ABSTRACT
While clinical benefits of iron chelation therapy (ICT) in red blood cell transfusion dependent (RBC TD) hereditary anemias such as beta-thalassemia major are incontrovertible, the evidence supporting a similar benefit in patients with TD myelodysplastic neoplasms (MDS) and iron overload (IOL) is sometimes debated. MDS presents later in life, has a limited repertoire of life extending therapies, and patients may have comorbidities acting as competing causes of death. However, refined prognostication identifies MDS patients with a reasonable life expectancy, and since 50% of patients will ultimately become RBC transfusion dependent and develop transfusional iron overload (IOL), iron chelation therapy (ICT) should be considered in some. Using illustrative cases, we summarize mechanisms of iron toxicity, strategies for the identification of IOL and propose definitions of IOL severity. We provide rationale for and recommend which patients may benefit from ICT. We discuss currently available chelators, their administration, monitoring, side effects and their management. Given challenges with the use of iron chelators, we suggest the nuances to be considered when planning chelation initiation include the rate of iron accumulation, the presence of organ iron and/or dysfunction, and detectable indicators of oxidative stress. Areas for future investigation are identified.
ABSTRACT
Iron overload (IO) reflected by elevated ferritin is associated with increased mortality in myelodysplastic syndromes (MDS), however, ferritin is an imperfect metric. Elevated labile plasma iron correlates with clinical outcomes and transferrin saturation (TSAT) >80%, but is not readily measurable. The trajectory of TSAT, and its association with clinical outcomes remain undefined. Canadian MDS registry patients were evaluated. Mean TSAT, mean ferritin and transfusion dose density (TDD) were determined. Survival was evaluated by TSAT and ferritin (<50%, 50-80%, >80%), (≤500 µg/L, 501-800 µg/L, >800 µg/L). In 718 patients, median age was 74 years; 12%, 31%, 29%, 15% and 13% were IPSS-R very low, low, intermediate, high and very high. TSAT and ferritin were moderately correlated (r=0.63, P<0.0001). TSAT increased over time in transfusion- dependent patients (P=0.006). Higher TSAT and ferritin were associated with inferior 5-year overall (OS), progression- free (PFS), and leukemia-free survival (LFS) (P≤0.008) and higher TDD with inferior 5-year OS. TSAT >80% trended with inferior cardiac death-free survival (P=0.053). In univariate analysis, age, IPSS-R, blast percentage by Eastern Cooperative Oncology Group Performance Status, frailty, Charlson Comorbidity Index, iron chelation (Y/N), TDD, TSAT and ferritin were significantly associated with inferior OS. By multivariable analysis, TSAT >80% (P=0.007) remained significant for OS (R2 30.3%). In MDS, TSAT >80% and ferritin >800 µg/L portended inferior OS, PFS and LFS. TSAT may indicate the presence of oxidative stress, and is readily measurable in a clinical setting. The relationship between TSAT and cardiac death-free survival warrants further study.
