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

A safety evaluation of ruxolitinib for the treatment of polycythemia vera

INTRODUCTION

Polycythemia Vera (PV) is a chronic myeloproliferative neoplasm hallmarked by deregulated proliferation of hematopoietic stem cells leading to prevalent expansion of red cell mass, increased rate of vascular events, splenomegaly, disease-associated symptoms, and risk of evolution to secondary myelofibrosis and blast phase. PV is pathogenetically associated with autonomously persistent activation of JAK2, which causes overproduction of blood cells and an inflammatory condition responsible for the clinical manifestations of the disease. Extensively supported by preclinical studies, targeting JAK2-dependent signaling represents a rational therapeutic approach to PV, finally leading to the approval of ruxolitinib, a JAK1/2 inhibitor.

AREAS COVERED (LITERATURE RESEARCH)

We analyzed reports of phase 2 and phase 3 trials with ruxolitinib in PV and relevant literature dealing with efficacy and safety aspects, including most recent real-world reports.

EXPERT OPINION

Ruxolitinib is the only JAK2 inhibitor approved for the treatment of PV with well-known efficacy for splenomegaly, symptoms, and potentially reduction of vascular events. The treatment regimen is notably manageable and safe, with the most prevalent side effects primarily encompassing myelosuppression, hyperlipidemia, non-melanoma skin cancer and infections, mainly reactivation of Herpes Zoster. These effects necessitate ongoing surveillance and proactive preventive measures.

Associations of Long-Term Exposure to PM2.5 and Its Constituents with Erythrocytosis and Thrombocytosis in Rural Populations

Evidence on the effect of long-term exposure to fine particulate matter (PM2.5) on erythrocytosis and thrombocytosis prevalence was limited. We aimed to investigate the association of PM2.5 and its constituents with the risks of erythrocytosis and thrombocytosis. The present study included a total of 33,585 participants from the Henan Rural Cohort at baseline between 2015 and 2017. A hybrid satellite-based model was employed to estimate the concentrations of PM2.5 mass and its constituents (including black carbon [BC], nitrate [NO3-], ammonium [NH4+], inorganic sulfate [SO42-], organic matter [OM], and soil particles [SOIL]). The logistic regression model was used to assess the associations of single exposure to PM2.5 and its constituents with the risks of erythrocytosis and thrombocytosis, and the quantile G-computation method was applied to evaluate their joint exposure risk. For the independent association, the odds ratios for erythrocytosis/thrombocytosis with 1 μg/m3 increase was 1.049/1.043 for PM2.5 mass, 1.596/1.610 for BC, 1.410/1.231 for NH4+, 1.205/1.139 for NO3-, 1.221/1.359 for OM, 1.300/1.143 for SO42-, and 1.197/1.313 for SOIL. Joint exposure to PM2.5 and its components was also positively associated with erythrocytosis and thrombocytosis. The estimated weight of NH4+ was found to be the largest for erythrocytosis, while OM had the largest weight for thrombocytosis. PM2.5 mass and its constituents were positively linked to prevalent erythrocytosis and thrombocytosis, both in single-exposure and joint-exposure models. Additionally, NH4+/OM was identified as a potentially responsible component for the association between PM2.5 and erythrocytosis/thrombocytosis.

Survey on the usage of therapeutic erythrocytapheresis in transfusion services in Italy for the treatment of polycythemia vera, secondary erythrocytosis and hemochromatosis

INTRODUCTION

Erythrocytapheresis, an apheresis treatment which selectively removes red blood cells, is an alternative to therapeutic phlebotomy, over which it has several advantages. Actually there is a high degree of variability in the use of this treatment. This prompted SIdEM (Italian Society of Hemapheresis and Cell Manipulation) to conduct a survey on the use of erythrocytapheresis in the Italian Transfusion Services. The purpose is to monitor this activity in the treatment of Polycythemia Vera (pv), secondary erythrocytosis and hemochromatosis.

MATERIALS AND METHODS

A data collection file was sent to the SIdEM regional delegates who, in turn, involved the Transfusion Centers in the areas they cover. The data collected were processed on a Microsoft Excel spreadsheet.

RESULTS

75 centers from 14 Italian regions responded to the Survey: 36 centers (48 %) use erythrocytapheresis (35 centers perform therapeutic apheresis and 1 center only donor apheresis), 39 centers (52 %) do not (15 centers perform therapeutic apheresis, 18 centers only donor apheresis and 6 centers do not perform either therapeutic apheresis or donor apheresis). Although most centers have a substantially uniform attitude concerning the indications for which erythrocytapheresis is used, the survey shows that there are still differences more evident in the treatment of secondary erythrocytosis than in the treatment of pv or hemochromatosis.

CONCLUSIONS

This survey has been useful to document the current Italian reality and to raise awareness about the need for improvement in optimizing and standardizing the use of a therapy with a great potential to exploit properly.

Biochemical and Hematological Indexes of Liver Dysfunction in Horses

In the present review, the authors, based on the multiple functions performed by the liver, analyze the multiple biochemical and hematological changes as an expression of altered liver function in the horse. The liver performs important metabolic functions related to the synthesis, degradation, and excretion of various substances. Modification of these functions can be evaluated and diagnosed by determining serum concentrations of several serum analytes, including enzymes and other endogenous substances. Hepatocellular enzymes, such as sorbitol dehydrogenase-SDH and glutamate dehydrogenase-GLDH, are released following hepatocellular necrosis. Hepatobiliary enzymes, such as γ-glutamyl transferase-GGT, increase in response to necrosis, cholestasis, and other alterations in bile conducts. Serum concentrations of mainly endogenous and exogenous substances that the liver should synthesize or eliminate, such as proteins (albumin and globulins), bile acids, urea, glucose, total and direct bilirubin, and coagulation factors, and fibrinogen should be included in the liver function test profile. The interpretation of laboratory tests of liver function will allow the diagnosis of functional loss of the organ. Some of the analytes considered provide information on the prognosis of liver disease. This review will provide an accurate and objective interpretation of the common biochemical and hematological tests in use in the diagnosis of equine hepatic disease patients, aiding still further the veterinary activity on the applied equine clinical cases.

A Screening Approach for Inherited Erythrocytosis due to the VHL:c.598C > T Mutation (Chuvash Polycythemia)

Genetic work-up of unexplained erythrocytosis that is suspected to be inherited in nature currently requires either laborious exon-by-exon gene panel testing by Sanger sequencing or expensive next-generation sequencing. A high prevalence of Chuvash polycythemia (61%) has been previously reported among north Indian erythrocytosis patients. We assessed PCR-RFLP for VHL c.598C > T mutation as a first-line test in 99 persons with JAK2 V617F-negative, unexplained erythrocytosis. We enrolled two groups: Group A (n = 38) had erythrocytosis patients (n = 33) or their first-degree relatives (n = 5), and, Group B with 61 healthy blood donation volunteers who were deferred after the discovery of unexplained high hemoglobin levels. Detailed history and clinical examination, hemogram, erythropoietin levels and PCR-RFLP for the VHL:c.598C > T;p.R200W mutation were done. In Group A, three (8%) persons aged 9, 13 and 30-years were homozygous for VHL:c.598C > T. Two were heterozygous (parents of a known case of Chuvash polycythemia). None of the Group B subjects had the Chuvash mutation. Erythropoietin levels in group A were low in 5/26 cases (19%) and normal in 18/26 (69%). In Group B, seven (11%) donors had normal values while the remaining 54 (89%) had high erythropoietin levels. Despite a lower frequency (8%) compared to literature, our results suggest that the relatively simpler PCR-RFLP for VHL:c.598C > T mutation may be considered for the initial genetic screening of unexplained, suspected congenital erythrocytosis in regions where Chuvash polycythemia comprises a large proportion of inherited erythrocytosis, after polycythemia vera and common acquired secondary causes are excluded.

