and it correlated with disease severity at presentation. Natural killer cell function was decreased in most patients despite a negative workup for p-HLH. Depending on disease severity, initial therapy included dexamethasone or dexamethasone and etoposide. Refractory patients were managed with blended regimens that included one or more of the following therapies: combination chemotherapy, alemtuzumab, emapalumab, and nivolumab. Rituximab did not appreciably decrease EBV viremia in most patients. Non-critically ill patients responded well to immunosuppressive therapy and are long-term survivors without undergoing allogeneic hematopoietic stem cell transplantation (HSCT). Alemtuzumab resulted in inflammation flare in two of the three patients. Three patients underwent allogeneic HSCT, with disease relapse noted in one. At a median follow-up of 3 years, 10 of the 15 patients are alive. Conclusion T cell-EBV-HLH occurs in the USA among the non-Asian populations, especially in those who are Hispanic.
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Affiliation(s)
- Oded Shamriz
- Aflac Cancer and Blood Disorders Center, Children's Healthcare of Atlanta and Department of Pediatrics, Emory University School of Medicine, Atlanta, GA, USA.,Allergy and Clinical Immunology Unit, Department of Medicine, Hadassah Medical Organization, Faculty of Medicine, Hebrew University of Jerusalem, Jerusalem, Israel
| | - Deepak Kumar
- Aflac Cancer and Blood Disorders Center, Children's Healthcare of Atlanta and Department of Pediatrics, Emory University School of Medicine, Atlanta, GA, USA.,Allergy and Clinical Immunology Unit, Department of Medicine, Hadassah Medical Organization, Faculty of Medicine, Hebrew University of Jerusalem, Jerusalem, Israel
| | - Jenny Shim
- Aflac Cancer and Blood Disorders Center, Children's Healthcare of Atlanta and Department of Pediatrics, Emory University School of Medicine, Atlanta, GA, USA.,Allergy and Clinical Immunology Unit, Department of Medicine, Hadassah Medical Organization, Faculty of Medicine, Hebrew University of Jerusalem, Jerusalem, Israel
| | - Michael Briones
- Aflac Cancer and Blood Disorders Center, Children's Healthcare of Atlanta and Department of Pediatrics, Emory University School of Medicine, Atlanta, GA, USA.,Allergy and Clinical Immunology Unit, Department of Medicine, Hadassah Medical Organization, Faculty of Medicine, Hebrew University of Jerusalem, Jerusalem, Israel
| | - Maa-Ohui Quarmyne
- Aflac Cancer and Blood Disorders Center, Children's Healthcare of Atlanta and Department of Pediatrics, Emory University School of Medicine, Atlanta, GA, USA.,Center for Cancer and Blood Disorders, Phoenix Children's Hospital, AZ, Phoenix, USA
| | - Satheesh Chonat
- Aflac Cancer and Blood Disorders Center, Children's Healthcare of Atlanta and Department of Pediatrics, Emory University School of Medicine, Atlanta, GA, USA.,Allergy and Clinical Immunology Unit, Department of Medicine, Hadassah Medical Organization, Faculty of Medicine, Hebrew University of Jerusalem, Jerusalem, Israel
| | - Laura Lucas
- Aflac Cancer and Blood Disorders Center, Children's Healthcare of Atlanta, Atlanta, GA, USA
| | - Holly Edington
- Aflac Cancer and Blood Disorders Center, Children's Healthcare of Atlanta and Department of Pediatrics, Emory University School of Medicine, Atlanta, GA, USA.,Allergy and Clinical Immunology Unit, Department of Medicine, Hadassah Medical Organization, Faculty of Medicine, Hebrew University of Jerusalem, Jerusalem, Israel
| | - Michael H White
- Aflac Cancer and Blood Disorders Center, Children's Healthcare of Atlanta and Department of Pediatrics, Emory University School of Medicine, Atlanta, GA, USA.,Allergy and Clinical Immunology Unit, Department of Medicine, Hadassah Medical Organization, Faculty of Medicine, Hebrew University of Jerusalem, Jerusalem, Israel
| | - Advay Mahajan
- Aflac Cancer and Blood Disorders Center, Children's Healthcare of Atlanta and Department of Pediatrics, Emory University School of Medicine, Atlanta, GA, USA.,Allergy and Clinical Immunology Unit, Department of Medicine, Hadassah Medical Organization, Faculty of Medicine, Hebrew University of Jerusalem, Jerusalem, Israel
| | - Sunita Park
- Department of Pathology, Children's Healthcare of Atlanta, Atlanta, GA, USA
| | - Shanmuganathan Chandrakasan
- Aflac Cancer and Blood Disorders Center, Children's Healthcare of Atlanta and Department of Pediatrics, Emory University School of Medicine, Atlanta, GA, USA.