Subject(s)
Iron , Myelodysplastic Syndromes , Humans , Aged , Canada , Ferritins , Myelodysplastic Syndromes/diagnosis , Myelodysplastic Syndromes/therapy , Transferrins , TransferrinABSTRACT
Myeloid and erythroid precursor vacuolation is a common dysplastic finding associated with myeloid malignancies, toxins, drug, and nutritional deficiencies. It has been described as a core morphologic feature in VEXAS (vacuoles, E1 enzyme, X-linked, autoinflammatory, somatic) syndrome. We sought to determine the number of cases attributable to VEXAS syndrome in bone marrow biopsies and aspirates (BAMB) reporting myeloid precursor vacuolation. We reviewed 1318 individual BAMB reports from January 2020 to July 2021 where "vacuole(s)," "vacuolation," or "vacuolated" was reported. Bone marrow biopsies with vacuolation confined to blasts or those completed as routine workup prior to stem cell transplant or post induction chemotherapy for AML (acute myeloid leukemia) were excluded. Myeloid and erythroid precursor vacuolation was noted in 219 reports representing 210 patients. The most common etiology was myelodysplastic syndrome (MDS) (38.6%), AML (16.7%), lymphoproliferative disorders and multiple myeloma (7.6%), drug or toxin exposure (5.2%) myeloproliferative neoplasm (MPN) or MPN/MDS overlap syndrome (4.3%). VEXAS syndrome was determined to be the etiology in 2.9% of patients. Two additional cases of VEXAS syndrome with bone marrow biopsies reported in the specified time frame did not explicitly report myeloid or erythroid precursor vacuolation but were identified based on clinical suspicion and repeat BAMB review. Myeloid and erythroid precursor vacuolation is a dysplastic feature attributable to VEXAS syndrome in at least 2.9% of cases. Standardized reporting of vacuolization, triaging of molecular sequencing and optimal treatment of this disorder are critical issues facing those seeing patients with suspected VEXAS syndrome.
Subject(s)
Leukemia, Myeloid, Acute , Myelodysplastic Syndromes , Myeloproliferative Disorders , Humans , Bone Marrow/pathology , Myelodysplastic Syndromes/pathology , Myeloproliferative Disorders/diagnosis , Myeloproliferative Disorders/etiology , Myeloproliferative Disorders/pathology , Leukemia, Myeloid, Acute/pathology , BiopsyABSTRACT
The incorporation of patient-reported outcomes with traditional disease risk classification was found to strengthen survival prediction in patients with myelodysplastic syndromes (MDS). In the present Canadian MDS registry analysis, we validate a recently reported prognostic model, the Fatigue-International Prognostic Scoring System among higher-risk patients [FA-IPSS(h)], which incorporates patients' reported fatigue, assessed by the European Organization for Research and Treatment of Cancer (EORTC) Quality of Life-Core 30 (QLQ-C30), with a threshold of ≥45 points, in higher IPSS score, stratifying them into distinct subgroups with different survival outcomes. We further validated this concept, using the Revised IPSS >3·5 as cut-off for the definition of higher-risk MDS, and patients' reported fatigue according to Edmonton Symptom Self-Assessment Scale (ESAS) Global Fatigue Scale (GFS), a single-item fatigue rating scale, which is easier to deploy. This emphasises the power of self-reported fatigue at refining overall survival predictions in higher-risk MDS and further bolsters the importance of considering patient-related outcomes in global assessments.
Subject(s)
Fatigue/complications , Myelodysplastic Syndromes/complications , Adult , Aged , Aged, 80 and over , Canada/epidemiology , Fatigue/diagnosis , Fatigue/epidemiology , Female , Humans , Male , Middle Aged , Myelodysplastic Syndromes/diagnosis , Myelodysplastic Syndromes/epidemiology , Patient Reported Outcome Measures , Prognosis , Quality of Life , RegistriesSubject(s)
CTLA-4 Antigen/genetics , Molecular Targeted Therapy , Purpura, Thrombocytopenic, Idiopathic/drug therapy , Purpura, Thrombocytopenic, Idiopathic/etiology , CTLA-4 Antigen/metabolism , Humans , Immune Checkpoint Inhibitors/therapeutic use , Male , Molecular Targeted Therapy/methods , Protein Kinase Inhibitors/pharmacology , Protein Kinase Inhibitors/therapeutic use , Purpura, Thrombocytopenic, Idiopathic/diagnosis , Treatment Outcome , Young AdultABSTRACT
Analyses suggest iron overload in red blood cell (RBC) transfusion-dependent (TD) patients with myleodysplastic syndrome (MDS) portends inferior overall survival (OS) that is attenuated by iron chelation therapy (ICT) but may be biassed by unbalanced patient-related factors. The Canadian MDS Registry prospectively measures frailty, comorbidity and disability. We analysed OS by receipt of ICT, adjusting for these patient-related factors. TD International Prognostic Scoring System (IPSS) low and intermediate-1 risk MDS, at RBC TD, were included. Predictive factors for OS were determined. A matched pair analysis considering age, revised IPSS, TD severity, time from MDS diagnosis to TD, and receipt of disease-modifying agents was conducted. Of 239 patients, 83 received ICT; frailty, comorbidity and disability did not differ from non-ICT patients. Median OS from TD was superior in ICT patients (5·2 vs. 2·1 years; P < 0·0001). By multivariate analysis, not receiving ICT independently predicted inferior OS, (hazard ratio for death 2·0, P = 0·03). In matched pair analysis, OS remained superior for ICT patients (P = 0·02). In this prospective, non-randomized analysis, receiving ICT was associated with superior OS in lower IPSS risk MDS, adjusting for age, frailty, comorbidity, disability, revised IPSS, TD severity, time to TD and receiving disease-modifying agents. This provides additional evidence that ICT may confer clinical benefit.