Supplementary Information

The online version contains supplementary material available at 10.1007/s12288-023-01668-9.

Testosterone Usage Leading to Pulmonary Embolisms and Deep Vein Thrombosis: A Case Report and Review of the Literature

Androgen usage has widely increased in recent times via prescribed and unprescribed means. Testosterone is a popular androgen taken by both athletes and the general population. While there is some evidence of androgens being thrombogenic, we report on a 19-year-old male who presented to the hospital after the usage of testosterone for one month, leading to the development of multiple pulmonary emboli and deep vein thrombosis. The authors hope to elucidate the relationship between testosterone usage and thrombosis formation.

Secondary erythrocytosis

INTRODUCTION

Erythrocytosis is associated with an elevation of the hemoglobin level above 16.5 g/dL in men and above 16 g/dL in women and an elevation of the hematocrit level above 49% in men and > 48% in women. In primary erythrocytosis, the defect is a clonal disorder in the myeloid compartment of the bone marrow, leading to an increased red cell production. Secondary erythrocytosis is the result of external stimuli to the bone marrow, leading to the production of red cells in excess. Secondary erythrocytosis is more common than primary erythrocytosis and has a broad differential diagnosis.

AREAS COVERED

This review will discuss secondary erythrocytosis, its causes, clinical presentation, and both diagnostic and therapeutic approaches.

EXPERT OPINION

Although secondary erythrocytosis is more common than PV, there are still challenges and difficulties associated with the distinction between these two conditions. Moreover, there is a paucity of data and guidance when it comes to the management of certain congenital and acquired conditions. A pragmatic approach is recommended in order to identify the cause for this condition. Treatment should be directed at the management of the underlying cause.

Revisiting the impact of serial therapeutic phlebotomy in polycythaemia on laboratory and clinical parameters using a fixed interval and fixed volume protocol

OBJECTIVES

Therapeutic phlebotomy allows for a controlled and gradual decrease in red cell mass leading to improved blood flow and symptomatic relief in polycythaemia. The present study was aimed to determine the impact of serial fixed volume and fixed interval therapeutic phlebotomy protocol on the laboratory and clinical parameters in patients of polycythaemia.

MATERIAL AND METHODS

This prospective longitudinal study was conducted over 18 months. The desired haematocrit for polycythemia vera and secondary polycythemia was 45% and 52% respectively. A fixed volume of 350 ml phlebotomy was performed every-three days till the achievement of desired haematocrit. Complete blood count was performed before and after each procedure and iron studies were done at the time of enrolment and after the achievement of desired haematocrit. Post-procedure symptomatic relief was assessed by a 10-point visual analogue scale (VAS).

RESULTS

Of the 29 patients enrolled in the study, 3 patients were lost to follow up and data of 26 patients was analyzed. Mean Hb declined from 17.84 ± 1.88 gdL^-1 to 14.67 ± 1.14 gdL^-1 (p < 0.001) and mean haematocrit decreased from a baseline of 57.11 ± 5.47% to 46.27 ± 3.763% (p < 0.001) upon achievement of desired haematocrit. There was a significant decline in serum iron from the baseline of 132.85 ± 94.136 μg dL^-1 to 69.41 ± 58.643 μg dL^-1 at desired haematocrit. A significant change in VAS score of almost all clinical parameters was observed. Post phlebotomy hematocrit correlated negatively with the number of procedures (p = 0.015).

CONCLUSION

Our protocol yielded rapid and marked improvement in patients of primary and secondary polycythemia with minimal adverse events and significant amelioration of clinical parameters.

Hemoglobin modulation affects physiology and patient reported outcomes in anemic and non-anemic subjects: An umbrella review

Background: An abnormal hemoglobin concentration has a substantial effect on a person's quality of life and physiology. Lack of tools that effectively evaluate hemoglobin-related outcomes leads to uncertainty regarding optimal hemoglobin levels, transfusion thresholds and treatment targets. We therefore aim to summarize reviews that assess the effects of hemoglobin modulation on the human physiology at various baseline hemoglobin levels, and identify gaps in existing evidence. Methods: We conducted an umbrella review of systematic reviews. PubMed, MEDLINE (OVID), Embase, Web of Science, Cochrane Library and Emcare were searched from inception to the 15th of April 2022 for studies that reported on physiological and patient reported outcomes following a hemoglobin change. Results: Thirty-three reviews were included of which 7 were scored as of high quality and 24 of critically low quality using the AMSTAR-2 tool. The reported data generally show that an increase in hemoglobin leads to improvement of patient reported and physical outcomes in anaemic and non-anaemic subjects. At lower hemoglobin levels, the effect of a hemoglobin modulation on quality of life measures appears more pronounced. Conclusion: This overview has revealed many knowledge gaps due to a lack of high-quality evidence. For chronic kidney disease patients, a clinically relevant benefit of increasing the hemoglobin levels up until 12 g/dL was found. However, a personalized approach remains necessary due to the many patient-specific factors that affect outcomes. We strongly encourage future trials to incorporate physiological outcomes as objective parameters together with subjective, but still very important, patient reported outcome measures.

Prevalence of elevated hemoglobin and hematocrit levels in patients with obstructive sleep apnea and the impact of treatment with continuous positive airway pressure: a meta-analysis

OBJECTIVES

Obstructive sleep apnea (OSA) is reported to be a cause of secondary polycythemia. The present study (i) reviewed the literature reporting the prevalence of secondary polycythemia in patients with OSA and (ii) determined the effect of continuous positive airway pressure (CPAP) therapy on hemoglobin and hematocrit levels in patients with OSA.

METHODS

We searched MEDLINE, Embase and Cochrane for studies of adult patients with OSA that reported hemoglobin and/or hematocrit levels. We performed summary estimates of (i) polycythemia prevalence and a subgroup analysis according to OSA severity, and (ii) change in hemoglobin and hematocrit levels following treatment with CPAP.

RESULTS

Synthesis of seven studies including 3,654 patients revealed an overall polycythemia prevalence of 2% (95% CI 1-4%); 2% (95% CI 1-3%) in mild-to moderate and 6 % (95% CI 3-12%) in severe OSA. In the pooled analysis of ten single-arm trials including 434 patients, CPAP treatment reduced hemoglobin by 3.76 g/L (95% CI -4.73 to -2.80 g/L). Similarly, pooled analysis of ten single-arm trials including 356 patients without baseline polycythemia showed that CPAP treatment reduced hematocrit by 1.1% (95% CI -1.4 to -0.9%).