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Chonat S, Graciaa S, Shin HS, Newton JG, Quarmyne MO, Boudreaux J, Tang A, Zerra PE, Rollins MR, Josephson CD, Brown C, Joiner CH, Fasano RM, Stowell SR. Eculizumab for complement mediated thrombotic microangiopathy in sickle cell disease. Haematologica 2020; 105:2887-2891. [PMID: 33256394 PMCID: PMC7716365 DOI: 10.3324/haematol.2020.262006] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Affiliation(s)
- Satheesh Chonat
- Department of Pediatrics, Emory University School of Medicine
- Aflac Cancer and Blood Disorders Center
| | | | - H. Stella Shin
- Department of Pediatrics, Emory University School of Medicine
- Division of Pediatric Nephrology, Children’s Healthcare of Atlanta
| | - Joanna G. Newton
- Department of Pediatrics, Emory University School of Medicine
- Aflac Cancer and Blood Disorders Center
| | - Maa-Ohui Quarmyne
- Department of Pediatrics, Emory University School of Medicine
- Aflac Cancer and Blood Disorders Center
| | - Jeanne Boudreaux
- Department of Pediatrics, Emory University School of Medicine
- Aflac Cancer and Blood Disorders Center
| | - Amy Tang
- Department of Pediatrics, Emory University School of Medicine
- Aflac Cancer and Blood Disorders Center
| | - Patricia E. Zerra
- Aflac Cancer and Blood Disorders Center
- Center for Transfusion and Cellular Therapy, Department of Pathology and Laboratory Medicine, Emory University School of Medicine, Atlanta, GA, USA
| | - Margo R. Rollins
- Aflac Cancer and Blood Disorders Center
- Center for Transfusion and Cellular Therapy, Department of Pathology and Laboratory Medicine, Emory University School of Medicine, Atlanta, GA, USA
| | - Cassandra D. Josephson
- Aflac Cancer and Blood Disorders Center
- Center for Transfusion and Cellular Therapy, Department of Pathology and Laboratory Medicine, Emory University School of Medicine, Atlanta, GA, USA
| | - Clark Brown
- Department of Pediatrics, Emory University School of Medicine
- Aflac Cancer and Blood Disorders Center
| | - Clinton H. Joiner
- Department of Pediatrics, Emory University School of Medicine
- Aflac Cancer and Blood Disorders Center
| | - Ross M. Fasano
- Aflac Cancer and Blood Disorders Center
- Center for Transfusion and Cellular Therapy, Department of Pathology and Laboratory Medicine, Emory University School of Medicine, Atlanta, GA, USA
| | - Sean R. Stowell
- Center for Transfusion and Cellular Therapy, Department of Pathology and Laboratory Medicine, Emory University School of Medicine, Atlanta, GA, USA
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Meier ER, Creary SE, Heeney MM, Dong M, Appiah-Kubi AO, Nelson SC, Niss O, Piccone C, Quarmyne MO, Quinn CT, Saving KL, Scott JP, Talati R, Latham TS, Pfeiffer A, Shook LM, Vinks AA, Lane A, McGann PT. Hydroxyurea Optimization through Precision Study (HOPS): study protocol for a randomized, multicenter trial in children with sickle cell anemia. Trials 2020; 21:983. [PMID: 33246482 PMCID: PMC7691962 DOI: 10.1186/s13063-020-04912-z] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2020] [Accepted: 11/17/2020] [Indexed: 12/22/2022] Open
Abstract
Background Sickle cell disease (SCD) is a severe and devastating hematological disorder that affects over 100,000 persons in the USA and millions worldwide. Hydroxyurea is the primary disease-modifying therapy for the SCD, with proven benefits to reduce both short-term and long-term complications. Despite the well-described inter-patient variability in pharmacokinetics (PK), pharmacodynamics, and optimal dose, hydroxyurea is traditionally initiated at a weight-based dose with a subsequent conservative dose escalation strategy to avoid myelosuppression. Because the dose escalation process is time consuming and requires frequent laboratory checks, many providers default to a fixed dose, resulting in inadequate hydroxyurea exposure and suboptimal benefits for many patients. Results from a single-center trial of individualized, PK-guided dosing of hydroxyurea for children with SCD suggest that individualized dosing achieves the optimal dose more rapidly and provides superior clinical and laboratory benefits than traditional dosing strategies. However, it is not clear whether these results were due to individualized dosing, the young age that hydroxyurea treatment was initiated in the study, or both. The Hydroxyurea Optimization through Precision Study (HOPS) aims to validate the feasibility and benefits of this PK-guided dosing approach in a multi-center trial. Methods HOPS is a randomized, multicenter trial comparing standard vs. PK-guided dosing for children with SCD as they initiate hydroxyurea therapy. Participants (ages 6 months through 21 years), recruited from 11 pediatric sickle cell centers across the USA, are randomized to receive hydroxyurea either using a starting dose of 20 mg/kg/day (Standard Arm) or a PK-guided dose (Alternative Arm). PK data will be collected using a novel sparse microsampling approach requiring only 10 μL of blood collected at 3 time-points over 3 h. A protocol-guided strategy more aggressive protocols is then used to guide dose escalations and reductions in both arms following initiation of hydroxyurea. The primary endpoint is the mean %HbF after 6 months of hydroxyurea. Discussion HOPS will answer important questions about the clinical feasibility, benefits, and safety of PK-guided dosing of hydroxyurea for children with SCD with potential to change the treatment paradigm from a standard weight-based approach to one that safely and effectively optimize the laboratory and clinical response. Trial registration ClinicalTrials.gov NCT03789591. Registered on 28 December 2018.
