Guidelines for the diagnosis, investigation and management of polycythaemia/erythrocytosis

Post-transplant erythrocytosis refractory to ACE inhibitors and angiotensin receptor blockers

Post-transplant erythrocytosis (PTE) is a condition with elevated haematocrit (hct) in renal allograft recipients. The mainstay of treatment is ACE inhibitors (ACEi) or angiotensin II receptor blockers (ARB), but seldom phlebotomy. PTE must be recognised early to prevent major thromboembolic events. We present a case of PTE that was refractory to blockade of renin-angiotensin system (RAS) by ACEi and ARB and required phlebotomy for control of hct. Our review of medical literature about prevalence and pathophysiology of PTE suggests that approximately 22% of patients with PTE are refractory to ACEi/ARB treatment. There are four plausible pathways that appear to play a role in causing PTE: disruption of erythropoietin regulation, mitogenic effect of the RAS on erythroid lineage, insulin-like growth factor 1 and androgenic stimulation. Presently, there is no unifying hypothesis involving these factors, but refractoriness to ACEi/ARB may represent a distinct subcategory of PTE.

The real-world outcomes of treating Polycythemia Vera: Physician adherence to treatment guidelines

Therapy in Polycythemia Vera (PV), a myeloproliferative neoplasm, focuses on reducing cardiovascular (CV) risk without increasing bleeding or hematological progression. However, the real-world practice of treating PV in North America is understudied. We performed a retrospective cohort study of newly diagnosed PV (JAK2V617F mutation positive) patients in Hamilton, Canada to fill this knowledge gap. Out of 108 patients included, (n = 45, 41.7%) patients did not receive therapy consistent with contemporary treatment guidelines. Multivariable analysis showed increased white blood cell count at diagnosis (HR, 1.09; 95% CI, 1.04-1.14; p < 0.001), older age (HR, 1.15; 95% CI, 1.07-1.23; p < 0.001) and diabetic history (HR, 3.71; 95% CI, 1.27-10.78; p = 0.012) associated with greater mortality. Not receiving pharmacological treatment according to guidelines was also independently associated with increased mortality (HR, 3.12; 95% CI, 1.13-8.65; p = 0.029).

Erythrocytes from patients with myeloproliferative neoplasms and splanchnic venous thrombosis show greater expression of Lu/BCAM

INTRODUCTION

Lutheran/BCAM protein (Lu) on the surface of erythrocytes is key for their adhesion to the endothelium, and erythrocytes from individuals with JAK2V617F-mutated myeloproliferative neoplasms (MPN) have increased endothelial adhesion. Splanchnic vein thrombosis (SVT) is a devastating thrombotic complication of MPN, and frequently, the only diagnostic feature is the JAK2V617F mutation. We sought to examine whether erythrocytes from patients with JAK2V617F mutated SVT (MPN-SVT) exhibited increased Lu expression, thereby supporting a mechanistic contribution to the development of thrombosis.

METHODS

We report the validation of a novel flow cytometry assay for Lu expression on erythrocytes. We examined the expression of Lu on erythrocytes from a cohort of MPN patients with and without SVT, and healthy controls. Samples were obtained from 20 normal individuals, 22 with MPN (both JAK2V617F-mutated and wild-type) and 8 with JAK2V617F-mutated MPN-SVT.

RESULTS

Lu expression by erythrocytes from patients with MPN and MPN-SVT is significantly increased compared to erythrocytes from healthy individuals (P < .05), but there was no significant difference between patients with MPN-SVT and MPN.

CONCLUSIONS

Patients with MPN have increased expression of the red cell Lu/BCAM adhesion molecule. Further work is required to determine the role of the increased Lu/BCAM adhesion to the endothelium in the development of thrombosis in MPN of all genotypes.

Hemoglobin Is a Vital Determinant of Arterial Oxygen Content in Hypoxemic Patients with Pulmonary Arteriovenous Malformations

RATIONALE

Pa_O2 and Sa_O2 are commonly measured in respiratory practice, but arterial oxygen content (Ca_O2) refers to the volume of oxygen delivered to the tissues per unit blood volume. Ca_O2 is calculated from Sa_O2 and the hemoglobin concentration in blood, recognizing that each gram of hemoglobin can transport approximately 1.34 ml of oxygen when fully saturated.

OBJECTIVES

To prospectively evaluate serial changes in Ca_O2 in humans, incorporating and excluding dynamic changes to oxygenation and hemoglobin parameters that may occur during life.