CONCLUSION

Our pooled analysis supports an increased prevalence of secondary polycythemia in OSA. This estimated prevalence is likely underestimated due to the change in the polycythemia diagnostic criteria in 2016. Future randomized controlled trials are needed to evaluate the effect of CPAP in patients with baseline polycythemia.

HIGHLIGHTS

Pooled analysis shows OSA is associated with an increased prevalence of secondary polycythemiaPrevalence of polycythemia is greater in severe OSACPAP treatment for OSA reduces both the hemoglobin and hematocrit.

Ruxolitinib in a Child With JAK2 Exon 12 Mutant Polycythemia Vera

BACKGROUND

Polycythemia Vera (PV) is a well-defined disorder of erythroid hyperproliferation that can result in life-threatening thromboembolic and hemorrhagic events. It is most prevalent in adults and is caused by mutations in Janus Kinase 2 (JAK2). Predominantly, PV is caused by a JAK2V617F mutation on exon 14.

OBSERVATIONS

A rare case of PV in a 9-year-old, driven by an uncommon, p.Glu543_Asp544del, JAK2 exon 12 mutation. Despite management with phlebotomy, aspirin and hydroxyurea, the patient suffered a dural sinus venous thrombosis, prompting a change in therapy to Ruxolitinib.

CONCLUSIONS

This is the first description of the successful use of ruxolitnib to treat a pediatric patient with PV caused by a JAK2 exon 12 mutation.

Effects of idiopathic erythrocytosis on the left ventricular diastolic functions and the spectrum of genetic mutations: A case control study

BACKGROUND

We have aimed at exposing left ventricular diastolic functions and the presence of known genetic mutations for familial erythrocytosis, in patients who exhibit idiopathic erythrocytosis.

METHODS

Sixty-four patients with idiopathic erythrocytosis (mean age, 46.4 ± 2.7 years) and 30 age-matched healthy subjects were prospectively evaluated. The regions of interest of the erythropoietin receptor, hemoglobin beta-globin, von Hippel-Lindau, hypoxia-inducible factor 2 alpha, and Egl-9 family hypoxia-inducible factor genes were amplified by PCR. Left ventricular (LV) mass was measured by M-mode and 2-dimensional echocardiography. LV diastolic functions were assessed by conventional echocardiography and tissue Doppler imaging.

RESULTS

As a result of genetic analyses, genetic mutations for familial erythrocytosis were detected in 5 patients. It has been observed in our study that the risk of cardiovascular disorders is higher in patients. Interventricular septum thickness, left atrial diameter, and some diastolic function parameters such as deceleration time and isovolumetric relaxation time have been found to be significantly higher in idiopathic erythrocytosis group than in the controls.

CONCLUSION

This study has shown that LV diastolic functions were impaired in patients with idiopathic erythrocytosis. In this patient group with increased risk of cardiovascular disorders, the frequent genetic mutations have been detected in 5 patients only. Therefore, further clinical investigations are needed as novel genetic mutations may be discovered in patients with idiopathic erythrocytosis because of cardiovascular risk.

The Paradigm Shift from Polycythemia to Anemia in COPD: The Critical Role of the Renin-Angiotensin System Inhibitors

INTRODUCTION

Although polycythemia has been considered a common adverse event in COPD, anemia is reported more often and has gained more importance than polycythemia over the last thirty years.

AREAS COVERED

Factors considered to be associated with the development of anemia in COPD have included: Aging and kidney dysfunction with erythropoietin deficiency and bone marrow suppression due to uremic toxins; heart failure (HF), which is often encountered in COPD and is accompanied by anemia in one third of the cases; Low-grade chronic inflammation, which can directly suppresses the bone marrow and diminish iron absorption and utilization via increased hepcidin levels; long-term oxygen therapy (LTOT), which ameliorates chronic hypoxia, and most important, RAS inhibitors, which are widely used for the co-morbidities associated with COPD (hypertension, HF, CKD, diabetes) and have previously been shown to lower hematocrit values or cause anemia in various clinical conditions.

EXPERT OPINION

Introduction of LTOT in COPD and especially the established use of RAS inhibitors form the basis for the shift from polycythemia to anemia in COPD. Interestingly, when the SGLT2 inhibitors are introduced for cardiorenal protection in COPD, one could anticipate correction of anemia or even reemergence of polycythemia, since this new class of drugs can augment erythropoietin secretion and increase hematocrit values.

Is obstructive sleep apnea associated with erythrocytosis? A systematic review and meta‐analysis

Objective

The aim of this systematic review and meta‐analysis was to investigate the association between obstructive sleep apnea (OSA) and erythrocytosis.

Methods

The PubMed, Web of Science, and Cochrane Library databases were searched for articles examining hematocrit values in patients with OSA and control individuals published till September 1, 2021. The pooled standardized mean difference (SMD) with 95% confidence interval (CI) was calculated, and subgroup analyses were performed.

Results

Eleven eligible studies with a total of 4608 patients with OSA were included in this meta‐analysis. Pooled outcomes revealed that hematocrit values were significantly higher in patients with OSA than in controls (SMD, 0.19; 95% CI, 0.08–0.29; p < .01). When studies were stratified by disease severity, the significant differences in hematocrit values between patients and controls were only observed in the severe OSA group (SMD, 0.34; 95% CI, 0.08–0.59; p < .01), but not in the mild and moderate OSA groups. In subgroup analyses according to sex and publication year, significant differences in hematocrit values between patients and controls remained stable in studies with only female patients (SMD, 0.25; 95% CI, 0.12–0.38; p < .01) and in studies published after 2012 (SMD, 0.17; 95% CI, 0.06–0.28, p < .01).

Conclusion

Our meta‐analysis revealed that the hematocrit value was significantly increased in patients with OSA, particularly in severe patients, compared with that in controls. However, the elevation was modest, and the hematocrit value is expected to be within the normal range in patients with OSA. These data suggest that OSA leads to slight increases in hematocrit but does not cause clinically significant erythrocytosis.