Subject(s)
Erythrocyte Transfusion/adverse effects , Iron Chelating Agents/therapeutic use , Iron Overload/drug therapy , Myelodysplastic Syndromes/mortality , Aged , Aged, 80 and over , Canada/epidemiology , Cause of Death , Chelation Therapy , Comorbidity , Female , Hematopoietic Stem Cell Transplantation , Humans , Iron Overload/blood , Iron Overload/epidemiology , Iron Overload/etiology , Male , Middle Aged , Myelodysplastic Syndromes/complications , Myelodysplastic Syndromes/epidemiology , Myelodysplastic Syndromes/therapy , Prognosis , Registries , Risk , Survival Analysis , Transplantation, HomologousABSTRACT
Prediction of response to erythropoietin stimulating agents (ESAs) in anemic MDS patients is often based on the Nordic score. We wished to validate the Nordic score (IWG 2006 response criteria) in a larger cohort and determine if other variables such as IPSS/IPSS-R, ferritin, LDH, and a novel European ESA response score (Santini 2013) were of prognostic importance. We analyzed 208 ESA-treated MDS patients (WHO 2008 criteria) from a prospective registry. Ninety-four and 93% had lower risk scores by IPSS (low/int - 1) and IPSS-R (low/very low), respectively. Erythroid response was achieved in 94 patients (47%); responses were similar with erythropoietin (50%) and darbepoetin (39%; p = 0.2). The Nordic and European scores were both validated on univariate analysis. Variables independently predictive of response in multivariate analysis were low-risk IPSS score (OR 0.1, p = 0.0016) and serum EPO level < 100 mIU/mL (OR 8.7, p < 0.0001). We propose a new ESA response score, consisting of (a) IPSS low score (1 point) and (b) serum EPO levels < 100 mIU/ml (2 points), yielding scores ranging from 0 to 3, with response rates varying from 17 to 81%. The Nordic score has validity but we observed lower than the expected response rates in the best risk group. Our proposed scoring system appears more discriminating but needs validation.