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Affiliation(s)
- Emily R Meier
- Indiana Hemophilia and Thrombosis Center, Indianapolis, IN, USA
| | - Susan E Creary
- Division of Hematology/Oncology/BMT, Nationwide Children's Hospital, Columbus, OH, USA.,Center for Innovation in Pediatric Practice, Nationwide Children's Hospital Research Institute, The Ohio State University, Columbus, OH, USA
| | - Matthew M Heeney
- Division of Hematology/Oncology, Boston Children's Hospital, Boston, MA, USA.,Harvard Medical School, Boston, MA, USA
| | - Min Dong
- Division of Clinical Pharmacology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA.,University of Cincinnati College of Medicine, Cincinnati, OH, USA
| | - Abena O Appiah-Kubi
- Pediatric Hematology, Children's Hospitals and Clinics of Minnesota, Minneapolis and St. Paul, MN, USA
| | - Stephen C Nelson
- Division of Hematology, Cincinnati Children's Hospital Medical Center, 3333 Burnet Ave, MLC 7015, Cincinnati, OH, 45229, USA
| | - Omar Niss
- University of Cincinnati College of Medicine, Cincinnati, OH, USA.,Department of Pediatrics, Division of Pediatric Hematology, Oncology, and Stem Cell Transplantation, Cohen Children's Medical Center of New York, New Hyde Park, NY, USA
| | - Connie Piccone
- Case Western Reserve University School of Medicine, Department of Hematology and Oncology, University Hospitals Rainbow Babies and Children's, Cleveland, OH, USA
| | - Maa-Ohui Quarmyne
- Emory University School of Medicine & Sickle Cell Disease Program, Children's Healthcare of Atlanta, Atlanta, GA, USA
| | - Charles T Quinn
- University of Cincinnati College of Medicine, Cincinnati, OH, USA.,Department of Pediatrics, Division of Pediatric Hematology, Oncology, and Stem Cell Transplantation, Cohen Children's Medical Center of New York, New Hyde Park, NY, USA
| | | | - John P Scott
- Medical College of Wisconsin, Milwaukee, WI, USA
| | | | - Teresa S Latham
- Department of Pediatrics, Division of Pediatric Hematology, Oncology, and Stem Cell Transplantation, Cohen Children's Medical Center of New York, New Hyde Park, NY, USA
| | - Amanda Pfeiffer
- Department of Pediatrics, Division of Pediatric Hematology, Oncology, and Stem Cell Transplantation, Cohen Children's Medical Center of New York, New Hyde Park, NY, USA
| | - Lisa M Shook
- University of Cincinnati College of Medicine, Cincinnati, OH, USA.,Department of Pediatrics, Division of Pediatric Hematology, Oncology, and Stem Cell Transplantation, Cohen Children's Medical Center of New York, New Hyde Park, NY, USA
| | - Alexander A Vinks
- Division of Clinical Pharmacology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA.,University of Cincinnati College of Medicine, Cincinnati, OH, USA
| | - Adam Lane
- University of Cincinnati College of Medicine, Cincinnati, OH, USA.,Department of Pediatrics, Division of Pediatric Hematology, Oncology, and Stem Cell Transplantation, Cohen Children's Medical Center of New York, New Hyde Park, NY, USA
| | - Patrick T McGann
- University of Cincinnati College of Medicine, Cincinnati, OH, USA. .,Department of Pediatrics, Division of Pediatric Hematology, Oncology, and Stem Cell Transplantation, Cohen Children's Medical Center of New York, New Hyde Park, NY, USA.
