Mast cell activation syndrome and the link with long COVID.

Mast cells are innate immune cells found in connective tissues throughout the body, most prevalent at tissue-environment interfaces. They possess multiple cell-surface receptors which react to various stimuli and, after activation, release many mediators including histamine, heparin, cytokines, prostaglandins, leukotrienes and proteases. In mast cell activation syndrome, excessive amounts of inflammatory mediators are released in response to triggers such as foods, fragrances, stress, exercise, medications or temperature changes. Diagnostic markers may be difficult to assess because of their rapid degradation; these include urinary N-methyl histamine, urinary prostaglandins D2, DM and F2α and serum tryptase (which is stable) in the UK. Self-management techniques, medications and avoiding triggers may improve quality of life. Treatments include mast cell mediator blockers, mast cell stabilisers and anti-inflammatory agents. 'Long COVID' describes post-COVID-19 syndrome when symptoms persist for more than 12 weeks after initial infection with no alternative diagnosis. Both mast cell activation syndrome and long COVID cause multiple symptoms. It is theorised that COVID-19 infection could lead to exaggeration of existing undiagnosed mast cell activation syndrome, or could activate normal mast cells owing to the persistence of viral particles. Other similarities include the relapse-remission cycle and improvements with similar treatments. Importantly, however, aside from mast cell disorders, long COVID could potentially be attributed to several other conditions.

Gynaecological management of women with inherited bleeding disorders. A UK Haemophilia Centres Doctors' Organisation Guideline.

Women with inherited bleeding disorders (IBDs) may present to healthcare professionals in a variety of ways and commonly will be encountered by either haematology or gynaecology services. Heavy menstrual bleeding is very often the first manifestation of an IBD. There is a wide variation in severity of bleeding for women with IBD and diagnosis and subsequent management of their condition requires multidisciplinary specialised care which is tailored to the individual and includes excellent cross-specialty communication between gynaecology and haematology teams. This guideline is intended for both haematologists and gynaecologists who are involved in the diagnosis and management of women with bleeding disorders. It sets out recommendations about how to investigate heavy menstrual bleeding (HMB), the commonest presentation for women with IBD to hospital services, to guide physicians about how to diagnose an IBD and covers the management of women with known IBD and HMB. The second section sets out recommendations for patients known to have IBD and covers management of patients with IBD in the setting of gynaecological surgery and management for all other non-surgical gynaecological situations.

A novel RUNX1 exon 3 - 7 deletion causing a familial platelet disorder.

Familial Platelet Disorder with associated Myeloid Malignancy (FPDMM) is a rare inherited disorder confirmed with the presence of a pathogenic germline RUNX1 variant and is thought to be heavily underdiagnosed. RUNX1 has also been found to be mutated in up to 10% of adult AML cases and other cell malignancies. We performed targeted next-generation sequencing and subsequent MLPA analysis in a kindred with multiple affected individuals with low platelet counts and a bleeding history. We detected a novel heterozygous exon 3-7 large deletion in the RUNX1 gene in all affected family members which is predicted to remove all of the Runt-homology DNA-binding domain and a portion of the Activation domain. Our results show that the combination of targeted NGS and MLPA analysis is an effective way to detect copy number variants (CNVs) which would be missed by conventional sequencing methods. This precise diagnosis offers the possibility of accurate counseling and clinical management in such patients who could go onto develop other cell malignancies.

A Study Protocol to Explore and Improve Access to Medical Services and Information for Recently Diagnosed Elderly Patients with Cancer in Rural Settings.

INTRODUCTION: This two-phase study seeks to contribute to research in the field of rural cancer health; specifically, the aim is to gain insight into the experiences of seeking, accessing and using information and health services throughout the cancer journey (diagnosis, treatment and follow-up care) for recently diagnosed (≤6 months) older patients (≥65 years) in rural areas. METHODS AND ANALYSIS: Data will be collected through in-depth semi-structured interviews. In phase 1 (before 23rd March 2020) interviews were conducted with healthcare professionals (HCP) to explore their experiences of delivering care to their elderly patients. In the second phase (starting January 2021) we will conduct interviews with cancer patients to understand the impact of COVID-19 and shielding on their experiences of being diagnosed, attending appointments and accessing and receiving support from community organisations and informal support from family and friends. Data gathered will be analysed using the Framework Method. ETHICS: The study has been approved by the Health Research Authority and the United Lincolnshire Hospitals NHS Trust. Initial favourable ethical opinion was granted on 1st October 2019. Second favourable ethical opinion for amendments to reflect the impact of COVID-19 was received on 10th August 2020. The study protocol has been registered on Research Registry.