METHODS

A cohort of 497 consecutive patients at risk of both hypoxemia and anemia were recruited. The patients had radiologically proven pulmonary arteriovenous malformations (PAVMs), which result in hypoxemia due to right-to-left shunting, and concurrent hereditary hemorrhagic telangiectasia, which placed them at risk of iron deficiency anemia due to recurrent hemorrhagic iron losses. Presentation Sa_O2 (breathing room air, by pulse oximetry), hemoglobin, red cell and iron indices were measured, and Ca_O2 calculated as Sa_O2 × hemoglobin × 1.34 ml/g. Serial measurements were evaluated in 100 cases spanning up to 32.1 (median, 10.5) years.

RESULTS

Presentation Ca_O2 ranged from 7.6 to 27.5 (median, 17.6) ml/dl. Ca_O2 did not change appreciably across the Sa_O2 quartiles. In contrast, hemoglobin ranged from 5.9 to 21.8 g/dl (median, 14.1 g/dl), with a linear increase in Ca_O2 across hemoglobin quartiles. After PAVM embolization and an immediate increase in Sa_O2, hemoglobin fell and Ca_O2 was unchanged 1.6-12 (median, 4) months later. When hemoglobin fell because of iron deficiency, there was no change in Sa_O2. Similarly, when hemoglobin rose after iron treatment, there was no change in Sa_O2, and the expected Ca_O2 increment was observed. These relationships were not evident during pregnancy when hemoglobin fell, and PAVMs usually deteriorated: in pregnancy Sa_O2 commonly increased, and serial Ca_O2 values (incorporating hemodilution/anemia) more accurately reflected deteriorating PAVM status. An apparent fall in Ca_O2 with age in females was attributable to the development of iron deficiency. There was an unexplained increase in Ca_O2 with age in follow-up of males after embolization.

CONCLUSIONS

Hemoglobin/Ca_O2 should be further incorporated into oxygenation considerations. More attention should be given to modest changes in hemoglobin that substantially modify Ca_O2.

Severe Secondary Polycythemia in a Female-to-Male Transgender Patient While Using Lifelong Hormonal Therapy: A Patient's Perspective

After a registered drug is available on the market and used in everyday circumstances, hitherto unknown adverse drug reactions (ADRs) may occur. Furthermore, the patient can experience a previously unknown course of a known ADR. Voluntary reports by patients play an important role in gaining knowledge about ADRs in daily practice. The Netherlands Pharmacovigilance Centre Lareb received a report from a 55-year-old female-to-male transgender patient who experiences secondary polycythemia while using lifelong testosterone therapy. The onset age of the symptoms was 38 years. The symptoms appeared gradually and after approximately 1 year it was clear that the patient’s hemoglobin and hematocrit had started to increase. A Naranjo assessment score of 6 was obtained, indicating a probable relationship between the patient’s polycythemia and use of the suspect drug. Polycythemia is a known ADR in testosterone treatment, but little attention has been paid to the possible severity and complications of these symptoms as well as the impact on the patient’s well-being.

Erythromelalgia: a cutaneous manifestation of neuropathy?

The low prevalence of erythromelalgia, classified as an orphan disease, poses diagnostic and therapeutic difficulties. The aim of this review is to be an update of the specialized bibliography. Erythromelalgia is an infrequent episodic acrosyndrome affecting mainly both lower limbs symmetrically with the classic triad of erythema, warmth and burning pain. Primary erythromelalgia is an autosomal dominant inherited disorder, while secondary is associated with myeloproliferative diseases, among others. In its etiopathogenesis, there are neural and vascular abnormalities that can be combined. The diagnosis is based on exhaustive clinical history and physical examination. Complications are due to changes in the skin barrier function, ischemia and compromise of cutaneous nerves. Because of the complexity of its pathogenesis, erythromelalgia should always be included in the differential diagnosis of conditions that cause chronic pain and/or peripheral edema. The prevention of crisis is based on a strict control of triggers and promotion of preventive measures. Since there is no specific and effective treatment, control should focus on the underlying disease. However, there are numerous topical and systemic therapies that patients can benefit from.

Guidelines for the Diagnosis and Treatment of testosterone deficiency (hypogonadism) in male patients with diabetes mellitus

Hypogonadism in men, defined as a reduction in serum testosterone in combination with characteristic symptoms and/or signs (described in detail later), is common in diabetes mellitus (DM). These recommendations do not cover the whole range of pathologies that cause the development of testosterone deficiency (hypogonadism), but focus on its clinical variants and characteristic for men with diabetes. The recommendations provide data on the prevalence of hypogonadism in diabetes, its etiology. In the section "diagnostics" the features of anamnesis of patients with hypogonadism with diabetes, the necessary methods of physical and laboratory examination are presented in detail. The risk factors and clinical consequences of hypogonadism are separately examined. In the section "choice of treatment methods", there are possible treatment options for such patients using various androgenic therapies, taking into account the needs of the man, maintaining his reproductive function and risk factors. Particular attention is paid to indications, contraindications and risk factors for androgen therapy in men with diabetes, especially in old age. With this in mind, principles for monitoring the treatment are developed. Based on a large number of studies, favorable effects of androgen replacement therapy in men with hypogonadism and diabetes have been demonstrated.