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7
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Bakshi N, Katoch D, Sinha CB, Ross D, Quarmyne MO, Loewenstein G, Krishnamurti L. Assessment of Patient and Caregiver Attitudes and Approaches to Decision-Making Regarding Bone Marrow Transplant for Sickle Cell Disease: A Qualitative Study. JAMA Netw Open 2020; 3:e206742. [PMID: 32469414 PMCID: PMC7260617 DOI: 10.1001/jamanetworkopen.2020.6742] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
IMPORTANCE Bone marrow transplant (BMT) is a potentially curative treatment for sickle cell disease (SCD). Patient and caregiver attitudes toward BMT for SCD and the willingness to accept risks of BMT vary, but these attitudes are not well understood. OBJECTIVE To understand patient and caregiver perceptions of and attitudes toward BMT for SCD and decision-making about BMT. DESIGN, SETTING, AND PARTICIPANTS Qualitative study of interview transcripts from a convenience sample. Transcripts were from adults with SCD and caregivers of patients with SCD recruited from national and regional SCD conferences, symposia, and sickle cell clinics in 2 cities. Interview transcripts were used from the needs assessment phase to develop a patient-decision aid in 2013 to 2014 (group 1) and from the baseline point in 2015 to 2016 (group 2) of the parent trial, a randomized clinical trial of adults and caregivers of patients with SCD to evaluate the effectiveness of a patient decision aid. MAIN OUTCOMES AND MEASURES Participant perspectives on decision-making regarding BMT for SCD. RESULTS Fifty-seven transcripts from adults with SCD and 50 transcripts from caregivers of patients with SCD were included. Median (interquartile range [IQR]) age of adults with SCD was 34 (21-50) years in group 1 and 30 (23-38) years in group 2. The median (IQR) age of caregivers was 42.5 (31-52) years in group 1 and 41 (35-46.5) years in group 2. Most transcripts from adults with SCD (75.0% in group 1 and 72.4% in group 2) and caregivers of patients with SCD (76.7% in group 1 and 85.0% in group 2) were from female participants. Bone marrow transplant was perceived as a treatment option associated with serious risks. Reported attitudes toward BMT occurred on a continuum ranging from unfavorable to favorable. Participants reported serious decisional dilemma regarding BMT for SCD. Most participants expressed interest in learning about BMT or curative treatments. CONCLUSIONS AND RELEVANCE This qualitative study found a continuum in attitudes toward BMT for SCD and highlights the complexity of decision-making in BMT for SCD. Patients and families with SCD expressed an interest in learning about BMT. Future prospective studies of patient decision-making regarding BMT, especially in the context of emerging curative and novel disease-modifying therapies for SCD, are warranted.
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Affiliation(s)
- Nitya Bakshi
- Department of Pediatrics, Division of Hematology-Oncology-BMT, Emory University School of Medicine, Atlanta, Georgia
- Aflac Cancer and Blood Disorders Center of Children’s Healthcare of Atlanta, Atlanta, Georgia
| | - Deeksha Katoch
- Department of Pediatrics, Division of Hematology-Oncology-BMT, Emory University School of Medicine, Atlanta, Georgia
- Aflac Cancer and Blood Disorders Center of Children’s Healthcare of Atlanta, Atlanta, Georgia
| | - Cynthia B. Sinha
- Department of Pediatrics, Division of Hematology-Oncology-BMT, Emory University School of Medicine, Atlanta, Georgia
| | - Diana Ross
- Department of Pediatrics, Division of Hematology-Oncology-BMT, Emory University School of Medicine, Atlanta, Georgia
| | - Maa-Ohui Quarmyne
- Department of Pediatrics, Division of Hematology-Oncology-BMT, Emory University School of Medicine, Atlanta, Georgia
- Aflac Cancer and Blood Disorders Center of Children’s Healthcare of Atlanta, Atlanta, Georgia
| | - George Loewenstein
- Department of Social and Decision Sciences, Carnegie Mellon University, Pittsburgh, Pennsylvania
| | - Lakshmanan Krishnamurti
- Department of Pediatrics, Division of Hematology-Oncology-BMT, Emory University School of Medicine, Atlanta, Georgia
- Aflac Cancer and Blood Disorders Center of Children’s Healthcare of Atlanta, Atlanta, Georgia
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8
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Hawkins LM, Sinha CB, Ross D, Yee MEM, Quarmyne MO, Krishnamurti L, Bakshi N. Patient and family experience with chronic transfusion therapy for sickle cell disease: A qualitative study. BMC Pediatr 2020; 20:172. [PMID: 32305060 PMCID: PMC7165370 DOI: 10.1186/s12887-020-02078-w] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/22/2019] [Accepted: 04/07/2020] [Indexed: 11/25/2022] Open
Abstract
