Proof of concept of triple COMBI therapy to prohibit MPN progression to AML.

Patients with accelerated or blast phase myeloproliferative neoplasms have a dismal prognosis. The report by de Castro et al. provides important information on the rationale and prospect for a novel therapeutic approach combining interferon-alpha2 with 5-azacytidine and a JAK1-2 inhibitor (ruxolitinib) to be explored in well-designed clinical trials. Commentary on: Castro et al. Ratio of stemness to interferon signalling as a biomarker and therapeutic target of myeloproliferative neoplasm progression to acute myeloid leukaemia. Br J Haematol 2024;204:206-220.

HSC Niche Dynamics in Regeneration, Pre-malignancy, and Cancer: Insights From Mathematical Modeling.

The hematopoietic stem cell (HSC) niche is a crucial driver of regeneration and malignancy. Its interaction with hematopoietic and malignant stem cells is highly complex and direct experimental observations are challenging. We here develop a mathematical model which helps relate processes in the niche to measurable changes of stem and non-stem cell counts. HSC attached to the niche are assumed to be quiescent. After detachment HSC become activated and divide or differentiate. To maintain their stemness, the progeny originating from division must reattach to the niche. We use mouse data from literature to parametrize the model. By combining mathematical analysis and computer simulations, we systematically investigate the impact of stem cell proliferation, differentiation, niche attachment, and detachment on clinically relevant scenarios. These include bone marrow transplantation, clonal competition, and eradication of malignant cells. According to our model, sampling of blood or bulk marrow provides only limited information about cellular interactions in the niche and the clonal composition of the stem cell population. Furthermore, we investigate how interference with processes in the stem cell niche could help to increase the effect of low-dose chemotherapy or to improve the homing of genetically engineered cells.

JAK2V617F drives gut microbiota differences in patients with myeloproliferative neoplasms.

BACKGROUND: Essential thrombocythemia (ET), polycythemia vera (PV), and primary myelofibrosis (MF) are myeloproliferative neoplasms (MPN). Inflammation is involved in the initiation, progression, and symptomology of the diseases. The gut microbiota impacts the immune system, infection control, and steady-state hematopoiesis. METHODS: We analyzed the gut microbiota of 227 MPN patients and healthy controls (HCs) using next-generation sequencing. We expanded our previous results in PV and ET patients with additional PV, pre-MF, and MF patients which allowed us to compare MPN patients collectively, MPN sub-diagnoses, and MPN mutations (separately and combined) vs. HCs (N = 42) and compare within MPN sub-diagnoses and MPN mutation. RESULTS: MPN patients had a higher observed richness (median, 245 [range, 49-659]) compared with HCs (191.5 [range, 111-300; p = .003]) and a lower relative abundance of taxa within the Firmicutes phylum; for example, Faecalibacterium (6% vs. 14%, p < .001). The microbiota of CALR-positive patients (N = 30) resembled that of HCs more than that of patients with JAK2V617F (N = 177). In JAK2V617F-positive patients, only minor differences in the gut microbiota were observed between MPN sub-diagnoses, illustrating the importance of this mutation. CONCLUSION: The gut microbiota in MPN patients differs from HCs and is driven by JAK2V617F, whereas the gut microbiota in CALR patients resembles HCs more.

Interferon alpha-2 treatment reduces circulating neutrophil extracellular trap levels in myeloproliferative neoplasms.