A spotlight on the management of complications associated with myeloproliferative neoplasms: a clinician's perspective

INTRODUCTION

Myeloproliferative neoplasms (MPNs) are associated with a variety of symptoms and signs which cause major morbidity for the patients. The disorders are associated with increased incidence of thromboembolic and hemorrhagic events which can lead to complications and shortened life expectancy. Areas covered: Using systematic literature review and expert clinical and research experience the authors discuss strategies for the management of symptoms and signs including pruritus, fatigue, splenomegaly, and cytopenia. Cytoreduction including treatments to inhibit the JAK/STAT pathway are considered. Pathogenesis and prevention and treatment of thrombotic and hemorrhagic events and their management is addressed and the suggested management of the special situations such as surgery and pregnancy are discussed. Expert commentary: Management of disease has traditionally focused on symptom treatment and complication prevention but the discovery of driver mutations has led to treatments aiming to eliminate the clone, which should be the ultimate goal of therapy. A future challenge is to develop safe and effective MPN therapy and to personalize therapy.

Atypical haematological presentation in a case of polycythaemia vera with a new variant mutation detected in exon 12: c.1605G>T (p.Met535Ile)

One of the major genetic insights into the pathogenesis of polycythaemia vera included the identification of the somatic point gain-of-function mutations in Janus kinase 2 gene-first JAK2V617F on exon 14, present in 95%-97% of the cases, and later on exon 12. In the literature, we can find some reported studies where different exon 12 mutations are identified. Unlike patients with JAK2V617F mutation in exon 14, the mutation at exon 12 is not usually associated with an increase in the three haematopoietic series (erythrocytosis, leucocytosis and thrombocytosis). It appears to be associated with a distinct syndrome, mostly characterised by isolated and more marked erythrocytosis, independently of the mutational variant. We report here the case of a patient who is JAK2exon 12 positive, presenting a novel mutation-c.1605G>T (p.Met535Ile)-associated with c.1612C>T (p.His538Tyr) mutation previously described, evidencing an atypical clinical phenotype.

Long-term outcomes of patients with pulmonary arteriovenous malformations considered for lung transplantation, compared with similarly hypoxaemic cohorts

INTRODUCTION

Pulmonary arteriovenous malformations (PAVMs) may not be amenable to treatment by embolisation or surgical resection, and many patients are left with significant hypoxaemia. Lung transplantation has been undertaken. There is no guidance on selection criteria.

METHODS

To guide transplantation listing assessments, the outcomes of the six patients who had been considered for transplantation were compared with a similarly hypoxaemic patient group recruited prospectively between 2005 and 2016 at the same UK institution.

RESULTS

Six patients had been formally considered for lung transplantation purely for PAVMs. One underwent a single lung transplantation for diffuse PAVMs and died within 4 weeks of surgery. The other five were not transplanted, in four cases at the patients' request. Their current survival ranges from 16 to 27 (median 21) years post-transplant assessment. Of 444 consecutive patients with PAVMs recruited between 2005 and 2016, 42 were similarly hypoxaemic to the 'transplant-considered' cohort (SaO2 <86.5%). Hypoxaemic cohorts maintained arterial oxygen content (CaO2) through secondary erythrocytosis and higher haemoglobin. The 'transplant-considered' cohort had similar CaO2 to the hypoxaemic comparator group, but higher Medical Research Council (MRC) dyspnoea scores (p=0.023), higher rates of cerebral abscesses (p=0.0043) and higher rates of venous thromboemboli (p=0.0009) that were evident before and after the decision to list for transplantation.

CONCLUSIONS

The non-transplanted patients demonstrated marked longevity. Symptoms and comorbidities were better predictors of health than oxygen measurements. While a case-by-case decision, weighing survival estimates and quality of life will help patients in their decision making, the data suggest a very strong case must be made before lung transplantation is considered.