Background There is a limited understanding of the patient and family experience of Chronic Transfusion Therapy (CTT) for prevention of complications of Sickle Cell Disease (SCD). We sought to understand patient and family experience with CTT using qualitative methods. Methods Fifteen parents of children < 18 years old and nine children 12–18 years old with SCD who were receiving CTT for > 1 year were interviewed using a semi-structured interview format, and interviews were analyzed using open coding methods. Results Four themes created a narrative of the patient and family experience of CTT: 1) Burden of CTT, 2) Coping with CTT, 3) Perceived benefits and risks of CTT, and 4) Decision making regarding CTT. Participants reported substantial burden of CTT, including the impact of CTT on daily life and family, distress about venous access, burden of chelation therapy, and anxiety about CTT complications. Participants described how they coped with CTT. Participants reported increased energy, decreased pain, fewer hospitalizations, and stroke prevention with CTT, but also recognized complications of CTT, though awareness was limited in adolescents. Parents described sharing in the informed decision-making process with their healthcare provider about CTT, but adolescent patient participants reported that they were not involved in this process. Conclusions CTT is associated with significant patient and family burden. Support from family, healthcare providers and school may help individuals cope with some of this burden. These findings provide the basis for future studies to identify strategies to mitigate the burden of CTT and improve the patient experience with this therapy. Future studies should also systematically assess patient knowledge about the key components of CTT and chelation using quantitative assessments.
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Affiliation(s)
| | - Cynthia B Sinha
- Division of Pediatric Hematology-Oncology-BMT, Emory University School of Medicine, Atlanta, GA, USA
| | - Diana Ross
- Division of Pediatric Hematology-Oncology-BMT, Emory University School of Medicine, Atlanta, GA, USA
| | - Marianne E M Yee
- Division of Pediatric Hematology-Oncology-BMT, Emory University School of Medicine, Atlanta, GA, USA.,Aflac Cancer and Blood Disorders, Children's Healthcare of Atlanta, Atlanta, GA, USA
| | - Maa-Ohui Quarmyne
- Division of Pediatric Hematology-Oncology-BMT, Emory University School of Medicine, Atlanta, GA, USA.,Aflac Cancer and Blood Disorders, Children's Healthcare of Atlanta, Atlanta, GA, USA
| | - Lakshmanan Krishnamurti
- Division of Pediatric Hematology-Oncology-BMT, Emory University School of Medicine, Atlanta, GA, USA.,Aflac Cancer and Blood Disorders, Children's Healthcare of Atlanta, Atlanta, GA, USA
| | - Nitya Bakshi
- Division of Pediatric Hematology-Oncology-BMT, Emory University School of Medicine, Atlanta, GA, USA. .,Aflac Cancer and Blood Disorders, Children's Healthcare of Atlanta, Atlanta, GA, USA.
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9
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Snyder AB, Zhou M, Theodore R, Quarmyne MO, Eckman J, Lane PA. Improving an Administrative Case Definition for Longitudinal Surveillance of Sickle Cell Disease. Public Health Rep 2019; 134:274-281. [PMID: 30970223 PMCID: PMC6505322 DOI: 10.1177/0033354919839072] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Objective: Several states are building infrastructure and data collection methods for longitudinal, population-based surveillance systems for selected hemoglobinopathies. The objective of our study was to improve an administrative case definition for sickle cell disease (SCD) to aid in longitudinal surveillance. Methods: We collected data from 3 administrative data sets (2004-2008) on 1998 patients aged 0-21 in Georgia who had ≥1 encounter in which an SCD International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM) code was recorded, and we compared these data with data from a laboratory and medical record review. We assessed performance (sensitivity, specificity, positive predictive value [PPV], and negative predictive value [NPV]) of case definitions that differed by number and type of SCD-coded encounters; addition of SCD-associated treatments, procedures, and complications; and length of surveillance (1 vs 5 years). We identified correct diagnoses for patients who were incorrectly coded as having SCD. Results: The SCD case definition of ≥3 SCD-coded encounters in 5 years simplified and substantially improved the sensitivity (96.0% vs 85.8%) and NPV (68.2% vs 38.2%) of the original administrative case definition developed for 5-year, state-based surveillance (≥2 encounters in 5 years and ≥1 encounter for an SCD-related treatment, procedure, or complication), while maintaining a similar PPV (97.4% vs 97.4%) and specificity (76.5% vs 79.0%). Conclusions: This study supports an administrative case definition that specifies ≥3 ICD-9-CM–coded encounters to identify SCD with a high degree of accuracy in pediatric patients. This case definition can be used to help establish longitudinal SCD surveillance systems.
