Pediatric hereditary angioedema due to C1-inhibitor deficiency

Clinical profile and management of pediatric hereditary angioedema in resource-constrained settings: our experience from a single centre in North India

Hereditary angioedema (HAE) is a rare genetic disorder. The pattern of HAE is different in children as compared to adults. There is limited literature from developing countries where all first-line treatments are either unavailable or not easily accessible. Data of children with HAE were retrieved from medical records of patients registered in the Pediatric Immunodeficiency Clinic at our institute. Of the 206 patients with HAE, 61 were diagnosed before the age of 18 years. Male: female ratio was 1.1:1. Median age at onset of symptoms and diagnosis were 6.2 years (range 1-17 years) and 10.7 years (range 1.5-18 years) respectively. Median delay in diagnosis was 4.9 years (range 0-16 years). The commonest presentation was facial swelling (51/61) followed by swelling of extremities (47/61). Laryngeal edema and abdominal symptoms were reported in 28/61 and 31/61 patients respectively. Abdominal attacks were found to be less common in children as compared to adults. Most patients in our cohort received fresh-frozen plasma (n = 5/61) as on-demand therapy. Long-term prophylaxis included attenuated androgens (n = 25/61) and tranexamic acid (n = 23/61). Median duration of follow-up was 2242 patient months. One patient died on follow-up in this cohort. This is the largest single-centre cohort of pediatric HAE from resource-constrained settings. Facial attacks were more common, and there were significant delays in diagnosis when the age of onset of symptoms was younger. Gastrointestinal symptoms were less common in children than adults. HIGHLIGHTS: One of the largest single-centre cohorts of pediatric HAE and the only one from resource-constrained settings. There were significant delays in diagnosis when the age of onset of symptoms was younger. Abdominal attacks were found to be less common in children as compared to adults.

Normalization of C1 Inhibitor in a Patient with Hereditary Angioedema

Hereditary angioedema is a potentially life-threatening autosomal dominant condition, causing attacks of angioedema due to failure to regulate bradykinin. Nearly all cases of hereditary angioedema are caused by mutations in the gene encoding C1 inhibitor, SERPING1. C1 inhibitor is a multifunctional protein produced in the liver that regulates the kallikrein-kinin system at multiple points. An infant with genetically confirmed hereditary angioedema and low C1 inhibitor levels (but without previous episodes of angioedema) underwent liver transplantation for biliary atresia, an unrelated condition. Liver transplantation led to normalization of the C1 inhibitor level and function. To our knowledge, this represents the first patient to be potentially cured of hereditary angioedema.

Plasma-derived C1 esterase inhibitor pharmacokinetics and safety in patients with hereditary angioedema

Background

Over 40 years of use demonstrates that complement 1 esterase inhibitor (C1-INH) concentrate is effective and well tolerated for acute edema attacks and prophylaxis in patients with hereditary angioedema. OCTA-C1-INH is a new stable, virus-inactivated, nanofiltrated concentrate of C1-INH derived from human plasma.

Objective

We investigated the pharmacokinetics and safety profile of new C1-INH in people with hereditary angioedema during an attack-free period.

Methods

In this prospective, multicenter, open-label, single-arm study, adults with hereditary angioedema type I/II received a single intravenous dose of 20 IU/kg C1-INH. Blood samples were taken ≤30 minutes before infusion, and 0, 0.25, 1, 2, 6, 12, 24, 48, 72, 120, 144, and 168 hours after infusion. The primary end point was assessing the pharmacokinetic parameters of C1-INH measured by C1-INH activity. Safety end points were also examined.

Results

Twenty patients received a single dose of 20 IU/kg new C1-INH with a mean (standard deviation) total dose of 1457.3 (356.51) IU. Mean (standard deviation) area under the curve normalized by dose was 51.6 (17.9) h∙IU/mL/IU, maximum blood concentration was 1.14 (0.989) IU/mL, incremental recovery was 0.0466 (0.051) (IU∙kg)/(IU∙mL), half-life was 0.598 (0.716) hours, and time to maximum concentration was 0.598 (0.716) hours. No thromboembolic events were recorded. No treatment-emergent adverse events were rated as severe/serious.

Conclusion

PK parameters of new C1-INH were in line with those reported for other C1-INH concentrates. New C1-INH demonstrated a favorable safety profile in patients with C1-INH deficiency. Further studies are warranted to determine the effectiveness and longer-term safety of new C1-INH.

[Hereditary angioedema due to C1-inhibitor deficiency, a national disease management programme]

Hereditary angioedema (HAE) is a rare, painful, disabling and potentially fatal disease, where early diagnosis and effective treatment are critical. These Austrian guidelines for the diagnosis and management of HAE provide instructions and advice on the state of the art management of HAE in Austria in contrast to global guidelines, where the situation of all countries worldwide must be taken into account. Our goal is to help Austrian physicians to consider HAE as a differential diagnosis with corresponding symptoms, to make rational decisions for the diagnosis and management of HAE with C1-inhibitor deficiency (type 1 or type 2). The guidelines provide information on common and important clinical symptoms, diagnostic methods, treatment modalities, available HAE-specific medications in Austria and last but not least to motivate physicians to refer patients to HAE centers for confirmation of the diagnosis and adequate treatment decisions.

Genetic Variants Leading to Urticaria and Angioedema and Associated Biomarkers

Advances in next generation sequencing technologies, as well as their expanded accessibility and clinical use over the past 2 decades, have led to an exponential increase in the number of identified single gene disorders. Among these are primary atopic disorders-inborn errors of immunity resulting in severe allergic phenotypes as a primary presenting feature. Two cardinal aspects of type I immediate hypersensitivity allergic reactions are hives and angioedema. Mast cells (MCs) are frequent primary drivers of these symptoms, but other cells have also been implicated. Even where MC degranulation is believed to be the cause, mediator-induced symptoms may greatly vary among individuals. Angioedema-particularly in the absence of hives-may also be caused by hereditary angioedema conditions resulting from aberrant regulation of contact system activation and excessive bradykinin generation or impairment of vascular integrity. In these patients, swelling can affect unpredictable locations and fail to respond to MC-directed therapies. Genetic variants have helped delineate key pathways in the etiology of urticaria and nonatopic angioedema and led to the development of targeted therapies. Herein, we describe the currently known inherited and acquired genetic causes for these conditions, highlight specific features in their clinical presentations, and discuss the benefits and limitations of biomarkers that can help distinguish them.

A safety review of prophylaxis drugs for adolescent patients with hereditary angioedema

INTRODUCTION

Hereditary angioedema (HAE) is characterized by recurrent subcutaneously and/or submucosally localized edematous swellings. The first symptoms often appear in childhood, and they may become more frequent and severe in puberty. Since the appearance of HAE attacks is unpredictable regarding the localization and the frequency, the attacks put a significant burden on the patients and crucially impacts their quality of life.

AREAS COVERED

This review article analyzes the safety data acquired from the clinical trials conducted with the currently available medicinal products for the prophylactic treatment of hereditary angioedema due to C1 inhibitor deficiency and the safety data of observatory studies based on clinical practice. A review of the published literature was conducted using the PubMed database, clinical trials from ClinicalTrials.gov, and abstracts published at scientific conferences.

EXPERT OPINION

The currently available therapeutic products have a good safety and efficiency profile and the international guidelines recommend them as first-line treatments. The choice should be made based on the evaluation of the availability and the preference of the patient.