Haemostatic and thrombo-embolic complications in pregnant women with COVID-19: a systematic review and critical analysis.

BACKGROUND: As pregnancy is a physiological prothrombotic state, pregnant women may be at increased risk of developing coagulopathic and/or thromboembolic complications associated with COVID-19. METHODS: Two biomedical databases were searched between September 2019 and June 2020 for case reports and series of pregnant women with a diagnosis of COVID-19 based either on a positive swab or high clinical suspicion where no swab had been performed. Additional registry cases known to the authors were included. Steps were taken to minimise duplicate patients. Information on coagulopathy based on abnormal coagulation test results or clinical evidence of disseminated intravascular coagulation (DIC), and on arterial or venous thrombosis, were extracted using a standard form. If available, detailed laboratory results and information on maternal outcomes were analysed. RESULTS: One thousand sixty-three women met the inclusion criteria, of which three (0.28, 95% CI 0.0 to 0.6) had arterial and/or venous thrombosis, seven (0.66, 95% CI 0.17 to 1.1) had DIC, and a further three (0.28, 95% CI 0.0 to 0.6) had coagulopathy without meeting the definition of DIC. Five hundred and thirty-seven women (56%) had been reported as having given birth and 426 (40%) as having an ongoing pregnancy. There were 17 (1.6, 95% CI 0.85 to 2.3) maternal deaths in which DIC was reported as a factor in two. CONCLUSIONS: Our data suggests that coagulopathy and thromboembolism are both increased in pregnancies affected by COVID-19. Detection of the former may be useful in the identification of women at risk of deterioration.

A case series review of patients with Thrombocytopenia and Absent-Radii syndrome (TARS) and their management during pregnancy.

Bleeding diatheses due to platelet-related disorders can present challenges to treating clinicians, especially in the context of peri- and post-partum patients in the obstetric setting. Thrombocytopenia and Absent-Radii syndrome (TARS) is an inherited disorder characterized by reduced bone marrow platelet production, skeletal deformities affecting radii and other limbs; cardiac, renal, and other heterogeneous anomalies may occur. It is caused by the co-inheritance of a microdeletion and a nucleotide polymorphism in the RBM8A gene on chromosome 1. Bleeding phenotype is more severe than platelet numbers which might predict especially in infants but improves with age. There is minimal literature regarding the impact of pregnancy and puerperium. We describe the management of three pregnancies in the hematology-obstetrics clinic. As platelet counts normally decrease through pregnancy, close monitoring is required in TARS. No major bleeding was seen antenatally but two required platelet transfusions during labor. No other treatment definitely improves bleeding, although case reports of steroids claim variable success. Tranexamic acid may be helpful, and thrombopoietin agonists represent a potential future option.

Hereditary Alpha-Tryptasemia: UK Prevalence and Variability in Disease Expression.

BACKGROUND: Hereditary alpha-tryptasemia (HAT) is a genetic trait caused by an increased alpha-tryptase tryptase alpha/beta 1 gene copy number. Basal serum mast cell tryptase (MCT) level is typically greater than or equal to 8.0 ng/mL. OBJECTIVES: To study the clinical disease spectrum of HAT and determine its UK prevalence. METHODS: Droplet digital PCR was used to determine tryptase alpha/beta 1 copy number in 432 DNA samples from an unselected UK birth cohort and in 70 patients referred with a basal MCT level greater than 8 ng/mL. Baseline MCT concentrations and clinical presentation were also assessed in 4283 samples sent to a regional immunology laboratory. RESULTS: Duplication in alpha copy number was present in 5% of the unselected British birth cohort, with all affected individuals having a basal MCT level of greater than or equal to 8.0 ng/mL. Basal MCT levels of greater than or equal to 8.0 ng/mL were also found in 5% of the 4283 individuals referred for MCT testing because of clinical symptoms. In 70 patients confirmed to have HAT (79% with a duplication; 21% with a higher alpha gene copy number), urticaria/angioedema (51%), skin flushing (41%), food intolerances (39%), and altered bowel habits (36%) were common presenting complaints. However, clinical manifestations were not more common in patients with gene triplications or quintuplications than in those with duplications. Some immediate family members with the same genetic trait and high basal MCT levels were asymptomatic. CONCLUSIONS: Five percent of people in the United Kingdom may have HAT. The diagnosis should be considered when basal MCT level is greater than or equal to 8 ng/mL. HAT has variable clinical penetrance. It may modify the expression of multifactorial allergic diseases rather than directly cause specific phenotypes.