Subject(s)
Erythropoietin/blood , Hematinics/administration & dosage , Models, Biological , Myelodysplastic Syndromes , Registries , Canada , Female , Ferritins/blood , Humans , Infant , Infant, Newborn , L-Lactate Dehydrogenase/blood , Male , Myelodysplastic Syndromes/blood , Myelodysplastic Syndromes/drug therapy , Myelodysplastic Syndromes/mortality , Prospective StudiesABSTRACT
UNLABELLED: Little is known about the effects of frailty, disability and physical functioning on the clinical outcomes for myelodysplastic syndromes (MDS). We investigated the predictive value of these factors on overall survival (OS) in 445 consecutive patients with MDS and chronic monomyelocytic leukaemia (CMML) enrolled in a multi-centre prospective national registry. Frailty, comorbidity, instrumental activities of daily living, disability, quality of life, fatigue and physical performance measures were evaluated at baseline and were added as covariates to conventional MDS-related factors as predictors of OS in Cox proportional hazards models. The median age was 73 years, and 79% had revised International Prognostic Scoring System (IPSS-R) risk scores of intermediate or lower. Frailty correlated only modestly with comorbidity. OS was significantly shorter for patients with higher frailty and comorbidity scores, any disability, impaired grip strength and timed chair stand tests. By multivariate analysis, the age-adjusted IPSS-R, frailty (Hazard ratio 2·7 (95% confidence interval [CI] 1·7-4·2), P < 0·0001) and Charlson comorbidity score (Hazard ratio 1·8 (95% CI 1·1-2·8), P = 0·01) were independently prognostic of OS. Incorporation of frailty and comorbidity scores improved risk stratification of the IPSS-R by 30% and 5%, respectively. These data demonstrate for the first time, the importance of considering frailty in prognostic models and a potential target for therapeutic intervention in optimizing clinical outcomes in older MDS patients. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT02537990.
Subject(s)
Myelodysplastic Syndromes/mortality , Activities of Daily Living , Aged , Comorbidity , Female , Frail Elderly , Humans , Leukemia, Myelomonocytic, Chronic/mortality , Male , Prospective Studies , Quality of Life , Registries , Risk Factors , Survival RateABSTRACT
Iron overload (IOL) portends inferior outcome in myelodysplastic syndromes (MDS). Erythropoiesis-stimulating agents (ESA) may reduce red blood cell transfusion requirements. MDS patients receiving ESA were reviewed for characteristics, response to ESA by International Working Group 2006 criteria and ferritin levels. Forty-nine patients received an ESA, had ferritin levels available, and were not receiving iron chelation therapy. Baseline characteristics were not significantly different between ESA responders (ER) and non-responders (ENR; P = NS). The median ESA treatment duration was 6.7 (1.5-85.9) months. Twenty-one (43 %) patients had an ESA response. Median ferritin level in ER was pre-ESA, 473 (range 91-2727) and post-ESA, 801 (130-11,164) ng/mL (P = 0.01), and in ENR pre-ESA, 672 (76-3285) and post-ESA, 1423 (431-6593) ng/mL (P < 0.0001). There was a significant association between ESA response, post-ESA hemoglobin ≥100 g/L, and post-ESA ferritin <1000 ng/mL (P = 0.0003 and 0.03, respectively). At a median follow-up of 28 months, the 2-year overall survival for ER and ENR, respectively, were 80 % and 86 % (P = NS). In lower-risk MDS patients responding to ESA, although an expected decrease in ferritin levels over treatment was not seen, ferritin levels increased less than in non-responders. Whether IOL may be reduced by ESA over a longer treatment duration may require analysis of larger numbers of patients.
Subject(s)
Hematinics/therapeutic use , Iron Overload/diagnosis , Iron Overload/drug therapy , Myelodysplastic Syndromes/diagnosis , Myelodysplastic Syndromes/drug therapy , Aged , Erythropoiesis/drug effects , Erythropoiesis/physiology , Female , Follow-Up Studies , Hematinics/pharmacology , Humans , Iron Chelating Agents/pharmacology , Iron Chelating Agents/therapeutic use , Iron Overload/epidemiology , Male , Middle Aged , Myelodysplastic Syndromes/epidemiology , Retrospective Studies , Risk FactorsABSTRACT
Castleman's disease (CD) is a rare lymphoproliferative disorder that is most commonly present in multicentric (MCD) form in association with HIV infection. Interleukin-6 (IL-6) and human herpesvirus-8 (HHV-8) play major roles in MCD pathogenesis. Important treatment options have recently become available, particularly with the introduction of IL-6 and IL-6 receptor inhibitors for the treatment of HIV-negative patients with MCD. Though advances in therapy may improve outcomes in some patients, the prognosis remains guarded, and a stratified approach to the management of MCD is needed.