Insights into the pathogenesis of hereditary angioedema using genetic sequencing and recombinant protein expression analyses

BACKGROUND

The pathogenesis of hereditary angioedema (HAE) type I and type II is linked to defective C1 esterase inhibitor (C1-INH) encoded by the SERPING1 gene. There are substantial variabilities in the clinical presentations of patients with HAE that are not directly correlated to the serum levels of C1-INH. The impact of SERPING1 variants on C1-INH expression, structure, and function is incompletely understood.

OBJECTIVE

To investigate the influence of SERPING1 variants on the C1-INH expression, structure, and function of 20 patients with HAE from 14 families with no prior genetic diagnosis.

METHODS

Patients underwent whole-exome sequencing (WES). If no variants were identified, whole-genome sequencing (WGS) was performed. Except for the frameshift and large deletions, each C1-INH variant was recombinantly produced and, if synthesized and secreted, was subjected to structural, oligosaccharide, and functional analyses.

RESULTS

We identified 11 heterozygous variants in the SERPING1 gene, of which 5 were classified as pathogenic (E85Dfs∗63, N166Qfs∗91, K201Qfs∗56, P399A, and R466H) and 6 as variants of uncertain significance (C130W, I224S, N272del, K273del, L349F, and F471C). Three large heterozygous deletions were discovered through WGS. Our data indicate that C130W, N272del, P399A, and F471C are poorly synthesized, I224S prevents proper C1-INH folding, and K273del impairs C1-INH function by adding an additional oligosaccharide. Further evaluation suggests that compound variant P399A/L349F contributes to a more severe clinical phenotype.

CONCLUSIONS

Our combined approach of WES and WGS uncovered SERPING1 gene alternations in each patient. The recombinant protein production followed by systematic antigenic, structural, and functional assessment facilitates the identification of underlying pathogenic mechanisms in HAE.

The impact of puberty on the onset, frequency, location, and severity of attacks in hereditary angioedema due to C1-inhibitor deficiency: A survey from the Italian Network for Hereditary and Acquired Angioedema (ITACA)

Introduction

Hereditary angioedema due to C1-inhibitor deficiency is influenced by hormonal factors, with a more severe course of disease in women. Our study aims to deepen the impact of puberty on onset, frequency, location and severity of attacks.

Methods

Retrospective data were collected through a semi-structured questionnaire and shared by 10 Italian reference centers of the Italian Network for Hereditary and Acquired Angioedema (ITACA).

Results

The proportion of symptomatic patients increased significantly after puberty (98.2% vs 83.9%, p=0.002 in males; 96.3% vs 68,4%, p<0.001 in females); the monthly mean of acute attacks was significantly higher after puberty, and this occurred both in females (median (IQR) = 0.41(2) in the three years before puberty vs 2(2.17) in the three years after, p<0.001) and in males (1(1.92) vs 1.25(1.56) respectively, p<0.001). The increase was greater in females. No significant differences were detected in attack location before and after puberty.

Discussion

Overall, our study confirms previous reports on a more severe phenotype in the female gender. Puberty predisposes to increased numbers of angioedema attacks, in particular in female patients.

The international WAO/EAACI guideline for the management of hereditary angioedema - The 2021 revision and update

Hereditary Angioedema (HAE) is a rare and disabling disease for which early diagnosis and effective therapy are critical. This revision and update of the global WAO/EAACI guideline on the diagnosis and management of HAE provides up-to-date guidance for the management of HAE. For this update and revision of the guideline, an international panel of experts reviewed the existing evidence, developed 28 recommendations, and established consensus by an online DELPHI process. The goal of these recommendations and guideline is to help physicians and their patients in making rational decisions in the management of HAE with deficient C1-inhibitor (type 1) and HAE with dysfunctional C1-inhibitor (type 2), by providing guidance on common and important clinical issues, such as: 1) How should HAE be diagnosed? 2) When should HAE patients receive prophylactic on top of on-demand treatment and what treatments should be used? 3) What are the goals of treatment? 4) Should HAE management be different for special HAE patient groups such as children or pregnant/breast feeding women? 5) How should HAE patients monitor their disease activity, impact, and control? It is also the intention of this guideline to help establish global standards for the management of HAE and to encourage and facilitate the use of recommended diagnostics and therapies for all patients.

The international WAO/EAACI guideline for the management of hereditary angioedema-The 2021 revision and update

Hereditary angioedema (HAE) is a rare and disabling disease for which early diagnosis and effective therapy are critical. This revision and update of the global WAO/EAACI guideline on the diagnosis and management of HAE provides up-to-date guidance for the management of HAE. For this update and revision of the guideline, an international panel of experts reviewed the existing evidence, developed 28 recommendations, and established consensus by an online DELPHI process. The goal of these recommendations and guideline is to help physicians and their patients in making rational decisions in the management of HAE with deficient C1 inhibitor (type 1) and HAE with dysfunctional C1 inhibitor (type 2), by providing guidance on common and important clinical issues, such as: (1) How should HAE be diagnosed? (2) When should HAE patients receive prophylactic on top of on-demand treatment and what treatments should be used? (3) What are the goals of treatment? (4) Should HAE management be different for special HAE patient groups such as children or pregnant/breast-feeding women? and (5) How should HAE patients monitor their disease activity, impact, and control? It is also the intention of this guideline to help establish global standards for the management of HAE and to encourage and facilitate the use of recommended diagnostics and therapies for all patients.

The characteristics of upper airway edema in hereditary and acquired angioedema with C1-inhibitor deficiency

Background

Angioedemas localized in the upper airway are potentially life threatening, and without proper treatment, they may lead to death by suffocation. Upper airway edemas (UAE) in bradykinin‐mediated angioedemas can even be the first symptoms of the disease.

Methods

Our survey was performed with a retrospective long‐term follow‐up method from the medical history of 197 hereditary (C1‐INH‐HAE) and 20 acquired C1‐inhibitor deficiency (C1‐INH‐AAE), 3 factor XII and 3 plasminogen gene mutation (FXII‐HAE, PLG‐HAE) patients treated at our center between 1990 and 2020. The UAE group included edemas localized to the mesopharynx, hypopharynx, and larynx, as narrowing of these anatomical regions can lead to suffocation.

Results

98/197 C1‐INH‐HAE (47 families) and 13/20 C1‐INH‐AAE, 1/3 PLG‐HAE, 1/3 FXII‐HAE patients had experienced UAE at least once according to their medical history. In case of C1‐INH‐HAE patients, in 6/47 families who had undiagnosed ancestors had 13 members who died of suffocation. After the diagnosis, 1‐1 member of two families died of UAE. 44/64 C1‐INH‐HAE patients did not smoke, 20/64 did. The occurrence of UAE was significantly higher in smoker patients. We analyzed 7607 HAE attacks of 56/98 patients. Out of all attacks, the incidence of UAE in the C1‐INH‐HAE group was 4%, and 9.5% in the C1‐INH‐AAE group, respectively.

Conclusion

Early diagnosis is key in bradykinin‐mediated angioedemas cases, since the patient must be provided with adequate treatment; and also it is essential to inform patients about the importance of avoiding the trigger factors and the early symptoms of UAE, as these measures could significantly decrease the incidence of lethal UAEs.