European LeukemiaNet study on the reproducibility of bone marrow features in masked polycythemia vera and differentiation from essential thrombocythemia

The purpose of the study was to assess consensus and interobserver agreement among an international panel of six hematopathologists regarding characterization and reproducibility of bone marrow (BM) histologic features used to diagnose early stage myeloproliferative neoplasms, in particular differentiation of so-called masked/prodromal polycythemia vera (mPV) from JAK2-mutated essential thrombocythemia (ET). The six members of the hematopathology panel evaluated 98 BM specimens independently and in a blinded fashion without knowledge of clinical data. The specimens included 48 cases of mPV according to the originally published hemoglobin threshold values for this entity (male: 16.0-18.4 g/dL, female: 15.0-16.4 g/dL), 31 cases with overt PV according to the updated 2016 WHO criteria, and 19 control cases. The latter group included cases of JAK2-mutated ET, primary myelofibrosis, myelodysplastic syndrome, and various reactive conditions. Inter-rater agreement between the panelists was very high (overall agreement 92.6%, kappa 0.812), particularly with respect to separating mPV from ET. Virtually all cases of mPV were correctly classified as PV according to their BM morphology. In conclusion, a central blinded review of histology slides by six hematopathologists demonstrated that highly reproducible specific histological pattern characterize PV and confirmed the notion that there are no significant differences between mPV and overt PV in relation to BM morphology.

Investigation and Management of Erythrocytosis

An absolute erythrocytosis is present when the red cell mass is greater than 125 % of the predicted value for sex and body mass. It can have a primary or secondary and congenital or acquired cause. New causes particularly congenital continue to be discovered and investigated. Investigation for the cause starts with repeat and confirmation of the raised hemoglobin and measurement of an erythropoietin level to indicate whether to pursue primary or secondary causes and then further investigations as appropriate. Management options include low dose aspirin and venesection. Specific management advice is available for certain specific clinical situations.

Does untreated obstructive sleep apnea cause secondary erythrocytosis?

BACKGROUND

The current literature suggests a relationship between obstructive sleep apnea (OSA) severity and hematocrit. However, the degree that OSA contributes to clinically significant erythrocytosis is uncertain. The aim of this study is to evaluate this association in a large study sample controlling for multiple confounders.

METHODS

We evaluated consecutive subjects with suspected untreated OSA using multivariate analysis to test the associations between apnea-hypopnea index (AHI) and hematocrit. Subjects were evaluated with sleep studies, comprehensive sleep questionnaires, and detailed electronic medical record reviews to document their medical comorbidities, and demographic and laboratory information.

RESULTS

1604 consecutive veterans (age 57.6 ± 13.4 years, 92% male) were included in the analysis with 77.4% diagnosed with OSA. However, few included subjects (1.6%) had clinical erythrocytosis. OSA severity defined by AHI was not associated with hematocrit or clinically significant erythrocytosis. Rather, awake oxygen saturation (-0.17 points, p < 0.001) and mean nocturnal oxygen saturation (-0.08 points, p = 0.04) were inversely proportional to hematocrit (per standardized Z-score). Other factors including active tobacco, increased alcohol ingestion and exogenous testosterone therapy were associated with higher hematocrit. Although AHI was not predictive of erythrocytosis, having severe OSA was predictive of nocturnal hypoxemia (adjusted OR 7.4, p < 0.001).

CONCLUSIONS

Hematocrit levels and presence of erythrocytosis appear not associated with OSA severity, but rather with hypoxemia as measured by awake and to a lesser extent mean nocturnal oxygen saturation. Nocturnal oximetry may provide diagnostic utility in the evaluation of unexplained secondary polycythemia and polysomongraphy may be warranted in those with unexplained nocturnal hypoxemia and erythrocytosis.

Epigenetics in Myeloproliferative Neoplasms

A decade on from the description of JAK2 V617F, the MPNs are circumscribed by an increasingly intricate landscape. There is now evidence that they are likely the result of combined genetic dysregulation, with several mutated genes involved in the regulation of epigenetic mechanisms. Epigenetic changes are not due to a change in the DNA sequence but are reversible modifications that dictate the way in which genes may be expressed (or silenced). Among the epigenetic mechanisms, DNA methylation is probably the best described. Currently known MPN‐associated mutations now include JAK2, MPL, LNK, CBL, CALR, TET2, ASXL1, IDH1, IDH2, IKZF1 and EZH2. Enhancing our knowledge about the mutation profile of patients may allow them to be stratified into risk groups which would aid clinical decision making. Ongoing work will answer whether the use of epigenetic therapies as alterative pathway targets in combination with JAK inhibitors may be more effective than single agent treatment.

Progression of primary myelofibrosis to polycythemia vera: A case report

RATIONALE

This case report describes the progression of primary myelofibrosis (PMF) to polycythemia vera (PV), and discuss its potential mechanisms.

PATIENT CONCERNS

The patient was admitted because of abdominal discomfort and enlarged spleen for 19 months.

DIAGNOSIS

A case of PMF progressed to PV was retrospectively analyzed. There were 19 months between the diagnosis of PMF and PV. The JAK2 V617F mutation was positive before and after the diagnosis of PV; however, new chromosomal abnormalities were detected during the progression.

INTERVENTIONS

For treatment of PMF, the danazol, calcitriol, and thalidomide were given. Then, the use of thalidomide and calcitriol was stopped, and hydroxyurea was started. For treatment of PV, interferon treatment was given, whereas hydroxyurea was continued.