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Affiliation(s)
- Angela B Snyder
- 1 Georgia Health Policy Center, Andrew Young School of Policy Studies, Georgia State University, Atlanta, GA, USA
| | - Mei Zhou
- 1 Georgia Health Policy Center, Andrew Young School of Policy Studies, Georgia State University, Atlanta, GA, USA
| | - Rodney Theodore
- 1 Georgia Health Policy Center, Andrew Young School of Policy Studies, Georgia State University, Atlanta, GA, USA
| | - Maa-Ohui Quarmyne
- 3 Emory University School of Medicine & Sickle Cell Disease Program, Children's Healthcare of Atlanta, Atlanta, GA, USA
| | - James Eckman
- 4 Departments of Hematology & Oncology, Emory University School of Medicine, Atlanta, GA, USA
| | - Peter A Lane
- 3 Emory University School of Medicine & Sickle Cell Disease Program, Children's Healthcare of Atlanta, Atlanta, GA, USA
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10
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Chonat S, Quarmyne MO, Bennett CM, Dean CL, Joiner CH, Fasano RM, Stowell SR. Contribution of alternative complement pathway to delayed hemolytic transfusion reaction in sickle cell disease. Haematologica 2018; 103:e483-e485. [PMID: 29794144 DOI: 10.3324/haematol.2018.194670] [Citation(s) in RCA: 52] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Affiliation(s)
- Satheesh Chonat
- Department of Pediatrics, Emory University School of Medicine, Atlanta, GA, USA .,Aflac Cancer and Blood Disorders Center, Children's Healthcare of Atlanta, Atlanta, GA, USA
| | - Maa-Ohui Quarmyne
- Department of Pediatrics, Emory University School of Medicine, Atlanta, GA, USA.,Aflac Cancer and Blood Disorders Center, Children's Healthcare of Atlanta, Atlanta, GA, USA
| | - Caroline M Bennett
- Department of Pediatrics, Emory University School of Medicine, Atlanta, GA, USA.,Aflac Cancer and Blood Disorders Center, Children's Healthcare of Atlanta, Atlanta, GA, USA
| | - Christina L Dean
- Center for Transfusion and Cellular Therapy, Department of Pathology and Laboratory Medicine, Emory University School of Medicine, Atlanta, GA, USA
| | - Clinton H Joiner
- Department of Pediatrics, Emory University School of Medicine, Atlanta, GA, USA.,Aflac Cancer and Blood Disorders Center, Children's Healthcare of Atlanta, Atlanta, GA, USA
| | - Ross M Fasano
- Aflac Cancer and Blood Disorders Center, Children's Healthcare of Atlanta, Atlanta, GA, USA.,Center for Transfusion and Cellular Therapy, Department of Pathology and Laboratory Medicine, Emory University School of Medicine, Atlanta, GA, USA
| | - Sean R Stowell
- Center for Transfusion and Cellular Therapy, Department of Pathology and Laboratory Medicine, Emory University School of Medicine, Atlanta, GA, USA
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11
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Quarmyne MO, Dong W, Theodore R, Anand S, Barry V, Adisa O, Buchanan ID, Bost J, Brown RC, Joiner CH, Lane PA. Hydroxyurea effectiveness in children and adolescents with sickle cell anemia: A large retrospective, population-based cohort. Am J Hematol 2017; 92:77-81. [PMID: 27761932 DOI: 10.1002/ajh.24587] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2016] [Revised: 10/14/2016] [Accepted: 10/17/2016] [Indexed: 11/11/2022]
Abstract
The clinical efficacy of hydroxyurea in patients with sickle cell anemia (SCA) has been well established. However, data about its clinical effectiveness in practice is limited. We evaluated the clinical effectiveness of hydroxyurea in a large pediatric population using a retrospective cohort, pre-post treatment study design to control for disease severity selection bias. The cohort included children with SCA (SS, Sβ0 thalassemia) who received care at Children's Healthcare of Atlanta (CHOA) and who initiated hydroxyurea in 2009-2011. Children on chronic transfusions, or children with inadequate follow up data and/or children who had taken hydroxyurea in the 3 years prior were excluded. For each patient healthcare utilization, laboratory values, and clinical outcomes for the 2-year