Use of tranexamic acid does not influence perioperative outcomes in ambulatory foot and ankle surgery-a prospective triple blinded randomized controlled trial

STUDY OBJECTIVE

TXA is an antifibrinolytic medication widely used to reduce perioperative blood loss, but it has been seldom used during foot and ankle surgery. Our study evaluates the impact of TXA use on blood loss, post-operative pain, peri-operative opioid consumption, and wound healing in ambulatory outpatient foot and ankle procedures.

DESIGN

Prospective, triple-blinded, randomized controlled trial.

SETTING

Peri-operative environment of a major academic health centre in New York City.

PATIENTS

A total of 100 participants who were scheduled for ambulatory foot and ankle surgery with a single surgeon.

INTERVENTIONS

Patients receive either 10 mg/kg TXA (TXA group) or 10 ml/kg of normal saline (placebo group) intravenously prior to skin incision.

MEASUREMENTS

Primary outcome was intra-operative blood loss. Secondary outcomes were peri-operative opioid consumption and wound complications between post-operative days 14 and 21.

MAIN RESULTS

We found no difference between TXA and placebo groups in terms of intra-operative blood loss, p value 0.71, 95% CI (63.13-19.80). There was no difference between the two groups in terms of post-operative morphine milliequivalents (MME). The incidence of wound complications was 16.3% in the TXA group compared to 15.7% in the placebo group with OR 1.04, p value 0.93, 95% CI (0.32-2.77). No adverse events associated with TXA were reported.

CONCLUSIONS

The use of TXA during foot and ankle surgery was not associated with any benefits in perioperative outcomes in our outpatient ambulatory surgical population. Considering potential risks, we do not support the routine use of TXA in this surgical model.

Health-related quality of life in children with hereditary angioedema compared with patients with histaminergic angioedema

Background: Hereditary angioedema (HAE) is a potentially life-threatening disease that remarkably impacts patients' health-related quality of life (HRQoL). This study evaluated the HRQoL in children with HAE and compared it with healthy controls and patients with histaminergic angioedema (HA). Methods: Fifty-nine children with HAE (median [interquartile range {IQR}], ages, 8.9 years [5.4-12.6 years]), 60 children with HA (median [IQR] ages, 10.3 years [8-15.4 years]), and 72 healthy controls (median [IQR] ages, 10.3 years [6.6-13.9 years]) were recruited. All the children and their families completed the age-adapted KINDL generic instrument for assessing health-related quality of life in children and adolescents. Results: The total HRQoL score and other subscales scores of both the patients with HAE and patients with HA, and the parent-proxy reports were significantly lower than those of the healthy children (p < 0.05). In the patients with HAE, the age at symptom onset was positively correlated with physical well-being (r = 0.335; p = 0.043) and negatively correlated with self-esteem (r = -0.324; p = 0.049). In addition, the physical well-being scores were affected by the site of attacks, which was significantly lower in the patients with abdominal pain attacks (p = 0.045). The family scores and total scores were statistically significantly higher in the HA group than the HAE group (p < 0.001 and p = 0.009, respectively). A significant correlation was found between self-report and parent-proxy HRQoLs in total and all subscales scores in the patients with HAE. For HA, there were no significant correlations for family scores. Conclusion: HAE caused significant impairment of the HRQoL of children and their families, and affected their lifestyle and quality of life. In pediatric patients with HAE, the HRQoL is mainly related to age at symptom onset and the site of attacks. Although patients with HAE are affected more negatively than the patients with HA, HA affected the quality of life as well.

Mitigating Disparity in Health-care Resources Between Countries for Management of Hereditary Angioedema

Hereditary angioedema (HAE) is a rare genetic disorder characterized by recurrent episodes of skin and mucosal edema. The main treatment goal is to enable a “normal life” for all patients. However, due to high costs, there are limited options for the management of HAE in most developing and low-income countries. As a result, most of the recommended first-line treatments are not available. In this review, we attempt to highlight the disparities in health-care resources for the management of patients with HAE amongst different countries. Data was collected from HAE experts in countries who provide tabulated information regarding management and availability of HAE treatments in their countries. We reviewed the two most recent international HAE guidelines. Using India, the world’s second most populous country, as a paradigm for HAE management in lower-income countries, we reviewed the evidence for second-line and non-recommended practices reported by HAE experts. Results suggest significant inequities in provision of HAE services and treatments. HAE patients in low-income countries do not have access to life-saving acute drugs or recently developed highly effective prophylactic medications. Most low-income countries do not have specialized HAE services or diagnostic facilities, resulting in consequent long delays in diagnosis. Suggestions for optimizing the use of limited resources as a basis for future discussion and reaching a global consensus are provided. There is an urgent need to improve HAE services, diagnostics and treatments currently available to lower-income countries. We recommend that all HAE stakeholders support the need for global equity and access to these essential measures.

Novel SERPING1 gene mutations and clinical experience of type 1 hereditary angioedema from North India

BACKGROUND

There is paucity of literature on long-term follow-up of patients with hereditary angioedema (HAE) from developing countries.

OBJECTIVE

This study was carried out to analyze the clinical manifestations, laboratory features, and genetic profile of 32 patients (21 male and 11 female) from 23 families diagnosed with HAE between January 1996 and December 2019.

METHODS

Data were retrieved from medical records of Paediatric Immunodeficiency Clinic, Postgraduate Institute of Medical Education and Research, Chandigarh, India.

RESULTS

Median age at onset of symptoms was 6.25 years (range 1-25 years), and median age at diagnosis was 12 years (range 2-43 years). Serum complement C4 level was decreased in all patients. All patients had low C1-esterase inhibitor (C1-INH) quantitative level (type 1 HAE). SERPING1 gene sequencing could be carried out in 20 families. Of these, 11 were identified to have a pathogenic disease-causing variant in the SERPING1 gene. While 2 of these families had a previously reported mutation, remaining 9 families had novel pathogenic variants in SERPING1 gene. Because of non-availability of C1-INH therapy in India, all patients were given long-term prophylaxis (attenuated androgens or tranexamic acid (TA) or a combination of the 2). Life-threatening episodes of laryngeal edema were managed with fresh-frozen plasma (FPP) infusions. We recorded one disease-related mortality in our cohort. This happened in spite of long-term prophylaxis with stanozolol and TA.

CONCLUSIONS

We report largest single-center cohort of patients with HAE from India. Attenuated androgens, fibrinolytic agents, and FPP may be used for management of HAE in resource-limited settings.

Recurrent angioedema in childhood: hereditary angioedema or histaminergic angioedema?

BACKGROUND

Recurrent angioedema is a rare entity during childhood. This study aimed to clarify differences between hereditary angioedema (HAE) and histaminergic angioedema (HA) in children.

METHODS

Fifty-seven children with HAE (male 36.8%, 8.9 years [5.4-12.5]) and 42 children with recurrent HA (male 42.9%, 11.5 years [8.1-16.8]) were analyzed.