OUTCOMES

After 30 months of the progression (at the recent follow-up), this patient had no obvious symptoms or thrombosis.

LESSONS

PMF rarely progresses to PV, however, the progression will significantly improve the quality of life and prognosis.

Frequency of polycythemia in individuals with normal complete blood cell counts according to the new 2016 WHO classification of myeloid neoplasms

INTRODUCTION

Polycythemia vera (PV) is a disorder characterized by clonal proliferation of myeloid cells and increased red blood cell mass. Recently, the revised 2016 WHO classification of myeloid neoplasms decreased the threshold levels of hemoglobin and hematocrit for the diagnosis of PV. However, the new proposed cutoffs have remarkable overlap with the normal reference values reported and the clinical impact of these new cutoffs has not been widely assessed in the general population.

METHODS

We retrospectively examined 248 839 patients with presumptively normal complete blood cell results, consecutively obtained in an outpatient setting.

RESULTS

The proportion of men with Hb >165 g/L was 5.99%, Hct>49% was 2.4%, and Hb >165 g/dL or Hct>49% was 6.48%, while the proportion of women with Hb >160 g/L was 0.22%, Hct>48% was 0.11%, and Hb >160 g/L or Hct>48% was 0.28%.

CONCLUSION

The isolated use of the proposed Hb/Hct levels as a definer of polycythemia may lead to a substantial increase in unnecessary diagnostic tests. In cases with borderline levels of hemoglobin, the diagnostic workup of PV should only be indicated in the presence of clinical and/or laboratorial features associated with MPN.

Experience with ruxolitinib in the treatment of polycythaemia vera

Polycythaemia vera (PV) is a myeloproliferative neoplasm classically characterized by an erythrocytosis and is associated with a high risk of thromboembolic events, constitutional symptoms burden and risk of transformation to myelofibrosis and acute myeloid leukaemia. Therapy is directed at the haematocrit (HCT) to reduce the risk of thrombotic events and usually comprises low-dose aspirin and phlebotomy to maintain HCT at >45%. Frequently in addition, cytoreductive therapy is indicated in high-risk patients for normalizing haematological parameters to mitigate the occurrence of thromboembolic events. Unfortunately, there is no clear evidence that current therapies reduce the risk of transformation to myelofibrosis and for some a risk of a therapy related complication is unknown for example leukaemia due to hydroxycarbamide (HC). First-line therapy for treating PV remains HC or interferon, the latter most often in younger patients, especially those of childbearing age. However, therapy related intolerance or resistance is a common feature and results in limited treatment options for such patients. The discovery of the JAK2 V617F mutation and consequently targeted therapy with Janus kinase inhibitors, in particular ruxolitinib, has extended the spectrum of agents that can be used as second or third line in PV. The findings of the phase II trial RESPONSE and the preliminary data from RESPONSE 2 trial have identified a role for ruxolitinib in PV patients who are resistant or intolerant to HC. In this article, using clinical cases we demonstrate our experience with ruxolitinib highlighting the clinical benefits and limitations we encountered in clinical practice.

Guidelines on the Use of Therapeutic Apheresis in Clinical Practice-Evidence-Based Approach from the Writing Committee of the American Society for Apheresis: The Seventh Special Issue

The American Society for Apheresis (ASFA) Journal of Clinical Apheresis (JCA) Special Issue Writing Committee is charged with reviewing, updating, and categorizing indications for the evidence-based use of therapeutic apheresis in human disease. Since the 2007 JCA Special Issue (Fourth Edition), the Committee has incorporated systematic review and evidence-based approaches in the grading and categorization of apheresis indications. This Seventh Edition of the JCA Special Issue continues to maintain this methodology and rigor to make recommendations on the use of apheresis in a wide variety of diseases/conditions. The JCA Seventh Edition, like its predecessor, has consistently applied the category and grading system definitions in the fact sheets. The general layout and concept of a fact sheet that was used since the fourth edition has largely been maintained in this edition. Each fact sheet succinctly summarizes the evidence for the use of therapeutic apheresis in a specific disease entity. The Seventh Edition discusses 87 fact sheets (14 new fact sheets since the Sixth Edition) for therapeutic apheresis diseases and medical conditions, with 179 indications, which are separately graded and categorized within the listed fact sheets. Several diseases that are Category IV which have been described in detail in previous editions and do not have significant new evidence since the last publication are summarized in a separate table. The Seventh Edition of the JCA Special Issue serves as a key resource that guides the utilization of therapeutic apheresis in the treatment of human disease. J. Clin. Apheresis 31:149-162, 2016. © 2016 Wiley Periodicals, Inc.