Thrombophilia and hormonal therapy in transgender persons: A literature review and case series

Background: Venous thromboembolism (VTE) is a rare side effect of hormonal therapy in transgender persons. Prothrombotic genetic variants can increase this risk. For this reason, previous VTE and/or genetic thrombophilia may be considered by some as contraindications to hormonal treatment. Aim: To formulate directions for clinical practice about the indications for thrombophilia screening and when to consider combination therapy of therapeutic anticoagulation and hormonal treatment as a safe alternative to withholding hormonal treatment. Methods: We conducted a literature search and describe a case series. All adult patients with gender dysphoria and a known prothrombotic genetic variant or history of VTE were invited by letter to participate in this study. Results: In our center, thrombophilia screening before start of hormonal treatment was restricted to those with a personal or family history of VTE. Sixteen individuals with a history of VTE and/or an underlying prothrombogenic condition were described. The time of follow up varied from 4 months to 20 years. Seven trans women had a positive thrombophilia screening (2 Factor V Leiden (FVL), 1 FVL + anticardiolipin antibodies, 1 FVL + high Factor VIII coagulant activity, 1 protein C deficiency, 1 prothrombin mutation, 1 positive lupus anticoagulant). Three trans women experienced an unprovoked VTE after start of hormonal therapy of which one lead to a positive thrombophilia screening. One VTE event in a trans woman was assumed to be provoked by surgery. Five trans men were identified with a prothrombogenic mutation (3 FVL, 1 protein C deficiency, 1 prothrombin mutation). One trans man, with a negative thrombophilia screen, experienced multiple provoked VTE events before start of hormonal therapy. Conclusion: Based on our literature review and case series we offer guidance when confronted with patients with previous VTE and/or genetic thrombophilia requesting hormonal interventions.

Testosterone therapy and secondary erythrocytosis

Secondary erythrocytosis is one of the most common adverse events associated with testosterone therapy (TT). Upon encountering this, clinicians will often either adjust TT dosing, stop therapy, order a phlebotomy, or recommend a combination of these. Despite this, the evidence for secondary polycythemia causing harm during TT is scarce, and the hematocrit-based cutoffs present in multiple guidelines appear to be arbritrarily chosen. In this review, we present the pathophysiology behind TT and secondary erythrocytosis, the evidence connecting TT, secondary erythrocytosis and major adverse cardiovascular events (MACE), and the data supporting varying interventions upon diagnosis of secondary erythrocytosis.

Clinical Characteristics of Pediatric Patients with Congenital Erythrocytosis: A Single-Center Study

Although congenital erythrocytosis (CE), an inherited disorder, impairs pediatric quality of life, physicians often overlook high hemoglobin (Hgb) levels and its symptoms due to lack of knowledge of age-adjusted pediatric Hgb levels and CE's rarity. In a retrospective, single-center study, data from hospital records of pediatric patients diagnosed with CE were evaluated. Twenty-six patients from 25 families (80.8% male) had been diagnosed with CE in 20 years, at a mean age of 14.9 ± 2.8 years (8.3-17.8) and with a mean Hgb level of 17.36 ± 1.44 g/dL (14.63-22.1). No serum erythropoietin levels exceeded the reference levels. Although the most common symptom was headache (85%), 38% of patients presented with at least one gastrointestinal symptom (e.g., nausea, vomiting, abdominal pain, and rectal bleeding), and 54% exhibited plethora. No patient had leukocytosis, thrombocytosis, JAK2 mutation; capillary oxygen saturation, venous blood gas analysis, and Hgb electrophoresis revealed no abnormalities. While 34.6% of patients had family histories of CE, 42.3% had 15-45-year-old relatives who had experienced myocardial infarction, stroke, and/or sudden death. Aspirin was routinely prescribed, and phlebotomy was performed when hyperviscosity symptoms were present. To detect CE, physicians should consider age-adjusted normal Hgb levels in children. Pediatric patients with CE may also present with gastrointestinal symptoms. Although no thrombotic episode occurred among the patients, their family histories included life-threatening thrombotic episodes, even in adolescents.

Risk factors and outcomes of post-transplant erythrocytosis among adult kidney transplant recipients: a systematic review and meta-analysis

Post-transplant erythrocytosis (PTE) can occur in up to 10-16% after kidney transplant (KT). However, the post-transplant outcomes of recipients with PTE in the literature were conflicting. We performed systematic review and meta-analysis of published studies to evaluate risk factors of PTE as well as outcomes of recipients who developed PTE compared with controls. A literature search was conducted evaluating all literature from existence through February 2, 2021, using MEDLINE and EMBASE. Data from each study were combined using the random-effects model. (PROSPERO: CRD42021230377). Thirty-nine studies from July 1982 to January 2021 were included (7,099 KT recipients). The following factors were associated with PTE development: male gender (pooled RR = 1.62 [1.38, 1.91], I²  = 39%), deceased-donor KT (pooled RR = 1.18 [1.03, 1.35], I²  = 32%), history of smoking (pooled RR = 1.36 [1.11, 1.67], I²  = 13%), underlying polycystic kidney disease (PKD) (pooled RR=1.56 [1.21, 2.01], I² =44%), and pretransplant dialysis (pooled RR=1.6 [1.02, 2.51], I² =46%). However, PTE was not associated with outcomes of interest, including overall mortality, death-censored graft failure, and thromboembolism. Our meta-analysis demonstrates that male gender, deceased-donor KT, history of smoking, underlying PKD, and pretransplant dialysis were significantly associated with developing PTE. However, with proper management, PTE has no impact on prognosis of KT patients.

High-throughput determination of oxygen dissociation curves in a microplate reader-A novel, quantitative approach

In vitro determination of the hemoglobin oxygen dissociation curve (ODC) requires highly elaborate, specialized, and costly technical equipment. In addition, there is a lack of methods that combine reliable ODC recordings with high throughput in small blood samples for routine analysis. We here introduce a modified, commercial 96-well plate with an integrated unidirectional gas flow system specifically adapted for use in fluorescence microplate readers. Up to 92 samples of whole or hemolyzed, buffered or unbuffered blood, including appropriate controls or internal standard hemoglobin solutions, can be analyzed within ~25 min. Oxygen saturation is measured in each well with dual wavelength spectroscopy, and oxygen partial pressure using fluorescence lifetime of commercial oxygen sensors at the in- and outlet ports of the gas-flow system. Precision and accuracy of this method have been determined and were compared with those of a standard method. We further present two applications that exemplarily highlight the usefulness and impact of this novel approach for clinical diagnostics or basic research.

A New High Affinity Hemoglobin Variant: Hb San Francisco-KP (HBB: c.104T>C)

The evaluation of erythrocytosis can fail to detect hemoglobin (Hb) variants if a thorough and systemic investigation is not undertaken. Here we report the identification of a novel high-oxygen affinity Hb that was previously misclassified as polycythemia vera (PV). Given that treatment recommendations can vary significantly based on the etiology of erythrocytosis, familiarity with reference laboratories and their methodologies is of crucial importance to conducting a precise consultation, as in the case of our Hb variant, named Hb San Francisco-KP [β34(B16)Val→Ala, HBB: c.104T>C] for the city and medical center where it was discovered. The Mayo Clinic's (Rochester, MN, USA) Erythrocytosis Evaluation (REVE) panel was instrumental in establishing a final diagnosis. Of note, the patient's clinical response to phlebotomy distinguishes this subtype from many of the other high affinity Hbs where the erythrocytosis is primarily compensatory and not in need of venesection.

Sex-specific associations between erythrocyte measures and obstructive sleep apnea

STUDY OBJECTIVES

Hypoxemic effects of obstructive sleep apnea (OSA) have been implicated in changes in erythropoiesis and hence erythrocyte measures. Sex differences are evident in both OSA and erythropoiesis. Whether sex modulates the relationship between severity of OSA and erythrocyte measures has not previously been studied.