RESULTS

The median age at symptom onset (6 [3-10]; 7.8 [4.5-13] years), frequency of angioedema episodes within last year (3 [2-5]; 5 [2-10]), and duration of symptoms (48 [24-48]; 24 [12-48] hours) were similar in the HAE and HA group, respectively. Recurrent urticaria was observed in 7.3% (n = 3) of patients in the HAE group and in 45.2% (n = 19) of the HA group (P < .001). While angioedema episodes involving the lips (n = 30; 71.4%; P = .035) and eyelids (n = 28; 66.7%; P = .012) were observed more frequently in the HA group, gastrointestinal involvement/abdominal pain (n = 15; 36.6%) was more common in HAE (P < .001). Itching as a prodromal symptom was detected in 47.6% (n = 20) of HA patients versus 14.6% (n = 6) of those with HAE (P = .002). In the logistic regression analysis for the diagnosis of HAE, a family history of angioedema (OR = 58.289 [95% CI 10.656-318.853], P < 001) and trauma (OR = 35.208 [95% CI [4.368-283.794]], P = .001) as a triggering factor were determined to be independent variables.

CONCLUSION

A family history of angioedema, trauma as a triggering factor, and abdominal pain should suggest the diagnosis of HAE and the need for further investigation.

Psychology and hereditary angioedema: A systematic review

Background: Hereditary angioedema (HAE) is caused by mutations in the C1 inhibitor (C1-INH) gene Serpin Family G Member 1(SERPING1), which results in either the decreased synthesis of normal C1-INH (C1-INH-HAE type I) or expression of unfunctional C1-INH (C1-INH-HAE type II). In recent studies, emotional stress was reported by patients as the most common trigger factor for C1-INH-HAE attacks. Moreover, patients reported considerable distress over the significant variability and uncertainty with which the disease manifests, in addition to the impact of physical symptoms on their overall quality of life. Objective: We did a systematic review of the literature to shed light on the advancements made in the study of how stress and psychological processes impact C1-INH-HAE. Methods: All of the articles on C1-INH-HAE were analyzed up to December 2019. Both medical data bases and psychological data bases were examined. The keywords (KWs) used for searching the medical and psychological data bases were the following: "hereditary angioedema," "psychology," "stress," "anxiety," and "depression." Results: Of a total of 2549 articles on C1-INH-HAE, 113 articles were retrieved from the literature search by using the related KWs. Twenty-one of these articles were retrieved, examined, and classified. Conclusion: Although the literature confirmed that stress may induce various physical diseases, it also warned against making simplistic statements about its incidence that did not take into account the complexity and multicausality of factors that contribute to C1-INH-HAE expression.

A robust multiplexed assay to quantify C1-inhibitor, C1q, and C4 proteins for in vitro diagnosis of hereditary angioedema from dried blood spot

Hereditary angioedema (HAE) is a rare genetic disease caused by deficiency or dysfunction of C1 esterase inhibitor (C1-INH). Plasma C1-INH activity and concentrations of C1-INH and complement components 1q and 4 (C1q, C4) are critical to the HAE diagnosis. We describe a novel multiplexed assay to simultaneously measure C1-INH, C1q, and C4 levels in dried blood spot (DBS) of HAE patients. The blood proteins were extracted from 3 mm punches of DBS samples and were subsequently digested by trypsin. The signature peptide derived from each protein was quantified by liquid chromatography-tandem mass spectrometry (LC-MS/MS). Analyte-depleted blood was generated as a surrogate matrix for the preparation of calibration curves to overcome the interference of endogenous proteins, and the assay reproducibility was further monitored by assessing the signal of plasma transferrin as a house-keeping protein. The assay was fully validated following regulatory guideline, with a quantification range of 12.5-800 μg/mL for C1-INH and C4 and 3.13-200 μg/mL for C1q. The precision and accuracy ranged from 3.3%-9.8% and -8.2%-12.6%, respectively. All the patient samples exhibited C1-INH levels lower than normal range except the Type II patient and the C4 and C1q concentrations were as expected. Results from the DBS-based LC-MS assay were highly correlated with the ELISA data measured in plasma of the same subjects. The method described here offers unique advantages such as less invasive sampling, minimal blood processing, and easy transportation and sample storage, allowing, for the first time, C1-INH, C4, and C1q levels to be simultaneously determined in a drop of dried blood.

A novel functional C1 inhibitor activity assay in dried blood spot for diagnosis of Hereditary angioedema

BACKGROUND

Hereditary angioedema (HAE) is a rare genetic disease caused by deficiency or dysfunction of C1 esterase inhibitor (C1-INH). Timely and accurate diagnosis is an ongoing challenge. Measurement of plasma C1-INH activity is currently the critical standard test. We describe a novel and highly robust point-of-care assay to quantify C1-INH activity in dried blood spot (DBS).

METHODS

C1-INH was extracted from 3 mm punches of DBS samples and incubated with excess amount of C1 esterase (C1s). The mixture was subsequentially incubated with C1s substrate, followed by liquid chromatography-tandem mass spectrometry (LC-MS/MS) quantitation of the enzyme reaction product.

RESULTS

The assay was validated within a quantification range from 100 to 1500 mU/mL. The intra-day precision and accuracy ranged from 4.0% to 11.6% and -11.1% to -2.1%, and the inter-day precision and accuracy were 8.1-13.1% and -10.3% to 0.9%, respectively. Normal C1-INH activity (n = 103) ranged from 311 to 1090 mU/mL, whereas 23 out of 24 HAE patients exhibited C1-INH activity lower than 100 mU/mL.

CONCLUSION

DBS specimen collection for measurement of functional C1-INH activity in a physician's office is straightforward and not limited by logistic considerations and therefore, appropriate for the diagnosis of HAE in high throughput diagnostic laboratories.

Recombinant human C1 esterase inhibitor treatment for hereditary angioedema attacks in children

BACKGROUND

Attacks of hereditary angioedema (HAE) due to C1 esterase inhibitor deficiency (C1-INH-HAE) usually begin during childhood or adolescence. However, limited data are available regarding indications and modalities of treatment of children. This study evaluated recombinant human C1-INH (rhC1-INH) for HAE attacks in children.

METHODS

This open-label, phase 2 study included children aged 2-13 years with C1-INH-HAE. Eligible HAE attacks were treated intravenously with rhC1-INH 50 IU/kg body weight (maximum, 4200 IU). The primary end-point was time to beginning of symptom relief (TOSR; ≥20 mm decrease from baseline in visual analog scale [VAS] score, persisting for two consecutive assessments); secondary end-point was time to minimal symptoms (TTMS; <20 mm VAS score for all anatomic locations).

RESULTS

Twenty children (aged 5-14 years; 73 HAE attacks) were treated with rhC1-INH. Seventy (95.9%) of the attacks were treated with a single dose of rhC1-INH. Seven (35.0%) children were treated for four or more attacks. Overall, median TOSR was 60.0 minutes (95% confidence interval [CI], 60.0-65.0); data were consistent across attacks. Median TTMS was 122.5 minutes (95% CI, 120.0-126.0); data were consistent across attacks. No children withdrew from the study due to adverse events. No treatment-related serious adverse events or hypersensitivity reactions were reported; no neutralizing antibodies were detected.

CONCLUSIONS

Recombinant human C1-INH was efficacious, safe, and well tolerated in children. Data support use of the same dosing regimen for HAE attacks in children (50 IU/kg; up to 4200 IU, followed by an additional dose, if needed) as is currently recommended for adolescents and adults.