Subject(s)
Castleman Disease , HIV Infections , Herpesvirus 8, Human , Humans , Interleukin-6 , PrognosisABSTRACT
BACKGROUND: The prevalence of physician burnout increased notably during the COVID-19 pandemic, but whether measures of burnout differed based on physician specialty is unknown. The authors sought to determine the prevalence of burnout, worklife conflict, and intention to quit among physicians from different specialties. METHODS: This is a cross-sectional online survey of physicians working at 2 urban hospitals in Vancouver, Canada, from August to October 2021. Responses were categorized by specialty (including surgical and nonsurgical), and data about whether physicians provided frontline patient care during COVID-19 were also included. Physician burnout was measured using the Maslach Burnout Inventory. RESULTS: The survey response rate was 42% (209/498). The overall prevalence of burnout was 69%. Burnout was not significantly different by specialty or between frontline COVID-19 specialties compared with other specialties. Physicians in surgical specialties were more likely to report work-life conflict than those in nonsurgical specialties (p = 0.012). Differences in intention to quit among specialties were not statistically significant. CONCLUSION: During the COVID-19 pandemic, physician burnout was high across physicians, without significant differences between specialties, highlighting the need to support all physicians.
Subject(s)
Burnout, Professional , COVID-19 , Physicians , Humans , Burnout, Professional/epidemiology , Burnout, Professional/psychology , Cross-Sectional Studies , COVID-19/psychology , COVID-19/epidemiology , Male , Female , Physicians/psychology , Physicians/statistics & numerical data , Adult , Surveys and Questionnaires , Middle Aged , Prevalence , SARS-CoV-2 , Work-Life Balance , British Columbia/epidemiologyABSTRACT
Many patients with lower-risk myelodysplastic syndromes (LR MDS) require long-term red blood cell (RBC) transfusions to manage anemia. The consequences of RBC transfusions in LR MDS with ring sideroblasts (LR MDS-RS) are not well known. We estimated the association between cumulative RBC dose density and clinical and patient-reported outcomes using data from the MDS-CAN registry for patients enrolled between January 2008 and December 2018. Outcomes included overall survival, hospitalization, and health-related quality of life (HRQoL). A total of 145 enrolled patients with LR MDS and RS ≥5% had a median follow-up time of 27.1 months; 45 had no transfusions during follow-up, 51 had <1 transfusion per month, and 49 had ≥1 transfusion per month. The cumulative density of RBC transfusions was associated with significantly greater mortality, hospitalization, and inferior HRQoL, suggesting that exposure to RBC transfusion may constitute a significant treatment burden in patients with LR MDS-RS.
Subject(s)
Erythrocyte Transfusion , Myelodysplastic Syndromes , Humans , Erythrocyte Transfusion/adverse effects , Myelodysplastic Syndromes/drug therapy , Quality of Life , Prospective Studies , RegistriesABSTRACT
Splicing factor (SF) gene mutations are frequent in myelodysplastic syndromes (MDS), and agents that modulate RNA splicing are hypothesized to provide clinical benefit. JNJ-64619178, a protein arginine methyltransferase 5 (PRMT5) inhibitor, was evaluated in patients with lower-risk (LR) MDS in a multi-part, Phase 1, multicenter study. The objectives were to determine a tolerable dose and to characterize safety, pharmacokinetics, pharmacodynamics, and preliminary clinical activity. JNJ-64619178 was administered on a 14 days on/7 days off schedule or every day on a 21-day cycle to patients with International Prognostic Scoring System (IPSS) Low or Intermediate-1 risk MDS who were red blood cell transfusion-dependent. Twenty-four patients were enrolled; 15 (62.5 %) patients had low IPSS risk score, while 18 (75.0 %) had an SF3B1 mutation. Median duration of treatment was 3.45 months (range: 0.03-6.93). No dose limiting toxicities were observed. The 0.5 mg once daily dose was considered better tolerated and chosen for dose expansion. Twenty-three (95.8 %) patients experienced treatment-emergent adverse events (TEAE). The most common TEAEs were neutropenia (15 [62.5 %]) and thrombocytopenia (14 [58.3 %]). JNJ-64619178 pharmacokinetics was dose-dependent. Target engagement as measured by plasma symmetric di-methylarginine was observed across all dose levels; however, variant allele frequency of clonal mutations in bone marrow or blood did not show sustained reductions from baseline. No patient achieved objective response or hematologic improvement per International Working Group 2006 criteria, or transfusion independence. A tolerable dose of JNJ-64619178 was identified in patients with LR MDS. However, no evidence of clinical benefit was observed.