Neutrophil extracellular traps (NETs) may play a pathogenic role in the thrombosis associated with myeloproliferative neoplasms (MPNs). We measured serum NET levels in 128 pretreatment samples from patients with MPNs and in 85 samples taken after 12 months of treatment with interferon alpha-2 (PEG-IFNα-2) formulations or hydroxyurea (HU). No differences in NET levels were observed across subdiagnoses or phenotypic driver mutations. In PV, a JAK2V617F+ allele burden ≥50% associated with increased NET levels (p = 0.006). Baseline NET levels correlated with neutrophil count (r = 0.29, p = 0.001), neutrophil-to-lymphocyte ratio (r = 0.26, p = 0.004) and JAK2V617F allele burden (r = 0.22, p = 0.03), particularly in patients with PV and with allele burden ≥50% (r = 0.50, p = 0.01, r = 0.56, p = 0.002 and r = 0.45, p = 0.03 respectively). In PV, after 12 months of treatment, NET levels decreased on average by 60% in patients with allele burden ≥50%, compared to only 36% in patients with an allele burden <50%. Overall, treatment with PEG-IFNα-2a or PEG-IFNα-2b reduced NETs levels in 77% and 73% of patients, respectively, versus only 53% of HU-treated patients (average decrease across treatments: 48%). Normalization of blood counts did not per se account for these reductions. In conclusion, baseline NET levels correlated with neutrophil count, NLR and JAK2V617F allele burden, and IFNα was more effective at reducing prothrombotic NET levels than HU.

The pathobiology of thrombosis, microvascular disease, and hemorrhage in the myeloproliferative neoplasms.

Thrombotic, vascular, and bleeding complications are the most common causes of morbidity and mortality in the Philadelphia chromosome-negative myeloproliferative neoplasms (MPNs). In these disorders, circulating red cells, leukocytes, and platelets, as well as some vascular endothelial cells, each have abnormalities that are cell-intrinsic to the MPN driver mutations they harbor (eg, JAK2 V617F). When these cells are activated in the MPNs, their interactions with each other create a highly proadhesive and prothrombotic milieu in the circulation that predisposes patients with MPN to venous, arterial, and microvascular thrombosis and occlusive disease. Bleeding problems in the MPNs are caused by the MPN blood cell-initiated development of acquired von Willebrand disease. The inflammatory state created by MPN stem cells in their microenvironment extends systemically to amplify the clinical thrombotic tendency and, at the same time, preferentially promote further MPN stem cell clonal expansion, thereby generating a vicious cycle that favors a prothrombotic state in these diseases.

Whole blood transcriptional profiling reveals highly deregulated atherosclerosis genes in Philadelphia-chromosome negative myeloproliferative neoplasms.

BACKGROUND: The Philadelphia-negative chronic myeloproliferative neoplasms (MPNs) are associated with a huge comorbidity burden, including an increased risk of cardiovascular diseases. Recently, chronic inflammation has been suggested to be the driving force for clonal evolution and disease progression in MPN but also potentially having an impact upon the development of accelerated (premature) atherosclerosis. OBJECTIVES: Since chronic inflammation, atherosclerosis, and atherothrombosis are prevalent in MPNs and we have previously shown oxidative stress genes to be markedly upregulated in MPNs, we hypothesized that genes linked to development of atherosclerosis might be highly deregulated as well. METHODS: Using whole blood gene expression profiling in patients with essential thrombocythemia (ET; n = 19), polycythemia vera (PV; n = 41), or primary myelofibrosis (PMF; n = 9), we herein for the first time report aberrant expression of several atherosclerosis genes. RESULTS: Of 84 atherosclerosis genes, 45, 56, and 46 genes were deregulated in patients with ET, PV, or PMF, respectively. Furthermore, BCL2L1, MMP1, PDGFA, PTGS1, and THBS4 were progressively significantly upregulated and BCL2 progressively significantly downregulated from ET over PV to PMF (all FDR <0.05). CONCLUSIONS: We have for the first time shown massive deregulation of atherosclerosis genes in MPNs, likely reflecting the inflammatory state in MPNs in association with in vivo activation of leukocytes, platelets, and endothelial cells being deeply involved in the atherosclerotic process.

High JAK2V617F variant allele frequency is associated with coronary artery but not aortic valve calcifications in patients with Philadelphia-negative myeloproliferative neoplasms.