Hereditary Angio-Oedema for Dermatologists

Among angio-oedema patients, hereditary angio-oedema (HAE) should not be overlooked. Besides skin swellings, these patients might have very painful abdominal attacks and potentially life-threatening angio-oedema of the upper airway. They will not respond to traditional anti-allergic therapy with antihistamines, corticosteroids, and adrenaline, and instead need specific drugs targeting the kallikrein-kinin pathway. Classically, patients with HAE have a quantitative or qualitative deficiency of the C1 inhibitor (C1INH) due to different mutations in SERPING1, although a new subtype with normal C1INH has been recognised more recently. This latter variant is diagnosed based on clinical features, family history, or molecular genetic testing for mutations in F12, ANGPT1,or PLG.The diagnosis of HAE is often delayed due to a general unfamiliarity with this orphan disease. However, undiagnosed patients are at an increased risk of unnecessary surgical interventions or life-threatening laryngeal swellings. Within the last decade, new and effective therapies have been developed and launched for acute and prophylactic therapy. Even more drugs are under evaluation in clinical trials. It is therefore of utmost importance that patients with HAE are diagnosed as soon as possible and offered relevant therapy with orphan drugs to reduce morbidity, prevent mortality, and improve quality of life.

HEREDITARY ANGIOEDEMA DUE TO C1-INHIBITOR DEFICIENCY IN PEDIATRIC PATIENTS IN CROATIA - FIRST NATIONAL STUDY, DIAGNOSTIC AND PROPHYLACTIC CHALLENGES

Hereditary angioedema (HAE) is a rare autosomal dominant disease with deficiency (type I) or dysfunction (type II) of C1 inhibitor, caused by mutations in the C1-INH gene, characterized by recurrent submucosal or subcutaneous edemas including skin swelling, abdominal pain and life-threatening episodes of upper airway obstruction. The aim of this study was to investigate healthcare experiences in children with HAE due to C1 inhibitor deficiency (C1-INH-HAE) in Croatia in order to estimate the number of affected children and to recommend management protocols for diagnosis, short-term prophylaxis and acute treatment. Patients were recruited during a 4-year period at five hospitals in Croatia. Complement testing was performed in patients with a positive family history. This pilot study revealed nine pediatric patients positive for C1-INH- HAE type I, aged 1-16 years, four of them asymptomatic. Before the age of one year, C1-INH levels may be lower than in adults; it is advisable to confirm C1-INH-HAE after the age of one year. Plasma-derived C1-INH is recommended as acute and short-term prophylactic treatment. Recombinant C1-INH and icatibant are licensed for the acute treatment of pediatric patients. In Croatia, HAE is still underdiagnosed in pediatric population.

Deletions in SERPING1 Lead to Lower C1 Inhibitor Function: Lower C1 Inhibitor Function Can Predict Disease Severity

BACKGROUND

How genotype affects phenotype in hereditary angioedema with C1 inhibitor deficiency (C1-INH-HAE) has not been totally clarified. In this study, we investigated the relationship between different types of mutations and various phenotypic characteristics.

METHODS

Clinical data from 81 patients from 47 families were recorded. Complement proteins were analyzed from 61 untreated patients. The coding exons and the exon-intron boundaries of the SERPING1 gene were sequenced, and deletion/duplication analysis with multiple ligation dependent probe amplification was performed. The relationship of complement protein with the mutation type was analyzed by using generalized estimating equations.

RESULTS

Thirty-five different mutations (15 novel and 2/15 homozygous) were identified. There was no causative mutation in 6 patients (7.4%). Patients with deletion and large deletion had the lowest (5.05%, 0-18.7; 5.8%, 0-16.5%, respectively), and the none mutation group had the highest C1 inhibitor function (23.3%, 11-78%, p < 0.001). C1 inhibitor function levels decreased as the age of the disease progressed (r = -0.352, p = 0.005). Lower C1 inhibitor function levels caused severer disease (r = -0.404, p = 0.001) and more frequent annual attacks (r = -0.289, p = 0.024). In the off-attack period, C1q levels were lower than normal in 9.8% of the patients.

CONCLUSION

Deletion mutations may represent the most unfavorable effect on C1 inhibitor function. The earlier disease onset age could be a sign for lower C1 inhibitor function levels in adult life. C1q levels could also be low in C1-INH-HAE patients, as in acquired angioedema. Lower C1 inhibitor function can predict disease severity and may have negative impacts on the course of C1-INH-HAE.

The international WAO/EAACI guideline for the management of hereditary angioedema-The 2017 revision and update

Hereditary Angioedema (HAE) is a rare and disabling disease. Early diagnosis and appropriate therapy are essential. This update and revision of the global guideline for HAE provides up-to-date consensus recommendations for the management of HAE. In the development of this update and revision of the guideline, an international expert panel reviewed the existing evidence and developed 20 recommendations that were discussed, finalized and consented during the guideline consensus conference in June 2016 in Vienna. The final version of this update and revision of the guideline incorporates the contributions of a board of expert reviewers and the endorsing societies. The goal of this guideline update and revision is to provide clinicians and their patients with guidance that will assist them in making rational decisions in the management of HAE with deficient C1-inhibitor (type 1) and HAE with dysfunctional C1-inhibitor (type 2). The key clinical questions covered by these recommendations are: (1) How should HAE-1/2 be defined and classified?, (2) How should HAE-1/2 be diagnosed?, (3) Should HAE-1/2 patients receive prophylactic and/or on-demand treatment and what treatment options should be used?, (4) Should HAE-1/2 management be different for special HAE-1/2 patient groups such as pregnant/lactating women or children?, and (5) Should HAE-1/2 management incorporate self-administration of therapies and patient support measures?

Long-term prophylaxis therapy in patients with hereditary angioedema with C1 inhibitor deficiency

OBJECTIVE

To review the criteria for long-term prophylaxis therapy in patients with hereditary angioedema due to C1 inhibitor deficiency (C1-INH-HAE), describe how these criteria have evolved over time, and anticipate how criteria may change in the future with the availability of new C1-INH-HAE treatment options.

DATA SOURCES

Treatment guidelines, consensus statements, and expert reviews.

STUDY SELECTIONS

Manuscripts that described long-term prophylaxis therapy in patients with C1-INH-HAE were selected.

RESULTS

Historically, patients with C1-INH-HAE were considered to be candidates for long-term prophylaxis therapy if they had at least 1 attack per month, had at least 5 days of disability per month because of C1-INH-HAE, or did not sufficiently respond to on-demand treatment. More recently, guidelines and reviews state that thresholds of number of attacks or days of disability are arbitrary and that treatment plans should be individualized to the patient's needs. Furthermore, all patients should have a comprehensive management plan that is reviewed periodically and should have at least 2 doses of on-demand treatment available. Prophylaxis therapy should be discussed as a potential treatment option for each patient; however, the decision for its use will depend on the patient's individual needs and the course of their symptoms.

CONCLUSION

The criteria for long-term prophylaxis therapy in C1-INH-HAE have changed with the recognition that treatments should be individualized to the patient's needs and with the availability of new medications that have more favorable benefit-risk profiles, are easier to use, and improve patients' quality of life.