period prior to hydroxyurea initiation were compared to those 2 years after initiation. Of 211 children with SCA who initiated hydroxyurea in 2009-2011, 134 met eligibility criteria. After initiation of hydroxyurea, rates of hospitalizations, pain encounters, and emergency department visits were reduced by 47% (<0.0001), 36% (P = 0.0001) and 43% (P < 0.0001), respectively. Average hemoglobin levels increased by 0.7 g/dl (P < 0.0001). Hydroxyurea effectiveness was similar across gender, insurance types and age, although there was a slightly greater reduction in hospitalizations in younger children. Am. J. Hematol. 92:77-81, 2017. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- Maa-Ohui Quarmyne
- Aflac Cancer and Blood Disorders Center; Children's Healthcare of Atlanta; Atlanta Georgia
- Department of Pediatrics; Emory University School of Medicine; Atlanta Georgia
| | - Wei Dong
- Connance, Inc; Waltham Massachusetts
| | - Rodney Theodore
- Aflac Cancer and Blood Disorders Center; Children's Healthcare of Atlanta; Atlanta Georgia
| | - Sonia Anand
- Aflac Cancer and Blood Disorders Center; Children's Healthcare of Atlanta; Atlanta Georgia
| | - Vaughn Barry
- Department of Pediatrics; Emory University School of Medicine; Atlanta Georgia
| | - Olufolake Adisa
- Aflac Cancer and Blood Disorders Center; Children's Healthcare of Atlanta; Atlanta Georgia
- Department of Pediatrics; Emory University School of Medicine; Atlanta Georgia
| | - Iris D. Buchanan
- Aflac Cancer and Blood Disorders Center; Children's Healthcare of Atlanta; Atlanta Georgia
- Department of Pediatrics, Morehouse School of Medicine; Atlanta Georgia
| | - James Bost
- Outcomes Center; Children's Healthcare of Atlanta; Atlanta Georgia
| | - Robert C. Brown
- Aflac Cancer and Blood Disorders Center; Children's Healthcare of Atlanta; Atlanta Georgia
- Department of Pediatrics; Emory University School of Medicine; Atlanta Georgia
| | - Clinton H. Joiner
- Aflac Cancer and Blood Disorders Center; Children's Healthcare of Atlanta; Atlanta Georgia
- Department of Pediatrics; Emory University School of Medicine; Atlanta Georgia
| | - Peter A. Lane
- Aflac Cancer and Blood Disorders Center; Children's Healthcare of Atlanta; Atlanta Georgia
- Department of Pediatrics; Emory University School of Medicine; Atlanta Georgia
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12
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Niss O, Chonat S, Dagaonkar N, Almansoori MO, Kerr K, Rogers ZR, McGann PT, Quarmyne MO, Risinger M, Zhang K, Kalfa TA. Genotype-phenotype correlations in hereditary elliptocytosis and hereditary pyropoikilocytosis. Blood Cells Mol Dis 2016; 61:4-9. [PMID: 27667160 DOI: 10.1016/j.bcmd.2016.07.003] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2016] [Revised: 07/15/2016] [Accepted: 07/15/2016] [Indexed: 10/21/2022]
Abstract
Hereditary elliptocytosis (HE) and hereditary pyropoikilocytosis (HPP) are heterogeneous red blood cell (RBC) membrane disorders that result from mutations in the genes encoding α-spectrin (SPTA1), β-spectrin (SPTB), or protein 4.1R (EPB41). The resulting defects alter the horizontal cytoskeletal associations and affect RBC membrane stability and deformability causing shortened RBC survival. The clinical diagnosis of HE and HPP relies on identifying characteristic RBC morphology on peripheral blood smear and specific membrane biomechanical properties using osmotic gradient ektacytometry. However, this phenotypic diagnosis may not be readily available in patients requiring frequent transfusions, and does not predict disease course or severity. Using Next-Generation sequencing, we identified the causative genetic mutations in fifteen patients with clinically suspected HE or HPP and correlated the identified mutations with the clinical phenotype and ektacytometry profile. In addition to identifying three novel mutations, gene sequencing confirmed and, when the RBC morphology was not evaluable, identified the diagnosis. Moreover, genotypic differences justified the phenotypic differences within families with HE/HPP.