BACKGROUND: Patients with Philadelphia-negative myeloproliferative neoplasms (MPNs) have a higher burden of cardiac calcifications compared to the general population. It is not known whether the JAK2V617F mutation is associated with increased cardiac calcification. AIM: To investigate if a higher JAK2V617F variant allele frequency (VAF) is associated with severe coronary atherosclerosis and the presence of aortic valve calcification (AVC). METHODS: Patients with MPNs were examined by cardiac computer tomography to establish coronary artery calcium score (CACS) and AVC score. The first VAF after diagnosis was registered. Severe coronary atherosclerosis was defined as a CACS >400 and AVC was defined as an AVC score >0. RESULTS: Among 161 patients, 137 were JAK2V617F mutation-positive, with a median VAF of 26% (interquartile range 12%-52%). A VAF in the upper quartile range was associated with a CACS >400 [odds ratio (OR) 15.96, 95% confidence interval [CI] 2.13-119.53, p = .0070], after adjustment for cardiovascular risk factors and MPN subtype. An association was not found for the presence of AVC (OR 2.30, 95% CI 0.47-11.33, p = 0.31). CONCLUSION: In patients with MPNs, there is a significant association between having a VAF in the upper quartile (>52%), and severe coronary atherosclerosis, defined as a CACS >400. The presence of AVC is not associated with VAF.

Labor market affiliation of patients with myeloproliferative neoplasms: a population-based matched cohort study.

BACKGROUND: Patients with myeloproliferative neoplasms (MPNs) suffer from substantial symptoms and risk of debilitating complications, yet observational data on their labor market affiliation are scarce. MATERIAL AND METHODS: We conducted a descriptive cohort study using data from Danish nationwide registries, including patients diagnosed with MPN in 2010-2016. Each patient was matched with up to ten comparators without MPN on age, sex, level of education, and region of residence. We assessed pre- and post-diagnosis labor market affiliation, defined as working, unemployed, or receiving sickness benefit, disability pension, retirement pension, or other health-related benefits. Labor market affiliation was assessed weekly from two years pre-diagnosis until death, emigration, or 31 December 2018. For patients and comparators, we reported percentage point (pp) changes in labor market affiliation cross-sectionally from week -104 pre-diagnosis to week 104 post-diagnosis. RESULTS: The study included 3,342 patients with MPN and 32,737 comparators. From two years pre-diagnosis until two years post-diagnosis, a larger reduction in the proportion working was observed among patients than comparators (essential thrombocythemia: 10.2 [95% CI: 6.3-14.1] vs. 6.8 [95% CI: 5.5-8.0] pp; polycythemia vera: 9.6 [95% CI: 5.9-13.2] vs. 7.4 [95% CI: 6.2-8.7] pp; myelofibrosis: 8.1 [95% CI: 3.0-13.2] vs. 5.8 [95% CI: 4.2-7.5] pp; and unclassifiable MPN: 8.0 [95% CI: 3.0-13.0] vs. 7.4 [95% CI: 5.7-9.1] pp). Correspondingly, an increase in the proportion of patients receiving sickness benefits including other health-related benefits was evident around the time of diagnosis. CONCLUSION: Overall, we found that Danish patients with essential thrombocythemia, polycythemia vera, myelofibrosis, and unclassifiable MPN had slightly impaired labor market affiliation compared with a population of the same age and sex. From two years pre-diagnosis to two years post-diagnosis, we observed a larger reduction in the proportion of patients with MPN working and a greater proportion receiving sickness benefits compared with matched individuals.

Clonal haematopoiesis of indeterminate potential and impaired kidney function-A Danish general population study with 11 years follow-up.