A Novel, Enriched Population Pharmacokinetic Model for Recombinant Factor VIII-Fc Fusion Protein Concentrate in Hemophilia A Patients.

BACKGROUND: The currently published population pharmacokinetic (PK) models used for PK-guided dosing in hemophilia patients are based on clinical trial data and usually not externally validated in clinical practice. The aim of this study was to validate a published model for recombinant factor VIII-Fc fusion protein (rFVIII-Fc) concentrate and to develop an enriched model using independently collected clinical data if required. METHODS: Clinical data from hemophilia A patients treated with rFVIII-Fc concentrate (Elocta) participating in the United Kingdom Extended Half-Life Outcomes Registry were collected. The predictive performance of the published model was assessed using mean percentage error (bias) and mean absolute percentage error (inaccuracy). An extended population PK model was developed using nonlinear mixed-effects modeling (NONMEM). RESULTS: A total of 43 hemophilia A patients (FVIII ≤ 2 IU/dL), aged 5 to 70 years, were included. The prior model was able to predict the collected 244 rFVIII-Fc levels without significant bias (-1.0%, 95% CI: -9.4 to 7.3%) and with acceptable accuracy (12.9%). However, clearance and central distribution volume were under predicted in patients <12 years, which was expected as this age group was not represented in the previous model population. An enriched population PK model was constructed, which was able to successfully characterize PK profiles of younger children. CONCLUSION: We concluded that the existing rFVIII-Fc population PK model is valid for patients ≥ 12 years. However, it is not reliable in younger patients. Our alternative model, constructed from real world patient data including children, allows for better description of patients ≥5 years.

Severe antithrombin deficiency in pregnancy: Achieving adequate anticoagulation.

Antithrombin deficiency is identified as one of the most potent risk factors for venous thromboembolism during pregnancy. Therapeutic low molecular weight heparin is recommended, but it can be difficult to attain sufficient anticoagulation since low molecular weight heparin requires antithrombin to exert its anticoagulant effect. We carried out a multicentre case-series assessing the dose of low molecular weight heparin required to achieve therapeutic anti-activated factor X levels in pregnant women with antithrombin deficiency. We assessed 27 pregnancies in 18 women with severe antithrombin deficiency, which we defined as an antithrombin level of <0.55 IU/ml (with or without prior venous thromboembolism) or an antithrombin level < 0.8 IU/ml and a personal history of venous thromboembolism. Our data illustrate the need for high doses of low molecular weight heparin to achieve therapeutic anti-activated factor X levels (average 20,220 IU/day). All pregnancies ended in live birth (excluding one elective termination), although intrauterine growth restriction occurred in five (18%).

Investigation of the contribution of an underlying platelet defect in women with unexplained heavy menstrual bleeding.

Heavy menstrual bleeding (HMB) is often undiagnosed in women and can cause discomfort and distress. A haemostatic cause for excessive bleeding is often not routinely investigated and can lead to hysterectomy at an early age. A prospective cohort study was carried out to determine whether certain patients with unexplained HMB have an underlying platelet function defect (PFD). The Genotyping and Phenotyping of Platelets (GAPP) study recruited 175 women with HMB and 44 unrelated volunteers from 25 Haemophilia Centres across the UK, and a tertiary gynaecology service. Bleeding history was assessed using the International Society on Thrombosis and Haemostasis Bleeding Assessment Tool (ISTH-BAT). Platelet count, platelet size, haemoglobin and mean corpuscular volume were measured in whole blood using the Sysmex XN-1000 Haematology Analyzer. Platelet function testing using lumiaggregometry and flow cytometry was performed in patients included in this study. A PFD was identified in 47% (82/175) of patients with HMB. Cutaneous bleeding was the most frequent additional bleeding symptom (89% in PFD and 83% with no PFD). Whole blood platelet count was significantly lower (P < 0.0001) between the PFD group and no PFD group. The prevalence of anaemia did not differ between patients and healthy volunteers. Clinical evaluation alone is insufficient to determine presence of an underlying PFD in patients with HMB. Platelet function tests may be considered and clinical guidelines may include them in their algorithms. An appropriate diagnosis and subsequent tailored management of HMB may prevent unnecessary surgery and help manage future haemostatic challenges.