METHODS

We examined a sample of 976 patients (38% women) who underwent overnight polysomnography and measurement of red blood cell count, hemoglobin, and hematocrit. Patients were divided into primary snoring and mild, moderate, and severe OSA groups, separately by sex.

RESULTS

In multiple regression models, we found significant interactions between sex and oxygen desaturation index and apnea-hypopnea index on erythrocyte measures. Higher oxygen desaturation index and higher apnea-hypopnea index were independently associated with higher red blood cell count, hemoglobin, and hematocrit in women but not in men. Further ordinal logistic regression analysis showed a significant association between oxygen desaturation index (odds ratio, 2.33; 95% confidence interval, 1.17-4.66) and apnea-hypopnea index (odds ratio, 2.44; 95% confidence interval, 1.23-4.84) and red blood cell count in women only. Correlation analysis also showed that erythrocyte measures and markers of cardiometabolic risk were more closely correlated in women than in men.

CONCLUSIONS

This study provides novel data suggesting a significant association between erythrocyte measures and OSA severity in women but not in men. Similarly, the relationship between hematologic metrics and cardiometabolic risk markers was more pronounced in women than in men. Our findings suggest a sex-specific impact of OSA on erythrocyte measures and on their relationship with indexes of cardiometabolic risk.

[A rare case of a functioning gonadotroph tumor accompanied by erythrocytosis in an elderly man]

Functioning gonadotroph adenomas are rare pituitary tumors secreting one or two gonadotropins (follicle-stimulating hormone (FSH) and/or luteinizing hormone (LH)), which are hormonally active. In the majority of cases, gonadotroph tumors are endocrinologically "silent" and make up more than a half of non-functioning pituitary adenomas. In this article we describe a rare clinical case of LH/FSH-secreting pituitary macroadenoma with bitemporal hemianopsia in a 62-year-old man. The patient underwent transnasal transsphenoidal adenomectomy, leading to remission. The distinctive feature of this case is the presence of secondary erythrocytosis due to endogenous hyperandrogenism, which required several blood exfusions to normaliza the level of hematocrit before surgery. It is noteworthy that clinical signs of erythrocytosis were present long before visual impairment. This clinical case demonstrates difficulties in the early diagnosis of functioning gonadotroph adenomas.

Successful use of phlebotomy to treat severe secondary polycythemia due to chronic lung disease

Secondary polycythemia (SP) occurs as a result of increase erythropoietin levels most commonly as a result of tissue hypoxia. Symptoms such as erythromelalgia, pruritis, and bleeding, which are frequently seen in polycythemia vera (PV), do not commonly occur in SP. Phlebotomy is considered one of the mainstays of therapy for PV but is rarely used for treatment of SP due to concern about worsening tissue hypoxia. We present the case of a patient with severe SP due to chronic hypoxic lung disease who presented with erythromelalgia, pruritis, and bleeding and was treated successfully with therapeutic phlebotomy. This case illustrates the importance of considering the use of therapeutic phlebotomy in symptomatic patients with severe SP.

Haematocrit level in obesity hypoventilation syndrome: a predictor of mortality?

BACKGROUND

The connection between obstructive sleep apnea and secondary erythrocytosis is controversial. We hypothesised that there may be a higher prevalence of erythrocytosis in patients with obesity hypoventilation syndrome (OHS) due to persistent hypoxemia.

METHODS

The study was a retrospective, cross-sectional review of patients with OHS derived from an established cohort of "non-invasive ventilation" patients at the Department of Sleep Medicine at the Royal Infirmary Medical Centre, Edinburgh (2004-2017). Relevant clinical data were obtained from patient records.

RESULTS

The cohort comprised 74 patients with OHS, 44 men (60%), mean age at diagnosis 54 ± 10 years. The mean haematocrit level for the group overall was 0.44, in men 0.45, and in women 0.41. Of 11 patients with erythrocytosis (15%), 7 were men. Thirteen patients (18%) died during follow-up (2004-2017). There was a statistically significant increase in risk of death in patients with higher and lower haematocrit levels compared to that in patients with OHS who had normal haematocrits.

CONCLUSIONS

This is the first study showing increased prevalence of erythrocytosis in OHS patients. There was a "U"-shaped correlation with mortality according to haematocrit levels.

Diagnosis and management of non-clonal erythrocytosis remains challenging: a single centre clinical experience

Erythrocytosis has a diverse background. While polycythaemia vera has well defined criteria, the diagnostic approach and management of other types of erythrocytosis are more challenging. The aim of study was to retrospectively analyse the aetiology and management of non-clonal erythrocytosis patients referred to a haematology outpatient clinic in an 8-year period using a 3-step algorithm. The first step was inclusion of patients with Hb > 185 g/L and/or Hct > 0.52 in men and Hb > 165 g/L and/or Hct > 0.48 in women on two visits ≥ two months apart, thus confirming true erythrocytosis. Secondly, polycythaemia vera was excluded and secondary causes of erythrocytosis (SE) identified. Thirdly, idiopathic erythrocytosis patients (IE) were referred to next-generation sequencing for possible genetic background evaluation. Of the 116 patients, 75 (65%) are men and 41 (35%) women, with non-clonal erythrocytosis 34/116 (29%) had SE, 15/116 (13%) IE and 67/116 (58%) stayed incompletely characterized (ICE). Patients with SE were significantly older and had significantly higher Hb and Hct compared to patients with IE. Most frequently, SE was attributed to obstructive sleep apnoea and smoking. Phlebotomies were performed in 56, 53 and 40% of patients in the SE, IE, and ICE group, respectively. Approx. 70% of patients in each group received aspirin. Thrombotic events were registered in 12, 20 and 15% of SE, IE and ICE patients, respectively. Congenital erythrocytosis type 4 (ECYT4) was diagnosed in one patient. The study demonstrates real-life management of non-clonal erythrocytosis which could be optimized using a 3-step diagnostic algorithm.

Erythrocytosis in a Large Cohort of Trans Men Using Testosterone: A Long-Term Follow-Up Study on Prevalence, Determinants, and Exposure Years

CONTEXT

Erythrocytosis is a known side effect of testosterone therapy that can increase the risk of thromboembolic events.

OBJECTIVES

To study the prevalence and determinants in the development of erythrocytosis in trans men using testosterone.

METHODS

A 20-year follow-up study in adult trans men who started testosterone therapy and had monitoring of hematocrit at our center (n = 1073).

RESULTS

Erythrocytosis occurred in 11% (hematocrit > 0.50 L/L), 3.7% (hematocrit > 0.52 L/L), and 0.5% (hematocrit > 0.54 L/L) of trans men. Tobacco use (odds ratio [OR] 2.2; 95% CI, 1.6-3.3), long-acting undecanoate injections (OR 2.9; 95% CI, 1.7-5.0), age at initiation of hormone therapy (OR 5.9; 95% CI, 2.8-12.3), body mass index (BMI) (OR 3.7; 95% CI, 2.2-6.2), and pulmonary conditions associated with erythrocytosis and polycythemia vera (OR 2.5; 95% CI, 1.4-4.4) were associated with hematocrit > 0.50 L/L. In the first year of testosterone therapy hematocrit increased most: 0.39 L/L at baseline to 0.45 L/L after 1 year. Although there was only a slight continuation of this increase in the following 20 years, the probability of developing erythrocytosis still increased (10% after 1 year, 38% after 10 years).