The myeloproliferative neoplasms are associated with chronic kidney disease but whether clonal haematopoiesis of indeterminate potential (CHIP) is associated with impaired kidney function is unknown. In the Danish General Suburban Population Study (N = 19 958) from 2010 to 2013, 645 individuals were positive for JAK2V617F (N = 613) or CALR (N = 32) mutations. Mutation-positive individuals without haematological malignancy were defined as having CHIP (N = 629). We used multiple and inverse probability weighted (IPW)-adjusted linear regression analysis to estimate adjusted mean (95% confidence interval) differences in estimated glomerular filtration rate (eGFR; ml/min/1.73 m2 ) by mutation status, variant allele frequency (VAF%), blood cell counts, and neutrophil-to-lymphocyte ratio (NLR). We performed 11-year longitudinal follow-up of eGFR in all individuals. Compared to CHIP-negative individuals, the mean differences in eGFR were -5.6 (-10.3, -0.8, p = .02) for CALR, -11.9 (-21.4, -2.4, p = 0.01) for CALR type 2, and -10.1 (-18.1, -2.2, p = .01) for CALR with VAF ≥ 1%. The IPW-adjusted linear regression analyses showed similar results. NLR was negatively associated with eGFR. Individuals with CALR type 2 had a worse 11-year longitudinal follow-up on eGFR compared to CHIP-negative individuals (p = .004). In conclusion, individuals with CALR mutations, especially CALR type 2, had impaired kidney function compared to CHIP-negative individuals as measured by a lower eGFR at baseline and during 11-year follow-up.

Healthcare resource utilization in patients with myeloproliferative neoplasms: A Danish nationwide matched cohort study.

Few studies have assessed healthcare resource utilization (HRU) in patients with Philadelphia-negative myeloproliferative neoplasms (MPN) using a matched cohort design. Further, no detailed assessment of HRU in the years preceding an MPN diagnosis exists. We conducted a registry-based nationwide Danish cohort study, including patients with essential thrombocythemia, polycythemia vera, myelofibrosis, and unclassifiable MPN diagnosed between January 2010 and December 2016. HRU data were summarized annually from 2 years before MPN diagnosis until emigration, death, or end of study (December 2017). We included 3342 MPN patients and 32 737 comparisons without an MPN diagnosis, matched on sex, age, region of residence, and level of education. During the study period, the difference in HRU (rate ratio) between patients and matched comparisons ranged from 1.0 to 1.5 for general practitioner contacts, 0.9 to 2.2 for hospitalizations, 0.9 to 3.8 for inpatient days, 1.0 to 4.0 for outpatient visits, 1.3 to 2.1 for emergency department visits, and 1.0 to 4.1 for treatments/examinations. In conclusion, MPN patients had overall higher HRU than the matched comparisons throughout the follow-up period (maximum 8 years). Further, MPN patients had substantially increased HRU in both the primary and secondary healthcare sector in the 2 years preceding the diagnosis.

Smoking impairs molecular response, and reduces overall survival in patients with chronic myeloproliferative neoplasms: A retrospective cohort study.

The effects of smoking on the molecular response (MR) and overall survival (OS) in patients with chronic myeloproliferative neoplasms (MPNs) have not been investigated before. We analysed a historical cohort of 498 consecutive patients diagnosed with MPNs. Moreover, we analysed a subgroup of 270 consecutive patients with MPNs with > 1 measurement of the JAK2V617F variant allele frequency. The data were analysed using Kaplan-Meier plots and Cox regression analysis, along with linear regression models. In all patients, the rate of MR was significantly higher in never-smokers compared with current smokers in the univariate model (HR, 1·9; 95% CI, 1·1-3·3; P = 0·033) and the multivariate model (HR, 1·9; 95% CI, 1·1-3·5; P = 0·029). Similar findings were observed with different cut-off values for a partial MR. A subgroup analysis including only interferon-α2-treated patients showed similar results. In multivariate analyses, the OS was significantly better for never-smokers (HR, 0·46; 95% CI, 0·29-0·75; P = 0·002) than current smokers. The differences were more pronounced in the pegylated interferon-α2-treated patients. However, no significant interaction of interferon-α2 treatment was observed. In conclusion, we found that tobacco smoking reduced the rate of MR and OS in patients with MPNs. Cessation of smoking should be encouraged.

Classification and Personalized Prognosis in Myeloproliferative Neoplasms.