Subject(s)
Anemia , Myelodysplastic Syndromes , Humans , Protein-Arginine N-Methyltransferases/genetics , Protein-Arginine N-Methyltransferases/therapeutic use , Myelodysplastic Syndromes/drug therapy , Myelodysplastic Syndromes/genetics , Anemia/drug therapy , Bone Marrow , Treatment OutcomeABSTRACT
Myelodysplastic syndromes (MDS) are a heterogeneous group of hematopoietic stem cell disorders characterized by ineffective hematopoiesis with abnormal blood cell development (dysplasia) leading to cytopenias and an increased risk for progression to acute myeloid leukemia (AML). Patients with MDS can generally be classified as lower- (LR-MDS) or higher-risk (HR-MDS). As treatment goals for patients with LR-MDS and those with HR-MDS differ significantly, appropriate diagnosis, classification, and follow-up are critical for correct disease management. In this review, we focus on the diagnosis, prognosis, and treatment options, as well as the prediction of the disease course and monitoring of treatment response in patients with LR-MDS. We discuss how next-generation sequencing, increasing knowledge on mechanisms of MDS pathogenesis, and novel therapies may change the current treatment landscape in LR-MDS and why structured assessments of responses, toxicities, and patient-reported outcomes should be incorporated into routine clinical practice.
Subject(s)
Anemia , Leukemia, Myeloid, Acute , Myelodysplastic Syndromes , Humans , Myelodysplastic Syndromes/therapy , Myelodysplastic Syndromes/drug therapy , PrognosisABSTRACT
Acute myeloid leukemia (AML) is a hematological malignancy that predominantly affects the elderly. Prognosis declines with age. For those who cannot tolerate intensive chemotherapy, historically established treatment options have been hypomethylating agents (HMAs), low dose cytarabine (LDAC), and best supportive care (BSC). As the standard of care evolves for those unfit for intensive chemotherapy, there is a need to understand established treatment pathways, clinical outcomes and healthcare resource utilization in Canada. The CURRENT study was a retrospective chart review of AML patients not eligible for intensive chemotherapy who initiated first-line treatment between 1 January 2015 and 31 December 2018. Data were collected from 170 Canadian patients treated at six hematology centers, of whom 118 received systemic therapy and 52 received BSC as first-line treatment. Median overall survival was 8.58 months and varied from 2.96 months for BSC to 13.31 months for HMAs. Over 80% of patients had at least one outpatient visit, and 67% of patients receiving systemic therapy and 71% of those receiving BSC had at least one admission to hospital, during their first line of therapy. A total of 96 (81.4%) patients receiving first line systemic therapy and 39 (75.0%) of those receiving first line BSC had at least one red blood cell or platelet transfusion. These findings highlight the unmet need for novel therapies for patients ineligible for intensive chemotherapy.