A comprehensive targeted next-generation sequencing panel for genetic diagnosis of patients with suspected inherited thrombocytopenia.

BACKGROUND: Inherited thrombocytopenias (ITs) are a heterogeneous group of disorders characterized by low platelet counts and often disproportionate bleeding with over 30 genes currently implicated. Previously the UK-GAPP study using whole exome sequencing (WES) identified a pathogenic variant in 19 of 47 (40%) patients of which 71% had variants in genes known to cause IT. AIMS: To employ a targeted next-generation sequencing platform to improve efficiency of diagnostic testing and reduce overall costs. METHODS: We have developed an IT-specific gene panel as a pre-screen for patients prior to WES using the Agilent SureSelectQXT transposon-based enrichment system. RESULTS: Thirty-one patients were analyzed using the panel-based sequencing, of which; 10% (3/31) were identified with a classified pathogenic variant, 16% (5/31) were identified with a likely pathogenic variant, 51% (16/31) were identified with variants of unknown significance, and 23% (7/31) were identified with either no variant or a benign variant. DISCUSSION AND CONCLUSION: Although requiring further clarification of the impact of the genetic variations, the application of an IT-specific next generation sequencing panel is an viable method of pre-screening patients for variants in known IT-causing genes prior to WES. With an added benefit of distinguishing IT from idiopathic thrombocytopenic purpura (ITP) and the potential to identify variants in genes known to have a predisposition to hematological malignancies, it could become a critical step in improving patient clinical management.

Diagnosis and management of maternal thrombocytopenia in pregnancy.

Thrombocytopenia is a common finding in pregnancy, occurring in approximately 7-10% of pregnancies. It may be a diagnostic and management problem, and has many causes, some of which are specific to pregnancy. Although most cases of thrombocytopenia in pregnancy are mild, and have no adverse outcome for either mother or baby, occasionally a low platelet count may be part of a more complex disorder with significant morbidity and may be life-threatening. Overall, about 75% of cases are due to gestational thrombocytopenia, 15-20% secondary to hypertensive disorders; 3-4% due to an immune process, and the remaining 1-2% made up of rare constitutional thrombocytopenias, infections and malignancies. In this review, a diagnostic approach to investigating thrombocytopenia in pregnancy is presented, together with antenatal, anaesthetic and peri-natal management issues for mother and baby, followed by a detailed discussion on the specific causes of thrombocytopenia and the management options in each case.

UK guidelines on the management of iron deficiency in pregnancy.

Iron deficiency is the most common deficiency state in the world, affecting more than 2 billion people globally. Although it is particularly prevalent in less-developed countries, it remains a significant problem in the developed world, even where other forms of malnutrition have already been almost eliminated. Effective management is needed to prevent adverse maternal and pregnancy outcomes, including the need for red cell transfusion. The objective of this guideline is to provide healthcare professionals with clear and simple recommendations for the diagnosis, treatment and prevention of iron deficiency in pregnancy and the postpartum period. This is the first such guideline in the UK and may be applicable to other developed countries. Public health measures, such as helminth control and iron fortification of foods, which can be important to developing countries, are not considered here. The guidance may not be appropriate to all patients and individual patient circumstances may dictate an alternative approach.

Bleeding and thrombotic complications of kidney disease.

With the rising prevalence of kidney disease, clinicians are increasingly faced with concerns about potential thrombotic and bleeding complications. Thrombotic risk, both arterial and venous, predominates with all severities of kidney disease but bleeding manifestations become an additional concern particularly with uraemia. This article reviews these contrasting problems and discusses strategies for prevention and management in the context of renal impairment, renal replacement therapy and renal transplantation.