BACKGROUND: Myeloproliferative neoplasms, such as polycythemia vera, essential thrombocythemia, and myelofibrosis, are chronic hematologic cancers with varied progression rates. The genomic characterization of patients with myeloproliferative neoplasms offers the potential for personalized diagnosis, risk stratification, and treatment. METHODS: We sequenced coding exons from 69 myeloid cancer genes in patients with myeloproliferative neoplasms, comprehensively annotating driver mutations and copy-number changes. We developed a genomic classification for myeloproliferative neoplasms and multistage prognostic models for predicting outcomes in individual patients. Classification and prognostic models were validated in an external cohort. RESULTS: A total of 2035 patients were included in the analysis. A total of 33 genes had driver mutations in at least 5 patients, with mutations in JAK2, CALR, or MPL being the sole abnormality in 45% of the patients. The numbers of driver mutations increased with age and advanced disease. Driver mutations, germline polymorphisms, and demographic variables independently predicted whether patients received a diagnosis of essential thrombocythemia as compared with polycythemia vera or a diagnosis of chronic-phase disease as compared with myelofibrosis. We defined eight genomic subgroups that showed distinct clinical phenotypes, including blood counts, risk of leukemic transformation, and event-free survival. Integrating 63 clinical and genomic variables, we created prognostic models capable of generating personally tailored predictions of clinical outcomes in patients with chronic-phase myeloproliferative neoplasms and myelofibrosis. The predicted and observed outcomes correlated well in internal cross-validation of a training cohort and in an independent external cohort. Even within individual categories of existing prognostic schemas, our models substantially improved predictive accuracy. CONCLUSIONS: Comprehensive genomic characterization identified distinct genetic subgroups and provided a classification of myeloproliferative neoplasms on the basis of causal biologic mechanisms. Integration of genomic data with clinical variables enabled the personalized predictions of patients' outcomes and may support the treatment of patients with myeloproliferative neoplasms. (Funded by the Wellcome Trust and others.).

Prevalence and phenotypes of JAK2 V617F and calreticulin mutations in a Danish general population.

The JAK2 V617F and calreticulin mutations (CALR) are frequent within myeloproliferative neoplasms (MPNs). JAK2 V617F has been detected in the general population, but no studies have previously investigated the CALR prevalence. Thus, we aimed to determine the CALR and JAK2 V617F population prevalence and assess the biochemical profile and lifestyle factors in mutation-positive individuals with and without MPN. 19 958 eligible participants, enrolled from 2010-2013, from the Danish General Suburban Population Study were screened for JAK2 V617F and CALR by droplet digital polymerase chain reaction with (3.2%) mutation positives of which 16 (2.5%) had MPN at baseline. Of 645 participants, 613 were JAK2 V617F positive, and 32 were CALR positive, corresponding to a population prevalence of 3.1% (confidence interval [CI], 2.8-3.3) and 0.16% (CI, 0.11-0.23), respectively. Increasing age, smoking, and alcohol were risk factors for the mutations. JAK2 V617F positives with and without MPN presented elevated odds for prevalent venous thromboembolism. The odds ratio for a diagnosis of MPN per percentage allele burden was 1.14 (95% CI, 1.09-1.18; P = 1.6 × 10-10). Mutation positives displayed higher blood cell counts than nonmutated participants, and 42% of mutation positives without MPN presented elevation of ≥1 blood cell counts; 80 (13%) even presented blood cell counts in accordance with current MPN diagnostic criteria. In conclusion, we present a novel population prevalence of CALR and a JAK2 V617F prevalence that is 3 to 30 times higher compared with less sensitive methods. Mutation-positive non-MPNs with elevated blood cell counts raise concerns of MPN underdiagnosis in the population.

Tobacco use in the Myeloproliferative neoplasms: symptom burden, patient opinions, and care.