Subject(s)
Leukemia, Myeloid, Acute , Humans , Aged , Retrospective Studies , Canada , Leukemia, Myeloid, Acute/drug therapy , Cytarabine/therapeutic use , PrognosisABSTRACT
Patients with lower-risk (LR) myelodysplastic syndromes (MDS) with ring sideroblasts (RS) have better prognosis than those without RS, but how they fare over time is not fully understood. This study's objective was to assess the natural history of LR MDS with RS ≥5% using MDS-CAN registry individual data. Kaplan-Meier estimates and generalized linear mixed models were used to describe time-to-event outcomes and continuous outcomes, respectively. One hundred and thirty-eight patients were enrolled; median times from diagnosis to enrollment and follow-up were 6.6 and 39.6 months, respectively. Within 5 years of enrollment, 65% of patients had ≥1 red blood cell transfusion dependence episode. Within 5 years of diagnosis, 59% developed iron overload, 38% received iron chelation therapy, 14% progressed to acute myeloid leukemia, and 42% died. Patients exhibited inferior health-related quality of life trends. These first real-world data in LR MDS-RS in Canada indicate a high level of morbidity and mortality over a 5-year period. Clinical Trial Registration: ClinicalTrials.gov Identifier: NCT02537990.
Subject(s)
Myelodysplastic Syndromes , Humans , Chelation Therapy , Myelodysplastic Syndromes/diagnosis , Myelodysplastic Syndromes/epidemiology , Myelodysplastic Syndromes/therapy , Prognosis , Quality of Life , RegistriesABSTRACT
The myelodysplastic syndromes (MDS) are clonal hematopoietic stem cell disorders. MDS patients often require red blood cell transfusions, resulting in iron overload (IOL). IOL increases production of reactive oxygen species (ROS), oxygen free radicals. We review and illustrate how IOL-induced ROS influence cellular activities relevant to MDS pathophysiology. ROS damage lipids, nucleic acids in mitochondrial and nuclear DNA, structural proteins, transcription factors and enzymes. Cellular consequences include decreased metabolism and tissue and organ dysfunction. In hematopoietic stem cells (HSC), consequences of ROS include decreased glycolysis, shifting the cell from anaerobic to aerobic metabolism and causing HSC to exit the quiescent state, leading to HSC exhaustion or senescence. ROS oxidizes DNA bases, resulting in accumulation of mutations. Membrane oxidation alters fluidity and permeability. In summary, evidence indicates that IOL-induced ROS alters cellular signaling pathways resulting in toxicity to organs and hematopoietic cells, in keeping with adverse clinical outcomes in MDS.
Subject(s)
Iron Overload , Myelodysplastic Syndromes , Erythrocyte Transfusion , Hematopoietic Stem Cells , Humans , Iron Chelating Agents , Iron Overload/etiology , Oxidative StressABSTRACT
Objectives: Reactive oxygen species (ROS) are under scrutiny as a participant in the pathophysiology of myelodysplastic syndrome (MDS) and the progression of MDS to acute myeloid leukemia (AML). Measurement of intracellular ROS (iROS) is particularly important since iROS is a direct indicator of cellular health and integrity.Methods: We developed a technique to measure standardize iROS (siROS) level in lymphocytes and bone marrow (BM) CD34+ hematopoietic progenitors using the fluorescent probe dichlorofluorescein (DCF). We then quantified the siROS in 38 consecutive BM specimens from 27 MDS patients over the course of 10 months. Disease outcome of these patients were also assessed.Results: High serum ferritin, high blast count and poor IPSS were associated with inferior survival and AML progression in this cohort. High blast MDS patients had lower siROS in their BM CD34+ cells than those of low blast patients, consistent with increased reliance on glycolysis and enhanced ROS defense in high blast MDS. We also observed narrower siROS distribution in the BM CD34+ cells of high blast patients, suggesting that loss of heterogeneity in ROS content accompanies the clonal evolution of MDS. Furthermore, we observed a strong correlation between CD34+ cells siROS and serum ferritin level in high blast patients. In one case, iron chelation therapy (ICT) resulted in parallel decreases in serum ferritin and CD34+ cells siROS.Conclusion: Our findings established the siROS profile in early hematopoietic cells of MDS patients and its relationship with blast count and iron overload.