Bumpy road to the diagnosis of polycythaemia vera

Polycythaemia vera (PV) is the most common myeloproliferative neoplasm, characterised by increased red cell mass that can present as an unspecified symptom or a thrombohaemorrhagic event. Its diagnosis is based on the presence of erythrocytosis, the identification of the Janus kinase 2 mutation and bone marrow aspirate or biopsy alterations. The challenge of this disease lies on the treatment approach. Its cornerstone is phlebotomy, but depending on the vascular risk, it can include cytoreductive agents, low-dose aspirin or even anticoagulation. We present the case of a 75-year-old woman, whose inaugural presentation of PV was an arterial peripheral occlusion followed by three recurrent events in the same arterial region and a pulmonary embolism. A phlebotomy was initially performed and, after the diagnosis was made, the patient was initiated on low-dose aspirin and anticoagulation with favourable outcome.

Erythrocytosis in hepatocellular carcinoma portends poor prognosis by respiratory dysfunction secondary to mitochondrial DNA mutations

Erythrocytosis is a common paraneoplastic syndrome associated with hepatocellular carcinoma. Although increased erythropoietin (EPO) is found in these patients, the clinical significance and molecular mechanisms underlying this observation are unclear. We demonstrate an inverse relationship between EPO production and overall prognosis in our cohort of 664 patients as well as in data from The Cancer Genome Atlas. In the subset of hepatocellular carcinoma patients with erythrocytosis, we identified somatic mutations of mitochondrial DNA, resulting in impairment of respiratory metabolism, which sequentially led to depletion of α-ketoglutarate, stabilization of hypoxia inducible factor-α, and expression of target genes such as EPO. Cell lines and patient-derived xenograft models were used to demonstrate that EPO promoted cancer stem cell self-renewal and expansion in an autocrine/paracrine manner through enhanced Janus kinase/signal transducer and activator of transcription signaling both in vitro and in vivo. Furthermore, to explore the therapeutic targeting of EPO-induced tumor changes, we found that blocking EPO signaling with soluble EPO receptor extracellular domain Fc fusion protein could inhibit tumor growth both in vitro and in vivo.

CONCLUSION

These findings suggest clinical and therapeutic implications for erythrocytosis in hepatocellular carcinoma. There is an underlying link between mitochondrial function and hypoxia inducible factor alpha signaling, revealing a mechanism of erythrocytosis in a subset of hepatocellular carcinoma patients who may benefit from treatment involving EPO signaling interference. (Hepatology 2017;65:134-151).

From leeches to personalized medicine: evolving concepts in the management of polycythemia vera

Polycythemia vera is a clonal disorder of hematopoietic stem/progenitor cells. It manifests as an expansion of red cell mass. It is the most common chronic myeloproliferative neoplasm. In virtually all cases, it is characterized by a V617F point mutation in JAK2 exon 14 or less common mutations in exon 12. The landmark discovery of the autonomously activated JAK/STAT signaling pathway paved the way for the clinical development of the first target drug, the JAK1 and JAK2 inhibitor ruxolitinib. This is now approved for patients with resistance or intolerance to hydroxyurea. Phlebotomies and hydroxyurea are still the cornerstone of treatment, and aim to prevent the first appearance or recurrence of cardiovascular events that, together with progression to post-polycythemia vera myelofibrosis and leukemia, represent the main causes of death. Interferon-α is an alternative drug and has been shown to induce molecular remissions. It is currently undergoing phase III trials that might eventually lead to its approval for clinical use. The last few years have witnessed important advances towards an accurate early diagnosis of polycythemia vera, greater understanding of its pathogenesis, and improved patient management. This review will focus on the most recent achievements and will aim to unify the different concepts involved in a personalized approach to the patient with polycythemia vera. In spite of many recent advances in the understanding of its pathogenesis and improved disease management, polycythemia vera remains a life-threatening myeloproliferative neoplasm for which there is no cure. This review will present a critical overview of evolving concepts in diagnosis and treatment of this disease.

Pregnancy outcomes in myeloproliferative neoplasms: UK prospective cohort study

The reported higher risk of maternal and fetal complications in women with myeloproliferative neoplasms (MPN) poses challenge during pregnancy. A national prospective study of maternal and fetal outcomes of pregnant women with a diagnosis of MPN was undertaken via the United Kingdom Obstetric Surveillance System between January 2010 and December 2012. Fifty-eight women with a diagnosis of MPN were identified; 47 (81%) essential thrombocythaemia, five (9%) polycythaemia vera, five (9%) myelofibrosis and one (2%) MPN-unclassified. There were 58 live births. The incidence of miscarriage was 1·7/100 (95% confidence interval [CI]: 0·04-9·24) and the perinatal mortality rate was 17/1000 (95% CI: 0·44-92·36) live and stillbirths. Incidence of maternal complications was 9% (5/57) pre-eclampsia, 9% (5/57) post-partum haemorrhage and 3·5% (2/57) post-partum haematoma. There were no maternal deaths or thrombotic events. Delivery was induced in 45% (24/53) of women and the Caesarean section rate was 45% (24/53). The majority (85%, 45/53) delivered at term (>37 weeks gestation). Twenty-two percent (12/54) of neonates were below the 10% centile for growth and 13% (7/54) required admission to a neonatal care-unit; there were no neonatal deaths. The findings of this large, UK prospective study suggests women with MPN appear to have successful pregnancies with better outcomes than would be anticipated from the literature.