BACKGROUND: Patients with Philadelphia-negative Myeloproliferative Neoplasms (MPN) suffer from numerous symptoms and decreased quality of life. Smoking is associated with an increased symptom burden in several malignancies. The aim of this study was to analyze the association between smoking and MPN-related symptom burden and explore MPN patients' opinions on smoking. METHODS: A total of 435 patients with MPN participated in a cross-sectional internet-based survey developed by the Mayo Clinic and the Myeloproliferative Neoplasm Quality of Life Group. Patients reported their demographics, disease characteristics, tobacco use, and opinions on tobacco use. In addition, MPN-related symptoms were reported via the validated 10-item version of the Myeloproliferative Neoplasms Symptom Assessment Form. RESULTS: Current/former smokers reported worse fatigue (mean severity 5.6 vs. 5.0, p = 0.02) and inactivity (mean severity 4.0 vs. 3.4, p = 0.03) than never smokers. Moreover, current/former smokers more frequently experienced early satiety (68.5% vs. 58.3%, p = 0.03), inactivity (79.9% vs. 71.1%, p = 0.04), and concentration difficulties (82.1% vs. 73.1%, p = 0.04). Although not significant, a higher total symptom burden was observed for current/former smokers (mean 30.4 vs. 27.0, p = 0.07). Accordingly, overall quality of life was significantly better among never smokers than current/former smokers (mean 3.5 vs. 3.9, p = 0.03). Only 43.2% of the current/former smokers reported having discussed tobacco use with their physician, and 17.5% did not believe smoking increased the risk of thrombosis. CONCLUSION: The current study suggests that smoking may be associated with increased prevalence and severity of MPN symptoms and underscores the need to enhance patient education and address tobacco use in the care of MPN patients.

Data-driven analysis of the kinetics of the JAK2V617F allele burden and blood cell counts during hydroxyurea treatment of patients with polycythemia vera, essential thrombocythemia, and primary myelofibrosis.

BACKGROUND: Hydroxyurea (HU) treatment of patients with essential thrombocythemia (ET), polycythemia vera (PV), and primary myelofibrosis (PMF) (MPNs) normalizes elevated blood cell counts within weeks in the large majority of patients. Studies on the impact of HU upon the kinetics of the JAK2V617F allele burden, leukocyte, and platelet counts over time are scarce. PURPOSE: Using data-driven analysis as a novel tool to model the kinetics of the JAK2V617F allele burden and blood cell counts over time during treatment with HU. MATERIAL AND METHODS: Using serial measurements of JAK2V617F and correlation analysis of routine hematological values (the Hb-concentration, leukocyte count, platelet count, and lactic dehydrogenase), we present a detailed description and analysis of the kinetics of the JAK2V617F, leukocyte, and platelet counts and lactic dehydrogenase in 27 patients (PV = 18; ET = 7; PMF = 2), who were followed in the Danish randomized trial (DALIAH). To further analyze the JAK2V617F kinetics, we use a machine learning clustering algorithm to group the response patterns. RESULTS: Response patterns were highly heterogeneous, with clustering resulting in 3 groups and 3 outliers. In the large majority of patients, HU treatment was initially associated with a modest decline in the JAK2V617F allele burden in concert with a decline in leukocyte and platelet counts. However, HU did not induce a sustained and continuous decrease in the JAK2V617F allele burden. CONCLUSION: Using data-driven analysis of the JAK2V617F allele burden, leukocyte, and platelet kinetics during treatment with HU, we have shown that HU does not induce a sustained decrease in the JAK2V617F allele burden and neither induces sustained normalization of elevated cell counts in MPN patients. Our results may explain why MPN patients during treatment with HU still have a substantially increased risk of thrombosis.

Smoking, blood cells and myeloproliferative neoplasms: meta-analysis and Mendelian randomization of 2·3 million people.