CONCLUSION

Erythrocytosis occurs in trans men using testosterone. The largest increase in hematocrit was seen in the first year, but also after the first years a substantial number of people present with hematocrit > 0.50 L/L. A reasonable first step in the care for trans men with erythrocytosis while on testosterone is to advise them to quit smoking, to switch to a transdermal administration route, and if BMI is high, to lose weight.

Recent Advances in the Use of Molecular Analyses to Inform the Diagnosis and Prognosis of Patients with Polycythaemia Vera

Genetic studies in the past decade have improved our understanding of the molecular basis of the BCR-ABL1-negative myeloproliferative neoplasm (MPN) polycythaemia vera (PV). Such breakthroughs include the discovery of the JAK2V617F driver mutation in approximately 95% of patients with PV, as well as some very rare cases of familial hereditary MPN caused by inherited germline mutations. Patients with PV often progress to fibrosis or acute myeloid leukaemia, both associated with very poor clinical outcome. Moreover, thrombosis and major bleeding are the principal causes of morbidity and mortality. As a result of increasingly available and economical next-generation sequencing technologies, mutational studies have revealed the prognostic relevance of a few somatic mutations in terms of thrombotic risk and risk of transformation, helping to improve the risk stratification of patients with PV. Finally, knowledge of the molecular basis of PV has helped identify targets for directed therapy. The constitutive activation of the tyrosine kinase JAK2 is targeted by ruxolitinib, a JAK1/JAK2 tyrosine kinase inhibitor for PV patients who are resistant or intolerant to cytoreductive treatment with hydroxyurea. Other molecular mechanisms have also been revealed, and numerous agents are in various stages of development. Here, we will provide an update of the recent published literature on how molecular testing can improve the diagnosis and prognosis of patients with PV and present recent advances that may have prognostic value in the near future.

Congenital erythrocytosis

Erythrocytosis, or increased red cell mass, may be labeled as primary or secondary, depending on whether the molecular defect is intrinsic to the red blood cells/their precursors or extrinsic to them, the latter being typically associated with elevated erythropoietin (EPO) levels. Inherited/congenital erythrocytosis (CE) of both primary and secondary types is increasingly recognized as the cause in many patients in whom acquired, especially neoplastic causes have been excluded. During the past two decades, the underlying molecular mechanisms of CE are increasingly getting unraveled. Gain-in-function mutations in the erythropoietin receptor gene were among the first to be characterized in a disorder termed primary familial and congenital polycythemia. Another set of mutations affect the components of the oxygen-sensing pathway. Under normoxic conditions, the hypoxia-inducible factor (HIF), upon hydroxylation by the prolyl-4-hydroxylase domain protein 2 (PHD2) enzyme, is degraded by the von Hippel-Lindau protein. In hypoxic conditions, failure of prolyl hydroxylation leads to stabilization of HIF and activation of the EPO gene. CE has been found to be caused by loss-of-function mutations in VHL and PHD2/EGLN1 as well as gain-of-function mutations in HIF-2α (EPAS1), all resulting in constitutive activation of EPO signaling. Apart from these, globin gene mutations leading to formation of high oxygen affinity hemoglobins also cause CE. Rarely, bisphosphoglycerate mutate mutations, affecting the 2,3-bisphosphoglycerate levels, can increase the oxygen affinity of hemoglobin and cause CE. This narrative review examines the current mutational spectrum of CE and the distinctive pathogenetic mechanisms that give rise to this increasingly recognized condition in various parts of the world.

Polycythaemia following treatment of lymphoplasmacytic lymphoma

A 61-year-old man presented to the department of clinical haematology in February 2016 with symptomatic anaemia, generalised lymphadenopathy and hepatomegaly. Routine investigations showed severe anaemia with the presence of lymphoplasmacytoid cells in the peripheral smear, and bone marrow examination with IHC and serum protein electrophoresis confirmed diagnosis of lymphoplasmacytic lymphoma. The patient received supportive transfusion therapy and combination chemotherapy. After VI cycles, the patient had a complete haematological response with marrow in remission. Maintenance rituximab was planned every 3 months for 2 years. At the time of first dose of maintenance rituximab, his haemoglobin (Hb) was 189 g/L with low normal erythropoietin level. During the last 3 years follow-up, his Hb ranged between 16.5 and 20.1 g/dL. All causes of secondary polycythaemia were ruled out. Workup for polycythAemia vera (PV), including JAK-2 and bone marrow, was not suggestive of PV. We labelled it as a case of polycythaemia due to undetermined aetiology.

Juvenile erythrocytosis in children after liver transplantation: prevalence, risk factors and outcome

Most reports of post-transplant erythrocytosis have involved kidney recipients and, so far, there have been no large studies of onset of erythrocytosis after orthotopic liver transplantation (OLT) in children. We present a long-term survey of pediatric liver recipients, evaluating prevalence, outcome and the main potential causes of erythrocytosis, including a comprehensive mutational analysis of commonly related genes (mutations of HBB and HBA, JAK2, EPOR, VHL, EPAS1 and EGLN1). Between 2000 and 2015, 90 pediatric OLT recipients were observed for a median period of 8.7 years (range 1–20.4 [IQR 4.9–13.6] years). Five percent of the study population (4 males and 1 female) developed erythrocytosis at 8.5 years post OLT (range 4.1–14.9 [IQR 4.7–14.7]) at a median age of 16.6 years (range 8.2–18.8 [IQR 11.7–17.7]). Erythrocytosis-free survival after OLT was 98.6% at 5 years, 95% at 10 years, and 85% at 15 years, with an incidence rate of 6/1000 person-years. No cardiovascular events or thrombosis were reported. No germinal mutation could be clearly related to the development of erythrocytosis. One patient, with high erythropoietin levels and acquired multiple bilateral renal cysts, developed clinical hyper-viscosity symptoms, and was treated with serial phlebotomies. In conclusion, this prospective longitudinal study showed that erythrocytosis is a rare complication occurring several years after OLT, typically during adolescence. Erythrocytosis was non-progressive and manageable. Its pathogenesis is still not completely understood, although male gender, pubertal age, and renal cysts probably play a role.

Obstructive Sleep Apnea Is Associated With Polycythemia in Hypogonadal Men on Testosterone Replacement Therapy

BACKGROUND

Polycythemia (erythrocytosis) is a known side effect of testosterone (T) replacement therapy (TRT) and appears to correlate with maximum T levels. There is also a well-established association between obstructive sleep apnea (OSA) and the development of polycythemia, which confers additional long-term cardiovascular morbidity. Synergy between TRT and OSA in the development of polycythemia remains poorly understood.

AIM

The objective of this study was to retrospectively assess the relationship of OSA and secondary polycythemia in hypogonadal men receiving TRT.