[Diagnosis of latent polycythemia vera: A clinician's opinion]

AIM

to identify the clinical features of latent polycythemia vera (PV) as an independent nosological entity.

SUBJECTS AND METHODS

The investigation enrolled 81 patients (50 with extensive (manifest) PV and 31 with latent PV) who had visited the Outpatient Department, Hematology Research Center, Ministry of Health of Russia, in 2014 to October 2015.

RESULTS

The gender distribution of the patients was statistically comparable in the analyzed groups. The patients with manifest PV were slightly older than those with latent PV: the median age in the compared groups was 56 and 44 years, respectively. Red blood cell counts, hemoglobin concentrations, and packed cell volume were higher in the patients with manifest PV. Blood platelet counts were higher in the latent PV group. There were no differences in the number of white blood cells in the compared groups. All the patients were JAK2 V617F mutation carriers. The JAK2 allele load was significantly higher in the manifest PV group than in the latent PV group. The compared patient groups differed in the rate of thromboses in the history or at diagnosis. In the patients with latent PV, thromboses were detected in 38% of cases versus 16% in those with manifest PV. In latent PV, there were mainly venous thromboses; abdominal vascular thromboses were diagnosed with a high frequency. Arterial thromboses were revealed in only 2 cases.

CONCLUSION

Chronic myeloproliferative disease that is characterized by the JAK2 V617F mutation, borderline hemoglobin counts, and morphological features of a bone marrow trephine biopsy specimen, which are specific for PV, is an independent PV variant, namely: latent PV.

Eritrocitosis secundaria a hipoxemia en neumopatías crónicas: de la reología a la práctica clínica

<p>La eritrocitosis es una condición infrecuente en las enfermedades pulmonares crónicas que cursan con hipoxemia; su adecuada aproximación fisiopatológica y clínica no es bien conocida. Aunque la eritrocitosis es una respuesta compensatoria frente a la hipoxemia, sus efectos en la microcirculación pueden afectar parámetros cardiovasculares con deterioro de la sintomatología de pacientes con esta patología. La corrección por medio de la flebotomía puede ser una medida terapéutica útil, pero no hay claridad sobre su indicación en consideración a la evidencia actualmente disponible; de igual forma, existen preocupaciones sobre los desenlaces adversos que podrían generarse con su uso en la reología y en la ferrocinética. Es también desconocida la pertinencia de la flebotomía ante el aparente pronóstico benigno de quienes presentan eritrocitosis en el contexto de una neumopatía crónica. Con la escasa información actual, se hace necesaria la ampliación de la investigación en los tópicos relacionados con la eritrocitosis debida a hipoxemia.</p>

Hb Tarrant [α126(H9)Asp→Asn; HBA2: c.379G > A (or HBA1)] in a Chinese Family as a Cause of Familial Erythrocytosis

Hb Tarrant [α126(H9)Asp→Asn; HBA2: c.379G > A (or HBA1)], is a rare high oxygen affinity hemoglobin (Hb) variant that causes erythrocytosis, previously described in a few Mexican-American families. Here we report the first Chinese family with this Hb variant presenting with unexplained familial erythrocytosis. No evidence of hemolysis was seen. A locally adapted approach to the diagnostic process in clinical laboratories is discussed. Molecular analysis has an important role in confirmation of the diagnosis. Proper identification of this rare but clinically significant Hb variant is helpful for family counseling and will help to guide appropriate management of absolute erythrocytosis.

Myeloproliferative neoplasms: Morphology and clinical practice

In myeloproliferative neoplasms (MPNs), controversy persists regarding the usefulness and reproducibility of bone marrow (BM) features. Disagreements concerning the WHO classification are mainly focused on the discrimination between essential thrombocythemia (ET) and prefibrotic/early primary myelofibrosis (prePMF) and prodromal polycythemia vera (PV). Criticism mostly refers to lack of standardization of distinctive BM features precluding correct morphological pattern recognition. The distinction between WHO-defined ET and prePMF is not trivial because outcome is significantly worse in prePMF. Morphology was generally considered to be non-specific for the diagnosis of PV. Recent studies have revealed under-diagnosis of morphologically and biologically consistent PV.