Meta-analyses and Mendelian randomization (MR) may clarify the associations of smoking, blood cells and myeloproliferative neoplasms (MPN). We investigated the association of smoking with blood cells in the Danish General Suburban Population Study (GESUS, n = 11 083), by meta-analyses (including GESUS) of 92 studies (n = 531 741) and MR of smoking variant CHRNA3 (rs1051730[A]) in UK Biobank, and with MPN in a meta-analysis of six studies (n (total/cases):1 425 529/2187), totalling 2 307 745 participants. In the meta-analysis the random-effects standardized mean difference (SMD) in current smokers versus non-smokers was 0·82 (0·75-0·89, P = 2·0 * 10-108 ) for leukocytes, 0·09 (-0·02 to 0·21, P = 0·12) for erythrocytes, 0·53 (0·42-0·64, P = 8·0 * 10-22 ) for haematocrit, 0·42 (0·34-0·51, P = 7·1 * 10-21 ) for haemoglobin, 0·19 (0·08-0·31, P = 1·2 * 10-3 ) for mean corpuscular haemoglobin (MCH), 0·29 (0·19-0·39, P = 1·6 * 10-8 ) for mean corpuscular volume (MCV), and 0·04 (-0·04 to 0·13, P = 0·34) for platelets with trends for ever/ex-/current smokers, light/heavy smokers and female/male smokers. Analyses presented high heterogeneity but low publication bias. Per allele in CHRNA3, cigarettes per day in current smokers was associated with increased blood cell counts (leukocytes, neutrophils), MCH, red cell distribution width (RDW) and MCV. The pooled fixed-effects odds ratio for MPN was 1·44 [95% confidence interval (CI): 1·33-1·56; P = 1·8 * 10-19 ; I2  = 0%] in current smokers, 1·29 (1·15-1·44; P = 8·0 * 10-6 ; I2  = 0%) in ex-smokers, 1·49 (1·26-1·77; P = 4·4 * 10-6 ; I2  = 0%) in light smokers and 2·04 (1·74-2·39, P = 2·3 * 10-18 ; I2  = 51%) in heavy smokers compared with non-smokers. Smoking is observationally and genetically associated with increased leukocyte counts and red blood cell indices (MCH, MCV, RDW) and observationally with risk of MPN in current and ex-smokers versus non/never-smokers.

Evidence of immune elimination, immuno-editing and immune escape in patients with hematological cancer.

There is mounting evidence that the immune system can spontaneously clear malignant lesions before they manifest as overt cancer, albeit this activity has been difficult to demonstrate in humans. The calreticulin (CALR) exon 9 mutations are driver mutations in patients with chronic myeloproliferative neoplasms (MPN), which are chronic blood cancers. The CALR mutations generate a neo-antigen that is recognized by patient T cells, and T cells isolated from a patient with a CALR-mutation can recognize and kill autologous CALR-mutant cells. Surprisingly, healthy individuals display frequent and strong T cell responses to the CALR neo-antigens too. Furthermore, healthy individuals display immune responses to all parts of the mutant CALR epitope, and the CALR neo-epitope specific responses are memory T cell responses. These data suggest that although healthy individuals might acquire a CALR mutation, the mutant cells can be eliminated by the immune system. Additionally, a small fraction of healthy individuals harbor a CALR exon 9 mutation. Four healthy individuals carrying CALR mutations underwent a full medical examination including a bone marrow biopsy after a median follow up of 6.2 years. None of these patients displayed any signs of CALR-mutant MPN. Additionally, all healthy individuals displayed strong CALR neo-epitope specific T cell responses suggesting that these healthy individuals retained their CALR-mutant cells in the editing stage for several years. Thus, we suggest that CALR-mutant MPN could be a disease model of cancer immuno-editing, as we have demonstrated that CALR-mutant MPN displays all three stages described in the theory of cancer immuno-editing.

Myeloproliferative blood cancers as a human neuroinflammation model for development of Alzheimer's disease: evidences and perspectives.