Icatibant for the treatment of hereditary angioedema with C1-inhibitor deficiency in adolescents and in children aged over 2 years

INTRODUCTION

Hereditary angioedema (HAE) due to C1-inhibitor deficiency (C1-INH-HAE) is a rare disorder with life-threatening complications if untreated. It begins during childhood, and reduces the patient's quality of life. Therefore, the availability of an easily administered agent to relieve unpredictable HAE episodes is indispensable for this age group. Areas covered: Randomized, double-blind, placebo-controlled, open-label extensions and prospective observational studies have proven the safety and efficacy of the subcutaneously administered bradykinin B2 receptor antagonist, icatibant, in the acute treatment of HAE episodes in adult C1-INH-HAE patients. Recently, a Phase 3, multicenter, open-label, non-randomized, single-arm study demonstrated the efficacy, safety, and tolerability of icatibant as an acute treatment for pediatric patients aged 2 years to less than 18 years. Expert commentary: The clinical study in pediatric patients showed that icatibant undergoes rapid absorption, reaches a therapeutic level, and promptly relieves the symptoms. It is well tolerated, and the subcutaneous preparation, presented in a pre-filled syringe, ensures ease of use. It can be administered anytime, anywhere, and instantly - even by the patients themselves, or - in the case of children and adolescents - by a caregiver. Icatibant may greatly contribute to the improvement of the quality of life of pediatric patients.

Pharmacological Management of Hereditary Angioedema with C1-Inhibitor Deficiency in Pediatric Patients

Hereditary angioedema with C1-inhibitor deficiency (C1-INH-HAE) is a form of bradykinin-mediated angioedema. It is a rare disorder with an onset during childhood in most instances. Therefore, familiarity with the options for the management of pediatric cases is indispensable. The recurrent angioedematous episodes do not respond to conventional treatments and may evolve into a life-threatening condition. In view of the recommendations adopted by international consensus in 2016, patient management and follow-up should be guided by an individualized strategy. During the last decade, various medicinal products with novel modes of action and different posology have been developed for the treatment of C1-INH-HAE. These drugs either inhibit the release of bradykinin (plasma-derived C1-inhibitors, recombinant C1-inhibitors, kallikrein inhibitors) or prevent the released bradykinin from binding to its receptor (bradykinin B₂ receptor antagonists). This review summarizes the properties of the medicinal products currently available for the treatment of C1-INH-HAE, the indications for their use in pediatric patients, and the findings of the clinical trials conducted in this patient population. It is concluded by a brief outline of future therapeutic options.

Health-related quality of life among children with hereditary angioedema

BACKGROUND

The clinical expressions of hereditary angioedema with C1-inhibitor deficiency (C1-INH-HAE) and its related burden may negatively affect patient quality of life. This study aimed to assess health-related quality of life (HRQoL) in children with C1-INH-HAE.

METHODS

Children (N = 98: 34 C1-INH-HAE patients, 64 healthy controls) aged 3-18 years were recruited in Israel and Hungary. All individuals completed a demographic questionnaire, a disease activity and site questionnaire, and the Pediatric Quality of Life Inventory (PedsQL™) 4.0 Generic Core Scales (child self-report and maternal proxy report) to assess HRQoL.

RESULTS

Among C1-INH-HAE patients, nine (26.5%) had 1-5 attacks/year, six (17.6%) had 6-18 attacks/year, eight (23.5%) had 25-60 attacks/year, and 11 (32.4%) were asymptomatic over the previous year. Children with C1-INH-HAE attacks demonstrated lower HRQoL than healthy control children across the total score, school, and psychosocial dimensions of the PedsQL™. The number of C1-INH-HAE attacks negatively correlated with the total HRQoL score (r = -0.48, p = 0.008), school-related HRQoL (r = -0.39, p = 0.02), and psychosocial HRQoL (r = -0.43, p = 0.01). Patients with multisite laryngeal, abdominal, and peripheral C1-INH-HAE attacks had a lower HRQoL compared with those who experienced solely peripheral attacks across the total score (p = 0.04), physical (p = 0.04), and school (p = 0.02) domains. There was no significant difference between asymptomatic C1-INH-HAE patients and healthy controls.

CONCLUSIONS

Children with symptomatic C1-INH-HAE demonstrate impaired HRQoL compared with healthy controls. HRQoL was affected by the frequency and site of C1-INH-HAE attacks and mostly in the school and physical domains.

Clinical characteristics and real-life diagnostic approaches in all Danish children with hereditary angioedema

Background

With a potentially early onset, hereditary angioedema (HAE) requires special knowledge also in infancy and early childhood. In children from families with HAE, the diagnosis should be confirmed or refuted early, which can be difficult. Studies of childhood HAE and the diagnostic approaches are limited. Our aim was to investigate the entire Danish cohort of children with HAE and non-HAE children of HAE patients for diagnostic approaches and clinical characteristics.

Results

We included 41 children: 22 with HAE and 19 non-HAE. Of the HAE children, 14 were symptomatic—median age at onset was 4 [1–11] years. The first attack was peripheral in 8/14 children and abdominal in 6/14 children, i.e. no one had their first attacks in the upper airways. Most children had less than one attack per month. All of the symptomatic children had been treated with tranexamic acid and/or C1 inhibitor concentrate. Unlike in other countries, androgens were not used in our pediatric cohort. Home therapy with C1 inhibitor concentrate was established in 9 cases: 6 children were trained in self-administration and 3 children were treated by parents. Of the children, 10 had been diagnosed by symptoms, including 3 without family history—median age of diagnosis among these children was 5.35 [2–13.2] years. In 31 children, HAE was diagnosed or refuted before symptoms by blood samples. In 23 of these children, complement values were investigated, and in 9 cases genetic testing was added to the complement measurements. In 8 children recently investigated, genetic testing was first choice. Cord blood was used for complement measurements in 9 children and for genetic testing in 4 children. Results of complement measurements were equivocal in several cases, especially in the cord blood samples, and the sensitivity of low complement C4 for the diagnosis of HAE was 75%.

Conclusions

We investigated clinical characteristics in all Danish children with HAE. The rate of home therapy was high and androgens had been avoided. Complement values were often equivocal, especially in cord blood samples. Consequently, we have changed diagnostic practice to early genetic testing in children where the family mutation is known.

International consensus on the diagnosis and management of pediatric patients with hereditary angioedema with C1 inhibitor deficiency

Background

The consensus documents published to date on hereditary angioedema with C1 inhibitor deficiency (C1‐INH‐HAE) have focused on adult patients. Many of the previous recommendations have not been adapted to pediatric patients. We intended to produce consensus recommendations for the diagnosis and management of pediatric patients with C1‐INH‐HAE.

Methods

During an expert panel meeting that took place during the 9th C1 Inhibitor Deficiency Workshop in Budapest, 2015 (www.haenet.hu), pediatric data were presented and discussed and a consensus was developed by voting.

Results

The symptoms of C1‐INH‐HAE often present in childhood. Differential diagnosis can be difficult as abdominal pain is common in pediatric C1‐INH‐HAE, but also commonly occurs in the general pediatric population. The early onset of symptoms may predict a more severe subsequent course of the disease. Before the age of 1 year, C1‐INH levels may be lower than in adults; therefore, it is advisable to confirm the diagnosis after the age of one year. All neonates/infants with an affected C1‐INH‐HAE family member should be screened for C1‐INH deficiency. Pediatric patients should always carry a C1‐INH‐HAE information card and medicine for emergency use. The regulatory approval status of the drugs for prophylaxis and for acute treatment is different in each country. Plasma‐derived C1‐INH, recombinant C1‐INH, and ecallantide are the only agents licensed for the acute treatment of pediatric patients. Clinical trials are underway with additional drugs. It is recommended to follow up patients in an HAE comprehensive care center.