METHODS

We performed a retrospective chart review of all men treated by a single provider from 2015 to 2019 for the diagnosis of hypogonadism. Patients who developed a hematocrit of 52% or greater were classified as having polycythemia. OSA was identified via clinical documentation or use of nocturnal continuous positive airway pressure. Demographics, laboratory values, treatment details, and comorbidities were recorded. Data were reported as mean ± SD for parametric variables and median [interquartile range] for non-parametric values.

OUTCOME

The primary outcome of this study was the association between OSA and polycythemia in hypogonadal men on TRT.

RESULTS

474 men were included in this study. 62/474 (13.1%) men met the criteria for the diagnosis of polycythemia with a median hematocrit of 53.6 [interquartile range 52.6, 55.5]. Univariate analysis demonstrated a strong positive association between polycythemia and the concomitant diagnosis of OSA in hypogonadal men (P = .002). Even after correcting for age, body mass index (BMI), and peak T levels in the multivariate analysis (P = .01), this relationship remained significant with an odds ratio of 2.09 [95% CI 1.17, 3.76]. 37 men on TRT with polycythemia and OSA were included in the final cohort with a mean age of 59.2 ± 11.4 years, mean BMI of 32.4 ± 6.0, and median time from TRT initiation to polycythemia diagnosis of 3 years. All patients diagnosed with OSA were prescribed continuous positive airway pressure with poor compliance noted in 52.8% of men. 37.8% were managed via phlebotomy and 59.5% were managed via dose de-escalation of TRT. In hypogonadal men on TRT with polycythemia, BMI was the only risk factor strongly associated with OSA (P = .013).

CLINICAL TRANSLATION

In hypogonadal men (particularly those with elevated BMI) on TRT who develop secondary polycythemia, a diagnosis of OSA should be strongly considered.

STRENGTHS & LIMITATIONS

This is a single provider retrospective study and further studies are needed to assess generalizability.

CONCLUSIONS

In this retrospective single-center cohort, the development of polycythemia in hypogonadal men on TRT was associated with an increased prevalence of OSA. Lundy SD, Parekh NV, Shoskes DA. Obstructive Sleep Apnea Is Associated With Polycythemia in Hypogonadal Men on Testosterone Replacement Therapy. J Sex Med 2020;17:1297-1303.

Dissecting Primary Erythrocytosis Among Polycythemia Patients Referred to an Indian Armed Forces Hospital

Referrals for evaluation of polycythemia cases have increased since the hemoglobin (Hb) thresholds for diagnosis of Polycythemia Vera (PV) have been lowered by WHO. The current study enrolled patients of age > 18 years from the Indian Armed Forces or their family members with polycythemia from November 2016 to October 2018. After exclusion of secondary causes, 49 patients were diagnosed as Primary Erythrocytosis (PE). The patients were classified into two groups: PV and Idiopathic Erythrocytosis (IE) and a systematic comparison of clinical and laboratory features of the two groups was done. The prevalence of PV in PE was 20.4% (10 of 49) while the rest 39 (79.6%) had IE. Seven PV patients had JAK2 ^V617F mutation, one had JAK2 ^Exon12 mutation, and two were JAK2 negative PV. Nine of 10 (90%) PV patients had Hb > 18.5 g/dl, while only 21 of 39 (53.8%) IE patients had Hb > 18.5 g/dl (p = 0.06). None of the JAK2 mutated patients had Hb < 18.5 g/dl. We conclude that PV is more prevalent in patients of PE with Hb > 18.5 g/dl. Most patients with Hb between 16.5-18.5 g/dl would still be classified as IE. We advocate the need for further studies evaluating the utility of investigating all patients of PE with the revised WHO Hb threshold as well as studies on genetic profile of IE patients from India.

[A new case of rare erythrocytosis due to EGLN1 mutation with review of the literature]

INTRODUCTION

The origin of polycythemia is often simple to detect. Sometimes it is necessary to look for hereditary forms, the decisive parameters being the dosage of erythropoietin and the measurement of the oxygen dissociation curve (P50). These rare diseases are related to high oxygen-affinity haemoglobins, abnormalities of the erythropoietin receptor or dysfunction of the HIF (hypoxia-inducible factor) pathway.

CASE REPORT

We report the case of a 56-year-old patient with unexplained polycythemia associated with normal serum erythropoietin and normal P50, in whom the never previously described mutation c.400C>T(p.Gln134*) on exon 1 in the EGLN1 gene (encoding PHD2) was found.

CONCLUSION

In the face of an unexplained polycythemia a good cooperation between clinicians and biologists is necessary to be able to characterize rare hereditary pathologies.

Therapeutic erythroapheresis: Experience in patients with polycythemia vera and secondary erythrocytosis

Therapeutic erythrocytapheresis (TE) is a more efficient strategy compared to phlebotomy to deplete levels of haematocrit in primary and secondary erythrocytosis.

OBJECTIVE

To analyse response rate and safety profile of TE in polycythemia vera (PV) and secondary erythrocytosis (SE).

PATIENTS AND METHOD

Retrospective review of all patients with PV or SE treated with TE, due to phlebotomy failure, or comorbidities that prevented changes of blood volumen.

RESULTS

217 TE sessions (48 PV and 79 SE) corresponding to 20 patients (12 ES and 8 PV). Response were achieved in 87.5% of PV patients and in 50% of SE patients. Adverse effects related to TE performance occurred in 7.08%.

CONCLUSION

Despite our small sample size and the heterogeneous nature of the patients included, we can postulate that TE is a secure strategy that can achieve haematocrit depletion in a shorter time than phlebotomy, specifically in PV patients and in selected cases of SE with expected haemodynamic intolerance to phlebotomies or in patients who fail to respond to phlebotomies.

Itching as the onset of pain (part 1)

PAIN is a psychophysiological reaction of an organism that occurs with severe irritation of the sensitive nerve endings embedded in organs and tissues. And also pain is the body’s protective reaction. It is signaling about a discomfort and triggers an appropriate response by the body to eliminate the cause of the pain. Pain is one of the earliest symptoms of some diseases [84]. ITCHING – an unpleasant sensation of irritation, heartburn and tingling in any area of the skin caused by various factors (exposure to chemicals, bacteria, parasites). This feeling is often manifested by the urgent need to rub or scratch some areas of the skin (or mucous membrane) [85]. When considering the pathogenesis of these concepts, a sufficiently large resemblance to the realization of mechanisms of origin, or a certain identity thereof is revealed. The question naturally arises whether itching is an early manifestation of pain, especially in those groups of diseases that are not characterized by pain. Pathology of the hematopoietic system is not accompanied by a symptom such as pain. But for conditions such as iron overload, iron deficiency or polycythemia, itching is a clear symptom. The unknown etiology of chronic itching of the skin is indicative of histological examination of the skin in order to exclude skin lymphoma. One of the least understood mechanisms of itching is itching associated with malignant solid tumors. What pain that itching is a subjective sensation that can have an acute or chronic course, a clear intensity and a very significant impact on quality of life, especially in the case of comorbidity. In addition, the question arises whether itching is an early manifestation of pain, especially in those groups of diseases that are not characterized by pain. How can a doctor manage itching effectively to prevent complications? To these and other questions, we have attempted to systematize the manifestations of itching in pathologies of organs and systems that are not traditionally accompanied by pain.