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Affiliation(s)
- Omar Niss
- Division of Hematology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA.
| | - Satheesh Chonat
- Emory University School of Medicine, Aflac Cancer and Blood Disorders Center, Children's Healthcare of Atlanta, Atlanta, GA, USA
| | - Neha Dagaonkar
- Division of Human Genetics, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA
| | | | - Karol Kerr
- SUNY Upstate Medical University, Syracuse, NY, USA
| | - Zora R Rogers
- Department of Pediatrics, The University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Patrick T McGann
- Division of Hematology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA
| | - Maa-Ohui Quarmyne
- Emory University School of Medicine, Aflac Cancer and Blood Disorders Center, Children's Healthcare of Atlanta, Atlanta, GA, USA
| | - Mary Risinger
- College of Nursing, University of Cincinnati, Cincinnati, OH, USA
| | - Kejian Zhang
- Division of Human Genetics, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA
| | - Theodosia A Kalfa
- Division of Hematology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA
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13
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Affiliation(s)
- Maa-Ohui Quarmyne
- Cancer and Blood Diseases Institute, Cincinnati Children's Hospital Medical Center, Cincinnati, OH
| | - Anita Gupta
- Cincinnati Children's Hospital Medical Center, Cincinnati, OH
| | - Denise M. Adams
- Cancer and Blood Diseases Institute, Cincinnati Children's Hospital Medical Center, Cincinnati, OH
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14
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Quarmyne MO, Risinger M, Linkugel A, Frazier A, Joiner C. Volume regulation and KCl cotransport in reticulocyte populations of sickle and normal red blood cells. Blood Cells Mol Dis 2011; 47:95-9. [PMID: 21576026 PMCID: PMC3406737 DOI: 10.1016/j.bcmd.2011.04.007] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2011] [Accepted: 04/07/2011] [Indexed: 11/25/2022]
Abstract
The potassium chloride co-transporter (KCC) is a member of the electroneutral cation chloride family of cotransporters found in multiple tissues that are involved in transepithelial ion transport and regulation of intracellular ion content and cell volume. We have shown previously that three of the four KCC genes - KCC1, KCC3, and KCC4 - are expressed in red blood cells (RBC) (Exp. Hem. 33:624, 2005). Functionally, the KCC mediates volume reduction of reticulocytes that establishes the higher cellular hemoglobin concentration (CHC) of mature RBC. KCC activity is higher in reticulocytes and diminishes with age. KCC activity in RBC containing sickle hemoglobin (SS RBC) is elevated compared to normal (AA RBC) in part due to reticulocytosis in SS blood. However, we have demonstrated that SS reticulocytes have abnormal regulation of KCC activity leading to increased CHC upon activation of KCC compared to AA reticulocytes (Blood 104:2954, 2004; Blood 109:1734, 2007). These findings implicate KCC as a factor in the dehydration of SS RBC, which leads to elevated Hb S concentration and enhances Hb S polymerization and hemolysis. Because KCC activity correlates with cell age, standard flux measurements on blood samples with different numbers of reticulocytes or young non-reticulocytes are not comparable. The Advia automated cell counter measures cell volume (MCV) and cellular hemoglobin concentration (CHC) in reticulocytes, an age-defined population of cells, and thus circumvents the problem of variable reticulocyte counts among SS and AA blood samples. In this study, reticulocyte CHC measurements on fresh blood demonstrated a clear difference between AA and SS cells, reflecting in vivo dehydration of SS reticulocytes, although there was significant inter-individual variation, and the CHC distributions of the two groups overlapped. After KCC activation in vitro by cell swelling using the nystatin method, the initial changes in reticulocyte MCV and CHC with time were used to estimate flux rates mediated by KCC, assuming that changes were associated with isotonic KCl movements. After 20-30min a final steady state MCV/CHC (set point) was achieved and maintained, reflecting inactivation of the transporter. CHC set points were 26.5-29g/dl in SS reticulocytes compared to 25-26.5g/dl in AA reticulocytes, reflecting abnormal regulation in SS cells. These results were reproducible in the same individual over time. KCC flux derived from CHC ranged from 5 to 10.3mmolK/kgHb/min in SS reticulocytes, compared to 2.9-7.2mmolK/kgHb/min in AA reticulocytes. Such measures of KCC activity in red cell populations controlled for cell age will facilitate further studies correlating KCC activity with phenotypic or genetic variability in sickle cell disease.
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Affiliation(s)
- Maa-Ohui Quarmyne
- Division of Hematology, Cancer and Blood Diseases Institute, Cincinnati Children's Hospital Medical Center
| | - Mary Risinger
- Division of Hematology, Cancer and Blood Diseases Institute, Cincinnati Children's Hospital Medical Center
| | - Andrew Linkugel
- Division of Hematology, Cancer and Blood Diseases Institute, Cincinnati Children's Hospital Medical Center
| | - Anna Frazier
- Division of Hematology, Cancer and Blood Diseases Institute, Cincinnati Children's Hospital Medical Center
| | - Clinton Joiner
- Division of Hematology, Cancer and Blood Diseases Institute, Cincinnati Children's Hospital Medical Center
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