Hematologic malignancies during pregnancy: A review

Malignancy is the second most common cause of mortality in the reproductive period and it complicates up to one out of every 1000 pregnancies. When cancer is diagnosed during pregnancy, the management approach must take into consideration both the mother and her fetus. Hematologic cancers diagnosed in pregnancy are not common, resulting in paucity of randomized controlled trials. Diagnosis of such malignancies may be missed or delayed, as their symptoms are similar to those encountered during normal pregnancy. Also, many imaging studies may be hazardous during pregnancy. Management of these malignancies during pregnancy induces many treatment-related risks for mother and baby and should consider patient's preferences for pregnancy continuation. In this article, hematologic malignancies diagnosed in pregnant patients including acute leukemias, chronic myeloid leukemia, lymphomas, multiple myeloma and myeloproliferative neoplasms, will be reviewed, including diagnostic and management strategies and their impact on the pregnant patient and the developing fetus.

[Inherited primitive and secondary polycythemia]

Myeloproliferative disorders and secondary polycythemia cover most of the polycythemia cases encountered in daily practice. Inherited polycythemias are rare entities that have to be suspected when the classical causes of acquired polycythemia have been ruled out. Recent advances were made in the understanding of these pathologies, which are still little known to the physicians. This review reports the state of knowledge and proposes an algorithm to follow when confronted to a possible case of inherited polycythemia.

Clinical impact of bone marrow morphology for the diagnosis of essential thrombocythemia: comparison between the BCSH and the WHO criteria

Essential thrombocythemia (ET) is currently diagnosed either by the British Committee of Standards in Haematology (BCSH) criteria that are predominantly based on exclusion and not necessarily on bone marrow (BM) morphology, or the World Health Organization (WHO) criteria that require BM examination as essential criterion. We studied the morphological and clinical features in patients diagnosed according either to the BCSH (n=238) or the WHO guidelines (n=232). The BCSH-defined ET cohort was re-evaluated by applying the WHO classification. At presentation, patients of the BCSH group showed significantly higher values of serum lactate dehydrogenase and had palpable splenomegaly more frequently. Following the WHO criteria, the re-evaluation of the BCSH-diagnosed ET cohort displayed a heterogeneous population with 141 (59.2%) ET, 77 (32.4%) prefibrotic primary myelofibrosis (prePMF), 16 (6.7%) polycythemia vera and 4 (1.7%) primary myelofibrosis. Contrasting WHO-confirmed ET, the BCSH cohort revealed a significant worsening of fibrosis-free survival and prognosis. As demonstrated by the clinical data and different outcomes between WHO-diagnosed ET and prePMF, these adverse features were generated by the inadvertent inclusion of prePMF to the BCSH group. Taken together, the diagnosis of ET without a scrutinized examination of BM biopsy specimens will generate a heterogeneous cohort of patients impairing an appropriate clinical management.

Rationale for revision and proposed changes of the WHO diagnostic criteria for polycythemia vera, essential thrombocythemia and primary myelofibrosis

The 2001/2008 World Health Organization (WHO)-based diagnostic criteria for polycythemia vera (PV), essential thrombocythemia (ET) and primary myelofibrosis (PMF) were recently revised to accomodate new information on disease-specific mutations and underscore distinguishing morphologic features. In this context, it seems to be reasonable to compare first major diagnostic criteria of the former WHO classifications for myeloproliferative neoplasm (MPN) and then to focus on details that have been discussed and will be proposed for the upcoming revision of diagnostic guidelines. In PV, a characteristic bone marrow (BM) morphology was added as one of three major diagnostic criteria, which allowed lowering of the hemoglobin/hematocrit threshold for diagnosis, which is another major criterion, to 16.5 g/dl/49% in men and 16 g/dl/48% in women. The presence of a JAK2 mutation remains the third major diagnostic criterion in PV. Subnormal serum erythropoietin level is now the only minor criterion in PV and is used to capture JAK2-unmutated cases. In ET and PMF, mutations that are considered to confirm clonality and specific diagnosis now include CALR, in addition to JAK2 and MPL. Also in the 2015 discussed revision, overtly fibrotic PMF is clearly distinguished from early/prefibrotic PMF and each PMF variant now includes a separate list of diagnostic criteria. The main rationale for these changes was to enhance the distinction between so-called masked PV and JAK2-mutated ET and between ET and prefibrotic early PMF. The proposed changes also underscore the complementary role, as well as limitations of mutation analysis in morphologic diagnosis. On the other hand, discovery of new biological markers may probably be expected in the future to enhance discrimination of the different MPN subtypes in accordance with the histological BM patterns and corresponding clinical features.