Chronic inflammation and involvement of myeloid blood cells are associated with the development of Alzheimer's disease (AD). Chronic inflammation is a highly important driving force for the development and progression of the chronic myeloproliferative blood cancers (MPNs), which are characterized by repeated thrombotic episodes years before MPN-diagnosis, being elicited by elevated erythrocytes, leukocytes, and platelets. Mutations in blood cells, the JAK2V617F and TET2-mutations, contribute to the inflammatory and thrombogenic state. Herein, we discuss the MPNs as a human neuroinflammation model for AD development, taking into account the many shared cellular mechanisms for reduction in cerebral blood, including capillary stalling with plugging of blood cells in the cerebral microcirculation. The therapeutic consequences of an association between MPNs and AD are immense, including reduction in elevated cell counts by interferon-alpha2 or hydroxyurea and targeting the chronic inflammatory state by JAK1-2 inhibitors, e.g., ruxolitinib, in the future treatment of AD.

Ruxolitinib and interferon-α2 combination therapy for patients with polycythemia vera or myelofibrosis: a phase II study.

We report the final 2-year end-of-study results from the first clinical trial investigating combination treatment with ruxolitinib and low-dose pegylated interferon-α2 (PEG-IFNα2). The study included 32 patients with polycythemia vera and 18 with primary or secondary myelofibrosis; 46 patients were previously intolerant of or refractory to PEGIFNα2. The primary outcome was efficacy, based on hematologic parameters, quality of life measurements, and JAK2 V617F allele burden. We used the 2013 European LeukemiaNet and International Working Group- Myeloproliferative Neoplasms Research and Treatment response criteria, including response in symptoms, splenomegaly, peripheral blood counts, and bone marrow. Of 32 patients with polycythemia vera, ten (31%) achieved a remission which was a complete remission in three (9%) cases. Of 18 patients with myelofibrosis, eight (44%) achieved a remission; five (28%) were complete remissions. The cumulative incidence of peripheral blood count remission was 0.85 and 0.75 for patients with polycythemia vera and myelofibrosis, respectively. The Myeloproliferative Neoplasm Symptom Assessment Form total symptom score decreased from 22 [95% confidence interval (95% CI):, 16-29] at baseline to 15 (95% CI: 10-22) after 2 years. The median JAK2 V617F allele burden decreased from 47% (95% CI: 33-61%) to 12% (95% CI: 6-22%), and 41% of patients achieved a molecular response. The drop-out rate was 6% among patients with polycythemia vera and 32% among those with myelofibrosis. Of 36 patients previously intolerant of PEG-IFNα2, 31 (86%) completed the study, and 24 (67%) of these received PEG-IFNα2 throughout the study. In conclusion, combination treatment improved cell counts, reduced bone marrow cellularity and fibrosis, decreased JAK2 V617F burden, and reduced symptom burden with acceptable toxicity in several patients with polycythemia vera or myelofibrosis. #EudraCT2013-003295-12.

The red blood cell count and the erythrocyte sedimentation rate in the diagnosis of polycythaemia vera.

BACKGROUND: Iron deficiency in polycythaemia vera (PV) may impact the validity of the haematocrit (HCT), since HCT is red blood cell count (RBC) × mean corpuscular volume (MCV). OBJECTIVES: To investigate (a) the effect of microcytosis on HCT, (b) the erythrocyte sedimentation rate (ESR) as a possible additional diagnostic marker for PV. MATERIAL AND METHODS: This study included 182 subjects: 39 with PV, 27 with essential thrombocythemia (ET) and 116 suspected of myeloproliferative neoplasm (MPN) with a secondary cause for either thrombocytosis or erythrocytosis. RESULTS: Patients with PV had significantly lower ratio of MCV and serum ferritin compared to MPN suspects. A good correlation of RBC versus HCT was found for PV and MPN subjects when individuals with microcytosis were excluded (R2  = .87 in PV and R2  = .82 in MPN suspects). We found a specificity of 98% and a sensitivity of 37% for ESR <2 mm in the diagnosis of PV. CONCLUSION: The RBC may more precisely reflect the total red cell mass and accordingly the hypercoagulable state of the PV patient, which is integrated in the ESR. A combination of RBC and ESR is proposed as a novel tool to substitute the Hb concentration and the HCT in the diagnosis of PV.