Conclusions

The pediatric‐focused international consensus for the diagnosis and management of C1‐INH‐HAE patients was created.

Management of Children With Hereditary Angioedema Due to C1 Inhibitor Deficiency

Hereditary angioedema (HAE) is a potentially life-threatening inherited disease characterized by attacks of skin swelling, severe abdominal pain, and upper airway swelling. Attacks typically begin in childhood, but the appropriate diagnosis is often missed. Attacks do not respond to epinephrine, antihistamines, or glucocorticoids. Recently, many effective drugs have been approved for treatment of adults with HAE, and the Medical Advisory Board of the HAE Patient's Association has developed and reported treatment recommendations for adults. Only 1 medication is approved for treatment of children <12 years of age, and there are no reported consensus recommendations for treatment of young children in the United States. The 11-member Medical Advisory Board, with extensive experience in the treatment of children, in concert with the leaders of the HAE Patient's Association, has developed these consensus recommendations to help in recognition, diagnosis, treatment of attacks, and prophylaxis of children with HAE.

Frequent life-threatening laryngeal attacks in two Croatian families with hereditary angioedema due to C1 inhibitor deficiency harbouring a novel frameshift mutation in SERPING1

OBJECTIVE

Hereditary angioedema due to C1 inhibitor deficiency (C1-INH-HAE) is a rare autosomal dominant disease caused by mutations in the SERPING1 gene. It can affect many regions in the body, but potentially life-threatening laryngeal oedemas are of concern.

METHODS

Twenty-three subjects from two families were recruited for clinical data evaluation and molecular analysis at General Hospital Šibenik, Croatia.

RESULTS

Decreased levels of C1 inhibitor were detected in 12 adult patients and three young asymptomatic persons. The same novel deletion of two nucleotides on exon 3 (c.74_75delAT) was identified in all of them. A history of laryngeal oedema was present in 10 patients (83%), and all patients reported laryngeal attacks at least once a year. The delay in diagnosis decreased noticeably from the first to the last generation.

CONCLUSIONS

We identified a novel causative mutation in SERPING1 in several affected members of two apparently unrelated families with a high frequency of laryngeal oedema. Molecular analysis of large C1-INH-HAE families will provide new insights on the genotype-phenotype relationship. Key messages Hereditary angioedema due to C1 inhibitor deficiency is a rare autosomal dominant disease caused by mutations in the SERPING1 gene, and laryngeal oedema is of concern because it can cause death by asphyxiation. A novel causative mutation in SERPING1, a deletion of two nucleotides on exon 3 (c.74_75delAT), was identified in several affected members of two apparently unrelated families with a high frequency of laryngeal oedema. Molecular analysis of large C1-INH-HAE families will provide new insights on the genotype-phenotype relationship because it appears that the mutation type may affect disease severity.

Diagnosis and screening of patients with hereditary angioedema in primary care

Hereditary angioedema (HAE) is a rare autosomal dominant disease that commonly manifests with episodes of cutaneous or submucosal angioedema and intense abdominal pain. The condition usually presents due to a deficiency of C1 esterase inhibitor (C1-INH) that leads to the overproduction of bradykinin, causing an abrupt increase in vascular permeability. A less-understood and less-common form of the disease presents with normal C1-INH levels. Symptoms of angioedema may be confused initially with mast cell-mediated angioedema, such as allergic reactions, and may perplex physicians when epinephrine, antihistamine, or glucocorticoid therapies do not provide relief. Similarly, abdominal attacks may lead to unnecessary surgeries or opiate dependence. All affected individuals are at risk for a life-threatening episode of laryngeal angioedema, which continues to be a source of fatalities due to asphyxiation. Unfortunately, the diagnosis is delayed on average by almost a decade due to a misunderstanding of symptoms and general lack of awareness of the disease. Once physicians suspect HAE, however, diagnostic methods are reliable and available at most laboratories, and include testing for C4, C1-INH protein, and C1-INH functional levels. In patients with HAE, management consists of acute treatment of an attack as well as possible short- or long-term prophylaxis. Plasma-derived C1-INH, ecallantide, icatibant, and recombinant human C1-INH are new treatments that have been shown to be safe and effective in the treatment of HAE attacks. The current understanding of HAE has greatly improved in recent decades, leading to growing awareness, new treatments, improved management strategies, and better outcomes for patients.

Swedish children with hereditary angioedema report good overall health and quality of life despite symptoms

AIM

Few studies have been published on children with hereditary angioedema (HAE), an autosomal dominant disease caused by mutations on chromosome 11. This study explored various aspects of the disease in the Swedish paediatric population.

METHODS

A retrospective questionnaire was sent to all 36 Swedish children known to have HAE, and a physician carried out follow-up telephone interviews.

RESULTS

Most of the questionnaires were completed by the parents of 31 (86%) children with HAE, with or without their input, at a median age of nine years (range 1-17), and the physician also interviewed 29. HAE symptoms were experienced by 23 children, including abdominal attacks (96%), skin swelling (78%) and swelling in the mouth and/or upper airways (52%). Psychological stress was the most common trigger for abdominal attacks and trauma and sports triggered skin swelling. The majority (n = 19) had access to complement-1 esterase inhibitor concentrate at home. Current health and quality of life were generally rated as good, independent of whether the child had experienced HAE symptoms or not.

CONCLUSION

Most children with HAE had experienced abdominal attacks and skin swelling, but their overall health and quality of life were generally perceived to be good.

Erythema Marginatum as an Early Symptom of Hereditary Angioedema: Case Report of 2 Newborns

Hereditary angioedema due to C1 inhibitor deficiency (C1-INH-HAE) is a rare genetic disease that causes recurrent swelling attacks that may affect various body tissues. Angioedematous attacks can be fatal in the case of upper airway edema and are often preceded by prodromal symptoms like erythema marginatum. Initial symptoms usually occur in the first decade of life. We report on manifestation of profound and recurrent erythema marginatum in 2 newborns. In both cases, prodromal symptoms could help determine the diagnosis of C1-INH-HAE such that, at a later time, angioedematous attacks could be treated promptly and effectively. Awareness of C1-INH-HAE is low among physicians and even lower among the general public. This report aims at raising the level of awareness and shows that initial symptoms of the potentially life-threatening condition can manifest in newborns and that erythema marginatum can even be present at birth. Recognition of early symptoms and timely diagnosis of the disease along with adequate education of the pediatrician and parents are a prerequisite for prompt and effective treatment of attacks and the successful management of the disease.

BSACI guideline for the management of chronic urticaria and angioedema

This guidance for the management of patients with chronic urticaria and angioedema has been prepared by the Standards of Care Committee of the British Society for Allergy and Clinical Immunology (BSACI). The guideline is based on evidence as well as on expert opinion and is aimed at both adult physicians and paediatricians practising in allergy. The recommendations are evidence graded. During the development of these guidelines, all BSACI members were included in the consultation process using a Web-based system. Their comments and suggestions were carefully considered by the Standards of Care Committee. Where evidence was lacking, a consensus was reached by the experts on the committee. Included in this management guideline are clinical classification, aetiology, diagnosis, investigations, treatment guidance with special sections on children with urticaria and the use of antihistamines in women who are pregnant or breastfeeding. Finally, we have made recommendations for potential areas of future research.