Guidelines on the Use of Therapeutic Apheresis in Clinical Practice - Evidence-Based Approach from the Writing Committee of the American Society for Apheresis: The Eighth 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 (TA) 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 Eighth Edition of the JCA Special Issue continues to maintain this methodology and rigor in order to make recommendations on the use of apheresis in a wide variety of diseases/conditions. The JCA Eighth Edition, like its predecessor, continues to apply the category and grading system definitions in fact sheets. The general layout and concept of a fact sheet that was introduced in the Fourth Edition, has largely been maintained in this edition. Each fact sheet succinctly summarizes the evidence for the use of TA in a specific disease entity or medical condition. The Eighth Edition comprises 84 fact sheets for relevant diseases and medical conditions, with 157 graded and categorized indications and/or TA modalities. The Eighth Edition of the JCA Special Issue seeks to continue to serve as a key resource that guides the utilization of TA in the treatment of human disease.

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.

Genetic basis of unexplained erythrocytosis in Indian patients

OBJECTIVE

To evaluate the spectrum of genetic defects in Indian patients with unexplained erythrocytosis.

METHODS

Fifteen families (18 patients) with unexplained erythrocytosis were enrolled after excluding polycythemia vera and secondary erythrocytosis. Focused Sanger sequencing from genomic DNA was performed for EPOR (exon 8), VHL (exons 2-3), EGLN1 (exons 2-5), EPAS1 (exon 12), and all exons of HBB, HBA1, and HBA2 genes.

RESULTS

Eleven of the 18 patients (including two pairs of brothers) had Chuvash polycythemia, that is, homozygosity for VHL:c.598C > T (p.Arg200Trp). Three patients (two of whom were brothers) had HBB mutations associated with increased oxygen-affinity hemoglobin-one had a heterozygous Hb McKees Rocks HBB:c.438T > A (p.Tyr146*), and two brothers showed heterozygous Hb Rainier HBB:c.437A > G (p.Tyr146Cys). No pathogenic variants were found in the remaining four cases.

CONCLUSION

A gene-by-gene Sanger sequencing approach could determine a genetic basis for erythrocytosis in 11 of the 15 (73%) Indian families, with homozygous VHL:c.598C > T (p.Arg200Trp) being the commonest pathogenic variant. This first study from the Indian subcontinent provides a rationale for analyzing this variant in patients with suspected congenital erythrocytosis from this region. Rare first occurrences of Hb McKees Rocks and Hb Rainier in Indians are also being reported.

How we diagnose and manage altered oxygen affinity hemoglobin variants

Altered oxygen affinity variant hemoglobins (Hbs) are caused by mutations of the globin genes. Changes in Hb oxygen affinity shift the oxygen dissociation curve, and can be identified by abnormal p50 measurements of patient red blood cells. Variants are categorized as either low oxygen affinity (high p50) or high oxygen affinity (low p50). Accurate diagnosis requires recognition of typical clinical and laboratory findings. In this case-based review, we present two patients with altered oxygen affinity variants, illustrating barriers to prompt and accurate diagnosis, and issues in management. We then review pathophysiology, diagnostic tests, clinical features, and management strategies.

Obesity hypoventilation syndrome: a current review

Obesity hypoventilation syndrome (OHS) is defined as the presence of obesity (body mass index ≥ 30 kg/m²) and daytime arterial hypercapnia (PaCO2 ≥ 45 mmHg) in the absence of other causes of hypoventilation. OHS is often overlooked and confused with other conditions associated with hypoventilation, particularly COPD. The recognition of OHS is important because of its high prevalence and the fact that, if left untreated, it is associated with high morbidity and mortality. In the present review, we address recent advances in the pathophysiology and management of OHS, the usefulness of determination of venous bicarbonate in screening for OHS, and diagnostic criteria for OHS that eliminate the need for polysomnography. In addition, we review advances in the treatment of OHS, including behavioral measures, and recent studies comparing the efficacy of continuous positive airway pressure with that of noninvasive ventilation.

How temperature influences the viscosity of hornworm hemolymph

Hemolymph is responsible for the transport of nutrients and metabolic waste within the insect circulatory system. Circulation of hemolymph is governed by viscosity, a physical property, which is well known to be influenced by temperature. However, the effect of temperature on hemolymph viscosity is unknown. We used Manduca sexta larvae to measure hemolymph viscosity across a range of physiologically relevant temperatures. Measurements were taken from 0 to 45°C using a cone and plate viscometer in a sealed environmental chamber. Hemolymph viscosity decreased with increasing temperature, showing a 6.4-fold change (11.08 to 1.74 cP) across the temperature range. Viscosity values exhibited two behaviors, changing rapidly from 0 to 15°C and slowly from 17.5 to 45°C. To test the effects of large particulates (e.g. cells) on viscosity, we also tested hemolymph plasma alone. Plasma viscosity also decreased as temperature increased, but did not exhibit two slope regimes, suggesting that particulates strongly influence low-temperature shifts in viscosity values. These results suggest that as environmental temperatures decrease, insects experience dramatic changes in hemolymph viscosity, leading to altered circulatory flows or increased energetic input to maintain similar flows. Such physical effects represent a previously unrecognized factor in the thermal biology of insects.

Recommendations for the diagnosis and treatment of patients with polycythaemia vera

OBJECTIVES

To present the Central European Myeloproliferative Neoplasm Organisation (CEMPO) treatment recommendations for polycythaemia vera (PV).

METHODS

During meetings held from 2015 through 2017, CEMPO discussed PV and its treatment and recent data.

RESULTS

PV is associated with increased risks of thrombosis/thrombo-haemorrhagic complications, fibrotic progression and leukaemic transformation. Presence of Janus kinase (JAK)-2 gene mutations is a diagnostic marker and standard diagnostic criterion. World Health Organization 2016 diagnostic criteria for PV, focusing on haemoglobin levels and bone marrow morphology, are mandatory. PV therapy aims at managing long-term risks of vascular complications and progression towards transformation to acute myeloid leukaemia and myelodysplastic syndrome. Risk stratification for thrombotic complications guides therapeutic decisions. Low-risk patients are treated first line with low-dose aspirin and phlebotomy. Cytoreduction is considered for low-risk (phlebotomy intolerance, severe/progressive symptoms, cardiovascular risk factors) and high-risk patients. Hydroxyurea is suspected of leukaemogenic potential. IFN-α has demonstrated efficacy in many clinical trials; its pegylated form is best tolerated, enabling less frequent administration than standard interferon. Ropeginterferon alfa-2b has been shown to be more efficacious than hydroxyurea. JAK1/JAK2 inhibitor ruxolitinib is approved for hydroxyurea resistant/intolerant patients.

CONCLUSIONS

Greater understanding of PV is serving as a platform for new therapy development and treatment response predictors.