Safety and efficacy of C1 esterase inhibitor for acute attacks in children with hereditary angioedema

BACKGROUND

Human plasma-derived nanofiltered C1 esterase inhibitor (C1 INH-nf) is used to treat acute angioedema attacks in patients with hereditary angioedema (HAE), but data regarding use in children are sparse.

METHODS

Patients 2 to <12 years of age, body weight ≥10 kg, with a diagnosis of HAE type I or II, were recruited for a multicenter open-label trial. Patients were recruited into 2 weight categories (10-25 kg, >25 kg). Each weight category included 2 dosing levels: C1 INH-nf (500 units [U], 1000 U) and C1 INH-nf (1000 U, 1500 U), respectively. Patients experiencing an angioedema attack were given a single intravenous dose. Primary efficacy end-point was the onset of unequivocal relief of the defining symptom within 4 h following initiation of C1 INH-nf treatment.

RESULTS

Nine children were treated: 3 (10-25 kg) received 500 U; 3 (>25 kg) received 1000 U; and 3 (>25 kg) received 1500 U. The lower weight/higher dose category (10-25 kg, 1000 U) was not successfully enrolled. All patients completed the study. Most angioedema attacks (n = 5) were abdominal. All patients met the primary end-point; median time to unequivocal symptom relief was 0.5 (range: 0.25-2.5) h. Doses of C1 INH-nf ranged from 20.8 to 51.9 U/kg.

CONCLUSIONS

Treatment of a single angioedema attack with C1 INH-nf doses of 500 U (in patients 10-25 kg), 1000 U, and 1500 U (in patients >25 kg) were well tolerated. Doses of C1 INH-nf <1000 U may be appropriate in some pediatric patients.

Plasma-derived C1-INH for managing hereditary angioedema in pediatric patients: A systematic review

Presently, medications approved for children with Hereditary Angioedema (HAE) are extremely limited. This is especially the case for children under 12 years of age. For this reason we reviewed and summarized the data on treatment of children with HAE. Available data indicate that plasma derived C1-inhibitor is a safe, effective treatment option for HAE in pediatric patients, including those below 12 years of age. Other therapies are also appear safe for the under 12 year of age, but less data are available. Importantly, home-based treatment of HAE in this age group appears to be safe and effective and can improve quality of life. These findings support current HAE consensus guidelines which strongly recommend the use of plasma derived C1-inhibitor as a first-line treatment in children and encourage home and self-treatment.

Clinical features of pediatric hereditary angioedema

BACKGROUND

There is a paucity of data that describe the clinical course of hereditary angioedema (HAE) in children.

OBJECTIVE

The purpose of this study was to examine the clinical features of children with HAE.

METHODS

Electronic medical records from the past 10 years at Cincinnati Children's Hospital Medical Center and an outpatient allergy community practice were searched for ICD-9 code 277.6 (Other deficiencies of circulating enzyme). Exclusion criteria included laboratory data not supportive of type I or II HAE diagnosis or age at diagnosis greater than 18 years. Chart review was performed and missing data were collected by telephone interviews with patient families. Descriptive statistics were performed using SAS version 9.4.

RESULTS

Twenty-one children were identified. The median age was 13.2 years (interquartile range [IQR], 9.1-18.8), 71% were male, 86% had an HAE family history, and 95% were Caucasian. The median age of symptom onset and diagnosis was 5.7 (IQR, 5-9 years) and 5.0 (IQR, 4-8 years), respectively. Five children diagnosed were asymptomatic. Three children without a family history had a 6.0-year delay in diagnosis. The most common angioedema attack sites were abdominal, peripheral, and laryngeal, which occurred at least once in 93%, 73%, and 27%, respectively. Of the 15 children with onset of symptoms, only 6 children received on-demand therapy for an acute attack, whereas 13 children were administered either short-term or long-term prophylaxis therapy.

CONCLUSIONS

In this pediatric HAE population, symptom onset and diagnosis occurred at a median age of 5 years with a delay in diagnosis in those without a family history. Abdominal attacks were more common than peripheral attacks in this population.

Paediatric hereditary angioedema: a survey of UK service provision and patient experience

Hereditary angioedema (HAE) is a rare disease characterized by episodes of potentially life-threatening angioedema. For affected children in the United Kingdom, there are relatively few data regarding disease prevalence, service organization and the humanistic burden of the disease. To improve knowledge in these areas, we surveyed major providers of care for children with HAE. A questionnaire was sent to major paediatric centres to determine patient numbers, symptoms, diagnostic difficulties, management and available services. In addition, all patients at a single centre were given a questionnaire to determine the experiences of children and their families. Sixteen of 28 centres responded, caring for a total of 111 UK children. Seven children had experienced life-threatening crises. One-third of patients were on long-term prophylactic medication, including C1 inhibitor prophylaxis in four children. Eight centres reported patients who were initially misdiagnosed. Broad differences in management were noted, particularly regarding indications for long-term prophylaxis and treatment monitoring. We also noted substantial variation in the organization of services between centres, including the number of consultants contributing to patient care, the availability of specialist nurses, the availability of home therapy training and the provision of patient information. Ten of 12 patient/carer questionnaires were returned, identifying three common themes: the need to access specialist knowledge, the importance of home therapy and concerns around the direct effect of angioedema on their life. To our knowledge, this study represents the first dedicated survey of paediatric HAE services in the United Kingdom and provides useful information to inform the optimization of services.

Pediatric hereditary angioedema

Hereditary angioedema (HAE) is a lifelong illness characterized by recurrent swelling of the skin, intestinal tract, and, ominously, the upper airway. It is caused by inadequate activity of the protein C1-inhibitor, with dysfunction in the kallikrein/bradykinin pathway underlying the clinical symptoms. In addition to the physical symptoms, patients experience significant decrements in vocational and school achievement as well as in overall quality of life. Symptoms often begin in childhood and occur by age 20 in most patients, but life-threatening attacks are uncommon in the pediatric population. The availability of new therapies has transformed the management of HAE.

US Hereditary Angioedema Association Medical Advisory Board 2013 recommendations for the management of hereditary angioedema due to C1 inhibitor deficiency

BACKGROUND

The treatment of hereditary angioedema (HAE) has undergone dramatic changes as newer medicines have become available in recent years. Optimal care of these patients requires a comprehensive management plan. Although several consensus papers have been published concerning the diagnosis and treatment of HAE, guidelines for a comprehensive management plan have not been developed.

OBJECTIVE

To develop state-of-the-art recommendations for the treatment and management of HAE due to C1 inhibitor (C1INH) deficiency in the United States.

METHODS

Members of the US Hereditary Angioedema Association Medical Advisory Board began by reviewing the literature concerning treatment of HAE. Preliminary recommendations were developed based on the literature review, discussions in a face-to-face meeting, and refinements in a series of drafts. Final recommendations reflect the unanimous consensus of the medical advisory board and the US Hereditary Angioedema Association leadership.

RESULTS

Recommendations are provided regarding a comprehensive care plan for HAE, including the following: development of an overall management plan, treatment of angioedema attacks, prophylactic treatment, and patient monitoring.

CONCLUSION

A comprehensive individualized management plan developed between an expert HAE physician and the patient, in collaboration with local medical providers and emergency departments, can provide patients with the best opportunity to lead a normal life.